基于流固耦合的厢式中置轴挂车联合仿真

Co-simulation of van centre axle trailer based on fluid-structure interaction

厢式货车的迎风面积较大,在强风天气高速行驶有很大安全隐患,结构参数是影响车辆空气动力学的因素之一。基于Fluent和TruckSim单向耦合的方法,建立厢式中置轴挂车的空气动力学和多体动力学流固耦合联合仿真模型。通过计算流体动力学(Computational fluid dynamics,CFD)对厢式中置轴挂车进行气动特性分析,运用多体动力学模型进行侧风稳定性验证。利用可实现k—ε湍流模型进行数值模拟,得到厢式中置轴挂车双力矩中心处的气动系数曲线。建立气动系数的数学模型作为联合仿真的接口,仿真结果表明挂车与牵引车车厢之间的间隙对挂车气动特性有一定影响。以横摆角速度和侧向加速度作为评价指标,发现当车速为80 km/h时,间隙越大车辆越不稳定;当车速为40 km/h时,间隙越大可有效提高车辆的行驶稳定性。因此,提出用可伸缩牵引杆来解决中置轴挂车行驶稳定性的方法。研究结果可为考虑空气动力学设计的多节车厢类挂车提供参考。

The van truck has a large windward area,and there are significant safety hazards when it run in strong wind weather.Structural parameter is one of the factors that affect vehicle aerodynamics.Based on the one-way coupling method of Fluent and TruckSim,a co-simulation model of aerodynamics and multi-body dynamics fluid-structure interaction of the van centre axle trailer is established.The aerodynamic characteristic of the van centre axle trailer is analyzed by computational fluid dynamics(CFD),and the multi-body dynamics model was used to verify the crosswind stability.The achievable k-εturbulence model is used for numerical simulation,and the aerodynamic coefficient curve at the center of the bi-moment of the van centre axle trailer is obtained.The mathematical model of the aerodynamic coefficient is established as the interface of the co-simulation.The simulation results show that the gap between the trailer and the tractor carriage has a certain influence on the aerodynamic characteristics of the trailer.Taking the yaw rate and lateral acceleration as evaluation indicators,it is found that when the vehicle speed is 80 km/h,the larger the gap,the more unstable the vehicle;when the vehicle speed is 40 km/h,a large gap can effectively improve the driving stability of the vehicle.Therefore,a retractable drawbar is proposed to solve the driving stability of center-axle trailers.The research result can provide a reference for the multi-carriage trailers considering the aerodynamic design.