• Home
  • Bo Ivar Sångfors
Bo Ivar Sångfors

Bo Ivar Sångfors
Bo Sångfors Consulting · www.bosangfors.se

Master of Science in Aeronautical Engineering

About

57
Publications
8,798
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
79
Citations
Introduction
http://bosangfors.se/TEKNIK.htm - Laboratory teacher/assistant, Institution of Gas Dynamics KTH Royal Institute of Technology, Stockholm 1967-1969 - Master of Science in Aeronautical Engineering, KTH 1969. -Manager, Dept. of Gas Regulator Development, AGA AB, Sweden 1969-1971. -Manager, Dept. of Heat Transfer and Gas Dynamics, Svenska Rotor Maskiner AB Sweden 1971-2001. Guest lecturer at KTH 1983-1986 -Own company: Bo Sångfors Consulting 2001-..
Additional affiliations
June 1969 - October 1971
AGA AB
Position
  • Manager
Description
  • Development and improvement of Gas Regulators for gas cutting and welding.
September 1967 - June 1969
KTH Royal Institute of Technology
Position
  • laboratory teacher and assistent
Description
  • Teaching students tests in subsonic windtunnel and shocktube. Different engineering work.
Education
September 1964 - June 1969
KTH Royal Institute of Technology
Field of study
  • Aeronautinutical engineering

