Technical Briefs Enhancement of Single-Phase Heat Transfer and Critical Heat Flux From an Ultra-High-Flux Simulated Microelectronic Heat Source to a Rectangular Impinging Jet of Dielectric Liquid D. C. Wadsworth, D. C. Wadsworth Boiling and Two-Phase Flow Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 Search for other works by this author on: This Site PubMed Google Scholar I. Mudawar I. Mudawar Boiling and Two-Phase Flow Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information D. C. Wadsworth Boiling and Two-Phase Flow Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 I. Mudawar Boiling and Two-Phase Flow Laboratory, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 J. Heat Transfer. Aug 1992, 114(3): 764-768 (5 pages) https://doi.org/10.1115/1.2911348 Published Online: August 1, 1992 Article history Received: April 1, 1991 Revised: January 1, 1992 Online: May 23, 2008

Experiments are performed to investigate boiling heat transfer from a smooth 12.7 mm x 12.7 mm heat source to a jet of dielectric Fluorinert FC-72 liquid issued from a thin rectangular orifice into a channel confined between the surfaces of the heat source and the nozzle. General boiling and critical heat flux (CHF) trends are examined with respect to variations in nozzle exit velocity, U = 1-13 m s-1, nozzle width, W = 0.127-0.508 mm, confinement channel height above the heated surface, H = 0.508-5.08 mm. and subcooling. DELTA-T(sub) = 0-40 C. Two regimes of CHF, medium and high velocity, are discovered, and an empirical correlation is developed for the medium velocity regime. The primary difference between the two regimes is a weak dependence of CHF on channel height for medium velocities compared to a stronger dependence for high velocities. It is found that operating in the high velocity regime, especially for the smallest channel height, can result in decreasing CHF with increasing jet velocity due to a stream-wise reduction of liquid subcooling within the channel. A self-contained cooling module consisting of a 3 x 3 array of heat sources confirms the uniformity and predictability of cooling for each of the nine heat sources, proving that the confined jet geometry is well suited for cooling large arrays of high-power-density heat sources such as electronic chips dissipating heat fluxes as high as 250 W cm-2.

Experiments were performed to investigate single-phase heat transfer from a smooth 12.7 × 12.7 mm2 simulated chip to a two-dimensional jet of dielectric Fluorinert FC-72 liquid issuing from a thin rectangular slot into a channel confined between the chip surface and nozzle plate. The effects of jet width, confinement channel height, and impingement velocity have been examined. Channel height had a negligible effect on the heat transfer performance of the jet for the conditions of the present study. A correlation for the convective heat transfer coefficient is presented as a function of jet width, heater length, flow velocity, and fluid properties. A self-contained multichip cooling module consisting of a 3 × 3 array of heat sources confirmed the uniformity and predictability of cooling for each of the nine chips, and proved the cooling module is well suited for packaging large arrays of high-power density chips.