Study On The Assessment And Prediction Of Drainage Capacity In High-Rise Residential Drainage System

With the rapid development of high-rise buildings,the storey number of residential buildings is increasing and increasing,sanitary devices used are increasing and increasing and the design of drainage system is becoming more complicated,too.At the same time,with the improvement of living standards,people pay more attentions on the safety performance and health performance of drainage system.As the safety barrier for the construction of drainage pipes,water seal plays a very important role on the sanitary condition of water environment and the health and safety of the people.Therefore,to keep the safety of the drainage system means to ensure the water seal not destroyed.A series of the research were conducted on the evaluation of drainage capacity of drainage system,which are introduced in this paper.They provide basic data and design standard for the safety of drainage system of high rise housing buildings by means of the combination of theoretical analysis and full-scale experiment studies on the testing platform of housing drainage performance,the research on the cause of pressure fluctuation and the law of the pressure distribution in different drainage system,the evaluation method on drainage capacity and the establishment of drainage capacit y prediction model.The main contents and conclusions of this paper are as follows:(1)The cause of pressure fluctuation in the system and laws of pressure distribution in drainage vertical pipe in constant flow methodIt is found that the moving of the fluid in the vertical pipe has various patterns with the different drainage flow rate.In particular,the phenomenon of "dispersion-atomization" from continuous flow to discontinuous flow has been found which not only changes the state of the flowing medium but also changes the properties of the flowing medium.By analyzing the causes of the water phase transition,expounding the pressure fluctuation mechanism in the drainage vertical pipe theoretically,measuring the density of the mixture of water and air in the center of the vertical pipe and estimating the magnitude of the influence of the "dispersion-atomization" on the pressure fluctuation,it is clear that the "dispersion-atomization" has great influence on the interior air pressure.In addition,an analysis on the parameters which influenced on the pressurefluctuation in the vertical pipe has been done according to the dimensional analysis principle and the relationship between the characteristic pressure and the main control parameters of different drainage systems have been given including vent system through the roof,specific vent system and special vent system with single pipe.According to an experimental scheme in which single variable principle is adopted,the curves of pressure distribution characteristics and laws are gained as well as the relationship between characteristic pressure and main control factors(pipe diameter,height of drainage system and rate of flow).They will provide the basis for the forecast of drainage capacity and design of drainage system on super high-rise buildings.(2)Research on the evaluation of the drainage capacity of high-rise residential drainage systemBy using the constant flow method and the instantaneous flow method,doing full scale experimental research on the water seal loss of various sanitary ware,the relationship between the loss of the water seal and pressure is analyzed and finally the criteria of the drainage capacity in residential drainage system is put forward.Using the constant flow method and the instantaneous flow method,doing the full scale experimental research on 14 different types of drainage systems,including vent system through the roof,specific vent system and special vent system with single pipe,the drainage capacity of three systems are evaluated,thus the drainage capacity values of them are gained.The comparison between the values and maximum design drainage capacity in the Code for Design of Building Water Supply and Drainage(GB50015-2003(2009 edition))will be the proposal and basis for the revise of the Code.(3)The prediction model of drainage capacity in super high-rise residential drainage systemBased on the full scale experimental research,using dimensional method and regression analysis method,the prediction model of the drainage capacity in super high-rise residential drainage system has been established.A kind of software by programming experimental result has been developed which could be directly used in the design of the drainage system in super high-rise buildings.By means of searching the air flow-field and the condition of water flow using numerical simulation methods,confirming a calculation model,the distribution law in vertical pipes will be put forwards,a regression analysis will be done and the corresponding prediction model will be established,too.