| Numerical simulation technology is an important research tool for studies andoptimization of flow measurement instrument. The similarity between numericalsimulation and real flow field has been the focus of many researchers. To get realinformation of flow field, we must rely on advanced experimental methods. Particleimage velocimetry (PIV) is a new flow visualization technique. Many researcherscombine numerical simulation and PIV experiments to verificate the similarity, whilerevealing the internal flow field flow. Based on wedge flowmeter, this paper usednumerical simulation and PIV technology and experimental methods, to research thecircular pipe flow over surface mounted triangle block.Several turbulence models in numerical simulation were studied, value of theparameter based on two turbulence models were detailed. Based on simplify mixinglayer flow model, controlequations were studied. Based on Bradshaw assuming andmixing length assuming, the turbulence model parameters a1and separated flowswere linked together. The impact of parameter a1on results was obtained. Based on3kinds of separated flow field, the impact of turbulence model parameters on numericalsimulation results was studied to verify the theoretical analysis conclusion. Based onthe theory of nonlinear eddy viscosity, using FLUENT software UDF technology, theturbulence model was optimizated.By PIV experiments, wedge flowmeter flow field was studied. Streamline,reattachment length, position of the core and boundary of recirculation zone wereobtained. Through the analysis of flow field data, obtained flow field transient flowconditions, revealing the whole process of vortex shedding, development anddisappear, downstream the wedge. Settings turbulence model parameters a1wasoptimized by compare the results of PIV experiment and numerical simulation results,which makes the numerical simulation results and PIV experiment results are moresimilar.By numerical simulation,5kinds of wedge flowmeter flow field were studied.The impact of different turbulence models on flow field was obtained. The impact ofparameter changes on flow field simulation was obtained. Sensitivity of simulationresults on discrete mesh was obtained. Through numerical simulation, a detaileddescription of the wedge flow downstream secondary vortex was made. By test, the measurement perfenmence of7kinds of wedgeflowmeter werestudied. Discharge coefficient, flow measurement repeatability were obtained. Awedge with best linearity and reproducibility was obtained; based on flow analysis,numerical simulation and the real flow experiments, several wedge pressuredownstream positions were studied. The best measurement position was obtained.The numerical simulation, PIV and real flow experiments combining threetechnologies used in flow sensor research method can be extended to other types offlow sensor design and research. |
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