PERFORMANCE IDENTIFICATION OF THE APPARATUS FOR TESTING COMPACT HEAT EXCHANGER SURFACES

Abstract

The description of a new test apparatus designed for an on-line determination of flow friction and heat transfer characteristics of compact heat exchanger surfaces is given. The test section of the empty apparatus has been mathematically modelled for transient response. Parameter identification of the empty test section model has been performed by an original statistical approach. One hundred experimental runs have been performed in order to identify the following parameters: (i) time constant of the exponential inlet temperature signal, (ii) maximum fluid temperature rise at various mass flow rates for constant heater power supply, (iii) number of fluid-to-wall heat transfer units, (iv) time constants of two thermopiles to measure the temperatures up- and down-stream of the matrix. Using humid air as the working fluid, each of these parameters is correlated at a high coefficient of determination with the Reynolds number in the range 10,770 less than Re//a less than 60,640.