Study On The Airflow Organization Of The Sliding Door Opening And Closing Process On The Existence Of Indoor And Outdoor Temperature Difference In The "Flat Epidemic Combination" Operating Room

Since the global outbreak of the COVID-19 in early 2020,the strategy of the so called ‘normal-epidemic available’(NEA)type operating room has become a practical need that is worth considering.The plane layout and pressure distribution of the ‘NEA’ operating room are much simpler than that of the special negative pressure operating room for treating infectious disease patients.It means that during the epidemic period,the pressure of the positive pressure operating room for ordinary patients is temporarily changed from positive pressure to negative pressure,but the envelop structure of the operating room is not changed.This structure may have the risk of the virus leakage.How to prevent or reduce the virus leakage of this new type of operating room is very important,but so far there is no result in this field that can be used or referenced.Based on the ‘NEA’ strategy and taking the operating room of a general hospital as the object,the airflow pattern and distribution characteristics are simulated by using numerical methods in the present study.According to the analysis of the simulation results of the influence of the door opening process on the pollutant overflow effect of the ‘NEA’ operating room,the inhibition effects of three measures to reduce the pollutant overflow of the ‘NEA’ operating room are discussed,such as the variation of indoor and outdoor temperature difference,increasing the exhaust air volume of the operating room,and installing the air curtain at the sliding door.The results show that the pressure difference between the operating room and the corridor disappeared rapidly in less than one second after the sliding door was opened,so there is a high risk of pollutant overflow in the operating room.Its main characteristics are that the pollutants in the corridor are mainly concentrated in the lower space of the corridor in summer,and mainly accumulated in the upper region of the corridor in winter.The amount of pollutants overflowing from the operating room to the corridor in summer and winter are positively correlated with the temperature difference,but the pollutants within the human respiratory height range of the corridor(1.1m≤h≤1.5m)are affected by the coupling effect of inertia-thermal buoyancy and the amount of pollutants.The number of pollutants are not clearly shown to be positively correlated with the temperature difference.For the most unfavorable temperature difference between the inside and the outside of the operating room,i.e.,4o C in winter and 1o C in summer,when the operating room and the corridor are isothermal,the amount of pollutants overflowing from the operating room into the corridor and the pollutants within the human respiratory height range of the corridor(1.1m h 1.5m)are the least.During the time span of opening-closing of the sliding door,temporarily increasing the exhaust air volume of the operating room and forming a stable air curtain in front of the door can effectively reduce the risk of pollutants from the operating room spilling into the corridor.Therefore,according to the numerical results,it is suggested that the indoor exhaust air volume temporarily increased during the opening-closing of the door in the ‘NEA’ operating room should not be less than 2.50 m3/s in summer,and 2.65 m3/s in winter.In addition,it is recommended that the blowing volume of the air curtain air outlet can be set at 0.15 m3/s in summer,and 0.2 m~3/s in winter.