The Study On Applicability Of The Physical Model Experiment For Long Highway Tnnel Ventilation

Tunnel ventilation of lang highway tunnel has become the problem more concerned inhome and aborad, the main methods of studying tunnel ventilation are numerical simulationand physical model test. The method of tunnel ventilation physical model test based on flowsimilarity theory establishes scale physical model and obtains distribution of velocity fieldand pressure field in tunnel by experiment. It can describe the complex flow phenomena intunnel and duct under complex ventilation, and cover the shortage which caused by “thelimitations of flow equations” in numerical simulation and become the main mean ofstudying highway tunnel ventilation. But in complex ventilation airflow organization iscomplex in tunnel, and now the study that the flow similarity theory and affinity self patternarea theory are whether applicable the physical model test of highway tunnel complexventilation is little. The paper taking the cross-harbor tunnel of the HongKong-Zhuhai-Macao bridge and the An Yuan tunnel, using flow mechanics theory, throughthe ways of theoretical derivation, model test and numerical simulation, analysis theserviceability of physical model test in complex tunnel ventilation, and conduct the study ofsemi-transverse exhausting ventilation of the tunnel and the tunnel blowing and exhaustingventilation with the shaft.1. With flow mechanics theory and based on the Nacier-Stokes equations, the paperhad deduced tunnel ventilation physical model experiment affinity theory——Reynoldsaffinity theory. Under the condition of Reynolds affinity theory, according to NikuratseTesting, the paper had ensured the experiment method of affinity self pattern area.2. Based semi-transverse ventilation of the tunnel and the tunnel exhaust ventilationwith the shaft, the paper analysis the flow organization in different tunnel ventilation, takinginto the flow organization equation, verifies the applicability of flow similaritytheory in semi-transverse exhausting ventilation of the tunnel and the tunnel blowing andexhausting ventilation with the shaft.3. Based on Reynolds affinity theory and model affinity self pattern area theory, themodel rate of semi-transverse ventilation physical model is1:9and the rate of the tunnelexhaust ventilation with the shaft physical model is1:22.5; ensuring critical speed of affinity self pattern area of semi-transverse ventilation physical model and tunnel exhaustventilation with the shaft physical model is1.75m/s、2.6m/s.4. Based on the filed testing on Qinling Zhongnan Mountain Highway Tunnelventilation, eatablishing computational fluid dynamic (CFD) simulation modle, comparingthe the result of filed testing and the result of its CFD simulation. Proposing the relisblityconditions of CFD simulation result is that CFD simulation modle friction coefficient isequal to tunnel friction coefficient.5. When the speed is greater then the critical speed of affinity self pattern area ofmodel, testing the friction coefficient of semi-transverse ventilation physical model andtunnel exhaust ventilation with the shaft physical model, verifying the applicationconditions of physical model experiment for semi-transverse exhaust ventilation and airejecting and blowing ventilation by verifying equal to the fticciton coefficient of physicalmodle section and the fticciton coefficient of its protopyte section and comparing with theresult of the physical modle experiment and the result of its prototype CFD simulation.6. Reseaching on the influence of the number and locationg of holes on the velocityfield and pressure field by semi-transverse exhaust ventilation physical model testing and itsprototype CFD simulation. Verifying the relisblity of semi-transverse ventilation CFDsimulation result by comparing the the result of its physical model experiment and the resultof its protopye CFD simulation.7. Reseaching on the influence of the locationg of short section and tennel length onthe velocity field and pressure field by physical model testing and its protoype CFDsimulation of air ejecting and blowing ventilation with the single shaft and air ejecting andblowing ventilation with the dual shaft ventilation. Verifying the relisblity of result of airejecting and blowing ventilation CFD simulation result by comparing the the result of itsphysical model experiment and the result of its protopye CFD simulation.