基于组合代理模型的变海拔工况车辆动力总成流动性能优化

随着海拔高度的增加,特种车辆的动力总成的流动性能会受到极大的影响。但是,受限于地域的影响,特种车辆动力总成流动性能的研究基本针对的是3 000 m以下的海拔工况,更高海拔环境的相关研究较少。因此,对更高海拔的特种车辆动力总成的流动性能进行研究十分重要。首先,建立流动结构的参数化仿真模型,揭示从海拔0 m (平原工况)到4 500 m(高原工况)特种车辆的动力总成流动特性变化规律。然后,为了提升特种车辆的变海拔适应性,基于组合代理模型对动力总成流动结构进行优化。结果表明,优化后的叶片扭曲度更大,且向着与旋转方向相反的方向偏移。优化后的叶轮使得上游总压分布更加均匀,叶片附近的低速区明显减少,叶片尾缘处的高总压和高马赫数的范围变大。在高原工况,特种车辆动力总成的流量增加7.7%,功率下降2.2%。在平原工况下,流量基本保持不变,功率下降12.03%。研究结果为高海拔车辆动力总成流动性能分析与优化设计提供借鉴与参考。

Optimization of Powertrain Mobility Performance of Vehicles with Variable Altitude Working Conditions by Ensemble of Surrogate Models

As the altitude increases, the powertrain mobility performance of special vehicles can be greatly affected. However, limited by the influence of the region, the research on the mobility performance of the powertrain of special vehicles is basically aimed at the altitude working condition below 3 000 m, and there are few related researches on the higher altitude environment. Therefore, it is very important to study the flow performance of special vehicle powertrains at higher altitudes. First, a simulation model of flow structure parameters is established to reveal the change rule of the powertrain flow characteristics of special vehicles from an altitude of 0m(plain condition) to 4 500 m(plateall condition). Then, in order to improve the variable altitude adaptability of special vehicles, the powertrain flow structure is optimized based on the ensemble of surrogate model. The results show that the optimized blades are more twisted and shifted in the opposite direction to the direction of rotation. The optimized impeller makes the upstream total pressure distribution more uniform, the low-speed zone near the blade is significantly reduced, and the range of high total pressure and high Mach number at the blade trailing edge becomes larger. In plateau conditions, the flow rate of the special vehicle powertrain increases by 7.7%, and the power decreases by 2.2%. In plain condition, the flow rate is nearily the same, and the power decreases by 12.03%. The study results provide a reference for the analysis and optimization design of the powertrain flow performance of high altitude vehicles.