Questions tagged [convection]
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Why do we consider the normal component of velocity in a flux and not the original direction of velocity?
Below is the equation of convective flux of an arbitrary property that is carried by particles. When particles move they carry their property along with them. Given a fixed surface in space, in order ...
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1answer
77 views
How to calculate heat loss across a process pipe with perpendicular air flow
My thermodynamics knowledge is extremely rusty, so I would appreciate some guidance on how to solve this problem.
As illustrated here, I have a process pipe (steel) with a gas flowing through it (blue)...
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1answer
18 views
Empirical correlation for low reynolds convective heat transfer coefficient
I am looking for a heat transfer coefficient for a shape (rectangular cross section preferred, could estimate with flow over flat plates) in 2 m/s cross flow.
I have found a few empirical correlations ...
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1answer
41 views
As a rugged and waterproof device, how does gopro dissipate heat?
I am new to designing rugged + waterproof products. I am curious about how to dissipate heat when the electronics are running and the ambient environment is even hotter. It seems like the mode of heat ...
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Heat Conduction/Convection Along discontinuous tube
I have a question regarding heat conduction/convection. I have a metallic tube over which a rope heater is wound, supplying power. A glass tube and a 2nd metallic tube lies at the exit of the first ...
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2answers
71 views
How to calculate heat and mass transfer rates from an enclosed box?
I'd like to know if it's possible to calculate the heat and mass transfer rates from a small volume to the environment.
Let's assume there is a box with a small opening at the top. The air inside the ...
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1answer
38 views
Heat transfer for a copper rod
For a copper rod heated by a heat gun, why might the temperature of the rod continue to increase for a short time after the heat gun has been removed as the heat source? With reference to transient ...
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1answer
22 views
How to consider the dimension of a cylinder when computing its radiative budget?
I am trying to derive a heat budget model to estimate the temprature of very small a stationary vertical cylinder (1mm) under environmental conditions. Imagine a wooden stick. Simply put, I have
R = ...
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33 views
How to calculate heat transfer between two solids in a medium?
If I have a cuboid block of metal and there is a cylindrical source of heat input (A) and I want to determine the heat energy at B (also cylindrical) how would I do this?
I understand considerations ...
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1answer
84 views
Wire heating and heat transfer in a cylindrical pattern
I have a series of copper coils with ¼” cooling plates between each coil. The cooling plates will be manufactured from aluminum and cooled using copper tubing. There are seven in series, and a plate ...
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1answer
151 views
Heat Transfer in Different Wire Configurations
I am trying to create a program which estimates the final temperature of a magnet made of copper wire. I have different configurations in mind, but I will start off with a straight square wire with a ...
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112 views
Minimum distance between long curtains and radiator for good air flow?
It's a known fact that you cannot place a curtain near a radiator because it will trap hot air behind the curtain and also block cold air from going through the radiator from bellow.
But obviously ...
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1answer
657 views
What is the difference between the wave equation and the advection equation?
I am trying to understand what is the difference between the wave equation ad the advection equation? Bot the equation seems to move a quantity. While in literature it is said that the advection ...
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86 views
Ventilation requirements of a closed housing of a video wall
Our company builds rather large video walls that are driven by computers next to them. In one of our current project the size of the installation is 21 55" displays side by side in portrait mode and 4 ...
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1answer
39 views
convection query
I am attempting some convection analysis for research I am doing. I was wondering someone could kindly confirm whether I am on the right track. The calculation is based up air being passed over a flat ...
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1answer
75 views
Convection Heat Transfer
I am working on a problem at the moment and would appreciate some of your expertise regarding this issue. If you see the image below, I am trying to calculate heat transfer from a fluid entering a ...
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1answer
239 views
Most effective heat transfer in a vertical pipe with small top/bottom temperature difference?
What would be most effective way to transfer heat in the following situation?
Specific conditions: A vertical cylinder or pipe, 30-100cm long, 5-10 cm in diameter, heavily thermally insulated except ...
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273 views
Calculating heat transfer in a cooling loop
Imagine a closed pipe like below, filled with a liquid. The pipe is copper. Then imagine a small point heat source of X watts applied to the outside of the pipe in the position shown. Heat warms the ...
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1answer
157 views
Characteristic dimension for combining free and forced convection?
I have a situation that I have a combination of free and forced convection over a cylinder. Remembering back from heat transfer, to combine these I use the formula
$$Nu_{\mathrm{comb}}^n = Nu_{\...
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1answer
108 views
Can I neglect kinetic energy when modeling convective heat transfer for viscous, low mach airflow? Why or why not?
I'm looking at convective heat transfer for air flow over a solid at Ma=0.2. At this speed, it is plausible to model the flow as incompressible because of small density variations in the air. ...
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1answer
468 views
Convective heat transfer coefficient in finite difference method boundary conditions
Suppose there is a cubic material with an internal heat source ($\Delta q / \Delta t =$ Constant), and is immersed in a sufficiently large amount of water. Now I would like to use finite difference ...
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1answer
217 views
How to determine if mass transfer convection is natural or forced?
I know that forced convection requires some external bulk flow, but is there an equation to determine which form of Convection is dominant? I looked around and found the Richardson number $\mathrm{Ri}=...
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1answer
347 views
Heat transfer characteristics in narrow rectangular channel
Please take a look at following figure:
System considered is a narrow rectangular channel of 2.5 mm depth (W x L is 60 mm x 150 mm). Since channel has low depth, it can be considered as mini-channel. ...
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1answer
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Heat Transfer coefficient calculation for hot air flow inside rectangular duct
I am working on modeling of air-heater component. A simplified representation of system is as follows:
Cold air flow enters steel duct at one end. Inside duct is Calrod heating element shaped as ...
