Advanced modelling and iterative approach for high-accuracy PCHE design in SCO2 Brayton cycle

Abstract

This study addresses the crucial challenge in the design of Plate Heat Exchangers (PCHEs) for SCO2 Brayton cycles, caused by inadequate mathematical models and heat transfer correlations. The paper introduces novel PCHE models that surpass existing approaches in accuracy and versatility. Three approximations (Models 1, 2, and 3) are evaluated and improved upon. Two new models, Basic Heat Transfer Analysis (Model 4) and Modified Heat Transfer Analysis (Model 5), are proposed, validated, and compared in both 2D and 3D scenarios. The innovation lies in the introduction of an Iterative Method to determine wall temperatures and integrating high-precision heat transfer correlations. Results demonstrate Model 5′s superiority over all models, achieving exceptional accuracy for standard and non-standard PCHE configurations. For standard setups, Model 5 exhibits ± 0.50 % RE, RMSE = 0.21 (2D), Error = 0.89 % (3D), outperforming other models. For non-standard configurations, Model 5 maintains superior accuracy (2D: RE = -0.5 %∼2%, RMSE = 0.67, 3D: Error = 1.53 % and 1.98 %).The study validates Model 4 and 5′s heat transfer coefficients through the Jackson correlation against CFD results, surpassing previous models using the Gnielinski correlation. In summary, the study introduces Model 5 as a novel, accurate, and versatile solution for PCHE design. The proposed Iterative Method further enhances accuracy and applicability. The paper's originality lies in the development of Model 5, its verification, and its recommendation as a preferred PCHE design tool, addressing critical industry needs and research gaps.