Questions related to Applied Thermodynamics
Remark_1: science is not only about publishing papers dealing with problems that are acceptable (well seeing) by the "normal" academic canon or, on the other hand, with problems that are, relatively speaking, much easier to solve or, at least, it is not highly complicated to try to "solve".
Remark_2: scientists from the developing world, regardless the discipline, might start thinking farther on what does the "hard" Sustainable Development (SD) version mean for their countries, and how bad is to replicate (to support) discourses that comes from communities (whether interested stakeholders, nations, international organizations, think-tanks...) that want to keep the high rates of economic growth regardless any physical, ecological, and climate-based constraints. Much to my regret, there is a concerning amount of advocates to such an approach (outer-space mining) in Latin America as a whole... We need to rethink what development is all about and what will be the fate of the Latin American nations under such sustained trend of a lack of governance of the outer space domain.
- Is it really necessary to go far beyond Earth atmosphere to carry out very risky outer-space mining activities...?
- Why specific sectors are pushing for investing in the outer space mining when it is highly visible and measurable (at naked eye) the amount of thrash that it is piling up and surrounding all cities in the world...?
- What about the amount of metal, plastic and other "strategic" material (including wood/timber) that should be recycled at great scale in all continents and regions in the planet...?
- What education policies should transfer the current effort aimed at funding already useless careers and titles to empower the next generation of skilled workers, technicians, and experts in recycling al at levels of the society....? What impede that transformations in the labor force worldwide...?
- To the fans and advocates of the circular economy scheme: (1) have you already thought about the huge amount of energy that would be required for such a large-scale recycling (The thermodynamics laws always will matter despite economics could claim)...? (2) Shouldn't be a maximum number of human population that make circular economy feasible...? (Human population trends) are not in the equations of the hard SD version). (3) Do we (humans) have time for a step-by-step circular economy development (more action and less "floppy" business papers)...?
As I have pointed out in all my questions, the 2030 SDGs agenda is already compromised and no major advancement is being achieved regarding the speeding up overlapping and non-linear climate and Earth's ecology breakdowns, therefore, why humanity should embark in another wishful-thinking reckless economic push within the "New Space Economy"...?
As we keep trying to keep humans outside the equations..., all what be published regarding sustainability (science), governance, and the so-called cutting-edge research on Climate Policies and Action will be just a futile act of absolute incompleteness and despair.
Thus, I call scholars from all the disciplines to carry out their major effort in adding the humans into their equations (schemes, models) and start writing as we are the root of the current problems , but also the solutions to those human-sparked messes... A major shift must be empowered in the way science is made... Science has being under crisis for twenty years or so... We all know by 2000 the problem will be greater and will advance faster than our potential response as a species... All has been an unprecedented large-scale denial...
Willing to interact to write more realistic (with policy implications) papers and for teaming (network-building) in searching for implementing sound "cutting-edge" research proposals whenever funds will be available.
Hernan L. Villagran
I have implemented in Matlab a code that calculates the excess Gibbs energy for a given compound in a mixture.
The goal would be to compute the binodal curve for an ATPS system, by equaling the chemical potential of each component (3 in total) in the hypothetical top and bottom phases.
I did this by using fmincon. I fixed the polymer (PEG) concentration on the top phase and then 5 equations were solved to obtain the other 5 variables:
Sum of volume fraction top phase = Sum of volume fraction bottom phase = 1
Chemical potential i top = Chemical potential i bottom
However, every time the algorithm is run, different solutions are obtained and I think it's due to the high nonlinearity of this problem. Could you provide me a better strategy to obtain the binodal curve?
It is known that the surface/interfacial tension tension can be measured by pendant drop method and the following equation: IFT=deltaro*g*de^2/H. 1/H is function of ds/de (1/H=f(ds/de)). I used this function for 1/H and it is okay for gas/liquid systems. When I used this this function for liquid-liquid mixtures, such as water-hexane (T=298.15 K and P=1 bar), it does not answer. Is 1/H different for liquid-liquid mixtures?
When studying statistical mechanics for the first time (about 5 decades ago) I learned an interesting postulate of equilibrium statistical mechanics which is: "The probability of a system being in a given state is the same for all states having the same energy." But I ask: "Why energy instead of some other quantity". When I was learning this topic I was under the impression that the postulates of equilibrium statistical mechanics should be derivable from more fundamental laws of physics (that I supposedly had already learned before studying this topic) but the problem is that nobody has figured out how to do that derivation yet. If somebody figures out how to derive the postulates from more fundamental laws, we will have an answer to the question "Why energy instead of some other quantity." Until somebody figures out how to do that, we have to accept the postulate as a postulate instead of a derived conclusion. The question that I am asking 5 decades later is, has somebody figured it out yet? I'm not an expert on statistical mechanics so I hope that answers can be simple enough to be understood by people that are not experts.
