ArticlePDF Available

Bases of the method of physical modeling of the process of crushing of municipal solid waste

Authors:

Abstract

A large number of studies are aimed at increasing the energy efficiency of grinding processes of various solid materials, while maintaining the values of other important indicators, such as material consumption, productivity, etc. Based on this trend, a new method for physically modeling the process of grinding municipal solid waste (MSW) was proposed for the first time. Existing physical modeling techniques are designed for homogeneous and isotropic materials (for example, soil, crushed stone, snow, coal, etc.). The strength properties of solid waste vary widely due to the significant heterogeneity of their components. Consequently, when crushing solid waste, traditional crusher designs have low efficiency in terms of energy intensity, material intensity and product quality. The purpose of this work is to develop a new technique for physical modeling of the grinding process, based on the main principles of similarity theory and modeling, considering the properties of waste heterogeneity. As a result of the research, a block diagram of the physical modeling methodology for the interaction of the working bodies of impact crushing machines with solid waste was developed. A list of tasks for the modeling process and similarity criteria have been determined based on the development of rheological models of the “working body - municipal solid waste” system and the laws of mechanics that characterize the waste grinding process. Based on the developed similarity criteria, scale equations for the grinding process are substantiated and formulas are derived for determining the expected parameters of the original based on the parameters measured on the model. The developed methodology makes it possible to create a crusher design with improved energy efficiency indicators with the least material and labor costs.
Istraživanja i projektovanja za privredu
ISSN 1451-4117
DOI:10.5937/jaes0-48591
www.engineeringscience.rs
publishing
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
Original Scientific Paper
Paper number: xx(xxxx)x, xxxx, xxx-xxx
1
BASES OF THE METHOD OF PHYSICAL MODELING OF THE
PROCESS OF CRUSHING OF MUNICIPAL SOLID WASTE
Tavbay Khankelov1*, Mavluda Irisbekova2, Kamoliddin Rustamov1, Dilorom Sabirova3, Maloxat
Abdukadirova4, Otabek Ochildiev5
1Tashkent State Transport University, Department of Engineering of Technological Machines,Tashkent, Uzbekistan
2Tashkent State Transport University, Department of Transport Logistic, Tashkent, Uzbekistan
3Tashkent State Transport University, Department of Natural Sciences, Tashkent, Uzbekistan
4National research university “Tashkent institute of irrigation and agricultural mechanization engineers”, Department
of Ecology and Water Resources Management, Tashkent, Uzbekistan
5Termez Institute of Engineering and Technology, Departments of Health, Safety and Environment, Termez,
Uzbekistan
*tavbay_q@tstu.uz
A large number of studies are aimed at increasing the energy efficiency of grinding processes of various solid
materials, while maintaining the values of other important indicators, such as material consumption, productivity, etc.
Based on this trend, a new method for physically modeling the process of grinding municipal solid waste (MSW) was
proposed for the first time. Existing physical modeling techniques are designed for homogeneous and isotropic
materials (for example, soil, crushed stone, snow, coal, etc.). The strength properties of solid waste vary widely due
to the significant heterogeneity of their components. Consequently, when crushing solid waste, traditional crusher
designs have low efficiency in terms of energy intensity, material intensity and product quality. The purpose of this
work is to develop a new technique for physical modeling of the grinding process, based on the main principles of
similarity theory and modeling, considering the properties of waste heterogeneity. As a result of the research, a block
diagram of the physical modeling methodology for the interaction of the working bodies of impact crushing machines
with solid waste was developed. A list of tasks for the modeling process and similarity criteria have been determined
based on the development of rheological models of the “working body - municipal solid waste” system and the laws
of mechanics that characterize the waste grinding process. Based on the developed similarity criteria, scale equations
for the grinding process are substantiated and formulas are derived for determining the expected parameters of the
original based on the parameters measured on the model. The developed methodology makes it possible to create
a crusher design with improved energy efficiency indicators with the least material and labor costs.
Keywords: physical modelling, crusher, municipal solid waste, similarity criteria, model
1 INTRODUCTION
Improving the quality of life of people and the growth of the urban population, as well as the pursuit of additional profit
on the part of manufacturers through small packaging of goods, have led to a significant increase in the volume of
municipal solid waste (MSW), because of which their negative impact on the environment has increased. Currently,
to reduce the negative impact of municipal solid waste on the environment, issues related to the collection,
transportation, crushing and sorting, disposal of waste in landfills, as well as their use in the form of secondary raw
materials remain relevant. It is known that the crushing operation is a key link in the system of integrated waste
processing, and, in this regard, many companies pay special attention to the creation and production of energy-
efficient crushing machines [1, 2, 3].
Existing universal technologies for grinding solid materials designed for grinding homogeneous solid materials (for
example, soil, snow, crushed stone, coal, etc.) are ineffective for grinding solid waste because they have a
significantly heterogeneous environment.
The development of a method for physical modeling of the process of crushing solid waste, taking into account the
heterogeneity of its components, will make it possible to create an energy-efficient crusher with the least material
and labor costs.
The method of physical modeling of various processes, based on the theory of similarity and modeling, allows not
only to set up experiments correctly, but also to take into account those factors that at first glance seem unimportant,
as well as to effectively process the results of experiments. In addition, physical modeling of the solid waste grinding
process to search for rational values of the main parameters serves as a link between theoretical and experimental
research [4].
Many works are devoted to the development of methods for physical modeling of the processes of cutting, digging,
compacting and transporting soil [5, 6,7,8], which will be the starting point for developing a method for physical
modeling of the solid waste grinding process.
To develop the fundamentals of a methodology for physical modeling of the solid waste grinding process, it is
necessary to solve the following problems:
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
2
develop a block diagram of an algorithm for the method of physical modeling of the solid waste grinding
process
develop a rheological model of the solid waste grinding process
develop a criterion equation for the waste grinding process
develop analytical dependencies for determining the main parameters of the crusher based on the data
obtained on the models.
2 LITERATURE REVIEW
A large number of studies are being conducted aimed at increasing the energy efficiency of the grinding process of
various solid materials. Existing methods of physical modeling and calculation of the main parameters of crushers
are designed for homogeneous and isotropic materials (for example, soil, crushed stone, snow, coal, etc.). The
strength properties of solid waste vary widely due to the significant heterogeneity of their components. Consequently,
when crushing solid waste, they have low efficiency in terms of energy and material consumption.
The values of the power and energy parameters of crushers used for grinding solid materials (for example, solid
waste) to specified fractions depend on many parameters: linear dimensions, shape of the source material, strength
characteristics, uniform composition of the material, water permeability and condition of the working bodies, etc.
Consequently, the establishment mathematical relationships between force and energy parameters, on the one hand,
and the properties of crushed materials, on the other, are possible only in general terms.
The studies in [9,10,11] describe the hypothesis put forward by P. Rittinger about the proportionality of energy costs
and the parameters of newly formed areas. F. Kick proposed that the energy costs of grinding geometrically similar
materials are equivalent to the volumes of materials. This statement was called the second hypothesis or the law of
volumes. Later, it was stated that V. Kirpichev was the first to propose such a formula (much earlier than F. Kick). He
developed this dependence based on the provisions of the theory of similarity. Therefore, the second hypothesis is
currently called the Kirpichev-Kick law [11].
In 1949, F. Bond proposed that the work expended in grinding brittle materials is equivalent to the product between
volume and area, taken under the square root. An analysis of literary sources suggests that all of the above provisions
can be considered hypotheses and not laws since they are not confirmed by practice. When the properties of crushed
materials fluctuate over a wide range (e.g., components of municipal solid waste), the values of energy consumption
for crushing and the value of energy calculated according to three hypotheses differ significantly from each other [11].
A thorough analysis of the essence of the above hypotheses made it possible to conclude that none of the above
hypotheses is adequate in theoretically determining energy consumption, even at small intervals, for example, when
crushing pieces of isotropic material of a simple shape in a laboratory. Numerous assumptions and restrictions added
to the considered crushing hypotheses only complicated the methods for calculating the energy consumption for
grinding, and the reliability of these hypotheses still needed to be improved [11].
V.I. Balovnev proposed a semi-empirical hypothesis to study the design and technological parameters when using
various crushing methods; the main essence of this hypothesis is as follows. The character of acting forces
determines the power and energy indices of the crushing process, the way they are applied to the crushed material,
and their share ratio in the grinding process [12].
In practice, one has to deal primarily with anisotropic materials, for example, when shredding wood waste and the
complexity of the process depends on many parameters. Combining all parameters into one analytical dependence
is a challenging task.
Methods for physical modelling of the working processes of the contact of the active bodies of road-building machines
with non-homogeneous and anisotropic media, such as municipal solid waste, were studied in [13, 14, 15,16,17, 18].
All three hypotheses and the generalized V.I. Balovnev hypothesis are applicable only in a limited area - in elastic
deformations; the viscous and plastic properties of natural bodies are not considered (most of the M.S.W.
components possess such properties).
In this connection, there is a need to develop simplified, but quite accurately consistent with experiments, methods
for physical modeling of the process of grinding solid waste and calculating the main parameters of crushers, which
use the original experimental data obtained on physical models.
3 METHODS
The algorithm for constructing a methodology for physical modelling and the stages of modelling "working body-
municipal solid waste" systems in relation to M.S.W. is shown in Fig.1.
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
3
Fig. 1. Block diagram of the technique of physical modeling of the processes of interaction of the working bodies of
crushing machines of impact type with municipal solid waste
An algorithm for performing specific tasks for optimizing power and energy parameters was developed using the N.
Hertz nonlinear elastoplastic model [19, 20, 21, 22]. As an example of using the developed physical modeling
technique, a physical model of a hammer crusher for grinding organic waste components has been developed. The
general view and design diagram of the crusher are shown in Fig.2.
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
4
a) b)
Fig.2. Hammer crusher: a) general view of the hammer crusher, b) structural diagram of the hammer crusher: 1-
bunker; 2-working chamber; 3-knife rotating; 4-hammer; 5-rotor; 6- side grate; 7-lower grate; 8-frame crusher; 9-
knife fixed; 10-electric motor; 11- V-belt
The hammer crusher consists of a hopper 1, which consists of steel sheets welded with a thickness of 3.0 mm in the
shape of an isosceles trapezoid, the lower ends of which are welded to a disk with a diameter of 300 mm, which in
turn serves as a cover for the working chamber 2. The working chamber 2 is made of a cast-iron pipe with a diameter
of 300 mm, the lower end of which is welded to the frame 8 of the crusher, and in the upper part of the working
chamber four through holes are drilled in a circle, the hopper 1 of the crusher is attached to them with bolts. The
electric motor 10 is bolted to frame 8 of the hammer mill. It is positioned so that crusher wash water or liquid waste
does not enter the electrical part of the electric motor. To do this, a pulley is installed in the lower part of the working
chamber, which is rigidly mounted on the shaft. A pulley is fixed to the output shaft of electric motor 10 by means of
a key, which is connected to the pulley of the working chamber 2 by means of a V-belt drive. A cruciform working
body is mounted on dowels to the upper part of the shaft of the working chamber. A rotor 5 is welded onto a sleeve
with a diameter of 20 mm from the bottom side. On the outer side of which hammers 4 are welded. A rotating knife 3
is also welded to the upper part of the sleeve, the ends of which are pointed for better grinding. To obtain crushed
waste to the desired size, a side grate 6 is installed in the lower side part of the working chamber 2. In addition, to
improve the efficiency of grinding the organic components of the waste, lower grates 7 are drilled along the periphery.
