2021 Volume 46 Issue 286 Pages 47-53
With an increase in the number of extremely hot days, the wet-bulb globe temperature (WBGT) is increasingly being used as an index of health management to prevent heatstroke at outdoor events and construction sites in the middle of the summer. WBGT is composed of natural wet-bulb, globe, and dry-bulb temperatures. However, these parameters are not estimated directly in numerical simulations such as CFD. Therefore, in order to predict WBGT by numerical simulation, it is necessary to convert simulation outputs such as air temperature, humidity, wind velocity, and radiative heat fluxes into natural wet-bulb and globe temperature. However, conversion formulas used in the general air-conditioning field are not based on whether the outdoor environment is greatly affected by solar radiation and wind velocity; therefore, the value of WBGT can be underestimated by using these formulas. In this paper, a conversion method based on the heat balance equation of the thermometer is proposed, and the effect of different conversion formulas on WBGT is discussed. In a case study, the calculation results based on the heat balance equation indicated a higher value of WBGT compared with that obtained using conventional methods.
