Numerical simulation of multi-pass parallel flow condensers with liquid-vapor separation

Liquid-vapor separation is an advanced technology recently developed enabling significant further heat transfer enhancement for condensers. This paper reports a distributed parameter model, using the epsilon-NTU method, to numerically simulate heat transfer performance of multi-pass parallel flow condensers with liquid-vapor separation (referred to as MPFCs-LS). For achieving higher accurate results and lower computational time, a segment self-subdivision method is used to locate the positions of onset and completion of condensation. Furthermore genetic algorithm is adopted to determine the refrigerant flow rates through tubes in a flow pass. Relevant empirical correlations are selected for heat transfer and frictional pressure drop in different flow regimes during condensation in microfin tubes. The predictions of the model agree well with the experimental data within +/- 20%. The model and numerical methods developed in this work for MPFCs-LS are of important value in design and performance optimization of these new advanced condensers. (C) 2019 Elsevier Ltd. All rights reserved.