For better grinding of waste on the walls working chamber 2 fixed knives 9 are welded.
Hammer crusher works as follows. The waste arriving for grinding enters the loading hopper 1. Then the waste enters
the working chamber 2, where it is accelerated to a rotation speed equal to the nominal rotation speed of the electric
motor 10 due to the creation of air pressure by means of a hammer 4. Accelerated waste to the nominal rotation
speed of the electric motor 10 is crushed due to the collision of waste with knives 9 rigidly welded to the walls of the
working chamber 2. In addition, the waste is crushed by colliding with the grate 5.
A hammer crusher is designed for crushing organic components of MSW in the system of their complex processing.
The working body of the crusher consists of horizontal plates and vertical plates welded on them, installed along the
rotor axis. Grinding of organic components of the waste is conducted due to the collision with the rotor blade, due to
the impact on the knives welded on the wall of the working chamber, and due to the impact of the waste on the walls
of the working chamber. In addition, the grinding of waste is conducted due to the impact of the organic components
of the waste on the openings of the grates.
The analysis of an a priori information and the search experiments conducted made it possible to determine the list
of factors influencing the crushing process: rotor speed - , ; rotor diameter - D, m; the average linear size of the
components of waste - , m; the linear size of the hammer - ,; setting angle of the hammer - α, degree;
crusher power - N, kW; the volumetric weight of waste - ,
; free fall acceleration - ,
; the area of the light
surface of the grate - ,; waste humidity - , % waste supply - , 
.
The technological scheme of waste processing and their properties at the final stage of processing made it possible
to reduce the number of factors affecting the crushing process significantly. Optimization of kinematic, geometric,
force and power parameters has dramatically reduced the time and material costs for determining the optimal
parameters of machines.
4 RESULTS
Analysis of the working process of crushing waste on a hammer crusher equipped with multicomponent working
bodies and the predominance of specific contact forces made it possible to study the active process of waste crushing
by various crusher working bodies.
The maximum value of the contact force  (formula 1) was determined when the waste components collided.
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
5
=󰇣()

󰇤
 =󰇣()
󰇤
 (1)
where is the reduced kinetic energy of the components of municipal solid waste; is the initial velocity of collision,
; is the mass of waste components, ; , are experimental coefficients. The critical value of the velocity of
collision  (formula 2) of the waste components with the blades of knives welded on the inner walls of the working
chamber and the blades of the rotating crusher rotor is determined.
 =
 =
= (2)
where  is the critical value of the required speed,
; is the volume of waste components, m3; is the modulus
of elasticity of waste components,
; =
 is the dimensional coefficient characterizing the physical and
mechanical properties of the organic components of waste,
;  is the ultimate strength of waste components,
.
The dependence of the contact force of the waste components on the main parameters of the process (formula 3)
makes it possible to optimize the value of the contact force in the process of collision of the waste components with
the internal walls of the crusher.
󰇱=.(
)
 .
 , 0 
.
= 0, >
.
(3)
where
is the standard component of the pre-impact velocity,
;  is the maximum value of elastic-plastic strain,
m; t is the contact duration time, sec.
A visual representation of the pattern of change in stresses and strains in the process of impact of the components
of municipal solid waste on the crusher rotor blades, on the walls of the working chamber of the crushing machine,
and on the knives welded on the inner walls of the crusher depending on the properties of the waste under the impact
is determined by rheological models, which, in turn, make it possible to develop more general similarity criteria for
the M.S.W. crushing process. The M.S.W. crushing process scheme and the process's rheological equivalent are
shown in Fig. 3.
Fig.3. Scheme of the M.S.W. crushing process and the rheological equivalent of the process.
In obtaining general similarity criteria, it is sufficient to represent the grinding process as an elastoviscous-plastic
model. The link (u) shows the rapid elastic shape change of the body under force. Links (v) and (j) imitate the
manifestation of rigid-plastic and viscous properties of the waste components.
==+ (4)
where is the total shear stress, MPa; is the shear stresses arising in the elastic stage of strain development,
MPa; is the rigid-plastic component of shear strain, MPa; is the viscous component of shear strain, MPa.
The shear stresses that arise during the impact of the rotor blade on the M.S.W. components, based on the
rheological model, can be divided into two zones: the zone of elastic deformations, where the shear stress is
determined as:
= (5)
where is the shear stress in the zone of elastic deformations, MPa; is the shear strain; G is the shear modulus,
MPa.
Shear stress in the zone of plastic deformations is:
=+ (6)
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
6
where is the shear strain in the zone of plastic deformation, m; is the shear modulus in the zone of plastic
deformation, MPa;  is the shear stress in the zone of plastic deformation, MPa. M.S.W. is presented as a medium
with friction and cohesion between waste components, i.e., a plastic Coulomb-Mohr medium. Based on the physical
modeling scheme developed above
1. We determine the resistance force and power of the grinding process and its efficiency. The resistance
force to crushing is:
=
(7)
where
is the contact area of the working body of the hammer crusher with waste components, m2. The power
required to perform the crushing process is:
= (8)
where is the speed of rotation of the hammer crusher rotor,
.
