Accession Number : AD0611019

Title :   HEAT TRANSFER CHARACTERISTICS OF VENTILATED SNOW,

Corporate Author : COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H

Personal Author(s) : Yen,Yin-Chao

Report Date : JAN 1965

Pagination or Media Count : 22

Abstract : A method of evaluating the effect of air flow on the rate of heat transfer due to vapor transfer is developed. Cold room snow samples screened for densities of 0.376 to 0.472 were used in snow beds where measurements of the steady-state temperature distribution were taken and the weight loss of the snow sample obtained at the completion of each experimental run. The essential part of the experimental apparatus is shown. The experimental technique consists of determining the effective diffusivity of water vapor through snow, which is subsequently used to calculate the contribution of heat transfer through the mechanism of vapor diffusion. The resultant equivalent thermal conductivity of snow due to vapor transfer (k sub v in cal/cm-C-sec) is represented in terms of air flow rates, ranging from about 2 to 40.0001 g/5q cm-sec. When there is no air flow through snow, k sub v contributes about 7.5% of the total value of the effective thermal conductivity of the snow (k sub e). For air flow rate of 10.0001 g/sq cm-sec or for a pore velocity of about 1.3 cm/sec, k sub v is about 19% of k sub e. Vapor pressure significantly affects the process of heat transfer in a natural snow cover.

Descriptors :   (*SNOW, THERMAL CONDUCTIVITY), (*HEAT TRANSFER, MATHEMATICAL ANALYSIS), WATER VAPOR, VAPOR PRESSURE, GAS FLOW, DIFFUSION

Distribution Statement : APPROVED FOR PUBLIC RELEASE