Effects of electric field on mixed convection in a vertical channel
- Univ. of Oklahoma, Norman, OK (United States). School of Aerospace and Mechanical Engineering
Heat transfer enhancement using electrohydrodynamic (EHD) technique is numerically examined for laminar mixed convection in a vertical channel. Attention is also focused on the effect of added thermal buoyancy on the flow stability when the temperature difference between the flowing gas and bounding walls cannot be neglected. The electrical field is generated by positive corona from a wire electrode charged with a DC voltage of 15 kV. The flow Reynolds numbers considered are 600, 1,200 and 1,800 with Grashof numbers varying from 10{sup 4} to 10{sup 6} for both aiding and opposing flows. Due to the existence of secondary flows, a combined effect from the electric field and thermal buoyancy, there is an improvement in heat transfer for aiding flows for Grashof number up to 10{sup 5}. At Gr = 10{sup 6}, aiding flows experience a drastic reduction in heat transfer due to the entrainment of colder air from ambient. For opposing flows, heat transfer is increased in all cases of Reynolds and Grashof numbers considered. Oscillation in the flow field has been observed for flows at Re = 600 and 1,200. The flow and temperature fields tend to stabilize when the Reynolds of Grashof number are increased. Due to the domination of the flow inertia, no oscillation has been observed at Re = 1,800.
- OSTI ID:
- 445503
- Report Number(s):
- CONF-950828--; ISBN 0-7918-1709-1
- Country of Publication:
- United States
- Language:
- English
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