Final answer:
The overall heat transfer coefficient (U) is a measure of the overall thermal resistance of a system. It is used to determine the rate of heat transfer through conduction. The formula for calculating U is: U = (1/h₁) + (d/k) + (1/h₂).
Step-by-step explanation:
The overall heat transfer coefficient (U) is a measure of the overall thermal resistance of a system. It is used to determine the rate of heat transfer through conduction. The formula for calculating U is:
U = (1/h₁) + (d/k) + (1/h₂)
where h₁ and h₂ are the heat transfer coefficients on the two sides of the system, d is the thickness of the material, and k is the thermal conductivity of the material. Here is an example:
Let's say a slab of material has a thickness of 0.1 meters, a thermal conductivity of 5 W/m·K, and a heat transfer coefficient of 10 W/m²·K on one side and 15 W/m²·K on the other side. The overall heat transfer coefficient can be calculated as:
U = (1/10) + (0.1/5) + (1/15) = 1.0333 W/m²·K