The Periodic Method for Testing Compact Heat Exchanger Surfaces

Abstract

The regular periodic method for testing the heat transfer performance of heat exchanger cores is studied in detail. This method, which has received very limited attention in the past, has certain advantages over the more conventional steady-state technique. It is shown to be useful especially in testing matrix surfaces. A theoretical analysis is performed, forming the basis for the periodic method. Directions for use in the range 0.2 < Ntu < 50, an uncertainty analysis, and test results for 2.6 < Ntu < 36.6 are included. It is concluded that the periodic method has the major advantages of: a wide Ntu range, easily generated experimental temperature waves, and the accuracy of an integral technique.