共查询到18条相似文献,搜索用时 531 毫秒
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针对某型柴油机功率提升后主轴承润滑性能恶化的现象,考虑轴颈与轴瓦表面粗糙度、曲轴与轴承座弹性变形的影响,建立了12 V90°柴油机主轴承的润滑分析计算模型.根据弹性流体动力润滑、轴承动力学及平衡率计算理论,分析了不同曲轴平衡率对主轴承的润滑性能的影响.采用正交试验研究了平衡率、轴承宽度及轴承间隙对最小油膜厚度、最大油膜压力、平均摩擦损失功和峰值粗糙接触压力的影响,并提出了改进方案.结果表明:曲轴平衡率对主轴承润滑性能有很大的影响,对最小油膜厚度、最大油膜压力和峰值粗糙接触压力的影响权重与轴承间隙相接近,均低于轴承宽度;平衡率对平均摩擦损失功的影响权重最大;相比轴承宽度、轴承间隙等影响因素,曲轴平衡率在强化柴油机主轴承润滑设计阶段也应重点考虑. 相似文献
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基于弹性流体动压润滑及多体动力学理论,以某船用大功率柴油机主轴承为研究对象,考虑曲轴主轴承的弹性变形、表面粗糙度、供油特性等因素,建立主轴承的弹性液体动力学仿真分析模型;通过试验对该模型建立方法进行了验证。基于该模型,分析了曲轴平衡率对主轴承最小油膜厚度、最大油膜压力、轴心轨迹及滑油填充率等润滑特性参数的影响规律,并就主轴承边缘接触压力较大的现象进行了变壁厚设计优化。研究表明:曲轴平衡率从0增大到100%,主轴承最大油膜压力平均值减小60%,最小油膜厚度平均值增大5倍,轴心轨迹偏心率减小;通过变壁厚优化设计,主轴承最小油膜厚度最小值增大24%,最大粗糙接触压力减小40%,粗糙边缘承载较大的现象得到有效改善。 相似文献
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《内燃机工程》2014,(6)
针对柴油机标定工况和单缸停油工况,建立了工作过程的仿真模型,计算了缸内气体压力。基于Reynold方程、Greenwood/Tripp微凸体接触模型和多体动力学模型对主轴承的润滑状态进行分析。以某六缸柴油机为研究对象,以标定工况和50%功率、单缸停油工况为计算工况进行了试验。研究结果表明:第三缸停油最小油膜厚度比标定工况的大,其他缸停油最小油膜厚度均变小,最小值出现在第一缸停油第七主轴承。第一缸停油时,主轴承摩擦功率变小,功率的有效输出能力降低;第七主轴承下轴瓦靠近飞轮一侧的边缘发生微凸体接触。标定工况最小油膜厚度为2.07μm,第一缸停油最小油膜厚度为1.82μm,相差12.1%;标定工况最大油膜压力为52.5MPa,第一缸停油最大油膜压力为50.0MPa,相差4.8%。 相似文献
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以某直列6缸柴油机为研究对象,建立活塞销-连杆-曲柄销柔性多体动力学分析模型。基于热弹性流体动力学(TEHD)润滑和微凸峰接触理论,建立连杆小头轴承的TEHD模型,分析了热负荷影响下轴承间隙和表面粗糙度对润滑性的影响规律。研究结果表明:计及热负荷影响,轴承最大油膜压力增加7.5%,最小油膜厚度降低8.1%,摩擦功耗增加10.1%,粗糙峰接触增加6.0%,轴承产生温升现象,最大温升为20.1℃;轴承间隙增加,轴承最大油膜压力增幅提高50%,最小油膜厚度减幅保持不变;表面粗糙度增加,轴承最大油膜压力增幅提高50%,最小油膜厚度减幅缩小55%。该热弹流模型研究方法为动力机械热负荷条件下摩擦副失效机理分析提供了一种可行的途径,研究结果对摩擦副滑动轴承加工精度制定具有一定的指导作用。 相似文献
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基于柔性多体动力学的发动机主轴承润滑仿真分析 总被引:1,自引:0,他引:1
针对某发动机的主轴承,在ADAMS/Engine模块中建立了其曲轴系柔性多体动力学与动力润滑耦合的仿真模型.通过计算得到了曲轴的轴心轨迹、最小油膜厚度,并比较了转速、温度和轴承间隙对最小油膜厚度的影响,从而为曲轴轴系动力学耦合分析和优化设计以及判断轴承工作的可靠性提供了重要依据. 相似文献
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对内燃机连杆轴承和主轴承进行动力学分析,得到了轴承最大载荷和最小油膜厚度等可靠性参数,进而评估了轴承润滑油消耗和摩擦损失等性能指标。研究发现,与使用15W-40润滑油相比,使用高黏度20W-50润滑油的轴承,其最小油膜厚度、润滑油消耗量和摩擦损失等参数都有很大的改善。 相似文献
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对12V240ZJ型柴油机进一步强化后,主轴承和连杆大端轴承的可靠性进行了分析计算。采用Southwest Crank/Bearing轴承计算程序进行数值计算,然后用EXCEL表做图形分析,得出最小油膜厚度、最大油膜压力、空载负荷线变化角、轴心轨迹、油膜分布等参数和图形。由油膜分布图确定轴颈最佳油孔位置,并对其余参数进行了评价。分析了两种发火次序(即连续和间断)对轴承可靠性的影响。 相似文献
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In this study, the Taguchi method was applied to determine optimum structural combination of a membrane electrode assembly (MEA) in obtaining maximum power density of a PEMFC. Performance measure analysis was also followed by performing a variance analysis, in order to determine the optimum levels and relative magnitude of the effect of combinations. The optimum structural combinations of MEA were found to be membrane, Nafion 112 with a thickness of 51 μm, amount of platinum loaded by sputtering, 0.05 mg Pt cm−2, Nafion ionomer content, 0.05 mg cm−2 and support material of gas diffusion layer (GDL), carbon paper. Under these conditions, the amount of maximum power density was predicted as 563.75 mW cm−2 by using experimental results obtained according to Taguchi's orthogonal array (OA) L16(24 × 22). Verification experiment was done for the same optimum structural combination and maximum power density was observed as 566 mW cm−2. According to the results of this optimization, it was seen that amount of platinum loaded by sputtering and thickness of membrane were the effective parameters. 相似文献
