Combined effects of inlet conditions and assembly accuracy on Nusselt and friction factors of plate heat exchangers

From 1920's on plate heat exchangers (PHE) became a successful industrial solution regarding energy conversion owing to their compactness and efficiency. Motivated by a well-organized assembly concept, the gasket plate heat exchanger (GPHE) grew into the most common PHE design. One century later PHE dimensioning is still a challenge: application of divergent Nusselt and friction factor correlations found in the literature yield significant differences on heat exchanger sizing and pumping power. In this work, the effects of inlet conditions and plate's features on the GPHE thermal-flow performance are investigated, since they affect the channel flow geometry. Furthermore, the effect of a modified tightening distance, which scales with typical measurement system bias, on the exchanger performance is likewise assessed. No systematic study was performed that considered the combined effects of inlet conditions and assembly accuracy on friction factors and Nusselt numbers for GPHEs. The present work aims at filling this gap. Experiments in GPHEs occurred with the inlet pressure difference between branches ranging from -1.5 to 1.5 bar, three plate thicknesses, two chevron angles, corrugation aspect ratios, plate materials and tightening distances, for Reynolds numbers ranging from 900 to 10,000.