| Most indoor high-temperature radiation sources in industrial buildings are centrally arranged,generating a large amount of radiant heat in a certain direction,that is,the radiant heat is extremely asymmetric.High temperature is a common physical occupational hazard factor of industrial enterprises.The Wet Bulb Globe Temperature(WBGT)index is currently the most widely used high temperature environment evaluation index,but WBGT can only be applied to the thermal environment evaluation of existing buildings,and cannot provide guidance for the design of the thermal environment of the building.At the same time,it takes a long time to test the standard WBGT value at the actual site,and it cannot be analyzed in time.In response to the above problems,the article has carried out research on the characteristics and evaluation methods of indoor high temperature environment under the condition of asymmetric radiant heat through experimental testing,regression analysis and numerical simulation.A local high-temperature environment experiment platform was built to test and analyze the indoor thermal environment parameters at different heat source temperatures,and the changes of indoor air temperature,air humidity,wind speed,directional radiation intensity and WBGT at different heat source temperatures were studied.The difference between the directional radiant temperature and the average radiant temperature under asymmetric radiant heat was discussed.It was found that the directional average radiant temperature at a distance of 1 m from the heat source was much higher than the average radiant temperature,and the radiant heat in all directions was extremely asymmetric.When the surface temperature of the heat source exceeds 200℃,the air temperature at1m and 2m away from the heat source exceeds 35℃,the directional radiant heat intensity exceeds 100W/m~2,and the WBGT also exceeds 28℃.At this time,measures to prevent heatstroke are needed.The cooling effect of the industrial spray fan on the local environment was analyzed through experiments,and the effects of air speed and relative humidity on the indoor high-temperature environment were studied.The results show that the low wind speed(0～2m/s)has a significant cooling effect on the thermal environment.When the air speed increases by 1m/s,the WBGT in the working area 1m away from the heat source decreases by 0.4～1.7℃.The higher wind speed(2～5m/s)has less effect on cooling the thermal environment.When the relative humidity increases by about 10%,the WBGT in the working area 1m away from the heat source drops by 0.2～0.8℃.The research results have guiding significance for the design of local air supply parameters.Correlation analysis and multiple regression analysis were performed on the experimental test data,and a WBGT calculation model based on four environmental parameters of air temperature,relative humidity,air velocity,and directional radiant heat intensity was established.The results show that the indoor air temperature and directional radiant heat intensity have a high linear correlation with WBGT,which satisfies the tests of multiple linear regression,and the predicted value of the indoor WBGT obtained from the calculation model is in good agreement with the measured value.As a simplified calculation method of WBGT value.Combined with numerical simulation,an evaluation method for indoor high-temperature environment under radiant heat asymmetry is proposed.The evaluation method was used to evaluate the WBGT of the indoor working area under different natural ventilation parameters of industrial buildings.This proves that the indoor thermal environment evaluation method proposed in this paper is feasible and reasonable under the condition of radiant heat asymmetry.The research results are of great significance for improving the high temperature environment and ensuring the safety and health of the workers. |
PDF Full Text Request