Three-dimensional simulation of the convective heat transfer coefficient of the human body under various air velocities and human body angles

Abstract

This study aimed to investigate the effects of air velocity and human body angles on the convective heat transfer coefficient (hc) of the whole body and body segments. A 20-zone computational thermal manikin and climate chamber were constructed using a three-dimensional body scanning technique and ANSYS software. Subsequently, the hc values were calculated through computational fluid dynamics simulation and validated against the measurement and simulation results in the literature. Then, 50 cases (10 air velocities ranging from 0 to 20 m/s and 5 human body angles of 0°, 45°, 90°, 135°, and 180°) were considered to further analyze the combined effects of air velocity and human body angle on hc. The results indicated that the hc values of both the whole body and body segments increase exponentially with the air velocity. The whole body hc increases by approximately 23 times when the air velocity increases from 0.2 to 20 m/s. On the other hand, whole body hc is lower at a human body angle of 90° than at other angles; the human body angle has a significant effect on the hc of body segments. The difference in the hc of the whole body does not exceed 8.5 W/m2·K for the five human body angles, but the largest difference for the body parts reaches 52 W/m2·K. Finally, the combined effect of air velocity and human body angle on hc was expressed by a regression equation. This study can offer insights into the heat transfer process between the human body and its thermal environment, as well as human thermoregulation and skin burn injuries.