Flow and heat transfer of supercritical hydrocarbon fuel in additively manufactured cooling channels

Abstract

As additive manufacturing (AM) technology has advanced, an increasing number of aero-engine cooling components are being fabricated by metal AM. However, the effects of the inherent rough surface morphology from using AM technology on the flow and heat transfer characteristics in the cooling channel are unclear. Therefore, this experimental investigation compared the flow behavior and thermal performance of supercritical hydrocarbon fuel between horizontal AM (Rz = 43.1 µm) and conventionally mechanically manufactured (CM) (Rz = 11.7 µm) mini-channels. The effects of system pressure (p), Reynolds number at the inlet (Rein), and heat flux rate (q) on the flow and heat transfer performance were evaluated. The findings indicate that heat transfer is significantly enhanced in the AM mini-channel compared to the CM channel. The thermal acceleration effect is inhibited in the AM channel owing to the rough topography. The non-dimensional roughness threshold of AM hydraulic rough channel is or lower than 2.2%. NuAM increased by approximately 16, but NuCM increased by 5 when the heat flow rate increased from 166 to 273 KW/m2. Furthermore,hAM increased by approximately 4 KW/(m2-k), but hCM only increased by approximately 2 KW/(m2-k) when the Rein increased from 6100 to 15,000. Moreover, both NuAMand NuCM decrease with increasing system pressure. Finally, the correlations between NuAM and NuCM for supercritical hydrocarbon fuel was proposed to support future research and design of aero-engine complex cooling structures.