Accession Number:

AD0680185

Title:

HEAT AND MASS TRANSFER TO A SUBFREEZING SURFACE IN A NON-UNIFORM ELECTRIC FIELD

Descriptive Note:

Technical rept.

Corporate Author:

OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Report Date:

1968-09-01

Pagination or Media Count:

184.0

Abstract:

An experimental and analytical program was undertaken to investigate the behavior of frost formation under an impinging electric wind induced by a positive wireplane corona in a nonuniform electric field. A vertical test plate precooled to subfreezing temperatures was exposed to the ambient air and the effects of electric fields were studied through the application of a high voltage between the grounded test plate and a corona wire. Considerable increases in heat and mass transfer were found. A simple theoretical model was developed for predicting the effects of electric fields upon the heat and mass transfer processes associated with frost formation. Two regions of the flow field created by the impinging electric wind are of primary importance in heat and mass transfer, namely, the stagnation flow and the wall jet regimes. In the stagnation flow, a linear relation for the local heat and mass transfer coefficients was assumed between the stagnation point and the wall jet region. In the wall jet, the analysis was based on laminar flow. An analysis was made of a simplified model of transient heat conduction in a frost layer. Using a method due to Portnov the position and the temperature of the progressing frost- air interface was obtained in a series expansion in powers of the square root of t. The coefficients up to the power n 6 were given.

Subject Categories:

  • Fluid Mechanics
  • Plasma Physics and Magnetohydrodynamics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE