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71.
Gerotor pumps are widely used in the automotive industry for engine oil lubrication, due to their high volumetric efficiency
and smooth pumping action. In many cases, the lubricating oil from the sump is mixed with contaminants, such as dust and tiny
solid particles, or becomes thickened, due to aging. These problems will lead to critical situations, such as increased noise,
enhanced wear and erosion, and poor lubrication of the engine. These critical situations were studied by conducting a detailed
CFD integrated investigation on a gerotor pump’s performance at different operating conditions in three phases, and the results
are presented in this paper. In first phase, a CFD model of a gerotor pump was developed with a dynamic mesh for the rotary
movement of both the inner and outer rotors. The effects on pump flow rate of important parameters, such as rotor speed, fluid
viscosity and number of ports, were simulated using non-contaminated oil at room temperature and an elevated temperature of
140oC. The relationship between flow rate and pressure at different rotor speeds was predicted and validated with test data
for further parametric study. The pressure ripples at different time steps were measured at different angular positions of
the rotors to examine the model accuracy. It was found that the flow rate increased and pressure pulsation, as well as flow
recirculation, was reduced when ports were added to the cover plate. A suction pipe with a strainer was added for the second
phase to capture the undesired changes in flow behavior, such as cavitation, which is caused by negative suction at the inlet
region of pump. A suitable size for the inlet suction pipe for this pump was chosen after performing tests to characterize
the flow behavior with single and double ports. Next, the relationship between pressure drop and strainer porosity was determined
using different porosity values for the strainers. In the final phase, oil with different concentrations of solids was simulated
to measure the effect of solid particles on flow rates and pressure losses. It was observed that the intensity of the recirculation
was reduced at the suction end at the higher concentration of 0.04%, due to particle inertial effects. It was also found that
particle size distribution affected the overall efficiency and pressure head of the pump. 相似文献
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Ki-Hyun Kim Sudhir Kumar Pandey Hang Thi Nguyen Soo-Yeoun Chung S.-J. Cho M.-Y. Kim J.-M. Oh Young Sunwoo 《Transportation Research Part D: Transport and Environment》2010,15(3):168-174
The concentrations of particulate matter, PM2.5, PM10, and TSP at an urban roadside and an urban background station are analyzed. Data collected over a 10 year period are analyzed. The concentrations of the particulates measured at the urban site are systematically larger than at the background station. The mean PM values at the former also exhibit a slight fall over the decade unlike those at the background station. Overall, the particulate matters at both locations are in an intermediate range of global level, e.g., approximately two times lower than those in other Asian regions but higher than in Europe. 相似文献
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基于船用燃气轮机外特性的建模方法 总被引:1,自引:0,他引:1
针对动力系统稳态、动态特性研究,旨在预报快速性、操纵性和机动性这一特点,借助生产厂家的燃气轮机外特性曲线,先将图形数字化,然后在MATLAB/Simulink仿真环境下,运用二维线性插值法,二维非线性插值法,曲面拟合法,神经网络法分别对燃气轮机的外特性进行了数学建模。运用中值法对建模结果即数学模型进行了检验,比较了上述四种方法的优缺点,指出了每种方法使用中的注意事项,适用场合。上述建模方法亦适用于舰船动力装置其它部件外特性的建模与仿真。 相似文献
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针对全自动无人驾驶地铁列车智能化、高安全性、高可靠性的特点,文章阐述了其网络控制系统的整体设计策略,从系统架构、平台架构及全自动控制核心功能等方面重点介绍其设计特点与功能,并结合实例分析了列车在无人场景下系统联动功能的设计。 相似文献
80.
卢森 《现代城市轨道交通》2021,(3)
为避免出现大直径土压平衡盾构机长距离掘进复杂地层时设备配置不当导致渣土改良效果差的问题,以太原铁路枢纽西南环线东晋隧道盾构区间为工程背景,通过采用可变开口率完整直角型式复合刀盘,布设"立体分层"式刀具,土仓壁安装 3 个固定的主动搅拌装置,按照刀盘的旋转轨迹布置 16 路泡沫、膨润土喷嘴,设置 U 型转渣螺旋机,并在箱体上设计喷水口及改良口等措施,获得大直径土压平衡盾构机在冲洪积复合地层渣土改良的良好效果。 相似文献