T-PVC Tee Local Head Loss Experiments And Numerical Simulation

Pipe tee is one of the most important unit of Water Distribution Networks,connected pipe connectionsflow situation is more complicated, the local head loss calculation of pipe tee helps determine the correctlocal energy loss of flow in the pipe network. This paper selected the more commonly used severaldiameter tee on the market,determined through experiments under different boundary conditions withdifferent diameters tee local head loss, as well as influencing factors for the optimization of irrigation pipenetwork layout and pipe works calculated to provide accurate scientific basis. Through theoretical analysisand experimental verification, and numerical simulation method and experimental results compared, itprovided an effective approach for the study of the characteristics of local resistance.Diameter50mm、75mm、90mm PVC pipes were used for the experimental of for the PVC pipe teelocal head loss.The local head loss coefficient of variation was obtained through the analysis of testresults:Tee local head loss was affected by the Reynolds number，there was a quadratic relationship betweenTee local head loss and the Reynolds number. At the entrance Reynolds number10000, the local head lossof the three kinds of diameter pipe was relatively small. The smaller the diameter of the tee was, the moreintense the diversion of water flow turbulent was.There was little difference between the local head loss oftwo branch pipes.Degree of bending of the water pipe was distinct by split ratio. The two tube velocities were similarand the generated vortex interaction was smaller when the split ratio change from0.4to0.6, relatively thechange was small in the local head loss. In other split ratio conditions, the difference was large in flowvelocity within the two tube greater flow rate at the branch pipe flow turbulence and swirl strength, anotherbranch pipe at the water disturbing effect of the increase, and therefore have a greater local head loss. Sowhen the pipe tee was used to water supply, the diversion should be better at the control of0.5.The diameter of the branch pipe with the competent diameter ratio had also affected the local headloss. Experiment, the with branched pipe diameter increases, the local head loss was reduced, the smallerthe ratio, the flow rate of the branched pipe was relatively larger, the flow rate of the cross-sectional areachanges, the flow rate distribution was nonuniform, causing local head loss.So the effects of diameter ratioshould be consider in engineering design, and try to avoid the small diameter of the branch pipe diameterthan competent.Numerical simulation and experimental results were basically consistent with the local head loss coefficient of the experimental values of the relative error between the simulated and minimum of3%,maximum to36%. Selected turbulence model in this paper was an accurate description of the pipe flowvelocity turbulence and pressure fluctuation, the RNG k-epsilon turbulence model suitable for suchsimulations to achieve convergence stability; given by simulating the local head of the110mm diameter teethe relationship between the loss coefficient and the inlet Reynolds number curve. T-tee, local resistance toa dramatic role in the general location was in the mainstream and tributaries of convergence and collisionposition, with the extension of the axial distance, and its role would be gradually weakened, until itdisappeared. Water bending was caused by the shearing of the fluid swirl intensity, the pressure distributionof the gradient magnitude were important factors to affect the local head loss.