The thermal performance of serpentine tube heat exchangers

Three commonly employed assumptions and a new assumption, which are employed to calculate the thermal performance of a pass in a serpentine tube heat exchanger, are compared. The new assumption employs the observation that the gas temperature profile along a pass will tend to a constant form as the gas proceeds from pass to pass. It is shown that the error in employing the assumption is either negligible or rapidly diminishes from pass to pass for the case of a uniform gas temperature inlet distribution. Methods for dealing with a non-uniform gas temperature distribution are outlined. (author)