Questions tagged [heat-conduction]

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Equation for simultaneous cooling and conduction

Imagine a long, uniform metal rod placed on the positive $x$-axis being heated with a power $P$ from its end at $x=0$. It is cylindrical in shape and the cross-section is a circle of radius $r$. ...
4answers
283 views

What is heat and heat transfer?

Physics books write that heat is the transfer of thermal energy. They also write that heat transfer is the transfer of thermal energy from a thermodynamic system of high temperature to a one of lower ...
1answer
342 views

How to develop a model for cooling rate of steel tube in air?

I am trying to develop an equation to determine the cooling rate of a steel tube in air. I'm using Fourier's Law, Stefan-Boltzman Law, Newton's Law as well as the specific heat capacity equation. The ...
1answer
474 views

Microscopic level - What happen to the particles in a heat transfer through conduction?

So on a macroscopic level, there is physical contact and the heat energy is being transferred from the higher temp. to lower temp. But what about in a microscopic level, what's going on? As far as I ...
2answers
61 views

Which heat equation should I choose if I want to toggle between conductive and convective heat transfer?

I have a science project where I have an aluminum cylinder, filled with oil, with a diode chain floating inside of it. The diode chain has a bimetallic temperature switch on it that turns off the ...
1answer
829 views

Calculating rate of heat loss through conduction and radiation

Calculate the rate at which a hollow cylinder with a heating element inside will lose heat, specifically through both conduction and radiation. My goal is to find the temperature inside this cylinder....
1answer
22 views

Will a measured “temperature above ambient” remain constant in the face of a changing ambient temperature?

I've got some fully-enclosed, outdoor brass landscape light fixtures. I chose a (12V) bulb that, when measured with a benchtop power supply, dissipates a constant 0.8W. On a cool, windless night, ...
0answers
26 views

Is heat conduction the dominant form of heat transfer in metals? [closed]

I need to perform a thermal analysis on the metal. A metal placed in the air is brought into contact with a heat source and the temperature change is observed. In this case, which of "heat ...
0answers
38 views

Thermal contraction for cooling

I've calculated by separation of variables function of temperature $T(x,y,z,t)$ for a cooling cube. I wanted to know how much the cube will contract in one dimension after 10 second of cooling, during ...
1answer
27 views

What is the temperature profile of hot and cold fluids for a double pipe parallel flow heat exchanger?

In books, they just mention the temperature profile is exponential. Can someone help me come up with the exact temperature profile (the relation) for the hot and cold fluids in a double pipe parallel ...
1answer
47 views

Is it wrong to derive Log mean temperature difference (LMTD) of a Heat Exchanger, this way?

I tried deriving the LMTD of a parallel flow double pipe heat exchanger by first finding the temperature profiles of the hot and cold fluid and then averaging them over the entire length of the Heat ...
0answers
31 views

Could this imaginary cooling solution work?

Imagine a perfectly insulated ideal closed cylinder. Inside, at the two ends there are two bodies, one with the temperature of T the other with temperature -T. Between the almost touching bodies with ...
0answers
15 views

Why doesn't ice in a glacier feel as cold when I touch it as the ice I get from my freezer?

When I was in Iceland, I went to a tour in a glacier and I remember the ice that was there. It looked and felt like a huge amorphous block of glass: hard, smooth, not wet, and not that cold. Not as ...
0answers
27 views

Why does bologna inflate radially when on stove?

I noticed that when heating up bologna in any way it inflates at the center, while other stuff tends to let the air escape sideways, or inflates in different places, like an egg or sausage. Nothing so ...
0answers
27 views

Through which medium is most of the heat transferred down (downwards) a glass tube filled with water: the glass walls or the water column?

If a much hotter object is attached to the tube from the outside, and the heat in question is transferred to the part of the tube that is below the source of heat, so there is no convection. ¨ The ...
1answer
39 views

What is the difference between rate of cooling and rate of heat loss?

I had a perception that rate of cooling and rate of heat loss are synonymous because the rate at which it looses heat indicates the rate at which it is cooling but this question changed my view There ...
1answer
32 views

Steady State conduction of cylindrical pipeline

I have this problem involving conduction of heat: Suppose that $z = 0$ represents the ground level on a street where an electric cable is buried at $x = 0$ and $z = −D$. The ground is kept at a fixed ...
0answers
29 views

Condensation of saturated vapor on subcooled droplet

Consider the process of condensation of vapor on falling subcooled droplet in the stagnant saturated vapor (neglect the vapor drag on droplet). What can be said about the relation between the droplet ...
0answers
50 views

How does the change in temperature of water in a tube depend on the angle that the tube makes with the gravitational field/the horizontal?

Let's imagine a tube that is open at one end and is filled with water. A constant source of heat is applied to a specific spot somewhere at the middle of the tube, for a example a preheated soldering ...
0answers
67 views

1answer
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How do I convert $W/(mK)$, $W/m^2$ and $W/(m^2K)$ to the same “dimensionality” and unit?

How do I convert $W/(mK)$, $W/m^2$ and $W/(m^2K)$ to the same "dimensionality" and unit? $W/(mK)$ is thermal conductivity. $W/m^2$ is heat flow density related to one unit. $W/(m^2K)$ is the ...
2answers
40 views

Will “stationary” air sorrounding a hot pipe from a wood stove act as insulation with a given time?

The inner pipe (colored in red) radiates considerable more heat than the current one so I'm planning on extending the more thermally conductive one so that it heats better. Will removing the outer ...
2answers
172 views

Should I walk or run to my towel when naked and wet? [closed]

This morning when I got out of the shower, I realised I had left my towel in the bedroom. Naked and wet I ran as fast as I could to get the towel. On my way back I didn't run, but rather walked, and ...
1answer
14 views

Will the temperature reading of a thermostat change as a result of direct skin contact? [closed]

If I was to place my hand on a thermostat for an extended period of time, would this eventually result in the temperature reading rising after a period of time - or would the reading not be impacted ...