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101.
A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity. At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5. 相似文献
102.
Theoretical study of flow ripple for an aviation axial-piston pump with damping holes in the valve plate 总被引:1,自引:0,他引:1
Based on the structure of a certain type of aviation axial-piston pump's valve plate which adopts a pre-pressurization fluid path (consisting a damping hole, a buffer chamber, and an orifice) to reduce flow ripple, a single-piston model of the aviation axial-piston pump is presented. This sin- gle-piston model comprehensively considers fluid compressibility, orifice restriction effect, fluid resistance in the capillary tube, and the leakage flow. Besides, the instantaneous discharge areas used in the single-piston model have been calculated in detail. Based on the single-piston model, a multi-piston pump model has been established according to the simple hydraulic circuit. The sin- gle- and multi-piston pump models have been realized by the S-function in Matlab/Simulink. The developed multi-piston pump model has been validated by being compared with the numerical result by computational fluid dynamic (CFD). The effects of the pre-pressurization fluid path on the flow ripple and the instantaneous pressure in the piston chamber have been studied and opti- mized design recommendations for the aviation axial-piston pump have been given out. 相似文献
103.
单叶片真空泵的设计主要是确定泵体内腔曲面,使同时作旋转运动和径向滑动的叶片的圆柱形端面和它保持相切。泵体内腔曲面的投影必须是一条封闭的光滑曲线。设计时,这条光滑曲线的一部分通常被提前选定,而剩余部分则根据几何约束产生。尽管一般的椭圆曲线可以满足参考曲线和生成曲线在连接点一阶可导,但在连接点通常是二阶不连续的。将找出一条最优的椭圆参考曲线,使得泵腔形线在连接点处不仅是一阶连续的而且是二阶连续的。这将使得泵的运转更加平稳并减小由于叶片径向加速度不连续产生的振动和噪声。 相似文献
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大型清洁超高真空获得初探 总被引:1,自引:0,他引:1
文章介绍了3200m3大型真空容器的清洁高真空系统的方案配置和使用情况.说明低温泵和涡轮分子泵的结合使用,可以获得清洁的超高真空环境. 相似文献
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为研究离心泵盘腔内外特性,将离心泵盘腔三维流动简化为动静腔一维流动,基于动量守恒方程和径向连续方程,构建了动静腔流动微分方程;积分该方程并应用到盘腔中,引入密封件阻力系数,考虑叶轮流动滑移,修正泵势扬程公式,建立了离心泵叶轮-盘腔-密封环-平衡孔回路的自封闭流动模型。提出了内外迭代相结合的求解方法,实现了离心泵盘腔流动快速计算。通过与盘腔压力测量结果对比表明:使用Stodola叶轮流动滑移系数的盘腔流动模型比使用Wiesner叶轮流动滑移系数的盘腔流动模型的计算精度提高了约3.5%。盘腔流动模型结果表明:泵工况从小流量调节至大流量,容积效率逐渐提高,盖板推力略微逐渐增大。该方法及结论为离心泵盘腔内外特性计算提供参考。 相似文献