Publications

Publications (57)
Conference Paper
Full-text available
This paper gives a short presentation of a method for the computer simulation of noise caused by the gas pulsations, created from the opening and closing of inlet and discharge ports of twin-screw compressors. The method takes into account influences from lobe combinations, wrap angle, length/diameter ratio, leakage through blowhole and clearances...
Conference Paper
Full-text available
In this paper a physical model for prediction of oil-flooded twin screw compressor performance is presented and discussed. Calculation results are presented.
Data
Full-text available
This data set shows that at high brine flows generated effect starts to decrease. For more information see the updated version of this data set.
Data
Full-text available
These graphs show how different built-in volume ratio effects the generated electric power and the screw expander adiabatic efficiency. Inlet pressure = 15 bar Outlet pressure = 1 bar Steam quality x = 1.00 Generator efficiency = 0.95 The rotor tip speeds are from 20 m/s up to 110 m/s. As can be seen low built-in volume ratio leads to high power ou...
Conference Paper
Full-text available
This paper gives a short presentation of a method for computer simulation of effects on the performance of screw compressor from injection of different liquids. The method takes into account liquid evaporation, subsonic or sonic two-phase leakage, heat transfer between liquid-gas-metal, flashing of dissolved gas, displacement of liquid volume and f...
Data
The expander is a dry twin screw expander with synchronizing bearings Profile = 4+6-combination Male rotor diameter = 285 mm Female rotor diameter = 285 mm. Male rotor tip velocity = 20-120 m/s Inlet pressure = 16.201 bar. Inlet temperatures = 202 (x=1), 302 and 402 centigrade Outlet pressure = 2.7 bar Built-in volume ration Vi = 2.7 The steam supe...
Data
This data file presents a 2 stage system consisting of a Steam Screw Expander and a R245fa Expander working in serie. The steam expander delivers the outcoming steam as brine to a R245fa-expander in a ORC-system.
Data
As is well-known the steam quality x is very important for the performance of a steam expander. This graph is just a way to present that. The presented data set shows the generated electrical power as a function of the steam flow at various steam quality x. As is obvious the decreasing steam quality increases the necessary steam flow for generation...
Data
In order to give more information about the effects of various built-in volume ratio Vi, when using a screw expander in an ORC-system these calculations are presented.
Data
In order to give some more information about the effects of different working media on the performance of a twin screw expander with the diameter 285 mm these calculations are presented. As is shown the choice of working media is very important and determines the size of the screw expander.
Data
As is well known it is important to have a good heat transfer from the brine to the working media. The intention of this short data set is to show how the brine outlet temperature effects the needed brine flow.
Data
In order to show the importance of the feed pump losses in an ORC-system using working media of different quality X this short paper sheet is presented.
Data
Trilateral Flash Cycle. In order to give more information about the effects of various built-in ratio at different steam quality X, when using a screw expander for generating electrical power these calculations are presented.
Data
This short data set describes the difference between using an approx. theory compared to direct use of the program REFPROP.
Data
The data file presents the effect of the built-in volume ratio upon the generation of Sound Pressure Level SPL from the outlet of a refrigeration Twin Screw Compressor. It is shown that the built-in volume ratio can cause high noise levels if not properly designed.
Data
This data set shows an easy method to predict the generated power from a twin screw expander working with 100 % adiabatic efficiency. The presented enthalpy data in the graph are obtained from the program REFPROP. Since the enthalpy is in kJ/kg the value is representative for a screw expander working with constant inlet mass flow. As can be seen th...
Data
In these calculations the steam mass flow is kept constant by changing the male rotor tip speed at different steam quality x. - As can be seen the generated power decreases with decreasing inlet steam quality x. Fig.1 shows that the generated effect decreases with decreasing steam quality. Fig.2 shows the necessary variation of the male rotor tip...
Data
In order to give some feeling about the effects of different working media on the performance of a twin screw expander with the diameter 285 mm these calculations are presented. As is shown the choice of working media is very important and determines the size of the screw expander. Furthermore is shown that the media pump power consumption can be i...
Data
This data set shows the generated electrical effect from a generator driven by a steam screw expander as a function of inlet steam quality x. Fig.1 shows the generated electrical effect as a function of the steam quality x. As is shown the generated effect is approximately the same for steam quality x > 0.2. It is also interesting to see that for...
Data
In these calculations the steam mass flow is kept constant by changing the rotor tip velocity. As can be seen the generated power and the adiabatic efficiency increase when the steam quality increases. Correction: 7.25 ton/h is at built-in volume ratio Vi = 3 not at Vi=1.
Data
This is a correction of the male rotor tip speed for stage 2 in the earlier uploaded data set "Using 2 screw expanders of same size for generation of power from a 2 stage Steam heat recovery system" . The new data is 30 < Vtip < 90 m/s.
Data
In order to give some feeling about the effects of different working media on the performance of a twin screw expander with the diameter 285 mm these calculations are presented. As is shown the choice of working media is very important and determines the size of the screw expander. Furthermore is shown that the media pump power consumption can be i...
Data
This 2-stage recovery system consists of two dry screw expanders of the same size. Stage one: Steam expander. Diam. = 285 mm, built-in volume ratio = 2.0 Stage two: R245fa screw expander. Diam. = 285 mm, built-in volume ration = 1.9
Data
This graph is just to show the importance of having a good steam quality at the screw expander inlet. One can say that this is typical for all displacement machines - not only screw expanders.
Data
Refrigeration Screw compressor. The presented computer simulations of pressure and gas/oil temperatures are performed in accordance with the theory and assumptions presented in the 1984 Purdue paper “Computer Simulation of the Oil Injected Twin Screw Compressor”.
Data
This is an addition to the data file "Importance of having good steam quality x at the inlet of a Steam Screw Expander generating electric power" and "Effect of inlet steam quality X if the inlet steam mass flow is constant" earlier uploaded on Research Gate. In these calculations the steam mass flow is kept constant by changing the built-in volume...
Data
The presented computer simulations of pressure and gas/oil temperatures are performed in accordance with the theory and assumptions presented in the 1984 Purdue paper “Computer Simulation of the Oil Injected Twin Screw Compressor”.
Data
These graphs show the difference between using approx. method versus use of for instance Mollier chart for real gases.
Data
