Basic constitutive equations


With known individual heat transfer coefficients, wall thickness, and wall thermal conductivity the overall heat transfer coefficient for plane walls is calculated as:

Plane wall

where

k = overall heat transfer coefficient [W/m2·K]
α = individual heat transfer coefficient [W/m2·K]
w = wall thickness [m]
α = wall thermal conductivity [W/m·K]


If the wall consists of several layers of varying thickness and thermal conductivity this equation becomes:

Composite wall


For a circular wall the equation becomes:

Circular wall

where

A = heating surface [m2]
ro = tube outer radius [m]
ri = tube inner radius [m]
L = tube length [m]



Back to heat transfer main page · Calculation example

 

Copyright © 2017 Rheoheat