Large-eddy Simulation Of Air Distribution Within The High-speed Train

With the sixth speed-raising of the railway in our country, the train at speed of 200km/h has been widely used in the railway passenger traffic. Simultaneity, the technologies on high-speed air-conditioning trains have been gulped down by domestic enterprises gradually, they also ameliorated them to fiting the situation of our country. The further improvement of the speed will bring new challenges to train design, traction driving, bogie design, train braking, and the indoor environment improvement of the train.Air supplying approach, the speed and temperature of the supplying air in the high-speed air-conditioned train affects the evaluation of comfort obviously. If an accurate three-dimensional indoor air velocity distribution and temperature distribution could be got, it is no doubt to set the most impotant base for improving conpartment comfort and optimization of air supplying in high-speed train. After analyzing the drawbacks of the past turbulence model.Train Set With Power Car of CRH₂ was studied and the large eddy numerical mode of turbulence was established. Airflow organization of high-speed train was studied by large eddy simulation method of FLUENT6.3.26.The mathematical mode of CRH₂ was established. The overall space was deal with by domain discretization. The whole of calculated domains was constituted by the complete continuous control volume. The regulation geometric was application of structured grid and the complexity geometric was application of unstructured grid. Wall-bounded turbulent flows were used by the boundary layer treatments and the regions of slightly larger than the flux density was encrypted by the grids. To enable the full development of turbulence, the exhaust airs at the entrance and exit have been calculated to expand the domain of the pre-treatment. The heat transfer of the wall retaining Structure and heat flux from windows was calculated through the first-order harmonic approximation, at the same time boundary conditions was taking into account, such as passengers' heat. Subgrid stress of the control equation was closed by dynamic Smago rinsky-Lilly model. The wall boundary conditions for the wall function in the large eddy simulation are treated in the way as the balance layer model and the velocity of the balance layer was adopted by logarithmic distribution. Convective kinematics was discreted by third-order accuracy QUICK scheme and the diffusion kinematics. The coupling problem of pressure and velocity was adopted by the ressure correction equation of the SIMPLEC and the interpolation of the pressure was used PRESTO scheme. The method in time discrete was used Adams-Bashforth scheme.Finally, parallel computing has been the adoption of the numerical results within airflow organization in the passenger compartments of the air-conditioned high-speed train.The results provide a basis for optimization for air conditioning and comfortable environment in the high-speed train passenger compartment.