Simulation And Optimization Strategy Of Outdoor Thermal Environment In A University Campus

The comfortable campus environment can provide good conditions for the daily life and teaching activities of teachers and students.The campus function is more divided,the living density is bigger and the personnel activities are complicated and changeable.Therefore,it is very important to study the campus wind and heat environment.This paper takes a university campus in Jinan as an example,use CFD and wind tunnel test to evaluate and optimize the campus thermal environment.The main contents are as follows:Firstly,the evaluation criteria of "green campus evaluation standard","green building evaluation standard","urban residential area thermal environment design standard" and WBGT thermal comfort evaluation coefficient are analyzed.This paper summarizes the evaluation criteria for the study of campus wind-heat environment.Secondly,according to Jonas Allegrini's wind tunnel experiment,the simulation experiment is carried out to verify the turbulence model and boundary condition of the simulation experiment.;appropriate grid precision is selected by GCI grid independence index comparison under current computer resources.Thirdly,Google Sketchup and AutoCAD software is used to build a complete threedimensional campus model including buildings,roads,greening,water environment,mountain and 30 m height of the plot.The influence of different factors on the outdoor thermal environment of campus was analyzed by using PHOENICS computational fluid dynamics software.It is found that the outdoor environment and thermal environment of the university campus meet the requirements of the "Green Campus Evaluation Criteria" on the outdoor environment.Due to the change of the terrain,the average outdoor wind speed and temperature of the campus is stratified with the height change.In the winter wind direction,the wind speed in the green area of the campus is less than 2.6m/s with windward side buildings and leeward mountain block,In addition to the first row of windward building,the building before and after the pressure difference in the range of 2Pa ~ 4Pa,is conducive to the winter wind and energy saving effect.In the summer and the transition season,the average wind speed in the campus is less than 3.0m/s,and the wind pressure on the outer surface of the outer openable window is more than 0.5Pa,which is beneficial to the indoor natural ventilation.In the summer dominant wind direction,the campus surrounding buildings and the mountain has obvious impact on the campus wind field and temperature field.The green area of the campus center has played a certain role in cooling the buildings under the dominant wind direction.The high temperature area in the campus is mainly concentrated in the outdoor playground,the east gate square and the wide road,and the temperature is up to 37?.The surface temperature of the campus building is significantly higher than the ambient temperature.The central greening area of the campus has played a certain role in cooling the buildings on the leeward side.The average temperature of the campus pedestrian height is 30?~35?,and the outdoor thermal comfort evaluation coefficient is 22?<WBGT<24?.Finally,the use of building shade,roof greening and greening the separation zone is used to improve the outer surface temperature of the outer surface of the building and the concrete floor.The influence of roof greening on the external surface temperature of the campus building and the influence of the green belt on the ambient temperature of the outdoor playground and the square are verified by the simulation method.This study provides a large amount of reference data for evaluating and optimizing the campus wind-heat environment using CFD method.