基于CFD的微孔端面机械密封流场分析及性能研究

发布时间：2018-08-14 16:39

【摘要】：激光加工微孔端面机械密封是一种新型密封,它是在普通机械密封的端面上加工出微米级的小坑孔,能够实现非接触,具有良好的润滑性能和密封性能。然而,目前对激光加工微孔端面机械密封的CFD数值模拟研究少有文献报道。本文通过Pro ENGINEER软件建立微孔端面间液膜的三维立体模型,采用Fluent软件对微孔端面间特定工况下的内部微间隙三维流场进行数值模拟,获得在给定工况下流场的压力分布、速度分布以及泄漏量等密封性能参数数值,并分析不同微孔深径比ε和三种不同类型微孔对其密封性能参数的影响规律,得到微孔深径比ε的最佳值和微孔类型的最佳选择。与此同时,进一步通过FLUENT计算出液膜开启力,得出液膜厚度与开启力的关系,最后计算并分析了刚度与液膜厚度的关系,获得最佳的微孔结构参数值。主要研究内容和结论如下: 1.应用Pro ENGINEER软件建立微孔端面间液膜的三维立体模型,根据假设,一个孔栏上的液膜压力分布可表征整个密封面上的液膜压力。Gambit软件对模型进行划分网格,Fluent软件对微孔端面间特定工况下的内部微间隙三维流场进行数值模拟,得到了流场的压力分布、速度分布以及泄漏量。 2.在对微孔端面间特定工况下,通过改变微孔深径比ε再次模拟,得到了不同参数下流场所对应的压力分布,速度分布及泄漏量,并分析了在同一液膜厚度的情况下,微孔深径比ε对端面机械密封性能的影响。 3.应用Pro ENGINEER软件分别建立了柱形面,锥形面,球缺形三种不同类型微孔端面间液膜的三维立体模型,在特定工况下,Fluent软件对微孔端面间的内部微间隙三维流场进行数值模拟,由此得到了三种流场的压力分布、速度分布以及泄漏量,并分析了在同一液膜厚度的情况下,同一微孔深径比ε情况下三种不同型面微孔对端面机械密封性能的影响,得出最佳微孔类型。 4.通过FLUENT计算出液膜开启力,得出液膜厚度与开启力的关系,最后计算并分析了刚度与液膜厚度的关系,结果表明:密封开启力和液膜刚度随着非孔区膜厚增大而下降,在较大的膜厚范围内均有较大的开启力和液膜刚度,这对密封的稳定操作是非常有利的。
[Abstract]:Laser machining of micro-hole end face mechanical seal is a new type of seal. It is a micro-sized pit hole on the end face of ordinary mechanical seal, which can realize non-contact, and has good lubricating performance and sealing performance. However, there are few literatures on the CFD numerical simulation of the mechanical seal of micro-hole in laser machining. In this paper, the three-dimensional model of the liquid film between the end surfaces of the microholes is established by Pro ENGINEER software, and the three-dimensional flow field of the internal micro-gap is numerically simulated by using the Fluent software to obtain the pressure distribution of the flow field under the given working conditions. The sealing performance parameters such as velocity distribution and leakage amount are calculated. The effects of different depth / diameter ratios of micropores and three different types of micropores on sealing performance parameters are analyzed. The optimum value of depth to diameter ratio 蔚 of micropores and the optimum selection of micropore types are obtained. At the same time, the liquid film opening force is calculated by FLUENT, and the relationship between the film thickness and the opening force is obtained. Finally, the relationship between the stiffness and the liquid film thickness is calculated and analyzed, and the optimum micropore structure parameters are obtained. The main contents and conclusions are as follows: 1. The three-dimensional model of liquid film between microporous end surfaces was established by using Pro ENGINEER software. The liquid membrane pressure distribution on a hole column can represent the liquid membrane pressure on the whole sealing surface. Gambit software is used to mesh the model and the fluent software simulates the three-dimensional flow field of the internal microgap under specific working conditions between the end surfaces of the microholes. The pressure distribution, velocity distribution and leakage volume of the flow field are obtained. The pressure distribution, velocity distribution and leakage amount corresponding to the flow place under different parameters are obtained by changing the ratio of depth to diameter of the microhole under specific conditions between the end surfaces of the micropore, and the pressure distribution, the velocity distribution and the leakage amount are obtained by changing the ratio of depth to diameter of the micropore, and the case of the same liquid film thickness is analyzed. The effect of microhole depth to diameter ratio on the mechanical seal performance of end face. 3. The three-dimensional models of liquid film between cylindrical, conical and spherical surfaces are established by using Pro ENGINEER software. The numerical simulation of the three-dimensional flow field between the end surfaces of micropores is carried out by fluent software under specific working conditions, and the results are as follows: (1) in this paper, three dimensional models of the liquid film between the different types of micropore end surfaces are established by using the Pro ENGINEER software, and the numerical simulation is carried out by fluent software. The pressure distribution, velocity distribution and leakage volume of three kinds of flow fields are obtained, and the effect of three different microholes on the mechanical seal performance of the end face under the same film thickness and the same hole depth to diameter ratio 蔚 is analyzed. The optimum micropore type was obtained. 4. The relationship between the film thickness and the opening force is obtained by FLUENT. Finally, the relationship between the stiffness and the liquid film thickness is calculated and analyzed. The results show that the sealing opening force and the liquid film stiffness decrease with the increase of the film thickness in the non-porous zone. In the larger film thickness range, there is a large opening force and liquid film stiffness, which is very beneficial to the stable operation of the seal.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH136

【相似文献】