Experimental study on transient and steady-state impinging jet cooling condition with TiO2-Water nanofluids

Effective thermal management is crucial for optimum performance and energy conservation in energy-intensive industries and power systems. This study explores the influence of TiO2-water nanofluids on enhancing heat transfer during impinging jet-cooling of a heated copper surface, both under transient and steady-state cooling conditions. TiO2-water nanofluids, with volume fractions (0.025 vol% ≤ ɸ ≤ 1 vol%), were prepared, characterized, and utilized in the investigation. The experimental setup involved a dimensionless nozzle-to-target gap (H/D = 4) and Reynolds number (10000 < Re < 30000), with transient cooling behavior tracked through a dimensionless cooling curve. The TiO2-water nanofluids demonstrated significant thermal enhancement of 14.75% and 16% at ɸ = 0.05 vol% and Re ≈ 22000, outperforming DI water in both steady-state and transient cooling conditions, respectively. The result also shows that heat transfer rates increase with higher Reynolds numbers but follow an ascent and descent pattern with increasing nanofluid volume fractions. Notably, for volume fractions exceeding ɸ = 0.1%, the nanofluid exhibited reduced heat transfer efficiency compared to DI water. The acquired data have been utilized to establish a correlation for estimating the Nusselt number as a function of Reynolds number and fluid volume fraction.