I need critical heat flux databases for water . Could anyone please recommend any CHF data of water . because i have tried to look for them but i couldn't reach any of them. All I have found was some data plotted in a graph form . I need such points references (values mentioned in table form )
thank you in advance
In theory, martensite (a titanium alloy) begins to form at temperatures ranging from 575 oC to 800 oC. This wide range of temperature reports creates ambiguity in the descriptive analysis of the related phenomena. Therefore, how do you determine martensite start alloy using experimental work (in this case with DSC analysis) and what is the theory behind these determination temperatures?
My reseacrh area is absorbtion refrigeration system with nanofluid. I know how can I calculate the performance parameters of NH3-WATER and LiBr-WATER as a base fluid. But the thing is, how can I integrate the nanoparticles to basefluid to calculate the performance parameters theoretically using Engineering Equation Solver ? I found some articles but they were useless. After adding nanoparticles to base fluid to make a nanofluid, how can I calculate entalphy, entropy, mass flow rate, COP, circulation ratio, variation of rich and poor concentrations, condenser and absorber capacity ?
In the optimization of gas turbine cycle, many researchers have used isentropic efficiency of gas turbine and air compressor as decision variables. Even I did the same. But recently while submitting a paper I got one comment from the reviewer which really made me think.
The reviewer comment:
"AC and GT isentropic efficiency are used as optimization parameters. Are these easily controllable metrics? The other metrics (pressure ratio and temperatures) are but I wonder about the isentropic efficiencies."
How should I justify?
I am looking for appropriate research on the process of matching the turbocharger to marine diesel engines. If you know relevant references, books and articles in this field, I will appreciate introducing them to me. Thanks.
Where can I find the publication "The theory of moving sources of heat and its application to metal treatments Trans"?
I designed a single effect absorption cooling system working with LiBr/H2O in Aspen Plus software. But the exergy flow rates don't seem right. For example, when I try to find the exergy destruction of the pump (and other components), the result is negative. What is the reason of this? My reference conditions are 25 oC and 101.325 kPa.
This refers to the smooth, labyrinth, honeycomb and brush seals used in steam turbines. If you know some more types, information is also welcome.
Hi, I have three constructs of my target protein that I am trying to characterize based on their Thermal Stability. Interestingly, I do not see much of Tm changes except an extra transition peak between them however, I see much of deltaH variability. Does anyone has similar experience?
Hello dear friends
Kindly I am studying cost variations versus entropy generation for a CCHP system including prime mover, absorption chiller and borehole. There are entropy generation for chiller and entropy generation number(non-dimensional form of entropy generation(EGN)) for borehole. These two criteria are positive and independent each other. Can I study cost variations (vertical axis) versus S+EGN (horizontal axis) in which "S" is chiller entropy generation? Or the S and EGN should be in a same dimension.
Is there a good heuristic to set the volume interval to calculate pressure along an isotherm? I mean I would like to have a plot that will cover the sub-cooled liquid- two phase region - and super-heated vapor region with good presentation rather than trying to fix the axis limit manually.
The other question is that when using cubic equations of state the pressure inside the two phase region may go below zero. Is there a way to avoid this negative pressure?
Earth's atmospheric temperature is increasing faster than climate change models predict. Heat from anthropogenic friction may explain this observation. Conservation of energy dictates that energy used to propel and stop vehicles eventually becomes heat. This previously unacknowledged heat emanates in part from vehicular boundary layer aerodynamics and braking systems. The number of aircraft and ground-based vehicles in use suggests anthropogenic frictional heat may be a significant contributor to global warming. These observations support much wider use of regenerative braking systems.
I want a cost function about thermoeconomic analysis of a pre-burner or fuel-rich combustion chamber. I would appreciate sharing it.
In case of electron plasma waves we consider adiabatic compression and take gamma equal to 3 [using equation (2+N)/N]. what do we mean by adiabatic compression here?I mean physical significance.
and in case of ion waves we take gamma equal to 1. here we consider isothermal phenomena.
Please explain this in detail.
with kind regards,
I need thermophysical and electrical oil properties to investigation of DC discharge in oil.
Are multicomponent mixture models effective and precise in such calculations? If yes, what MC-modells can You suggest?
Can somebody advice something?
Thank you a lot in advance!
Basically, it's a cylindrical tube of steel with inlet temperature of milk at 4 degrees Celsius and the outlet temperature would be 72 degrees Celsius. The mass flow rate is 1 Kg/s while the length and diameter of the tube are to be chosen, and the heat energy requirement to fulfill the above conditions is to be found.
