Comparative Analysis And Numerical About Six Low Reynolds K-? Models In Offset Jet And Wall Jet

Numerical simulation is an important method to deal with engineering turbulence.The advantage of RANS turbulence model in numerical simulation is that it has high computational accuracy and does not occupy too much computer resources.RANS turbulence model contains different turbulence models.It is very important to choose the appropriate turbulence model for numerical calculation,k-? two equation model is one of the most widely used turbulence models in engineering.Offset jet and wall jet are widely used in engineering turbulence.Such as air deflecting device,fuel injection system,Combining numerical simulation method to study such problems has significant engineering significance Turbulence model has some limitations in dealing with turbulence problems.When different turbulence models are used to simulate the same turbulence problem,the computational accuracy is different.However,the applicability of different turbulence models to numerical simulation of offset jet and wall jet has not been clearly studied.In this paper,the standard k-? turbulence model and the low Reynolds number k-? turbulence model are used to numerical simulation of offset jet and wall jet under different conditions.Compared with the experimental data,the applicability of different turbulence models to such physical phenomena can be obtained.First of all,in this paper,the standard k-? turbulence model,AB mode,LB model,LS model,YS model,AKN model and CHC model are used to numerically simulate the ofset jet under different working conditions,Including normal emperature jet,heating jet,constant temperature wall condition.The difference of velocity and temperature and surface heat transfer coefficient calculated by different models is compared.The details are as follows:(1)In the numerical simulation of the offset jet with offset ratio of 3,5 and 7.Compared with the surface friction coefficient and velocity,The calculated results of AKN model are most similar to the experimental results.Although the results of the standard k-? turbulence model in the high Reynolds number region(far from the wall region)are similar to the experimental values,However,the calculated results are quite different from the low Reynolds number k-? turbulence model near the wall.All turbulence models underestimate the maximum velocity,attenuation of the jet.AKN1 and AKN2 models obtained by changing the model coefficients of the AKN model,The results of the two models are all improved.(2)In the numerical simulation of the offset jet with offset ratio of 0,3 and 7,By comparing the temperature field,it is found that none of the above turbulence models can accurately predict the maximum temperature attenuation of the jet.On the whole,the AKN model performs best.The velocity and pressure fields calculated by different turbulence models are also slightly different,but the overall trend is basically the same.(3)Due to the complexity of the near wall region,the results of different turbulence models in this area are the largest.Numerical simulation of wall jet under constant temperature wall by using different turbulence models.By comparing the calculated results of temperature field and velocity field with the experimental data,The performance of different turbulence models in the near wall is compared and analyzed.