Response of Single-Pass Heat Exchangers to Disturbances in Flow Rate

Abstract

From distributed and lumped parameter models of a single-pass, shell and tube heat exchanger, transfer functions are derived relating the outlet-temperature responses to tube-side flow-rate disturbances. Predicted and measured data are compared over a range of mass flows and of amplitudes of the disturbing, tube-side flow signal. Good agreement is shown between measured responses and responses predicted by sectionally lumped and distributed parameter models for amplitudes of up to ±30 per cent of the mean value. The effects on the dynamic response of a distributed single-pass heat exchanger, of altering such characteristics as tube length, tube and shell-wall capacitance and mass flow rates, are illustrated graphically, and discussed.