高速列车内气流组织的大涡模拟

【作者】 匡骁；

【导师】 齐朝晖；

【作者基本信息】 中南大学 ， 供热、供燃气、通风及空调工程， 2009， 硕士

【摘要】 随着我国铁路全面进入第六次大提速之后,时速可达200km以上的动车组已广泛应用于铁路客运运输上,在此高速空调列车的相关技术也在逐一被国内企业消化吸收,并根据本国的具体国情加以革新和改进。列车运行时速的进一步提高,将使列车的外形设计、牵引传动技术、转向架技术、制动技术以及列车室内环境面临新的挑战。高速空调列车内送风方式,送风气体的速度、温度等对乘客的舒适度影响明显,如果能准确得到室内气流的三维速度分布和温度分布情况,将无疑对改善车厢内乘客的舒适度和优化高速列车的送风方式提供最重要的依据。本文在详细分析过去湍流模型的弊端之后,以动车组CRH₂为研究对象,建立湍流大涡数学模型。应用FLUENT6.3.26软件中的大涡数值模拟方法对高速列车内的气流组织进行了研究。本文对动车组CRH₂建立了数学模型,对整体空间进行分区域网格处理,把所计算的区域划分成连续的控制容积,规则几何区域应用结构型网格,复杂几何区域应用非结构型网格,在壁面处采用了边界层处理,热流密度大的区域进行了网格加密;为使湍流得到充分发展,送风入口处和排风出口处都进行了扩大计算域的前处理;通过一阶谐波近似计算了车厢壁面的传热量以及车窗热流量,考虑了乘客散热等边界条件。用动力Smagorinsky-Lilly模型来封闭控制方程中的亚格子应力,大涡数值模拟壁模型中采用了修正后的平衡层模型,平衡层中的速度分布采用了对数分布。对流项采用了三阶精度的QUICK格式来离散,压力与速度的耦合采用了SIMPLEC压力修正方程,压力插值项选择PRESTO格式,在时间离散方法上采用了Adams-Bashforth格式。最后通过并行运算得到了高速列车内气流组织的数值结果。本文的计算结果对高速空调列车内送风方式的优化,以及列车车厢内的舒适度改善提供准确、可靠的依据。更多还原

【Abstract】 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.更多还原