Can someone guide me how to proceed. What is the relationship to be used, which would include these parameters, length and diameter of the Tube and the uniform heat energy supplied to the tube to make the temperature reach 72 degrees at the outlet, from the 4 degrees inlet temperature?
there is a formula but asks for hydrogen and water content in the fuel, which is hard to find hydrogen contents in that fuel thank you.
these are my fuels 2-Butoxyethanol, Diethyl ether and Ethylene glycol
Why is the enthalpy and entropy values of aspen plus different from engineering equation solver? Are there any conversion methods?
I have completed uncertainty analysis for my heat exchanger calorimetric lab.but I am not sure the calculation of enthalpy ( it is required for Q=mr*deltaH) due to ref.prop program. Normally my main equation is U=cv*dT+P*v and I have calculated uncertainity according to temperature and pressure sensor and I admitted constant the value of specific heat and specific weight but these values have a uncertainty due to Refprop uncertanities. I am not sure whether to add this uncertainty. I would like to learn your opinions and advices.
I need the following tutorial zip files to learn the basics of the software:
- Using sliding and dynamic meshes
- Modeling solidification
- Using the Eulerian Granular Multiphase Model with heat transfer
- Using the Adjoint Solver – 2D Laminar Flow Past a Cylinder
- Simulating a Single Battery Cell Using the MSMD Battery Model
- Simulating a 1P3S Battery Pack Using the MSMD Battery Model
I'm using OpenFOAM to run a CFD study of thermal comfort within a hall. I'm using OpenFOAM v1912 and BouyantBoussinesq(Simple&Pimple)Foam solver. eI have 6 inlets and outlets each with specific flow rates. I specified the flow rates accordingly at the inlet using flowrateinletvelocity BC and at the outlet using flowrateouletvelocity BC. Based on the height, I computed (p-rgh)/rho and fixed it at one of the outlets.
My mesh quality is good (Non-Orthogonality less than 50). The dimension of my hall is 30m *30m *4.5m. It was okay so far when I was doing the simulation for small halls, but I'm facing this problem at the moment.
This happens each time I start the simulation, at the beginning of iterations, p rgh iteration (1st step) reaches 1000 or 2000. The final residual is very high (greater than zero). After the cumulative value (continuity error) begins to rise and becomes greater than 1. The value of Pressure ranges from 1e18 to -1e18 (Two extreme values) even after after 1 or 2 time steps, then the simulation blows off.
I have tried the following options
2)Mesh quality check
3)Defining pressure at all the outlets
4)Using prefcell and prefpoint in fvsolutions to define the pressure in fvsolutions.(if I use this I get continuity error at the start of simulation)
5)Both steady state and transient analysis
6) keeping URF very low and also reltor for pressure to 0.0 in fvsolutions
7)first order and 2nd order fvschemes
7)nNonOrthogonal correction raised to 20.
8) I have turned off turbulence.
9)simplifying the geometry.
I am trying to model a single-effect absorption refrigeration system using LiBr/H2O in Aspen Plus. Who can help me model the absorption cooling system? Please send a private message.
How can I define the following mixture in Aspen Plus:
If you know, could you please explain step by step via some screenshots from Aspen Plus ?
This is a isothermal process , So I need to If the compression ratio of a reciprocal compressor is 4.5, how many compressors are
needed in series to compress air in the cavern?
Although there are already studies in the literature but not much , the use of potassium formate/water or potassium formate+LiBr/Water are not available in the commercial sector for absorption refrigeration systems? what is the actual reason ?
I am looking for a formula to calculate specific temperature drop in duct based on airflow, knowing the specific power loss, airflow, thermal properties of the duct, and air temperatures. The goal is to be able to produce the graph attached.
How to retrieve thermodynamic description for a phase, which is not included in the mobility database in DICTRA? I need thermodynamic description for the phases including Mg2Si, alpha-AlFeSi, beta-AlFeSi, and Al18Fe2Mg7Si10.
I need to calculate exhaust gas temperature at the engine exhaust valve outlet theoretically since I do not have teh luxury to calculate it using EGT thermocouple sensor. Any research references/equations will be helpful.
I am simulating gas flow from a high-pressure (700 bar) to a low-pressure container as shown in the attached figure. The red curve shows the pressure curve obtained from the testing, while the blue curve shows the pressure curve of the lo-pressure container. I tried to change parameters and simulate, but still I end up getting more or less linear pressure curve from the simulation. I am unable to understand the root cause for the deviation.
