Effect of intermittent interruption of fluid supply on flow boiling phenomenon in micro-pinned heat sinks

Abstract

Among promising cooling options, flow boiling in micro-structures is a strong alternative. However, for systems operating under very high heat loads, any shortage or discontinuity of working fluid can lead to irreversible problems and system failure. Hence, here, this problem is addressed; and as the first time, effect of intermittent interruption of fluid supply on flow boiling phenomenon in expanding cross sectional heat sinks with micro pins and cavities (EHSPC) is experimentally studied. In addition to EHSPC, a classical heat-sink having parallel channels (PHSC) is used for comparison. Different downtimes (DT), more clearly, time for duration of interruption of water flow (0, 3, 6, 9, 12 s), heating powers (145 and 200 W) and heat sinks (EHSPC and PHSC) constitute variable conditions, while mass flux (G = 180kgm−2 s−1) and inlet temperature (Ti = 73 °C) are constant conditions. As conclusion, for pump-failure conditions, EHSPC can successfully manage cooling process. Simultaneous existence of micro-cavities, micro-pin-fins and enlarging cross-section successfully tolerates time-period at which pump doesn't work. The magnitude of quasi-sinusoidal type oscillations of EHSPC is significantly small compared to those obtained for PHSC. Compared to PHSC, enhancement percentage of htp in favor of EHSPC are 19.2 %, 33.9 %, 44.1 % and 119.5 %, respectively for DT = 0, 3 s, 6 s, and 9 s.