transport mechanism involving bulk motion of a medium

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Realistic calculation of heat loss for pipe

Good day everyone, I am new on this site and I hope to find here help, since I am not going anywhere with the literature I have found. I try to calculate realistically the heat loss of a hot, ...
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1answer
94 views

Can convection cells evolve in stably stratified fluid?

Assume stably stratified fluid but not in equilibrium, e.g. with non-constant temperature gradient for example. Can convection cells be present? Typical example of convection cells is Rayleigh–Bénard ...
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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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Does transverse flow always assist in mixed convection?

I am dealing with both natural convection and transverse forced convection over a flat plate. There are 4 different situations: Upward-facing cold plate Downward facing cold plate Upward facing hot ...
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Poseuille number for flat channel?

For a flat channel with fully developed flow, the Poseuille number when using the hydraulic diameter is $$Po=C_fRe_{D_{H}}=24$$ But when using 2b as the length scale, the Poseuille number is ...
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Do I ever not account for temperature variation from wall temperature in pipe flow?

Let's say I have internal pipe flow with a constant wall temperature. If I evaluate the properties at either the mean inlet temperature of the average of the inlet and outlet, do I always have to ...
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Thermography time evolution

I have an imaging problem. I essentially have a metallic plate with a number of holes through it. I am looking at the number of holes with a thermal camera. While looking at the plate I have two ...
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73 views

Determine pipe outlet temperature without length?

Let's say I am flowing a fluid through a pipe that has a constant surface temperature. Is it possible to determine the heat flux on the inner surface without knowing the pipe's length when the only ...
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51 views

Convective heat transfer coefficient for counter-current flow

This is not a counter-current heat exchanger. It is two phases, Gas and Water, flow in one flow path but in opposite direction. I have found many source doing analysis on flow pattern of the ...
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Transient conduction - Biot number with irradiation?

I understand that the Biot number is essentially the ratio of the convective effects to the conductive effects in transient conduction but what if there is some sort of radiation from a heat source ...
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98 views

Characteristic length of differential element of cylinder surface?

I am trying to find the Nusselt number for a small element of the outside of a cylinder that has a height of $Delta z$. I found the average Grashof number of a surface as $$Gr_{L}=\frac{\beta \rho ...
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Fluid mechanics Grashoff number

When I derived the Grashof number (for natural convection at a vertical plate) starting with the ratio of buoyancy forces to viscous forces, I realized that I had set the Reynolds number to 1 (ie I ...