Read about thermal | 55 Discussions | Page 1

  1. imselva

    Coefficient of Thermal conductivity

    We know that, Conduction Heat Transfer Q = KA(t2-t1)/thickness K is the coefficient of thermal conductivity. If T2 = 1020°C and T1= 22°C also consider we know A and thickness value. K depends on temperature. K varies with temperature. For all the materials we have a tabular data of K for...
  2. imselva

    Radiation Heat transfer

    I have two bodies, one at a higher temperature say 1000°C (Body A) and the other is at 22°C (Body B). Body A emits Radiation (Surface to Surface interaction). The temperature of Body A is maintained by a constant supply of Energy. The Body B will absorb the Radiation Energy from Body A, and its...
  3. I

    Question about thermal physics -- Ice cubes melting in water

    First, I calculated the heat required for the ice to melt: Q=mLf Q=0.150×330 Q=49.5 J Then, I calculated the final temperature of the water by forming the following equation: Q=mcΔT −49.5=(0.15+0.35)×4200×(Tf −80) Tf=80.0 degrees Celcius But the answer says 32 degrees Celsius.
  4. Paper glider rides a thermal!

    Paper glider rides a thermal!

  5. LordGfcd

    I What is the continuity condition for the heat flux through a boundary?

    Assume there is a boundary seperates two medium with different heat conductivity [κ][/1] and [κ][/2]. In one medium, the temperature distribution is [T][/1](r,θ,φ) and on the other medium is [T][/2](r,θ,φ). What is the relationship between [T][/1] and [T][/2] ? Is it - [κ][/1]grad [T][/1]=-...
  6. I

    I Most probable macrostate

    ## \Omega(E_1)## is the number of microstates accessible to a system when it has an energy ##E_1## and ##\Omega(E_2)## is the number of microstates accessible to the system when it has an energy ##E_2##. I understand that each microstate has equal probability of being occupied, but could...
  7. N

    Heating up the Attic

    Hi guys, I am currently exploring dissertation ideas and have been looking into the heat recovery potential from domestic gas boilers and ovens. More specifically, I am seeing if it is viable to collect heat from these appliances during or after their use, and then pump this heat into the attic...
  8. N

    Sophisticated Experiment (Thermal Conductivity of Housing Materials)

    Hi everyone, I am currently a third year University Student in the UK and I'm in the midst of doing my dissertation. My dissertation topic (Effective methods of decreasing the thermal Conductivity of Housing Materials) requires that I produce several experiments to test and analyse a certain...
  9. W

    I Thermal Physics: Reversible processes

    Hi all, I have been having some issues trying to show that a reversible expansion of gas does not create new entropy. Assistance is greatly appreciated! So suppose that a gas expands reversibly as shown below at fixed temperature At fixed temperature, internal energy doesn't change so...
  10. W

    Thermal Physics: Reaction problem

    Homework Statement Hi all, I am having issues with the following problem. Assistance is greatly appreciated! Homework Equations The Attempt at a Solution a) The "law of mass action" I know of is just the equilibrium constant, which I wrote in terms of partial pressures at equiilbrium $$K...
  11. W

    I Thermal Physics: Interpretation of equilibrium constant

    For a reaction defined as such, $$A\rightleftharpoons B$$ the equilibrium constant ##K## is defined by ##K = p_B / p_A##, with ##p## denoting the partial pressure (edit: at equilibrium). However, if ##K<<1##, which implies ##p_A >> p_B##, it is said that the backwards reaction dominates and that...
  12. W

    I Question regarding Blundell: Concepts in Thermal Physics

    Hi all, I have an issue with understanding the following passage in the aforementioned book. I have uploaded the relevant passage as an image below. Any assistance is greatly appreciated! The paragraph under equation (22.57) says that the total Helmholtz function ##F## is a sum of Helmholtz...
  13. W

    I Heat bath and canonical ensembles

    Hi all, I have encountered the idea of a heat bath but am slightly perplexed as to what it is. There was a textbook example that looked to find the number density expression for gas molecules as a function of position (image below). It then said that the probability ##P(z)## of finding the...
  14. D

    Heating efficiency of a Heat Pump and a Space Heater

    Homework Statement Instead of pumping heat into the cabaret air from the outside air, you could simply put an electric space heater inside the cabaret. A space heater turns electrical energy directly into thermal energy. Why would operating a space heater consume more electric power than...
  15. D

    Heating a Cabaret during the winter

    Homework Statement During the winter, your climate control system must begin warming the cabaret air so that the cabaret air is hotter than outdoor air. Amazingly enough, it can do this relatively efficiently by transferring heat from the outside air into the cabaret. However, your system must...
  16. D

