Pool boiling enhancement with submerged liquid jet impingement on a laser-engineered microchannel surface

• Laser-engineered surfaces designed for submerged liquid jet impingement. • HTC on laser-textured surfaces increased by up to 178 % at 4000 kW m −2 . • CHF on untreated surface improved by 79 % as mass flux increased to 6.44 kg m −2 . • Maximum CHF of 9.1 MW m −2 observed on a 5 × 5 mm 2 surface. • Jet impingement reduced surface superheat by up to 8.3 K at high heat fluxes. Effective thermal management of high-power electronics requires cooling solutions capable of dissipating high heat fluxes while maintaining low surface temperatures. This study investigates the pool boiling performance of two surfaces: a reference surface and a laser-textured microchannel surface, both tested with and without submerged liquid jet impingement. Experiments were conducted using saturated, twice-distilled water at atmospheric pressure, with three different mass fluxes delivered by a jet impingement device. Results show that incorporating microtubes into the microchannels to deliver direct jet impingement reduces surface superheat, particularly at higher heat fluxes. The positioning of the jet impingement device plays a key role in critical heat flux (CHF) performance. Devices embedded within the microchannels at the bottom surface yield a higher CHF enhancement with increasing mass flux compared to those positioned just above the surface. For the reference surface, CHF increases significantly with higher mass flux, while the laser-textured surface shows relatively constant CHF values. At mass fluxes of 0.64 and 3.22 kg·m −2 ·s −1 , both surfaces exhibit similar CHF, but at the highest mass flux, the reference surface outperforms the laser-textured one by 20 %. The highest recorded CHF of 9098 kW·m −2 was achieved on the reference surface. The reduced performance of the laser-textured surface is attributed to the formation of an oxidation layer, which acts as a thermal barrier, lowering heat transfer efficiency and contributing to localized dry-out. This ultimately decreases both the CHF and the heat transfer coefficient.