Investigation,Test And Numerical Simulation On Thermal Environment Of School Canteens In Winter

The safety and health of the school canteen is related to the health of the whole school teachers and students.Students spend most of their meal time in the canteen,so it is very important to have a clean and comfortable dining environment.At present,there are many problems in school canteens,which have a great impact on the dining environment.Especially in winter,the outdoor temperature is too low for natural ventilation.When indoor heating is used to adjust the ambient temperature,the phenomenon of insufficient indoor fresh air and cold air invasion often occurs.In addition to the hot and humid environment in the canteen is not ideal,the smell of lampblack is more serious.This paper makes a case study of a school canteen in Zhengzhou which adopts indoor multi-on-line heating system.Through questionnaire survey and field test,the environment of the canteen is investigated,and the existing problems are found out by analyzing various factors.Finally,effective solutions are proposed by combining with numerical simulation.It provides reference for the design and later operation of the thermal environment of the school canteen in the future.In this paper,we first conducted a questionnaire survey on the dining people of each layer of the school canteen,including the feeling of indoor temperature and humidity,the ventilation situation in the canteen and the existence degree of lampblack smell.Combined with the visit and research,understand the basic spatial layout of the canteen,heating forms and the layout of supply outlet.After investigation,it is found that the temperature distribution of each floor is uneven,and the upper and lower floors are colder and the upper floors are hotter.The student of the third floor feel that it is hot.The ventilation of the third floor is the worst,and the evaluation of the dining environment is also the worst.Respondents generally felt that the air was drier at all levels.Overall,teachers and students generally hope to improve the comfort of the restaurant environment,reduce the degree of smell such as lampblack,and strengthen indoor ventilation to enhance the effect of ventilation.Compared with the evaluation results of each floor,the dining environment of the third floor was the worst,so a more detailed field test was carried out on the third floor.Secondly,the temperature and relative humidity of each layer are measured,and the causes of the corresponding phenomena in each layer are analyzed,and the corresponding improvement measures are proposed.The air supply and exhaust volume of the third floor are measured,and the measurement results are analyzed,the reasons for the existence of odor such as lampblack are found out,the improvement measures are put forward,and the solution to the bad ventilation situation is put forward from the perspective of the balance of air volume.Through the analysis of various factors affecting the thermal environment of the canteen and the improvement measures,it provides a theoretical basis for the design of the canteen of HVAC specialty in the future,so as to improve the thermal environment comfort in the use of the canteen.Finally,a physical model of the school canteen was established for numerical simulation,and the accuracy of the model was verified by comparing the simulated velocity field and temperature field with the measured results.Then,the improved scheme is simulated to simulate the influence of different air supply locations and air supply temperatures on the temperature and velocity fields of the studied model.Finally,the best solution is determined to solve the problems existing in the school canteen and improve the comfort of the thermal environment of the canteen.