The convection tag has no wiki summary.
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What happens to pipe outlet temperature here?
I have a fluid flowing through a pipe in the ocean and there is heat transfer from the ocean to the fluid in the pipe. I prepared a simulation and the results show that if I increase the mass flow ...
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Calculating the Heat Losses of Convection and Radiation [closed]
A water pipe for central heating with length $L=10m$ and diameter $25 mm$ is running over a cold attic with $T_{air} = 278 K$. The radiation temperature of the surroundings is usually lower than the ...
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2answers
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Is it cheaper to boil water on high gas heat or low gas heat?
Assume my time value is \$0. High gas heat adds more energy per second to the water but the pot may absorb the heat less efficiently, or maybe the shape of the flame is less good, or for other reasons ...
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3answers
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What's the physical difference between a convective heater and an infrared heater?
Could someone please explain why there are 2 types of space heaters-- one that is convective and one that is infrared? Why does the first one not radiate and why does the second one not heat the air?
...
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1answer
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Rayleigh-Benard Convection
I found this nice paper about RB convection. However I am confused by what is going on page 6. In particular why we are suddenly using Helmholtz equation to find spatially periodic solutions. Aren't ...
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What is the characteristic length of a cylinder
I have a cold cylinder that is submerged in hot water and I need to find the convective heat transfer coefficient. I can do the whole process but I am stuck finding the characteristic length. I found ...
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1answer
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Boussinesq approximation for the Navier Stokes' equation - discrepancy
In the Navier Stokes' equation:
$\rho_0 \left( \frac{\partial v}{\partial t} + v \cdot \nabla v\right)
= -\nabla p + \mu \nabla^2 v + \hat{f}$
I included the temperature variation of density as ...
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3answers
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What is the microscopic picture for warm air rising?
The usual explanation for warm fluids rising past cooler ones is that the warmer fluid has a lower density. I'm trying to understand what this looks like at a molecular scale. The density seems to ...
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1answer
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What exactly is the difference between advection and convection?
After reading Wikipedia articles on advection and convection, I still cannot determine whether there is a consensus on a difference between these two terms.
Sometimes, the term convection seems to ...
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1answer
257 views
How would I calculate the convection coefficient in transient convection?
So I have faced a problem dealing with transient conduction and I need a little help with the problem solving concepts. I need to determine how long it would take to reach the final temperature but I ...
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2answers
141 views
How would I go about solving this transient convection problem if the mean fluid temperature is constantly changing?
Let's say I have a ceramic slab on a conveyor belt that is initially at $450\,^{\circ}\mathrm{C}$ and there is air being blown over it at a speed of $35 \frac{m}{s}$ with an ambient temperature of ...
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1answer
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Bifurcation of convection of fluid in container, when adding temperature
I once read a paper, in which:
a fluid in a container was heated from below,
after reaching temperature $T_1$, a circular motion (convection) was clearly distinguishable, in form of cylinder,
after ...
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2answers
527 views
Why is oil a poor conductor of heat?
Why is oil a poor conductor of heat? Does it help in insulation?
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1answer
207 views
Per unit area, is there more heat transfer through the open top of a mug or the side walls?
I had a mug of hot coffee cool too rapidly for my liking the other day, which made me wonder what was the greater contributor to heat loss for a typical open-top ceramic mug: the open top, the walls, ...
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3answers
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What exactly is the difference between radiation and convection?
Okay, so everywhere I've read, I hear the main difference is the requirement of a medium. But for example, if you take the case of heat 'radiating' from a red-hot iron, isn't that actually convection ...
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1answer
451 views
Finding electric power generated using heat transfer
I'm working through an example I have been given to study. Suppose I have a 2m X 4m photovoltaic panel on my roof that is irradiated with a solar flux of $G_s = 700W/m^2$.
Given:
$\alpha_s = 0.83$
...
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2answers
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Convective and Diffusive terms in Navier Stokes Equations
My question has 2 parts:
I just followed the derivation of Navier Stokes (for Control Volume CFD analysis) and was able to understand most parts. However, the book I use (by Versteeg) does not ...
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1answer
441 views
How does smoke move in the air and how can I direct it so it will go to a place I want it to go?
Let's assume a close room with 1-2 people who only one of them smoking cigarette.
What is the equation describe the smoking spreading? is it diffusion? what are the parameters is so?
Is there a ...
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1answer
459 views
In what situations do I use the characteristic length of a fin to find the surface area?
So I'm learning about fins in heat transfer and it seems that there are two separate formulas for the surface area of a rectangular fin of length L, width w and thickness t. The fin is attached to a ...
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2answers
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Air velocity in a double-skin facade
I was wondering how the air flows in a double skin facade? Say I have a glass facade with a depth of 1m, a height of 200m and a width of 10m. It is a single vertical shaft all the way up with openings ...
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3answers
456 views
What is the most efficient way to use hand dryer?
What's the most efficient way to place your hands under the hand dryer?
Let's assume that dryer creates simple donward flow of hot air.
Here are some examples:
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3answers
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Are there convective movements similar to those in clouds everywhere in the atmosphere?
I heard there were powerful convective movements in clouds which were responsible for increasing the size of water droplets or ice crystals. My question is: do the same movements appear outside of ...
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2answers
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Is this a weather phenomenon or an instrumental artifact?
The radar image of the midwest provided by Weatherunderground at 10:30 PM Central time, May 8 2011 has odd patterns.
Are these patterns real? Perhaps caused by large scale convection over cities? Or ...
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2answers
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Can the earth's magnetic field be generated by heat from a natural nuclear reactor?
I've come upon Dr. J. Marvin Herndon's theory that the earth's magnetic field is generated by a hot nuclear reactor operating in the center of the earth. This is backed by various papers, some of them ...
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4answers
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Is there an equation for convective heat transfer?
Is there an equation I can use to calculate the temperature (as a function of time) of an object which is gaining or losing heat by convection? Or equivalently, the rate of energy transfer from the ...
