紧凑型缩尺模型风洞流道设计及其仿真验证

Compact Airline Design of an Automotive Scaled Model Wind Tunnel And its Computational Fluid Dynamics Validation

摘要:

汽车风洞设计中，地面积不足是常见的工程难题，因此为了符合风洞喷口和试验段长度设计的标准，不得不采用紧凑型流道设计来减小风洞占地面积，以保证流场品质和风洞能量比等风洞核心技术指标不降低。应用计算流体动力学仿真方法，分析评估被压缩的扩散段内流动分离及二次流风险，优化转角导流片尺寸和间距，确保转角4出口的流场均匀性和湍流度指标最优。提出汽车风洞工程经济性指标风洞占地面积比，对比基础设计方案，紧凑型流道设计风洞占地面积减少近30%。

关键词:汽车模型风洞;紧凑型流道计;流场品质;能量比;计算流体动力学;风洞占地面积系数

Abstract:

Inadequate land availability is a common engineering issue for automotive wind tunnel planning. To ensure no compromise of the design criteria for nozzle area and test section length， a compact airline design has to be adapted for smaller land occupancy. Meanwhile， the core wind tunnel specifications such as flow qualities and energy ratio shall also be guaranteed with no concession. Using computational fluid dynamics （CFD） simulation， the study has performed risk assessment regarding flow separation and secondary flows in shorten diffusors. Dimensions and spacing distance of turning vanes has been optimized as well for best flow uniformity and turbulence level at the exit of corner 4. Wind tunnel land occupancy ratio is proposed as the economic specification of wind tunnel engineering. Compared with the basic design， the compact airline gives approximately 30% saving of land occupancy.

Key words:automotive model wind tunnel;compact airline design;flow qualities;wind tunnel energy ratio;computational fluid dynamics (CFD);wind tunnel land occupancy ratio