New directives and increasing competition push automakers to get better performances (engine power increase), along with mass and size reduction (consumption). These evolutions lead to an increase of the thermal solic...New directives and increasing competition push automakers to get better performances (engine power increase), along with mass and size reduction (consumption). These evolutions lead to an increase of the thermal solicitations undergone by the automotive clutches whereas their weight must be decreased, as it is one of the main influent factors on CO2 emissions. Previous studies only focused on the air flow created by the clutches, but none of them have shown the impact of the clutch housing on the cooling of the clutch parts. In order to determine the influence of the clutch housing on the thermal behavior of automotive clutch systems, a numerical study has been performed on a simplified model of a clutch system. A parametric variation has been performed on the clutch housing size in order to evaluate its impact on the flow and the thermal behavior of clutches. The results show that clutch housing has a significant impact on the air flow and the thermal behavior of clutches. Thermal tests on real clutches with and without clutch housing have confirmed these results.展开更多
湿式离合器高速旋转时内部形成的复杂油气两相流动会对离合器的性能产生影响,因而需要对湿式离合器内的两相流动特性展开研究。基于有限体积法,采用流体体积函数(Volume of fluid,VOF)多相流模型、RNG k-ε湍流模型,建立考虑径向沟槽影...湿式离合器高速旋转时内部形成的复杂油气两相流动会对离合器的性能产生影响,因而需要对湿式离合器内的两相流动特性展开研究。基于有限体积法,采用流体体积函数(Volume of fluid,VOF)多相流模型、RNG k-ε湍流模型,建立考虑径向沟槽影响的三维湿式离合器对偶片间油气两相流动模型。通过对流动模型中油气两相N-S方程进行数值求解,获得了湿式离合器对偶片间油气两相流动的流场分布特性,分析沟槽数量和转速对流场中油相分布及带排转矩的影响。结果表明:湿式离合器内部的润滑油分布是不均匀的,随沟槽的分布呈现出周期性变化,沟槽处润滑油油液体积分数最大;转速和沟槽数目的增加均会使对偶片间油液体积分数下降,影响湿式离合器内润滑油分布的不均匀性;沟槽总面积不变时,增加沟槽数量能使带排转矩最大值减小,最大转矩对应的转速提前。本研究为湿式离合器内部流场分析和带排转矩研究提供了一种新方法。展开更多
文摘New directives and increasing competition push automakers to get better performances (engine power increase), along with mass and size reduction (consumption). These evolutions lead to an increase of the thermal solicitations undergone by the automotive clutches whereas their weight must be decreased, as it is one of the main influent factors on CO2 emissions. Previous studies only focused on the air flow created by the clutches, but none of them have shown the impact of the clutch housing on the cooling of the clutch parts. In order to determine the influence of the clutch housing on the thermal behavior of automotive clutch systems, a numerical study has been performed on a simplified model of a clutch system. A parametric variation has been performed on the clutch housing size in order to evaluate its impact on the flow and the thermal behavior of clutches. The results show that clutch housing has a significant impact on the air flow and the thermal behavior of clutches. Thermal tests on real clutches with and without clutch housing have confirmed these results.
文摘湿式离合器高速旋转时内部形成的复杂油气两相流动会对离合器的性能产生影响,因而需要对湿式离合器内的两相流动特性展开研究。基于有限体积法,采用流体体积函数(Volume of fluid,VOF)多相流模型、RNG k-ε湍流模型,建立考虑径向沟槽影响的三维湿式离合器对偶片间油气两相流动模型。通过对流动模型中油气两相N-S方程进行数值求解,获得了湿式离合器对偶片间油气两相流动的流场分布特性,分析沟槽数量和转速对流场中油相分布及带排转矩的影响。结果表明:湿式离合器内部的润滑油分布是不均匀的,随沟槽的分布呈现出周期性变化,沟槽处润滑油油液体积分数最大;转速和沟槽数目的增加均会使对偶片间油液体积分数下降,影响湿式离合器内润滑油分布的不均匀性;沟槽总面积不变时,增加沟槽数量能使带排转矩最大值减小,最大转矩对应的转速提前。本研究为湿式离合器内部流场分析和带排转矩研究提供了一种新方法。
文摘为探究汽车空调用电磁离合器皮带轮上减重槽的加工位置、切槽深度和宽度对电磁离合器产生电磁吸力大小的影响,建立了该离合器的有限元优化计算模型,在忽略了影响计算精度的部分不规则结构后,根据单一变量原则,借助有限元软件ANSYS电磁分析模块,计算得到了该电磁离合器在各单一因素影响下的电磁吸力变化规律,给出了皮带轮减重槽的加工位置和尺寸的优先选取值.结果表明:为了在实际加工时能较多地切除材料并保证精度,在仅考量电磁吸力而不考虑结构刚度等因素的情况下,该电磁离合器皮带轮的减重槽可以偏向皮带轮内测加工,减重槽切槽宽度可选择为6 mm,切槽深度可选择为7 mm.
