ChemSOF

The rate of heat transfer in heat exchangers is calculated by

Q = U x A x ( Ft x LMTD )

where Ft(<1) is interpreted as a geometric correction factor, that when applied to the LMTD (Log Mean Temperature Difference) of a counter flow heat exchanger, provides the effective temperature difference of the heat exchanger under consideration.

It is a measure of the heat exchanger′s departure from the ideal behavior of a counter flow heat exchanger having the same terminal temperatures. The Log Mean Temperature Difference is widely used in heat exchanger analysis, particularly for heat exchanger selection, (sizing problems) when as a result of the process requirements the temperatures are known and the size of the heat exchanger is required.

Determination of Ft is done based on the work by Bowman et al, in which they compiled the available data, and presented a series of equations and charts to find Ft for a variety of heat exchangers, including different shell and tube exchangers.

This application plots the charts provided by Bowman and calculate the correction factor Ft, for different exchanger geometries.