Thermal resistance parameters of the air environment at various altitudes

摘要

The thermal properties of atmospheric air surrounding the human body at various altitudes are characterized with a system of parameters. This system comprises resistance of the air to convective heat transfer h_c~(-1) °C (W/m~2)~(-1) and to water vapour transfer h_D~(-1), s/m. The concept of 'evaporative resistance' h_e~(-1), hPa (W/m~2)~(-1)) following the similarity of the processes is introduced. In obtaining the altitude dependencies of investigated paramters, a respective heat transfer equationexpressing the rate of heat exchange at the boundary body surface -ambient air is applied. The use of the body thermal state of the established altitude dependencies is discussed. The concept of 'thermal stability' related to the evaporative resistanceparameter h_e~(-1) is introduced. This parameter is assumed as: (1) an indicator of the human body thermal stability and (2) distributor and predictor of environmental influence on the body thermal state.