Hydraulic Study On Siphonic Drainage System Of Roof

The siphonic drainage system, also called press drainage system, is a more advanced roof drainage system in the world. It is applied widely in large-scaled workshop, exhibition, airport lounge and gymnasium whose roofs have large span and complex structure, and it's a valid way to solve roof drainage. But the siphonic roof outlet of system has complex hydraulic peculiaritys, high velocity of flow and limited capability of dealing with overflow. The error of any design might cause the system invalid or to be insiphonic, furthermore, it can lead to drainage hitch or make big noise, and overflow will appear when the rainfall exceeds the design value of tube. So we should make further studies to consummate the hydraulic peculiarity and the method of calculation continuously.In this thesis, I summarize the theoretical calculation method, applied scope and notice of siphonic drainage system, and point out the advantage of siphonic drainage system compared with gravitation drainage system. In the archetype experiment study of siphonic drainage tube, I adopt different tube diameter and different structural height to survey the drainage volume and press in different place. I observe various kinds of flow state, and get chief factors which influence hydraulic peculiarity of system as the tube diameter or structural height, and find out the relevance of factor to flux. I apply CFD Fluent software and adopt standard k-ε model and RNG k-ε model, then use finite volume method and second-order upwind scheme to discrete numerical model, while coupling numeration of velocity field and press is based on SIMPLE. In the numerical simulation of curved part of tube, siphonic drainage tube experiment system and multi-outlet siphonic drainage system, I make research on internal velocity and press of system in different project condition by changing the tube diameter of curved part, negative press value in tube export and improving the quantity of water gutter. This thesis first adopts a method of combining archetype experiment and numerical simulation to study the siphonic drainage system, test and verify the validity of experiment and numerical simulation, and makefurther study on system, it solves the problems of limited testing conditions, and has a logical results, it can provide a valid method for optimizing and designing the drainage tube-net system. The conclusion have referring value for study and design of siphonic drainage system.