? RheoHeat - Basic constitutive equations

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


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


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

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