2. The internal forces arising before the working body are calculated according to the Mohr-Coulomb theory.
The initial form of the process is shown in Figure 3. The shear stress equation has the following form:
=++

(9)
3. The similarity conditions are determined by the method of integral analogs and using the laws of mechanics,
equations (5) - (9):
=
 , =
, =
 , =
 , =,
=
, =
, =
, =

(10)
Development of similarity criteria for crushing municipal solid waste based on the dimensional analysis method.
Additional criteria characterizing the working body's parameters and the active process of grinding are determined
using the dimensional analysis method.
The analysis of the influence of factors acting on the process of waste grinding and the statement of criterion
dependencies was conducted based on the methods of the theory of similarity and dimensions using the π-theorem
[23]. Crushing performance depends on many parameters, the most important of which are power, degree of
crushing, and type of material being processed. In our case, the type of material is known, and the degree of required
crushing =
' is also known. According to the analysis of the initial information, 3 allows one-stage grinding
technology to be conducted. Accepting certain assumptions and restrictions, the performance of crushing the organic
components of M.S.W. using hammer crushers (depending on their design and technological parameters) can be
characterized by the following functional dependence:
=(,,,,,,,,) (11)
where is the power of a crusher, W; is the rotor diameter, m; n is the rotor speed, s-1; is the crusher
productivity, m3/hour; is the light surface area of the grate, m2; is the linear size of the hammer, m; is the
hammer setting angle, degree; is the volumetric weight,
; is free-fall acceleration, m/s2;  is the average
linear size of the components of waste, m.
Let us define the similarity criteria for this process. In our case, there are 10 physical quantities characterizing the
process (=10).
It follows from consideration of these quantities that one of them, i.e., is automatically a similarity criterion [24].
The dimensions of the remaining 10-1=9 physical quantities can be expressed in terms of three basic units of
measurement - force P, length L, and time T.
We write out the formula for the dimensions of these quantities:
[]=[]= [] = , []=, []=, []=, []=,[]=, []= ,
To find an additional number of similarity criteria, we should choose base quantities with independent dimensions,
which would include all the main units of measurement. We take three quantities with independent dimensions: ,,
(= 3).
Then, it remains to find 9-3=6 similarity criteria. To find criterion , we take, for example, the dimension of
parameter Q and write it into the numerator, and the product of the dimensions of the quantities ,, with unknown
exponents ,,, we write into the denominator.
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
7
=󰆓
()()(),
The exponents are determined by equating the dimensions of the numerator and denominator to each other to obtain
a dimensionless complex. So, for = 0, = 2,5, = 0,5, we obtain:
=󰆓
(),(),,
Let us substitute symbols of physical quantities instead of dimensions. Then, raising these quantities to the indicated
powers, we finally obtain:
=
,, (12)
In the same way, we obtain the remaining similarity criteria. Finally, we obtain the following system of criteria:
 =
,  =
, =
,,,  =, =
,  =
(13)
If we divide criterion  by , then we obtain new criterion
=/=
,
=
 (14)
If we multiply criterion  by , then we obtain criterion 
==

=
(15)
If we divide criterion  by , then we obtain new criterion 
=/=
....
=
(16)
If we divide criterion  by , then we obtain new criterion 
=/=
 =
 (17)
The experiments were conducted under conditions of approximate physical modeling when the properties of the
medium are not changed, when such parameters as the cohesion force between the components of waste, the
angles of external and internal friction between the components of waste, and the shear forces of elastic and plastic
zones of the crushing process are the same.
Under these conditions, the criterion dependencies obtained by analyzing the dimensions are particularly interesting.
The criterion equation has the following form:
..=(
,,
..,
) (18)
Development of scaled equations for crushing organic components of municipal solid waste.
To find the value of the similarity indices, we should determine the ratio of the similarity feature of a life-size machine
to the similarity feature of the model.
From , it is possible to calculate scale dependencies
= (19)
From = (20)
From = (21)
From == (22)
From  = 1 (23)
From = (24)
From ==
(25)
From = (26)
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
8
From = = (27)
From  =
. (28)
From  =
(29)
From   = (30)
From  =
. (31)
From  = 1 (32)
From  =
(33)
From  = (34)
From  =
.
. (35)
From  =
 (36)
From  = (37)
From  = (38)
From scaled equations (23), (25), (26), and (28)
for = 1 and = 1, it follows that
= === and = (39)
From scaled equations (23) and (32)
 == 1, (40)
Since the experiments were conducted on the ground, =1, it follows from (23) that
= (41)
Therefore, the scale of forces of resistance to grinding from (29) is
=
, (42)
The performance scale from (28) is
=
., (43)
The scale of rotor shaft speed from (33) is
=
, (44)
The scale of linear dimensions from (34) is
 =, (45)
The power scale from (37) is
=
., (46)
The scale of the area of the grate from (29) is
=
, (47)
The performance scale from (31) is
=
.=
. (48)
The speed scale from (32) is
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
9
=
=
(49)
The power scale from (33) is
==
. (50)
The scale of the linear size of the hammer from (34) is
= = (51)
Determination of the crusher model parameters used for crushing organic waste components.