2. After 30 to 35 ms the pressure of high-pressure container has to be 300 - 400 bar from the testing. In simulation it reduces just to 630 bar which is not acceptable.
Mass Flow Rate (MFR) has to be close to 500 g/s . This value is matches with the simulation. Only pressure behaviour is not matching.
Please find attached image for the simulation and problem details.
Any lead on suggestions are highly appreciated.
Many thanks in advance.
I am looking for paint or in an extreme case a coating material on inAtmosphere flying object to reduce the heat dissipation caused by aerodynamic heating for a relatively longer period, considering the speed range of upper hypersonic range.
I am working on calculating the exhaust temperature in the upstream and downstream section of an IC engine catalytic converter. Please share any methodology or research article to corroborate your response.
probably it is a silly question.
I need to create a solution with a fixed quantities of N, P, K starting from different sources: NH4NO3, (NH4)3PO4, KNO3.
Namely, I have to reach the concentration 4,28M for N, 0,846M for P and 1,275M for K.
I am starting my calculation, but I suppose that I need partial volume tables of this system to take account volume variation during the mixing.
Apparently it is a silly exercise but when we analyze our solution we observed strong deviation from the ideal solution.
As anyone performs this kind of solution? It is the creation of "liquid fertilizer" from solid ones. I want to generalize this calculation to different concentration to implement in a project that I follow.
For calculating packing area, packing height and volumetric heat transfer coefficient is necessary. In my case study, I have the information of packing height in my hand. But I am looking toward to get the specific method to calculate volumetric heat transfer coefficient or get the data of volumetric heat transfer coefficient for Natural draft cooling tower.
Please don't answer because U(T,V) don't have S entropy as argument!!!!!!
May I ask a question on thermodynamic? We know that U(V,T) (caloric eq. of state) and S(P,V) (thermodynamic eq of state) can both be derived from thermodynamic potentials (U F G H) and the fundamental relations. However, U(V,T) doesn't hold full thermodynamic info of the system as U(S,V) does, yet S(P,V) also holds full thermodynamic info of the system.
In which step in derivation to get U(T,V) from U(S,V) lost the thermodynamic info? (the derivation is briefly：1. derive U=TdS+ PdV on V, 2. replace the derivative using Maxwell eq. and 3. finally substitute ideal gas eq or van der waal eq)
Why the similar derivation to get S(P,V) retain full thermodynamic info?
Even if we only have U(T,V), can't we get P using ideal gas eq, then calculate the S by designing reversible processes from (P0,V0,T0) to (P',V',T')? If we can still get S, why U(T,V) doesn't have full thermodynamic info?
The Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by others in the 1830s and 1840s. It can be shown that it is the most efficient cycle for converting a given amount of thermal energy into work, or conversely, creating a temperature difference (e.g. refrigeration) by doing a given amount of work.One of the great virtues of the Carnot cycle is its potential applicability to any working substance.The Carnot cycle for a photon gas provides a very useful tool to illustrate the thermodynamics laws and it is possible to use for introducing the concepts of creation and annihilation of photons in an introductory course of physics.
What is the thermal conductivity value of graphite in the xy plane? I've seen several papers with different values so is it 100s or 1000s at room T?
Hello to all:
I'm trying to think in the following interesting problem:
I have a system which are polycrystals (grains) of Bi2Te3 (actually this compound is a quaternary alloy of Bi, Te, Se and Sb). The grains ended coated with Carbon, in the form of Graphene Nanoplatelets: a stack of several (or could be many) Graphene single Layers.
Does anyone know, have experience or have literature references about the following questions:
1. How an increment in temperature will affect the Chemical Stability of the Bi2Te3-alloy ? for two scenarios:
i. A normal day-to-day working temperature between 10 °C - 37 °C
ii. Or in the scenario reaching the 100°C
And second. The same question but for the aging of the device, rather than the stability in function of the temperature.
or for both conditions for the matter of the subject.
If someone can comment something about, I'll appreciate it !
Best Regards !
Dear Colleagues :
Does anyone have literature referencing the diffusion process of Carbon (I mean Carbon atoms) into Bismuth Telluride (Bi2Te3) or into some other compound alike ? E.g. PbTe, (Sb,Se)Bi2Te3, Sb2Te3, etc ... ?
I'll really appreciate if someone can help me out
Kind Regards Sirs !
A mixture of gases 11% CO2 - 89 % N2 (molar) at a temperature of 300 °C and total pressure of 1400 psi. ¿CO2 and N2 at these conditions are in the gas phase or in supercritical state? I mean, ¿what is the pressure to determine the behavior of each component (CO2, N2)?
