# Questions tagged [heat-transfer]

Questions relating to the transfer of heat via the mechanism of convection, conduction, or radiation, in forms of systems (or your device) attempting to obtain thermodynamic equilibrium with another system (the environment or your other device)

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### How to solve transient heat conduction equation at a point in space with volumetric heat source?

My system is a fluid exposed to light and I want to calculate the temperature change with time at a point, hence there are no spatial effects or convection due to the flow of the fluid. The heat ...
1 vote
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### Can pyrolytic graphite sheets effectively be used as a thermal gap-fill interface?

Pyrolytic graphite sheets are used as a high-performance thermal interface in applications with high power density because they can have a very high conductivity of 1000+ W/mK, but only in the ...
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### What is the quantity of electric energy necessary to cool the water in a tank heated by P = 30 kW?

A pump draws cold water from the reservoir of industrial chiller and pumps it at a flow q in a 5 m3 tank filled with water. The tank has a 30 kW parasitic heat source inside (see Fig. 1). The ...
1 vote
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### What causes water to always drip from an electric furnace when its turned on?

I made an electric furnace as a university project. It can heat up air inside up to 1000 degrees Celsius. It's not fully sealed so some air can escape from small gaps. Not sure if this would cause a ...
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### What is a good way/formula to approximate heat/energy loss of not fully sealed electric oven filled with only air?

I made an electric furnace that consume ~18 kW (3 phase) of power. I want to know how much energy is lost when its used to heat only air. The only sensing tool available as of now are thermocouple ...
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1 vote
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### Heat transfer: does the heat generated in a cable get transferred to the electrical components?

I have a 1000 V, 50 sq mm, double insulated (XLPE) copper conductor cable. This cable is being connected to a power electronic component. The current flowing through it is 230 Amps DC. The cable ...
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### Heat Loss from Domestic Oven Door

Our kitchen electric oven has a large glass door approx 530 x 440mm, overall thickness 35mm. There is a front and back glass pane, no insulation and the air cavity is open at the bottom. I'm wondering ...
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### What is the solutions of the following 1D diffusion equality using Crank–Nicolson method?

Through my research I faced to the following equality and need to find $c_i^{t+1}$. Moreover, I found that it can be solved by Crank–Nicolson method (see here: https://en.wikipedia.org/wiki/Crank%...
1 vote
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### What happens to insulation?

What exactly happens when an insulating material comes in contact with heat through any mode (conduction, convection, or radiation). Something like aluminized mylar will reflect the heat back. How ...
1 vote
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### What materials to use indoors to absorb sunlight and store it as heat?

This is a very practical question; the underlying principles are, I imagine, extremely well-known. I'm buying a new place in the northern hemisphere (49° N) with lots of southern (or rather SES) ...
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1 vote
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### Sun exposure in room as a function of day and time?

Background (may be safely ignored): I am buying (most of) a rowhouse from the 1930s. I am now working with an architect to improve its energy efficiency. Let us focus on the main room, which can be ...
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1 vote
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### Changing temperature under adibiatic conditions?

Can a temperature change be adiabatic? For example if no 'heat' leaves or enters the system and we compress a fluid such that it's temperature changes is this still adiabatic? If energy is transferred ...
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### How do I find the amount of energy needed to evaporate water below its boiling point?

Let's say I have a container filled with water and its surface is in direct contact with air. How much heat/energy do I have to supply to the water such that it evaporates under its boiling point? is ...
1 vote
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### Why heat transfer happens only via conduction in this case?

Why heat transfer between a heated flat plate and a fluid happens via conduction only and not convection, when the fluid is present below it? Consider a plate under which a fluid is present and it ...
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### Heat transfer coefficient in forced convection and its dependence of temperature

I'm working on a Ansys Fluent of an Aluminium coil annealing furnace with the goal of estimating the heat transfer coefficients at different temperatures and ventilator/fan speed conditions. The ...
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### Mean temperature of a fluid in a pipe

Consider a pipe in which a fluid flows such that the pipe is at a higher temperature than the fluid. At any cross section of the pipe we get a varying temperature profile. We can define a mean ...
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### Internal Forced Convection of Water/Air

Should I take the film mean temperature or bulk mean temperature to obtain the water/air properties from the Steam Tables? (In order to calculate Re number - for Petukhov's empirical relation ...
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### Calculate Thermal Conductivity of Layered Structure

I am having a problem determining the thermal conductivity of a layered sample. The sample is made of two materials, one whose thermal conductivity is known (λ-1) and one whose thermal conductivity is ...
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### why the fluidity test for casting is made in spiral shape?

Why fluidity test uses a spiral shape of casting? Is it to reduce the heat transfer? make it compact? Or any other reason?
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### Does forced convection account for energy transfer in this case?

I have to confess that thermodynamics is not a friend of mine. My system consists of a volatile droplet sitting on a thermally conductive substrate. The energy balance comprises heat lost due to ...
1 vote
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### Calculating the difference in heat loss from human body in different environments

I'm interested in personal cooling devices and would like to know if there's a way to make a rough estimate of rate at which you would need to extract heat from the body of an average male walking in ...
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### Thermal Conductivity and Energy gain

I have a two part question: Part 1: I understand thermal conductivity as The measure of a material's ability to allow thermal energy transfer to it, from it and within it via conduction My very first ...
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### Does a higher temperature difference result in a faster rate of heat transfer?

Suppose that I have a thermally insulated tank with hot air at a temperature of 400 C, and the tank is stored in a room with an ambient temperature of 25 C. I also have another identical insulated ...
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