We determine the dimensional values of the parameters for the model. If the indices of similarity of volumetric weight
for the original and the model are equal, the volumetric weights of waste must be similar to each other
= (52)
The compound of waste components is determined by formula (39)
=
(53)
The coefficient of internal friction with the M.S.W. components is determined based on (40)
= (54)
The stress in the M.S.W. medium in front of the working body (a determined value) is found by formula (38)
=
(55)
Grinding resistance forces are determined based on (46)
=
, (56)
Crusher capacity is determined based on (39)
=
. , (57)
Crusher rotor shaft speed is determined based on (44)
=
. , (58)
Based on formula (45), we determine the linear dimensions of the crushing machine
=
, (59)
The power value for model drive is determined based on (46)
=
. , (60)
In formulas (51)-(60), is the set value determined by the simulation scale.
Formulas for determining the expected parameters of the original according to the parameters measured on the
model.
Following the inverse relationships, formulas for the transition from the model to the original are established to
determine the parameters of the crusher model.
The strength properties of the original medium, during operation in which the working bodies of the machine are
subjected to the loads predicted in modeling, are determined by the following formulas:
The relationship between waste components is
= (61)
the specific gravity of waste components is
= (62)
friction characteristic (external and internal friction) is
= (63)
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
10
shear stresses arising in the mass of waste components in front of the working body of the fill-size machine are:
= (64)
loads acting on the hammers of full-size crushing machines are:
=
(65)
Full-size crusher performance is:
=
. (66)
The rotor shaft speed of the full-size crusher is:
=
. (67)
Linear dimensions of the full-size crusher are:
= (68)
The drive power of the original is:
=
. (69)
The results obtained in were used to select a linear scale.
In the above study, the scale factor of the physical model is substantiated; its value depends on two aspects:
on the properties of waste (composition and structure; the composition of waste depending on the structure;
volume density, humidity, compression properties, etc.);
on the accuracy of the measuring equipment.
Calculations conducted based on the developed methodology and limitations related to the properties of the medium
made it possible to determine the value of = 2.5. For the original, a single-rotor hammer crusher SMD-112 was
chosen.
5 DISCUSSION
Analytical determination of the maximum value of the contact force and the impact speed of the waste components
made it possible to determine the dependence of the contact force on the main parameters of the collision process
and this, in turn, made it possible to optimize the value of the contact force. The value of which makes it possible to
select the optimal values of the main parameters of the crusher, providing a minimum of energy intensity at a constant
value of productivity.
The developed algorithm for the physical modeling of the solid waste grinding process made it possible to consistently
determine the process similarity criteria, starting with criteria representing unambiguous relationships between
stresses. In addition, dependencies were identified that determine the energy and power characteristics of the
process.
A comprehensive study of the grinding process made it possible to obtain a full range of criteria characterizing all
stages of solid waste grinding.
The results of a comparative analysis of the list of criteria obtained based on the laws of mechanics and rheological
models with similarity criteria obtained by dimensional analysis showed that these methods, when used correctly,
complement each other on the one hand, and on the other hand make it possible to concentrate efforts on more
important criteria.
6 CONCLUSIONS
1. The developed block diagram of the method of physical modeling of the process of crushing organic
components made it possible: first, to cover the entire range of tasks performed according to the scheme
in strict sequence; second, to determine the entire set of similarity criteria that fully describe the crushing
process with the least material and time costs.
2. The rheological equivalent of the process of crushing the organic components of MSW, completes the
entire system of criteria that describe the crushing process.
3. Dependencies (64)-(69) made it possible to calculate the power and energy parameters of a full-scale
crusher based on the results obtained on the models.
7 LIMITATIONS
The significant heterogeneity of the composition of waste and the variability of its properties do not allow the
development of clear mathematical models describing the process of their grinding. These limitations did not allow
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
11
us to use the method of integral analogues when developing a physical modeling method (the derivation of similarity
criteria is carried out through the use of a system of differential equations describing the waste grinding process).
In this regard, we used the method of dimensional analysis when developing a system of similarity criteria. The
disadvantage of this method is that in the absence of a sufficient amount of primary information or the lack of
necessary experience of the researcher, some parameters and indicators may not be taken into account when
drawing up the criterion equation. This in turn can affect the efficiency of the crushing machine.
Further research in this direction can be developed through experimental studies. The use of waste samples of
various compositions for their grinding will allow us to outline research directions.
8 REFERENCES
[1] Khankelov,T.(2021). Results of experimental studies of the process of sorting of elastic components of
municipal solid waste. Academic Journal of Manufacturing Engineering, volume 19, ISSUE 4/2021,97-102,
DOI: https://ajme.ro/PDF_AJME_2021_4/L14.pdf
[2] Khankelov,T, Askarhodzhaev, T., Mukhamedova, N., (2020). Determination of key parameters of a device for
sorting municipal solid waste. Journal of Critical Reviews. Vol.7, Issue: 4, 27-33, DOI:
https://doi.org/10.1016/jcr.07.04.07
[3] Fabrice Tanguay-Rioux, Martin Heroux, Robert Legros. (2021). Physical properties of recyclable materials
and implications for resourse recovery. Waste Management. Vol.136, 195-203. DOI:
https://doi.org/10.1016/j.wasman.2021.10.007
[4] Yuekai Xie, Jianfeng Xue, Alistair Deane. (2023).Waste Management. Numerical modeling of Settlement of
municipal solid waste in landfills coupled with effects of biodegradation. Volume 163,108-121.
