Forced convective boiling from a discrete heat source in a curved rectangular channel has been experimentally investigated. The flow area height and radius of curvature of the channel were varied to ascertain the effects of induced buoyancy and secondary flow. For comparison, results were also obtained for a similar heat source in a straight channel. 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 additional channel height of 1.14 mm was investigated for the straight geometry only. Data were obtained for subcoolings of 5, 20, and 35 C and flow velocities of 1-7 m/s. For the straight geometry, critical heat flux (CHF) did not vary much for heights greater than 1.14 mm. The percent increase in curved channel CHF over straight channel CHF was highest for 5 C subcooling. This implies that buoyancy effects are most important when there is significant vapor generation. For a given subcooling and velocity, the radius of curvature had little effect. This implies that secondary flow has little effect under these conditions. A correlation is developed that describes the effects of buoyancy and secondary flow on CHF in the curved channel.
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