Correlation of critical heat flux in hybrid jet impingement/micro-channel cooling scheme

Experiments were performed to investigate the two-phase cooling characteristics of a new hybrid cooling scheme combining the cooling attributes of slot jets and micro-channel flow. A test module was constructed in which dielectric PF-5052 liquid was introduced through five 0.48 mm wide and 12.7 mm long slot jets, each leading to a 1.59 mm wide and 1.02 mm deep channel. Increases in flow rate and subcooling yielded similar trends of delaying the inception of boiling and increasing critical heat flux (CHF). A previous channel flow correlation predicted CHF values far smaller than measured, while those for slot jets yielded closer predictions. This proves the cooling performance of the hybrid configuration is dominated more by jet impingement than by micro-channel flow. By dividing the test surface into a portion that is dominated by jet impingement and another by micro-channel flow, and applying the appropriate CHF correlation for each portion, the CHF data for this hybrid cooling configuration are predicted with a mean absolute error of 8.42%.