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Questions tagged [convection]

transport mechanism involving bulk motion of a medium

Convection is that mode of transport or mass or energy which results from bulk motion of the transporting medium. The term is commonly used to describe transport of heat energy and/or momentum. Convection is principally of two types- natural and forced. Natural convection results from gradient in the density of a medium, while forced convection results from an external forcing agent e.g a pressure gradient.

259 questions
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Will a liquid boil quicker if it is stirred versus if it is not stirred

Will the whole liquid boil quicker on a stove-top if it stirred versus if not stirred? What should be the frequency of stirring to get to boiling point quickly? please explain your hypotheses with experiments(or links to) preferrably
Pranay Aryal
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Calculating heat transfer coefficient from cooling rate of a block?

If I have a cube of metal with known surface area and time to cool from $T_2$ to $T_1$, determined experimentally. Can I calculate the convective heat transfer coefficient, h of this situation from this? Seen as h is the rate of transfer per unit…
FEA42
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Nusselt number in Rayleigh-Bénard convection derivation

I read, that for a box with length L, with heated bottom and cooled top and boundary layers of thickness $\delta$, the Nusselt number Nu can be approximated as $$ \text{Nu}= \begin{cases} 1,& \text{if } \text{Ra} \ll \text{Ra}_\text{crit}\\ …
Luca Thiede
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Heat loss via convection

Suppose I have a glass container (trough) and I want to heat the water inside. I put it on a hot plate. Now, even though the hot plate is at $110\,^{\circ}C$, the liquid only reaches $50\,^{\circ}C$. I want to know why. The heat loss to the…
Dr. Harish Ravi
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Equation for Convective Heat Transfer

In this Wikipedia link: https://en.wikipedia.org/wiki/Convection_(heat_transfer)#Convective_heat_transfer on convective heat transfer, the following equation for convection is provided: $$\dot{Q}=hA(T-T_f)^b$$ where it is claimed that $b$ is some…
SurfaceIntegral
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Heat Transfer Coefficient

What is the relationship between time and heat transfer coefficient? Actually are there any at all? What happens to time taken in heat transfer if the coefficient is value is raised or lowered? All we know is $$Q=hA(T-T_a)$$ which does not include…
hellomecha
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Convection vs diffusion

Convection is a combination of advection and diffusion, where the former is a macroscopic movement of bulk fluid and the latter is a microscopic movement of fluid particles. But often in literature, I see sentences like "The second and third terms…
user5965026
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