heat transfer

  1. E

    A mathematical model for natural cooling of a cup of tea/coffee/ etc.

    hello I have some problem modeling an approximate model of natural cooling of a cup of tea/coffee left in a closed and controlled room. I attached a detailed PDF document (called 01.10.19) that describes all the details regarding the questions I am going to ask below. 1st questions...
  2. S

    Time required to cool an object using a fan

    Hello, A flat object with a known surface area is at a temperature of 285F. The ambient temperature in the room is 80F. The object needs to be cooled down to 100F within a time limit of 5 minutes. To accelerate the heat transfer process, there is a fan in the setup. The objective is to...
  3. E

    Calculate the time it takes for river gravel to take on the same temperature as the a

    Heres the scenario: Water level drops in a river. The previously saturated gravel slowly takes on the same temperature as the air. Assuming the gravel was originally the same temperature as the water, and the surface is flat, How long does it take? I believe these are the relevant formulas...
  4. C

    project research

    Hi guys, I am taking a class about heat transfer this semester. (physics is not my major) I found this equation in my textbook. has anyone encountered this equation before? This is the energy differential equation through a rectangular tube...
  5. S

    Transient Heat loss problem

    I am working on a project where I have to calculate the energy/heat loss over a period of time of a box filled with warm water. Normally I would use the following formula: T=Tamb+(Ti-Tamb)e^((alpha*As*t)/(m*c)) Where: T = Temperature after x amount of time Tamb = Temperature of surroundings...
  6. W

    Which transfers more heat as a whole in the universe?

    Which transfers more heat as a whole in the universe? Conduction vs radiation The most obvious guess is radiation due to stars. Conduction seems to be considered negligible in stars but I've only read that in the context of energy transport to the surface and not necessarily just back and...
  7. J

    Heat pipe solar collector modelling

    I am an engineering student reading for an M.Sc. degree by research. As part of my studies, I am working on a project which regards data monitoring and control of solar cooling systems for industrial wine production. The project deals with two different, independent cooling systems. One...
  8. B

    Thermodynamics Problem

    So I got some homework from a past paper and for the most part I was doing good until I came upon the first question in section B. The work is not graded but he says it will really help on the finals, he stressed on the really so I am taking it as a hint. Attached are pictures of the question...
  9. C

    The role of the principle of least action in heat transfer and fluid motion

    When the principle of least action is discussed, Fermat's Principle is usually used as an example. This is probably a really novice question, but could it be said (at least on a macro level) that heat transfer and the motion of fluids is also governed by the least action principle?
  10. C

    Heat flux on a cylinder

    Hi! I'm used to problems which ask me to find the heat flux for when, for example I have a very long cylinder covered with an insulator, each with their respective thermal conductivity coefficient. I'd use the Fourier's formula. But now I have a situation where the cylinder is covered with two...
  11. K

    Question about thermal conductivity

    Hi. I have a bit of trouble understanding the logic behind a principle written in my physics textbook. The situation in question concerns heat being transferred through a two-layered wall consisting of insulation and plywood, and the insulation is thicker than the plywood. The temperature...
  12. P

    Heat Help!

    So here is the question: A 50-g chunk of silver (c=0.056 cal/g/C*) at 130 *C is placed in 200 g of water at 2*C. Ignore heat flows between this system and its surroundings. Describe and calculate heat flows within the system. Calculate the final temperature of the system. I have described the...
  13. L

    who lives in England and did AQA GCSE ?

    loft insulation - stops conduction cavity wall - stops both condeuction and convection double glazing - stops both condeuction and convection foil behind radiator - stops radiation is this correct ??? i'm confused