Experimental and numerical investigation of brazed plate heat exchangers – A new approach

Abstract

• Thermofluid characteristics of brazed plate heat exchanger (BPHE) are studied. • Effect of brazing joints in numerical modeling of BPHEs is investigated. • The brazing joint imposes significant effect on pressure drop. • The brazing joint casts very minor influence on heat transfer. • The numerical predictions are in good agreements with existing correlations. Experimental and numerical investigations of a brazed plate heat exchanger are performed in this study. Three approaches are considered in numerical modeling of brazed plate heat exchanger in order to realize the difference amid simulations and experimental data. The departures between simulations and experiments are strongly associated with the complicated configurations of the plate geometry. Hence, modeling regarding the modified geometry, modeling of original geometry, and modeling of original geometry by considering brazing joints are conducted in numerical simulations for elaborations. Results show that the third geometry yields the best agreement with the experimental data, indicating the importance of considering brazing joints in the modeling of brazed plate heat exchangers. However, the modified geometry has the worst agreement with the experimental data. This approach has been adopted by many existing literatures. Flow field for all approaches illustrates that a zig-zag pattern from the inlet to outlet nozzles exists. This is because of large chevron angle of plates (75°). Comparison of Nusselt number and friction factor of this brazed plate heat exchanger with the existing correlations demonstrates the necessity of developing new correlations for brazed plate heat exchangers. Correlations for Nusselt number and friction factor of the modeled heat exchangers are developed in a wide range of Reynolds number (50–10,000) with mean deviations of 5.1% and 3.4%, respectively.