Heat transfer characteristics of single-phase flow through dimple plate heat exchanger

Dimple plate heat exchangers featuring with continuous-curved surface between adjacent dimples have garnered attention due to lower material consumption and lower internal volume compared to the conventional herringbone plate heat exchanger. However, a comprehensive analysis on thermal–hydraulic performance under different dimple parameters is still lacking. This study experimentally investigates the heat transfer characteristics of water flow in three dimple plate patterns (depth: 1.2 − 2.0 mm; pitch: 5.2 − 7.6 mm) with inlet hot- and cold- water temperatures at 70 and 50 °C, mass flux of 50 − 1000 kg⋅m⁻²⋅s⁻¹. The simulation was conducted under even broader conditions, with mass flux ranging from 20 to 465 kg⋅m⁻²⋅s⁻¹, encompassing a wide range of dimple depths (0.7 − 1.5 mm) and pitches (2.8 − 7.6 mm). The results indicated that heat transfer coefficient increased by 40 % and 80 % maximum at the same Reynolds number as the dimple depths and pitches ranges 0.7 − 2.0 mm and 2.8 − 6.0 mm, respectively. The surrounding flow and symmetric vortices among dimples instead of swirl up-and-down flow in the herringbone corrugated channel was initially identified based on different combinations of dimple depth and pitch. Laminar flow transition to turbulence was detected at a Reynolds number of approximate 300. Finally, a new correlation for the Nusselt number was developed using 118 data points, with a mean deviation of 7.6 %.