A parametric study of dielectric spray cooling of a row of heaters in a narrow channel

The cooling efficiency of dielectric liquid spray cooling in a narrow channel formed by two parallel simulated circuit boards was investigated as a function of fluid inlet temperature, supply pressure, heater temperature, power level, and channel length. The 400 mm channel was formed by a circuit board with a row of nine 38.1 mm square heat sources on one side, and a smooth acrylic plate 25 mm above. A single full cone atomizer (D0=0.33 mm) provided spray entering from one end which was directed parallel to and centered on the row of heaters. Reduction in fluid subcooling provided higher heat removal efficiency and uniform temperatures, at the expense of dryout on the final heater(s). Increases in liquid supply pressure improved heat removal efficiency at all heaters uniformly. The leading heater (centered at 23 mm downstream) was impinged more heavily and showed the highest heat removal efficiency (up to 14/spl times/10/sup -6/ W/m/sup 2/ K) and power handling of up to 60 W. Heater 9 (375 mm downstream) dissipated as much as 20 W, with heat transfer coefficients up to 2/spl times/10/sup -6/ W/m/sup 2/ K. Temperatures at all locations typically ranged from (35 to 70)/spl deg/C with as little as 2/spl deg/C variation from Heaters 1 to 8 (317 mm downstream).