How do I calculate heat loss due to wind?

[moonman239]

Is there a formula for calculating heat loss due to wind (not wind chill temperature)?

 

[klimatos]

Is there a formula for calculating heat loss due to wind (not wind chill temperature)?

Unless there is vaporization from the surface, there is no heat loss due to wind. If the air is hotter than the surface, heat will flow from the air to the surface. If the surface is hotter than the air, then heat will flow from the surface to the air. If they are both at the same temperature, then there will be no heat transfer. All this, of course, assumes that we have radiative balance.

If vaporization is involved, then the amount of heat loss will be a function of the surface temperature, the humidity of the air, the enthalpy of vaporization at that temperature, and the diffusion rate.

 

[lalbatros]

moonman239,

There are many semi-empirical formulas to calculate heat transfer between a surface and a fluid.
There are many books reviewing all that.

First of all, you need to explain the geometry of your system.
This means, the shape of the surface, if there are irregularities and their scale, the direction of the wind. Eventually, you might even need to calculate the complete flow of the wind past your surface, which would impliy a CFD software.

• Personally, I have used very often formulas for heat transfer between a large cylinder and wind perpendicular to the cylinder. On this basis, I can calculate the heat loss from a rotary kiln.
  
• I also sometimes used a formula for a rotating cylinder without wind, but in that case I had to figure out a plausible formula taking into account the rugosity of the surface. In this case the wind is related to the rotation of the cylinder.
  
• Sometimes I had to use formulas for natural convection. In this case, there is no forced convection due to wind, but there is anyway a motion of air past the object dur to the natural convection.

My preffered book on this topic is this one:

https://www.amazon.com/dp/0070479828/?tag=pfamazon01-20

Unfortunately, there is no preview available for this book.

 

[klimatos]

If vaporization is involved, then the amount of heat loss will be a function of the surface temperature, the humidity of the air, the enthalpy of vaporization at that temperature, and the diffusion rate.

Plus, of course, wind velocity and angle of incidence.

 

[fluidistic]

To all the helpers, I think the OP refers to his last thread https://www.physicsforums.com/showthread.php?t=473490.
Basically he wants to heat up (using fire) a pan filled with water and he wants to consider the effect of the wind on the net heat transfer in the pan.