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In order to show the effects of different diameter combinations on crude oil temperature when a crude oil pipeline and a products pipeline are laid in one trench, four typical diameter combinations are selected to conduct numerical simulation. After a series of calculations, the minimum mean temperature difference and the maximum temperature difference of the crude oil along the pipelines are obtained. In real pipeline constructions, the effects of other diameter combinations on crude oil temperature can be predicted by the method of linear interpolation to calculate results of the four diameter combinations obtained in this study. 相似文献
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Bo Yu Yue Shi Xin Liu Jinjun Zhang Jinjia Wei 《Frontiers of Energy and Power Engineering in China》2010,4(2):192-197
In order to show the effects of different diameter combinations on crude oil temperature when a crude oil pipeline and a products
pipeline are laid in one trench, four typical diameter combinations are selected to conduct numerical simulation. After a
series of calculations, the minimum mean temperature difference and the maximum temperature difference of the crude oil along
the pipelines are obtained. In real pipeline constructions, the effects of other diameter combinations on crude oil temperature
can be predicted by the method of linear interpolation to calculate results of the four diameter combinations obtained in
this study. 相似文献
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《Solar Energy》2013
In this paper, an attempt has been made to evaluate and compare the energy matrices of a hybrid photovoltaic thermal (HPVT) water collector under constant collection temperature mode with five different types of PV modules namely c-Si, p-Si, a-Si (thin film), CdTe and CIGS. The analysis is based on overall thermal energy and exergy outputs from HPVT water collector. The temperature dependent electrical efficiency has also been calculated under composite climate of New Delhi, India.It is observed that c-Si PV module is best alternative for production of electrical power. Maximum annual overall thermal energy and exergy is obtained for c-Si PV module. The maximum and minimum EPBT of 1.01 and 0.66 years on energy basis is obtained for c-Si and CIGS respectively, whereas on exergy basis maximum EPBT of 5.72 years is obtained for a-Si and minimum of 3.44 in obtained for CIGS PV module. EPF and LCCE increase with increasing the life time of the system. 相似文献
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Electrohydrodynamic conduction pumping of free surface dielectric liquid film, using flush electrodes, has been studied experimentally for various film temperatures. Volume flow rate, heat transfer and power consumption ratio and conduction pumping efficiency of free surface liquid film in different film thicknesses and temperatures have been investigated and then the best operating conditions have been presented. Also, the heat transfer coefficient on free surface liquid film passing on flush electrodes is compared with similar liquid film in absence of flush electrodes in different temperatures. Results show that as applied voltage increases, significant differences in volume flow rates have been observed by changing the temperature. Applied voltage related to the highest percentage of heat transfer coefficient enhancement demonstrates the reverse relation with temperature. Results confirm that there is a direct relationship between film thickness and the applied voltage related to the maximum heat transfer per pumps power consumption. 相似文献