IMMERSION COOLING OF A SIMULATED ELECTRONIC CHIP PROTRUDING INTO A FLOW CHANNEL

Nucleate boiling and critical heat flux from the top and side surfaces of a simulated electronic chip protruding into a rectangular channel has been studied. To ascertain the contributions of heat transfer from the sides and top of the simulated electronic chip, boiling from the sides was virtually eliminated by the use of a thin (0.025 mm) foil he ater on top of a block of insulating material. It was found that singl e-phase heat transfer and critical heat flux are markedly greater for a surface protrusion height of 0.71 mm as compared to a hush surface. This increase was seen for flow velocities greater than 1 m/s and a su bcooling of 20 degrees C. The results are compared to that for a coppe r block heated from below under similar fluid and geometry constraints . These comparisons show that the vapor emanating from the upstream si de of the copper block plays an important role in either decreasing or increasing the critical heat flux. Additional results were obtained f or the copper block where heal transfer from the upstream side was obs tructed. These results indicate that under some conditions of subcooli ng and flow rate an optimal amount of upstream side vapor production e xists.