Study On The Effect Of Door And Window Coupling On Gas Explosion In Kitchen

In recent years,natural gas explosion accidents have occurred frequently in China,and the kitchen is a high-risk place for natural gas explosion accidents,causing a large number of casualties and property losses.Therefore,the prevention and control of civil natural gas explosion accidents has important practical significance for promoting urban safety and stable economic and social development.The explosion overpressure and high-temperature flame of natural gas in the kitchen are usually released to the outside through weak walls such as doors and windows,forming a multi-port coupled explosion venting process.The differences in parameters such as the area,position,and opening mode of doors and windows aggravate the complexity of the explosion venting process and the uncertainty of the distribution of indoor and outdoor disasters.Therefore,it is necessary to systematically understand the interaction mechanism of door and window in the process of natural gas explosion venting,as well as the distribution characteristics of indoor and outdoor explosion disasters under the synergistic effect of door and window.In this regard,this paper studies the influence of door and window characteristic parameters on the evolution of door and window coupled explosion venting flow fields and disaster distribution by means of computational fluid dynamics technology.The main conclusions are as follows:(1)The vent mechanism of a natural gas explosion under the coupling of doors and windows is revealed.The natural gas explosion in the kitchen presents a typical bimodal structure under the coupling effect of doors and windows.The first peak is formed by the opening of the window,and the second peak is caused by the combined effects of the maximum indoor flame area,the secondary explosion outside the window,and the opening of the door.The interaction between the door and the window is reflected in the fact that the release of the window consumes a lot of explosive energy and delays the opening time of the door,while the release of the door reduces the lifting effect of the secondary explosion outside the window on the indoor overpressure.Compared with the single vent,the maximum indoor peak overpressure,external high temperature area,and high temperature duration under the door and window coupling vent are shorter.(2)The influence of the relative position of doors and windows on the evolution of explosion disasters is explored.By increasing the distance between doors and windows,the opening order of doors and windows does not change.The peak value of indoor overpressure is less affected by the relative position of doors and windows,while the distribution of external disasters is very sensitive to this.The door vent has an inhibitory effect on the peak overpressure outside the window,and this inhibitory effect increases with the shortening of the distance between the door and the window.(3)The influence of the opening pressure and area of the window on the coupled explosion venting of the door and window is clarified.With the increase in the opening pressure of the window,the opening order of the door and window experienced the evolution process of the window opening first,the door and window opening at the same time,and the door opening first.As a result,the indoor overpressure curve gradually changed from a double peak to a single peak structure,and the secondary explosion outside the window disappeared.The indoor peak overpressure under different window areas has a bimodal structure,but as the window area decreases,the maximum indoor peak overpressure increases first and then decreases.With the increase in window area,the external flame velocity increases first and then decreases,the peak overpressure outside the window increases gradually,the peak overpressure outside the door increases first and then decreases,and the safety distance of high-speed airflow outside the door increases first and then decreases.(4)The influence of door opening pressure and door weight on the coupling vents of doors and windows is summarized.As the opening pressure of the door gradually decreases,the opening order of the door and window gradually changes from the window opening first to the door opening first.The peak structure of the indoor overpressure curve is significantly affected by the opening pressure of doors and windows.When the door is opened first,it is usually a single-peak structure,and the other conditions are double-peak structures.The external peak overpressure,peak high temperature,and peak high-speed airflow all increased significantly when the window opened first.Although the weight change of the door does not change the opening order of the door and window,as the weight of the door decreases,the influence of the door on the release process of the window increases,the flame length outside the window gradually decreases,and the flame length outside the door gradually increases.