hc is called the heat transfer coefficient. This equation tells you how much heat is passing through the surface into the air above. If the air is pretty well mixed and you are heating it from the surface, you can determine the rate of temperature rise of the air by also knowing the mass and heat capacity of the air: $$MC_p\frac{dT_a}{dt}=h_cA(T_s-T_a)$$dmehling said:Maybe I don't quite understand the point of the equation: q = hc A dT . I plugged in values of hc = 100, A = .01, dT = 40 and the answer was q = 40 w per second. I just want to know what that answer tells me about how much a given volume of air above a hot surface will increase over a given amount of time. Are there other values and factors that I need to know in order to figure this out.
Convective heat transfer is the transfer of heat between a solid surface and a fluid in motion. This process occurs when the fluid is in direct contact with the surface, and the heat is transferred through the fluid's movement.
The convective heat transfer rate is calculated using the convective heat transfer coefficient, the temperature difference between the solid surface and the fluid, and the surface area of contact. The formula for calculating convective heat transfer rate is Q = hA(Ts - Tf), where Q is the heat transfer rate, h is the convective heat transfer coefficient, A is the surface area, Ts is the surface temperature, and Tf is the fluid temperature.
The convective heat transfer rate can be affected by several factors, including the fluid's velocity and properties (such as density, viscosity, and thermal conductivity), the surface roughness, the temperature difference between the surface and the fluid, and the geometry of the surface.
Convection is the transfer of heat through the movement of a fluid, while conduction is the transfer of heat through a solid material, and radiation is the transfer of heat through electromagnetic waves. Unlike conduction and radiation, which can occur without any medium, convection requires a fluid to transfer heat.
Convective heat transfer can be enhanced by increasing the fluid's velocity, increasing the surface area of contact, and using materials with high thermal conductivity. Additionally, using fins or other heat transfer devices can increase the convective heat transfer rate by increasing the surface area of contact between the solid surface and the fluid.