An experimental study of liquid jet impingement cooling of electronic components with and without boiling

With the ever increasing heat fluxes in electronic components, enhanced cooling technology is required. This paper describes a study of heat transfer from single-phase and two-phase boiling free jet impingement. Experiments were carried out on a free jet impinging on the surface of a 2 mm and 3 mm thick film resistor. Different jet velocities and subcooling were studied. Boiling curves were obtained from the experiments. It was found that higher velocities led to higher heat transfer coefficients in single-phase heat transfer while jet diameter had very little effect on single-phase heat transfer. However, higher velocities and larger jet diameters normally led to higher heat transfer coefficients in boiling heat transfer. Active nucleation sites distribution coming from probabilistic effects and surface conditions may have a strong influence on the boiling heat transfer. Subcooling had an apparent effect on boiling heat transfer by changing flow and thermal patterns. The critical heat flux (CHF) was found to increase with increasing jet velocity, jet diameter and jet inlet subcooling. The transient CHF value under large increment of the heating power was lower than steady-state CHF, which was possibly caused by heterogeneous spontaneous nucleation (HSN). Correlation on steady-state CHF was consistent with the experimental results.