Concentric tube heat exchanger - Overall Heat Transfer coefficient

Description

Concentric Tube (or Pipe) Heat Exchangers are used in a variety of industries for purposes such as material processing, food preparation, and air-conditioning. They create a temperature driving force by passing fluid streams of different temperatures parallel to each other, separated by a physical boundary in the form of a pipe. This induces forced convection, transferring heat to/from the product.

After the heat transfer coefficients hi and ho are determined, knowing the resistance due to fouling and thermal conductivity of the boundary material kw, the Overall Heat Transfer coefficient Uo can be calculated from the shown formula

If the cross-sectional area of the annulus is not circular, the equivalent (hydraulic) diameter can be used. it can calculated by this formula

Related formulas

Variables

UoOverall Heat Transfer coefficient (W/(m2K))
Rfofouling resistance of the outer tube (m2*K/W)
Rfifouling resistance of the inner tube (m2*K/W)
Dodiameter of the outer tube (m)
Didiameter of the inner tube (m)
kwthermal conductivity of the tube wall (W/(m*K))
hoconvective heat transfer coefficient of the outer tube's fluid (W/(m2K))
hiconvective heat transfer coefficient of the inner tube's fluid (W/(m2K))