    Energy Efficient AC unit by returning air to the building

    Homework Statement You arrange your climate control system so that as it pumps heat out of the cabaret air and thereby chills and dries that air. Part of the heat your system removes from the cabaret air goes to the outdoor air and part goes back to the cabaret air. It turns out that delivering...
  17. D

    Thermal Energy when Heating and Cooling a Cabaret

    Homework Statement Having chilled the air until it contains only the perfect amount of moisture, you want to reheat it to the ideal cabaret temperature. You could use an electric space heater or wood fire, but you already have another source of heat: the same system that chilled the air in the...
  18. D

    Energy in an engine

    Homework Statement You're in Paris, working on your first novel and short on cash. The owner of the cabaret downstairs has offered to take care of your rent if you'll help her design a climate control system for the place. It gets too hot and damp in the summer, and too cold and dry in the...
  19. TheSlovakEngineer

    A Storing Energy as Heat in Vegetable Oil

    Hello, I am writing a blog article about storing solar energy as heat. Can someone credible check this? I calculated I need 185.4 liters of vegetable oil to substitute a 6.4kWh battery if I had the same energy conversion (Tesla says 90%) and energy loss over time (no idea about this value) as...
  20. Cassius1n

    Heat loss in a conductor based on Fourier's law

    Homework Statement Find the admissible current density Jadm for a wire that has no insulation and also for a wire that has two layers of insulation and compare it to Jadm for the case when the wire has only one layer of insulation. 2. The attempt at a solution and equations In the image...
  21. Ricardo Gomes

    ANSYS - Radiation of a satellite - Surface-to-surface or to-ambient

    Hi all, I'm performing a thermal analysis of a satellite subsystem (antenna). However, I'm having some issues relating to the model that I'm implementing on ANSYS. I've already computed the values for the solar flux, albedo and IR that the satellite is subject and I've applied it to different...
  22. Jo MacDonald

    Thermal Expansion of Air

    We did an activity today in class where we placed an empty 2L bottle in the Freezer, let it contract, then calculated the coeffcient of volumetric expansion using ΔV = VoβΔT. We got pretty close to the accepted value. The question is..... Does the coefficient of thermal expansion only work for...
  23. W

    Partial Pressures and Vapour Pressure

    Homework Statement Two systems in diffusive equilibrium have equal chemical potentials. We can use this fact to solve the following problem. We begin with a closed system consisting of a liquid such as water in diffusive equilibrium with its vapour. At the start, only the liquid and its vapour...
  24. W

    Multiplicity/Probability: Einstein model of Solids

    Homework Statement I'm having some trouble with this problem as it seems my concept of the problem is completely wrong. Could someone look through my solutions and point out what I understood wrongly? Thanks in advance. Homework Equations The Attempt at a Solution a) 21 macrostates -...
  25. Leo_lee

    Calculate the volume of 1.00 mol of liquid water

    Homework Statement Calculate the volume of 1.00 mol of liquid water at 20°C (at which its density is 998 kg>m3),and compare that with the volume occupied by 1.00 mol of water at the critical point, which is 56 * 10-6 m3. Water has a molar mass of 18.0 g>mol. Full answer please! Thanks...
  26. W

    Fourier Conduction Law

    Homework Statement The question below is asking how long it would take for the cooler side of the handle to heat up till its unbearably hot. I'm having a bit of trouble trying to understand the solution and would like some guidance. I can't seem to get how the ##\Delta T ## that represents...
  27. W

    Thermodynamic Identity: Chemical Potential

    Homework Statement Homework Equations Thermodynamic Identity The Attempt at a Solution While I was able to work out the problem with the help of the hint, I couldn't completely understand the implication of said hint. The hint suggests that the equations for Chemical Potential in a process...
  28. W

    Thermal Physics: Thermodynamic Identity

    Homework Statement Homework Equations ##dS = \frac{1}{T} (dU - PdV)## assuming dN = 0 The Attempt at a Solution I have actually managed to solve all 4 parts correctly, except for the fact that I solved Part d) with the Sackur-Tetrode equation rather than the thermodynamic identity. I...
  29. R

    Magnetic conductive material but thermally non conductive

    HI, I have application where i need to lift metal plate, 3kg weight, ( 3mmX 15mm), 250degree.C hot, for the period of 1min and put it back. For lifting purpose i am using actuators. As i have no opportunity to make hole in plate i have to use magnet for lifting purpose. I got Electromagnet...
  30. W

    Thermal Physics: Freezing Lake

    Homework Statement Homework Equations dQ/dt = -kA(dT/dx) The Attempt at a Solution I tried to use Fourier's law of Conduction on this one. I subbed dT for (Θ0 - Θ1), and l(t) (function for thickness of ice against time) for dx, reason being that the sheet of ice should get thicker. I then...
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