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Technical Paper
Genghua Liao, Shaoyun Sun, Kelong Lu, Qiang Fu, Kecheng Pan, Heinz Friz, Bo Li
The implementation of an advanced process for the aerodynamic development of cab-over type heavy trucks at FAW requires a rigorous validation of the tools employed in this process. The final objective of the aerodynamic optimization of a heavy truck is the reduction of the fuel consumption. The aerodynamic drag of a heavy truck contributes up to 50% to the overall resistance and thus fuel consumption. An accurate prediction of the aerodynamic drag under real world driving conditions is therefore very important. The tools used for the aerodynamic development of heavy trucks are wind tunnels and CFD. Wind tunnels have a number of limitations which make it difficult to predict on road performance of the truck. Such limitations are limited availability, blockage and pressure gradient effects, lack of road simulation and Reynolds number effects. While on the other hand CFD does not have such limitations the accuracy of CFD is often questioned and needs to be proven.
Journal Article
Fuliang Wang, Zhangshun Yin, Shi Yan, Jia Zhan, Heinz Friz, Bo Li, Weiliang Xie
Abstract The validation of vehicle aerodynamic simulation results to wind tunnel test results and simulation accuracy improvement attract considerable attention of many automotive manufacturers. In order to improve the simulation accuracy, a simulation model of the ground effects simulation system of the aerodynamic wind tunnel of the Shanghai Automotive Wind Tunnel Center was built. The model includes the scoop, the distributed suction, the tangential blowing, the moving belt and the wheel belts. The simulated boundary layer profile and the pressure distribution agree well with test results. The baseline model and multiple design changes of the new Buick Excelle GT are simulated. The simulation results agree very well with test results.
Technical Paper
Kebing Tang, Li He, Yao Zhao, Heinz Friz, Bo Li
Abstract The development of a new Dongfeng Heavy truck had very strict targets for fuel consumption. As the aerodynamic drag plays a crucial role for the fuel consumption, a low drag value had to be achieved. It was therefore essential to include evaluation and optimization of the aerodynamics in the development process. Because wind tunnel facilities were not available, the complete aerodynamics development was based on digital simulation. The major portion of the aerodynamic optimization was carried out during the styling phase where mirrors, sun visor, front bumper and aero devices were optimized for drag reduction. For optimizing corner vanes and mud guards, self-soiling from the wheel spray was included in the analysis. The aero results did also show that cooling air flow rates are sufficiently high to ensure proper cooling. During the detailed engineering phase an increase of the drag above the target required further optimization work to finally reach the target.
Journal Article
Shaoyun Sun, Yin-ping Chang, Qiang Fu, Jing Zhao, Long Ma, Shijie Fan, Bo Li, Andrea Shestopalov, Paul Stewart, Heinz Friz
Abstract In the development of an FAW SUV, one of the goals is to achieve a state of the art drag level. In order to achieve such an aggressive target, feedback from aerodynamics has to be included in the early stage of the design decision process. The aerodynamic performance evaluation and improvement is mostly based on CFD simulation in combination with some wind tunnel testing for verification of the simulation results. As a first step in this process, a fully detailed simulation model is built. The styling surface is combined with engine room and underbody detailed geometry from a similar size existing vehicle. From a detailed analysis of the flow field potential areas for improvement are identified and five design parameters for modifying overall shape features of the upper body are derived. In a second step, a response surface method involving design of experiments and adaptive sampling techniques are applied for characterizing the effects of the design changes.
Technical Paper
Shaoyun Sun, Yin-ping Chang, Xinyu Wang, Qiang Fu, Kelong Lu, Zuofeng Pan, Bo Li, Heinz Friz
Abstract A challenge for the aerodynamic optimization of trucks is the limited availability of wind tunnels for testing full scale trucks. FAW wants to introduce a development process which is mainly based on CFD simulation in combination with some limited amount of wind tunnel testing. While maturity of CFD simulation for truck aerodynamics has been demonstrated in recent years, a complete validation is still required before committing to a particular process. A 70% scale model is built for testing in the Shanghai Automotive Wind Tunnel Center (SAWTC). Drag and surface pressures are measured for providing a good basis for comparison to the simulation results. The simulations are performed for the truck in the open road driving condition as well as in an initial digital model of the aerodynamic wind tunnel of SAWTC. A full size truck is also simulated in the open road driving condition to understand the scaling effect.
