Evaluation of the Convective Heat Transfer Coefficient of the Human Body Using the Wind Tunnel and Thermal Manikin

Abstract

This study was conducted to determine the convective heat transfer rates (α c ) of each part of the human body and of the whole body when a human is in a standing or sedentary posture in an outdoor environment. A wind tunnel was used to reproduce the side wind in an outdoor environment, and a naked thermal manikin was used to control the detailed thermal characteristics of the human body. Accurate radiation analysis was employed to evaluate the radiation effect of the thermal manikin. The α c s of the whole body and of each part of the body increased along with the wind velocity in the standing and sedentary postures. In the standing position, the α c s of the head, feet, and hands, the terminuses of the human body, were about 20-30% higher than the average α c of the whole body. In the sedentary position, the α c s of the head, hands, and arms, the terminuses of the human body, were about 20% higher than the average α c of the whole body. The α c s in this study were lower than those obtained from the climate chamber. Meanwhile, they were similar to or slightly higher than those from the results in wind tunnels.

Micro-environmental control for efficient local cooling

“…The total heat flux of each segment consists of radiant heat flux and convective heat flux . And the convective heat flux equals to the product of the convective heat transfer coefficient and temperature difference between the surface and room air .The convective heat transfer coefficient obtained in this study was compared with some previous studies[25][26][27]. de Dear et al[25] used a purely experimental approach which measured the total sensible heat flux with a thermal manikin and isolated the convective part from it by covering the manikin with the low-emissivity material.…”

“…Various studies have been done, either by experiments or simulations, to determine the heat transfer flow rates over a human body in a still-air or uniform wind condition. The most advanced method is using a human-shaped thermal manikin with the control of surface temperature or heat flux [25][26][27]. However, very few studies were conducted to investigate the effect of a single air jet on the heat transfer flow rates of a human body.…”

“…The accuracy of this method depended on the measurement accuracy, including temperature and heat flux measurements. Yang et al[27] used a hybrid method, with which they measured the total sensible heat flux using a thermal manikin and subtracted the radiant heat flux obtained from numerical simulation to get the convective heat flux. The accuracy of this method also depended on the accuracy of the measurement since obtaining the radiant heat flux by numerical simulation also required accurate surface temperature measurement.…”

Influence of Internal Structure and Composition on Head’s Local Thermal Sensation and Temperature Distribution

“…In order to keep the body in a comfortable state, the relative balance of heat production and dissipation must be guaranteed [16,[19][20][21][22]. A lot of studies [23][24][25] have been carried out on heat generation, heat dissipation and heat exchange with the environment of the body. Some scholars carried out the experiment with subjects, to study the heat generation and dissipation [26][27][28][29][30], and obtained the thermal response of the human body to the environment, which includes the temperature change and skin temperature distribution, as well as the subjective thermal sensation and thermal comfort state of subjects [7,11,20,29,[31][32][33][34].…”

Experimental investigations of heat transfer coefficients of cutting fluids in metal cutting processes: analysis of workpiece phenomena in a given case study

“…Rahman and Kumar 11 used air blowing over drying vegetables and found the values of h to be around 1.5 and 2.5 × 10 W · m −2 · K −1 . Yang et al 17 used air flowing around a human body shape, and the values were around 0.5 and 2.5 × 10 W · m 2 · K −1 for an air speed between 0.2 and 1.4 m · s −1 . In quenching metals for heat treatment applications, water was the fluid and Al–Cu alloys were the metal bodies in the cooling process.…”