Semester

Summer

Date of Graduation

2006

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

John M. Kuhlman.

Abstract

Spray cooling is an efficient thermal management technique that may possibly be improved by employing an electric Kelvin force to control the fluid motion and delay the onset of critical heat flux. In the present study, a spray cooling apparatus consisting of a spray chamber (housing a spray nozzle and electrically heated surface) and a flow generating base package has been built and tested for varying nozzle-to-heater distances and also varying electrode geometries for a range of spray conditions and electrode voltages. The two part goal was to first determine the qualitative sensitivity of the distance between the heated surface and nozzle exit, and second, to determine the magnitude of the effects of the electric Kelvin force on the performance of the spray cooling apparatus for the various electrode geometries.;An experimental nozzle-to-heater spacing comparison performance test indicated that confined flows provide less efficient cooling than unconfined flows but are less dependent on the nozzle-to-heater distance. An experimental and numerical study of four cap electrode designs showed no significant effect of the electric Kelvin force on spray cooling performance. This may have been due to the non-optimal electrode geometries and also possibly due to the properties of the FC-72 fluid used. A redesigned electrode configuration that has been designed using the electric field module of the multiphysics code CFD ACE+ and the use of a different fluid, HFE-7000, showed a cooling effect of the heated surface as well as an increase of approximately 5% in the convection heat transfer coefficient.

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