Flow boiling critical heat flux of FC-72 from flush-mounted and protruded simulated chips in a vertical rectangular channel

Experiments on flow boiling heat transfer and critical heat flux (CHF) of t he dielectric coolant FC-72 are carried out for four in-line simulated elec tronic chips of 10 mm x 10 mm, for both flush-mounted and protruded chips o n one wall of a vertical rectangular channel. The fluid velocity and subcoo ling are varied from 4.2 to 78 cm/s (Re-L = 1.0 x 10(3) to 3.0 x 10(4)), an d from 15 to 33 degrees C, respectively. The fully-developed nucleate boili ng regime is not affected by changes in flow velocity and subcooling, where as the surface temperatures decrease with increasing flow velocity and subc ooling in the partial boiling regime. CHF generally increases with the degr ee of subcooling and with velocity at higher inlet velocities, but velocity has little effect at values less than 20 cm/s. The surface temperatures fo r the flush-mounted chips are lower than those for protruding chips, and th e CHF data for the flush-mounted chips are higher than those for protruding chips; the differences between these two cases increase with increasing ve locity. (C) 2000 Elsevier Science Ltd. All rights reserved.