A Transient Heat Exchanger Evaluation Test for Arbitrary Fluid Inlet Temperature Variation and Longitudinal Core Conduction

Abstract

An improved version of the transient technique is described which utilizes a finite-difference model of the heat exchanger for the evaluation of an average hem transfer coefficient. The model, which can accommodate arbitrary inlet fluid temperature variation as well as longitudinal conduction in the heat exchanger core, is well suited for a computer-based data reduction procedure. The finite-difference model is validated by comparison with the predictions of exact solutions for a step change in inlet temperature. Actual tests on a core of known performance indicate that the overall accuracy of the technique can be within ± 2 percent.