Enhancement of critical heat flux and heat transfer during jet impingement quenching using Al2O3 and SiO2 nanofluids

Jet impingement quenching is widely used in high-heat-flux cooling applications such as thermal processing, nuclear safety, and electronics thermal management. Although nanofluids are known to enhance heat transfer, the comparative performance of nanofluid quenching and deionized (DI) water quenching on nanoparticle-deposited surfaces under identical conditions remains insufficiently explored. This study investigates the enhancement of Critical Heat Flux (CHF) and Maximum Heat Transfer Coefficient (MHTC) using Al 2 O 3 and SiO 2 nanofluids at 0.01% v/v concentration, along with the influence of nanoparticle surface deposition. Experiments were conducted at set wall temperatures of 200–300 °C and mass flow rates of 4–9 g/s. SiO 2 nanofluid exhibited the best thermal performance, achieving up to 60% enhancement in MHTC and nearly 35% improvement in CHF compared to DI water quenching on a bare surface. Al 2 O 3 nanofluid showed enhancements of 40% in MHTC and 25% in CHF under similar conditions. In addition, DI water quenching on nanoparticle-deposited surfaces produced MHTC enhancements of 50% for SiO 2 and 30% for Al 2 O 3 . The results demonstrate that nanoparticle-induced surface nanotexturing can effectively enhance quenching performance without the stability issues associated with continuous nanofluid use. Because DI water quenching on the SiO 2 -deposited surface alone recovers most of the enhancement obtained with continuous SiO 2 nanofluid use (50% vs. 60% MHTC enhancement), the incremental benefit of maintaining a nanofluid suspension throughout operation is comparatively modest (~ 10% points); this trade-off between marginal performance gain and the added cost and complexity of nanofluid preparation is discussed further in the Conclusions.