This is an addition to the data file "Importance of having good steam quality x at the inlet of a Steam Screw Expander generating electric power" earlier uploaded on Research Gate. In these calculations the steam mass flow is kept constant by changing the inlet pressure and temperature. As can be seen the generated power as well as the inlet press...
Data
The interesting in these calculations are that the built-in volume ratio = 1.0 (similar to a Roots blower). This means that the flashing during expansion takes place outside the closed control volume. i.e. the effect from flashing can be neglected. This short set of data also presents comparative calculations between a Screw Expander having built-i...
Data
Having built-in volume ratio Vi =1.0 means that the effect of flashing or condensation during the expansion process in a closed volume can be neglected. All expansion or condensation takes place in a volume that is open to the outlet. As can be seen it is very important to have a good steam quality at the screw expander inlet
Data
The data set presents the effect of R245fa inlet quality X upon the Performance of a Screw Expander. Most interesting is the ORC-efficiency at X-values close to zero.
Data
This graph is just an addition to my earlier data set " Screw Expander Inlet Pressure Drop and it's Effect on Performance as a function of R245fa inlet quality X " on Research Gate The data set shows the importance of having a good quality X at the expander inlet.
Data
Fig 1 shows what happens if you change the steam quality x at the inlet of the screw expander. As you can see the generated power as well as the ORC-efficiency decreases as x decreases, but the brine flow increases. As is obvious it is important to have a good quality x at the expander inlet. Brine = Water. Coolant = Water. Working medium =R245a, 0...
Data
The first graph shows the generated electric power from a screw expander as a function of the steam flow at different inlet steam quality x. Another graph shows that at built-in volume ratio =1.0 no effect is obtained from condensation or flashing, since all condensation or flashing occur in a volume open to the compressor outlet.
Data
In order to give more information about the effects of various steam quality X, when using a screw expander in an ORC-system these calculations are presented.
Data
In order to give some more information about the effects of different working media on the performance of a twin screw expander with the diameter 285 mm these calculations are presented. The presented results are additional to those presented in the file " Different Working Media " uploaded on Research Gate. As is shown the choice of working media...
Data
In order to give more information about the effects of various built-in volume ratio Vi, when using a screw expander in an ORC-system these calculations are presented. This data set presents 2 graphs, where fig.1 shows the performance as a function of the male rotor tip speed and fig.2 the performance as a function of the brine flow. The expander i...
Data
In order to give some more information about the presented calculations in " Avoiding inlet flow choking at a Screw Expander inlet " this updated version is made. This version contains 2 graphs – very equal – but fig.1 is performance as a function of Brine flow and fig.2 is performance as a function of Male rotor tip speed. The expander is a dry sc...
Data
This data set shows the importance of having good steam quality at the inlet of a steam expander when generating electric power.
Data
Full-text available
Fig 1 and 2 show what happens if you change the brine flow but have the coolant flow constant. As is obvious it is important to have enough coolant flow if you want an efficient ORC performance.
Data
Estimated Performance of a Waste Heat Recovery System Stage 1: Steam Screw Expander Stage 2: ORC using Screw Expander and R134a as the working medium. Why not change the working media from R134a to R245fa? Then it is necessary to change the rotor diameter from 285 mm to 403 mm to get the same performance. - Why not use a turbine instead, since the...
Data
Full-text available
This graph shows the effect of the steam quality at the inlet. With decreasing steam quality the mass flow through an expander increases. Decreasing steam quality means increased density. Can easily be seen in for instance REFPROP.
Data
Full-text available
This show how the different leakages are effected when the axial seal clearnace is increasing.
Data
Full-text available
This show how the different leakages are effected when the axial seal clearnace is increasing in a Tri-sector Rotary Heat Exchanger.
Data
Full-text available
In order to recover the waste heat from wet flue gas in a Power station a rotary heat exchanger can be used. These calculations show that the heat transfer is much higher for a rotary heat exchanger than a recuperative. This because the rotary heat exchanger can evaporate back the condensed water to the air.
Data
Full-text available
When SCR for reduction of NOx-emissions is used in coal-fired power stations the flue gas entering the rotary heat exchanger for waste heat recovery contains sulhpuric acid and ammoniumbisulfat. Therefore a heat exchanger must be designed in such a way that operational problems are reduced.
Data
Full-text available
These calculations are made with the same theory as reported in the paper “Modeling, Measurements and Analysis of Gas-Flow Generated Noise From Twin-Screw Compressors” . This is an example with a large chamber after the outlet. The Fourier analysis is based on computed data in the pipe after the large chamber.
Data
Full-text available
Results from discussions with Elvedin Mujic, City University London. As can be seen reduction of SPL also causes decrease of the adiabatic efficiency.
Data
Full-text available
These computer simulations are using a modified theory of that described in the papers:“Computer Simulation of Effects from Injection of Different Liquids in Screw Compressors”, Purdue 1998“ and "Numerical calculation of effects from injection of different liquids in twin screw compressors”, VDI 1998. In these calculations two screw compressors us...
Data
Full-text available
The channels inside this type of sun collectors consists of rectangular channels. These computer simulations are made for 3 different designs as can be seen in the picture. Notice that it is the short side that is towards the incoming heat from the collector area. The increased heat transfer to the air in the channels is caused by the heat conducti...
Data
Full-text available
This shows the importance of having a good Steam Quality X at the inlet of a Screw Expander
Research
Full-text available
This shows the importance of having a good Steam Quality X at the inlet of a Screw Expander.
Data
Full-text available
Conference Paper
Full-text available
These computer simulations are using a modified theory of that described in the papers: “Computer Simulation of Effects from Injection of Different Liquids in Screw Compressors”, Purdue 1998 “Numerical calculation of effects from injection of different liquids in twin screw compressors”, VDI 1998. In this case two screw compressors using silencer a...
Conference Paper
Full-text available
In this paper a numerical method for prediction and analysis of oil-free and oil-flooded screw compressor performance is presented. The model includes inlet and discharge dynamics, leakage throughout the machine, and the thermodynamics within the thread volumes and leakage paths.

Questions

Questions (11)

Projects

Projects (2)
Project
Looking for how different parameters effect the performance of an ORC-system using a Twin Screw Expander. System using low Brine temperatures are most interesting.
Project
The aim is to get an understanding of the thermodynamic behaviour of twin screw expanders operating with a two-phase working medium at the inlet.