https://doi.org/10.1016/j.wasman.2023.03.025
[5] Khankelov,T, Askarhoodzaev, T., Aslanov, N., (2023). Modeling of segmental excavator working tool for soil
compaction.E3S Web of Conferences 401(826),1-11. DOI: https://doi.org/10.1051/e3sconf/202340102052
[6] Khankelov, T, Mukhitdinov, A., Ibrokhimov, S., Aslonov, N., Mirkholikov, S., (2022). Determination of the
lengths of rebounds of elastic components of solid municipal waste/The 1st International Conference on
problem and Perspectives of Modern Science AIP Conf.Proc,1-6. DOI: https://doi.org/10.1063/5.0089528
[7] Khankelov, T, Mukhamedova, N., (2023). Choice of garbage trucks with rational parameters according to
criterion of minimum operation cycle time.E3S Web of Conferences, 401, CONMECHYDRO-2023,1-6.DOI:
https://doi.org/10.1051/e3sconf/202340102053
[8] Khankelov, T, Sarmoov, A., Kadirov, A., The analytical dependence of the resistance force to digging with a
bulldozer blade on the main influencing factors. E3S Web of Conferences, 458, 10001 (2023) EMMFT-2023,
1-9. DOI: https://doi.org/10.1051/e3sconf/202345810001
[9] Khankelov, T, Maksudov, Z., Mukhamedova, N., Tursunov, Sh., Crushing and screening complex for the
production of compost from organic components of municipal solid waste // II International Scientific
Conference «Construction Mechanics, Hydraulics and Water Resources Engineering» (CONMECHYDRO-
2021), April 1-3, Tashkent, Uzbekistan, 2021,1-8.DOI: https://doi.org/10.1051/e3sconf/202126401026
[10] Kosimbetov, B, Khankelov,T.(2021).Use of advanced technological methods for the recovery of cone crusher
equipment // II International Scientific Conference «Construction Mechanics, Hydraulics and Water
Resources Engineering» (CONMECHYDRO-2021), April 1-3, Tashkent, Uzbekistan, 1-9.DOI:
https://doi.org/10.1051/e3sconf/202126402063
[11] Klushantsev, B.V., Kosarev, A.I., Muizemnek, Yu.A.(2007). Crushers. Design. Calculation. Features of
operation: Mashinostroyeniye, Moskva.
[12] Balovnev, V.(2014). Similarity and modeling in the design system of road-building mashineri. MADI,Moskva.
[13] Gonopolsky, A., Zinyakina, E., Denisova, T., (2017). Waste cutter roller. (Bulletin of SUSU. Series "Food and
Biotechnology”. Vol.5, No.1, 45-54.DOI: https://doi.org/10.14529/food170106
[14] Kuznetsova V. (2019).Physical modeling of the contact integration between working body of digging machine
and frozen soil.Journal of Mathematics and Mechanics, Volume 61, 70-81,DOI:
https://doi.org/10.17223/19988621/61/7
[15] Ikechukwu, O., International Journal of Engineering Technologies. Design of used PET bottles crushing
machine for small-scale industrial applications.2017, 3(3), 157-168. DOI: https://doi.org/10.19072/ijet.327166
[16] Sothea, K., Fazli, N., Hamdi, M., & Aoyama, H. In AIP Conference Proceedings. American Institute of
Physics. Development of a crush and mix machine for composite brick fabrication. 2011.Vol. 1315, No. 1,
1437-1442. DOI: https://doi.org/10.1063/1.3552388
[17] Islamova O, Tokov A, Ataeva F. (2019). Energy efficiency is the most important indicator of the quality of
food grinders. Proceedings of the Voronezh State University of Engineering Technologies, 56-62. DOI:
https://doi.org/10.20914/2310-1202-2019-2-56-62
O N L I N E F I R S T
Journal of Applied Engineering Science
Vol. 22, No. 2, 2024
www.engineeringscience.rs
publishing
Tavbay Khankelov et al. - Bases of the method of
physical modeling of the process of crushing of
municipal solid waste
12
[18] Savinyx, P., Isupov, A., Ivanov, I., Determination of the kinematic indicators of particle motion in the channel
of the distribution bowl of a centrifugal grinder. Vestnik NGIEI.2020. №7(110),37-45. DOI:
https://doi.org/10.24411/2227-9407-2020-10062
[19] Suxoparov, A., Plotnikova, Yu., Ivanov, I., Determining velocity and trajectory of particles when designing
rotary centrifugal crushers. Tekhnologii i technicheskie srestva mekhanizirovannogo proizvodstva produkcii
rastenovodstva i zhivotnovodstva.2020.1 (102),63-72.DOI: https://doi.org/10.24411/0131-5226-2020-10228
[20] Petrov, A., Stenovsky, V., Belousova, N., Method of optimizing the feed mill hammers durability’s
improvement. Forestry journal. №1, 2016,186-192.DOI: https://doi.org/10.12737/18741
[21] Khankelov, T.(2001). A theory of sorting solid domestic waste. Stroitelnye i Dorozhnye Mashiny, 2001, (5),
34-36. DOI: https://portal.issn.org/resource/ISSN/0039-2391
[22] Khankelov,T, Mukhamedova, N., Kudaibergenov, M., Khamidov, S., (2022). Determination of similarity criteria
for the solid waste shredding process// Eurasian journal of academic research. -Tashkent.Vol.2. Issue13,
533537. DOI: https://doi.org/10.5281/zenodo.7456256
[23] Kharlamov S, Janghorbani M. (2022). Aspekts of computer modeling the processes of transport and cleaning
from cuttings in horizontal wellof Petroleum and Mining Engineering.Vol.22,73-84. DOI:
https://doi.org/10.15593/2712-8008/2022.2.4
[24] Teshome, F.B., (2021). Municipal solid Waste management in Ethiopia; the gaps and Ways for improvement.
