CHANNEL HEIGHT AND CURVATURE EFFECTS ON FLOW BOILING FROM AN ELECTRONIC CHIP

Forced convective boiling from a discrete heat source in a curved rect angular channel has been experimentally investigated, The flow area he ight and radius of curvature of the channel were varied to ascertain t he effects of induced buoyancy and secondary flow, For comparison, res ults were also obtained for a similar heat source in a straight channe l, Three configurations encompassing two radii of curvature, 28.6 and 56.4 mm, and three heights, 3.18, 5.56, and 6.35 mm were studied, An a dditional channel height of 1.14 mm was investigated for the straight geometry only, Data were obtained for subcoolings of 5, 20, and 35 deg rees C and flow velocities of 1-7 m/s. For the straight geometry, crit ical heat flux (CHF) did not vary much for heights greater than 1.14 m m, The percent increase in curved channel CHP over straight channel CH F was highest for 5 degrees C subcooling, This implies that buoyancy e ffects are most important when there is significant vapor generation, For a given subcooling and velocity, the radius of curvature had littl e effect, This implies that secondary flow has little effect under the se conditions, A correlation is developed that describes the effects o f buoyancy and secondary flow on CHF in the curved channel.