Enhancement of heat transfer and hydrogen fuel flow characteristics in a wavy cooling channel with secondary branch design

Abstract

The heat transfer and hydrogen fuel flow characteristics in the novel fin structure for the branched-wavy cooling channel of the rocket engine combustion chamber where three different gap widths (wz = 0.4, 0.6, and 0.8 mm) and three different amplitudes were examined numerically. Nusselt number, heat wall temperature, pressure drop, and thermal stratification were studied using Ansys fluent to investigate how configuration, wavy amplitude, and transfer gap width influenced these variables. The findings show that the heat wall temperatures and the average Nusselt number for the original symmetric configuration are better than the parallel one. The modified symmetric wavy design results show that the secondary branch flow considerably enhances Nusselt numbers due to the promoted fluid mixing between neighboring channels; the average Nusselt number of the modified symmetric configuration channel (A = 0.3 mm) enhanced up to 28.23% compared to the original straight configuration when adopting transverse gaps of 0.8 mm. The modified configuration (amplitude of 0.1 mm with a 0.8 mm transfer gap) achieved the highest thermal performance factor, which was enhanced by 21% compared to the original wavy design. Modified symmetric designs can slightly reduce the pressure drop penalty by creating a transverse gap.