Performance Factors of a Periodic-Flow Heat Exchanger

A numerical finite-difference method of calculating the effectiveness of the periodic-flow type heat exchanger is presented by considering the metal “stream” in crossflow with each of the gas streams as two separate but dependent exchangers. A general purpose digital computer was used to accommodate the large number of subdivisions necessary for accuracy and an extrapolation of data to zero element area such that the values of effectiveness are good to four significant figures. The exchanger effectiveness has been evaluated over the following range of dimensionless parameters $1.0⩾Cmin/Cmax⩾0.101.0⩽Cr/Cmin⩽∞1.0⩽NTUo⩽101.0⩾(hA)′⩾0.25$