Journal of Material Cycles and Waste Management. Municipal solid waste management in Ethiopia.Vol.23,
issue 1,18-31. DOI: https://doi.org/10.1007/s10163-020-01118-y
Paper submitted: 07.01.2024.
Paper accepted: 12.04.2024.
This is an open access article distributed under the CC BY 4.0 terms and conditions
O N L I N E F I R S T
... A rational technological scheme for processing solid waste, considering local conditions, was substantiated. Issues of substantiating the rational parameters of machines using methods of physical modeling of solid waste processing and the issues related to developing technological schemes for waste processing are considered in articles by T.K. Khankelov et al. [20][21][22][23][24][25][26][27][28][29][30]. Despite the considerable number of studies conducted on addressing the collection, transportation, and processing of solid waste, there are still questions on the development of an integrated approach to selecting the most suitable machinery and devising a technological scheme for sorting and crushing waste. ...
Article
Full-text available
The article is devoted to solving a complex problem, including the issues of selecting the optimal set of machines and the technological scheme for implementing the sorting and crushing of municipal solid waste at transfer and recycling stations, and the justification of the key parameters of crushing and sorting machines, considering properties of waste. When examining the main parameters, the input and output characteristics of machines are considered in the developed technological scheme. When determining the properties of waste, 12 administrative districts of the territory of Tashkent were used as objects for cluster sampling. Through an in-depth study of the process of sorting and crushing municipal solid waste, based on the developed technological scheme, the type and design of the crushing machine were determined. Based on the methods of regression analysis and mathematical statistics, a series of multifactor experiments were conducted on the main parameters of a hammer crusher. In addition, considering the properties of waste, the main parameters of the drum screen were determined, in particular, the diameter of the grid opening. The developed optimal set of machines with substantiated rational parameters will make it possible to maximally prepare the components of municipal solid waste for use in the form of secondary raw materials.
... Generators have been released from their responsibility of defining the way of processing waste. Waste disposal has been historically divided into liquid and solid, but it is still influenced by many different variables such as location, local religion, politics, and technical expertise [17]. ...
Article
Full-text available
and, in particular, the waste of medical institutions - the activities of healthcare institutions. The development of the issue of environmental safety and human health protection has drawn attention to the role of waste, which is an echolocation of the effectiveness of the healthcare system and a source of danger to human health. The experience of many countries that have developed in this direction has shown that the most important condition for addressing the environmental safety of waste management is the categorization of waste as hazardous and non-hazardous according to their physical and chemical characteristics using consistent, comprehensive methods and technical means for effective incoming waste handling, “design” of sites for the separate collection and storage of waste, the use of waste as an alternative source of energy - substitution of raw materials and thus dramatic reduction of the concentration of waste, and the development of the renewable waste treatment system - the setting of standards for the restriction of waste flow to the environment and control of waste into the atmosphere, water, and soil, and as a result, the prevention of extreme pollution and the regulation of the environment on an appropriate level and protection of man from morbidity.
Article
Full-text available
The criteria for the similarity of the process of digging soil with a bulldozer blade are determined based on the use of the principles of the theory of similarity and modeling. When determining the similarity criteria, a rheological model of the process of interaction of the bulldozer blade with soil and the method of dimensional analysis were used. The processing of experimental data obtained with large-scale physical models in a criterion form made it possible to significantly reduce the time and material costs for conducting experiments. The criterion equation is valid for any change in the parameters included in the dependence that determines the force of digging the soil with a bulldozer blade. The main limitation is compliance with the equality of similarity criteria for the model and the original.
Article
Full-text available
In conditions of limited commercial information on costs and rational costs, machines' efficiency and rational parameters at the stage of their manufacturing can be established based on an analysis of technical and operational indices. On this basis, the technical efficiency of the machine can be established. The corresponding technical and operational indices are calculated based on known technical parameters and operating conditions of the machine. These are such indices as specific energy consumption (kVt∙h/m³), material consumption (t∙h/m³), productivity (m³/h), output per worker (m³/w∙h), and several generalized indices derived from the indicated ones. The choice of a rational solution is based on single-criteria optimization (on the one-criterion analysis).
Article
Full-text available
The development of a methodology for physical modeling of the working process and a replaceable working tool of an excavator for soil compaction in the construction, maintenance, and repair of man-made engineering structures in confined spaces are considered in the article. This methodology is based on a rheological model of the soil compaction process containing Hooke and Newton's elements connected in parallel (the Voigt model is the method of integral analogs that have been used to obtain the main similarity criteria that adequately characterize the process of static compaction during elastoviscoplastic soil deformation). The formulas for the transition from the model parameters to the parameters of the full-scale process of soil compaction by a segmental working tool are obtained based on similarity criteria for modeling the option without changing soil properties.