I am working on absorption refrigeration system using LİCl-H2O. I used state points of a article. I confronted a problem using Engineering Equation Solver (EES). Error showed by EES: This equation attempts to raise a negative number to a non-integer power.How can it be fixed ?
I wish to understand how to integrate Yokozeki Equation of state for solids or any cubic equation of state in order to derive the fugacity expression for a pure component or mixture.
If I want to calculate the energy use of an AHU fan, knowing the maximum airflow, fan efficiency, and static pressure, what would be the most accurate way?
We all know thermal conductivity / diffusivity of solids (metals, insulators, semiconductors) is a function of temperature. However, does it depend on mechanical stress, e.g. uniaxial? Has someone ever measured this?
UPD: I have actually just seen some papers on the stress dependence of thermal conductivity in semiconductors (e.g. Ramdane, A., Salce, B., & Challis, L. J. (1983). Stress dependence of the thermal conductivity of Cr-doped GaAs. Physical Review B, 27(4), 2554.); I think it's more or less clear that stress changes the density of electrons in the conduction band and hence the effect. However, it's not clear to me whether there is any effect of stress on the thermal conductivity of metals where the electron density is much greater than for semiconductors and the Fermi surface is simply spherical. Any thoughts on this?
I am fabricating magnesium composite by reinforcing alumina nanoparticles. in this connection, I want to estimate the shooting temperature (temperature rise) while incorporating the ceramic particles in magnesium at molten state. I am in need of your valuable suggestions.
Thanks in advance.
I am trying to use my code in EES software and link it with Matlab to do multi-objective optimization without rewriting the code again. Does anyone know any methods or approaches?
I have a solar field. and I have a system.
I want my system to work in a steady state condition, but the nature and the base of solar energy is intermittent.
How can I use solar energy as a non-intermittent source? What system do I need between my solar collector and my system?
For instance, consider the following example: Solar field+ORC cycle 1 kW electricity is needed in a steady state way, but solar energy is not steady-state. What system is required between the solar field and the ORC cycle?
*I know that I should use a TES, but which one is good for this purpose?
I've seen the Modified Arrhenius equation in several forms. For instance, three kinds are attached.
Please consider the first attachment. There is an activation energy (Er). In some cases, authors do not use this form and they use the form just like two other form (see ar-2 and ar-3). They use "thetha" or "Tar". Now, I need to calculate Er from thetha/Tar. I think I have to multiply thetha or Tar by R. Am I right? R is universal gas constant and here its unit here is J/kgmol-K. I guess it should be 8314. Am I right?
I'm working on a project that uses some waste heat to provide the motive steam for multi-effect desalination with the thermal compressor.
Pressure, Temperature, and flow rate of the motive steam are known. I need to calculate the amount of salt-free water and detailed state of the effects.
I would appreciate if anyone can help me with Matlab or EES code.
Let's say I have a material with a stable phase A that transitions to another stable phase B at temperature T. If the material also has a metastable phase A', I know that if I cool B fast enough I would get:
B -> A'
and if I cool very slowly I'd get
If I were to look at the interface between B and the new phase and somehow extract all possible information (energy/mass transfer, etc), what signal would indicate to me that I would expect A' (metastable) to form over A?
I have seen phase separation as a phenomenon taking place.However I do not understand why this phenomenon occurs as a counter example to the natural laws of diffusion along the concentration gradient.During phase separation the richer side becomes richer with the atoms which it already has and becomes more and more deficient with the poorer atoms and vice-versa.Similar things will occur in the opposite case as well.Now please give me an insight to this phenomenon with close reference to factors like Chemical Potential etc.
I am looking for binary diffusion coefficients of water vapour in air at normal pressure for various water/air temperatures. I found the following relation
Diff (T) = 22.5*10-6 (T/273.15K)1.8 [m2/s]
However, no reference is given, where it comes from. Do you have an equation or coefficients in tabular format or a reference for the formula shown above?
Hi again, while working on the carbon capture methods from a renewable energy project, i realized that thermodynamics has somewhat of a huge role to play when discussing gaseous capture, what are some of the available methods such as OxyFuel where co2 and o2 can be captured however but aren't energy intensive or are very low energy requiring methods?
This is in continuation of previous question wherein I had asked about applications of near-critical fluids. Most of the applications suggested to me were pertaining to chemical extraction, drying etc.
Does any one know about applications of these fluids space technology. Are there any applications which involve movement of these fluids from sub-critical to super-critical state?
I am looking for material which can replace aluminium in aerospace industry as i want material which will be having high melting point and must be light in weight. As i am looking at this from commercial point of view so if that material is easily available and cheap then it would be better. Especially Aluminium 7075