Technical Paper
Yan Jiang, Jingyan Liu, Qiming Chi, Fang Lu, Bo Li, Amanda Learned, Rui Song, Heinz Friz
Abstract The recent facelift of the Chinese version of the VW Bora incorporated several changes of the styling of the upper body. In particular, front facia, A-Pillar and rear end were subject to design changes. As major effects on the aerodynamics performance were not expected, extensive wind tunnel testing for the upper body design changes was not included in the development plan except for final performance evaluation. Nevertheless, an aerodynamic study of the effects of the design changes was undertaken using a CFD based process. At the same time, the facelift offered the opportunity for reducing the aerodynamic drag by improving the underbody flow. The design of the engine undercover and the wheel spoilers were considered in this effort. For this purpose the CFD based aerodynamic study was extended to include respective design features.
Technical Paper
Wei Yang, Xuemao Zhou, Jing Peng, Bo Li, Long Wu, Heinz Friz
Abstract The Wuling Rongguang is a small van which uses a mid-engine layout where the engine is located underneath the floor panel in-between front and rear wheels. A particular challenge for this kind of layout is the protection of the engine against soiling. Typical protective measures consist of large mudguards in combination with an engine cover. While needed for soiling protection, these parts can have a strongly adverse effect on aerodynamic drag. This paper describes process and the results of the aerodynamic optimization of the underbody of the Wuling Rongguang. Because design changes had to be evaluated for aerodynamics performance as well as for their effect on the soiling, a digital approach was used which allowed to do the soiling analysis as a post processing to the flow simulation. As a first step, a baseline model was built and analyzed. This included the development of a soiling model taking into account wheel spray and splashing effects.
Journal Article
Ming Jiang, Huaizhu Wu, Kebing Tang, Minsuk Kim, Sivapalan Senthooran, Heinz Friz, Yingzhe Zhang
The engineering process in the development of commercial vehicles is facing more and more stringent emission regulations while at the same time the market demands for better performance but with lower fuel consumption. The optimization of aerodynamic performance for reduced drag is a key element for achieving related performance targets. Closely related to aerodynamics are wind noise and cabin soiling and both of them are becoming more and more important as a quality criterion in many markets. This paper describes the aerodynamic and aero-acoustic performance evaluation of a Dongfeng heavy truck using digital simulation based on a LBM approach. It includes a study for improving drag within the design of a facelift of the truck. A soiling analysis is performed for each aerodynamic result by calculating the accumulation of particles emitted form the wheels on the cabin. One of the challenges in the development process of trucks is that different cabin types have to be designed.
Technical Paper
Lipeng Lu, Linfeng Zhang, Shuying Liu, Erwan Le Loc'h, Heinz Friz
The engineering process in the development of commercial vehicles is facing more and more stringent emission regulations while at the same time the market demands for better performance but with lower fuel consumption and higher reliability. Respective targets require better utilization of existing or even higher engine cooling capacity and optimization of aerodynamic performance for reduced drag. In order to aid on achieving both goals, special attention should be paid on understanding both external and under hood flow structures. This paper describes an optimization study for reducing aerodynamic drag and increasing engine cooling performance conducted on a Light Truck at Jiangling Motors Corporation (JMC). The approach is using simulation based on a LBM solver coupled with a heat exchanger model. Such methodology was used to predict both aerodynamic and cooling characteristics and help highlighting potential areas for improvement.
Journal Article
He Li, Jiang Guangfu, Meng Guodong, Li Lan, Mike Li, Bing Xu, Heinz Friz, Keiko Abe, Jaehoon Han, Ales Alajbegovic
This paper presents a simulation of the cooling airflow and surface temperatures of a midsize truck. The simulation uses full detailed geometry of the truck. Performance of the under-hood cooling airflow is analyzed and potential design changes leading to better cooling airflow are highlighted. Surface temperature over certain under-hood part is studied. Possible optimizations using various material and configurations are proposed. It is shown that the presented simulation approach provides valuable information to evaluate cooling system and thermal protection performance. Fast design iterations can be achieved using this approach.
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