Article
Full-text available
The existing technology for processing solid household waste (MSW) at waste transfer stations in the city of Tashkent does not allow obtaining high-quality raw materials for compost production. In this regard, a crushing and screening complex has been developed to produce compost with low energy and material consumption. The carried out theoretical and experimental studies made it possible to determine that the rotor blades should be installed along the rotor line with an angle equal to zero degrees. To overcome the resistance arising between the bottom of the crusher and the lower surface of the rotor, several holes with a diameter of 12 mm are drilled on the bottom of the crusher in the radial direction. It was found that the rotational speed of the electric motor of the crusher, as well as the sorting device, is 1500 min-1, the angle of impact of organic waste on the rotor blades of the sorting device is approximately 45 degrees. The use of a crushing and screening complex made it possible to effectively grind and extract ballast inclusions from the composition of crushed organic waste by 85-90 percent.
Article
Full-text available
Cone crushers of various sizes and modifications are used widely for rock processing now. The most widespread are crushers of the KDM and KMDT types. Depending on the types and modifications, crushers are used in various industries: crushing abrasive, extra strong rocks and building materials, in the production of cement and other materials in the construction industry; for crushing rocks in the mining industry.
Article
Full-text available
A brief analysis of the methods of grinding technological raw materials from the standpoint of energy efficiency has been performed. Studies show that cutting (grinding) the feedstock into pieces of a certain size is the most energy-intensive. Existing designs of cutting elements of grinding mechanisms (cutting blade, cutting edge) are not optimal from the standpoint of energy efficiency. For example, the cutting blade in the working hole has a taper angle of 90°, and the taper angle of the cutting blade on the blades of the movable knife is also in the range of 80–90°. It is proposed to make the sharpening angles of the cutting blades on the blades of a movable knife equal to 5–8°. In addition, the blades of such a knife should have the shape of a classic wedge in all cross sections. Reducing the angle of sharpening of the cutting blade in the working hole of the grill to such values does not succeed in terms of design features (in particular, without violating transparency indicators). The reserves of reducing the angle of sharpening of the cutting blade in the working hole are shown (this angle can be less than 90°). The performed studies indicate that the smaller the energy costs for grinding the feedstock, the less it is rubbed and squeezed out of the holes of the grate. It can be assumed that the organoleptic properties did not deteriorate after grinding (but remained). The lower the transparency of the lattice, the grinding process is more energy-consuming. The smaller the sharpening angles of the cutting blades of the knives, the more energy-efficient the grinding process. The worse the quality of the crushed raw materials, for example, meat, which is characterized by the excessive presence of connective and cartilage tissues, films, etc., the more energy-efficient is the grinding process with knives with cutting blades with minimal sharpening angles.
Article
This paper presents the development of a new settlement model to predict the long-term settlement of municipal solid wastes (MSWs). The total settlement of the MSWs results from the direct loss of solids due to decomposition and compression due to stress variation induced by loss of solids, flow of gas and liquid and mechanical creep. The geotechnical properties of MSWs are considered as functions of degrees of biodegradation (DOB). To validate the model, two settlement profilers (2.5 years) and three geodetic monitoring networks (2 years) were installed at Mugga Lane Landfill, ACT, Australia to monitor the settlement of an MSW lift and three closed landfill cells, respectively. The settlement rates of the landfill cells with the ages of 7, 8, 14, and 8, 9 and 15 years are 0.53, 0.35, 0.06 and 0.46, 0.36, 0.05 mm/day, respectively. In addition, 5 large scale and 3 small scale bioreactors were set up in the field and laboratory to address the long-term physical, mechanical and biochemical behaviours of the MSWs under different stress levels. The predicted settlement is compared to the test results from the bioreactors, in-situ monitoring data and the settlement predicted using an existing model, which has been improved by coupling the geotechnical properties of MSWs with DOBs. The predicted settlement using the proposed model well fits the test results and monitoring data. The settlement strain is predicted to be 28.2 % during the filling stage of the landfill and 5.9 % in 5 years after the closure.
Conference Paper
The article deals with the theoretical substantiation of the process of sorting elastic components of waste. The experience of foreign countries shows that the use of waste, their segregation into useful components used as secondary raw materials at enterprises, allows not only to extract financial benefits from waste but also to clean up the environment. The aim of the study is to theoretically substantiate the process of sorting elastic components of waste from the rest of the mass. The theoretical and empirical methods were used in the study, in particular: a review and analysis of the literature sources, logical and system analysis, the main provisions of the theory of impact. The regulatory legal framework in the field of waste management in the Republic of Uzbekistan has undergone significant changes. There appeared laws, resolutions and decrees of the President, projects aimed at solving the problem of waste separate collection. The existing technology for the processing of solid municipal waste (SMW) in the Republic of Uzbekistan, in particular, in the city of Tashkent, does not allow the mechanized extraction of valuable components from the composition of SMW. In this regard, an analysis of the existing designs of sorting devices was conducted and a prototype was selected for the development of the design of a sorting device. A significant difference in the values of the rebound lengths of elastic components of waste from non-“elastic” ones was theoretically determined and experimentally confirmed.
Article
Mechanical sorting plays a pivotal role in current municipal solid waste management systems for resource recovery. However, material recovery facilities, generally face several challenges in meeting quality standards for multiple waste fractions. Improving these facilities requires a better understanding of municipal solid waste physical characteristics, since they are directly targeted by mechanical sorting unit operations. Three waste physical properties (bulk density, particle size and shape factor) were characterized for several recyclable materials. Narrow ranges of densities were observed for similar waste materials, while the particle size distributions were found to vary widely. Statistical parameters were determined for these two properties. A novel approach, based on the void fraction of a waste item, is proposed to quantify the shape factor. Potential applications of the characterization results for improving mechanical sorting are demonstrated through the analysis of the recovery of corrugated cardboards and multilayer cardboards in a material recovery facility.