摘要
滑动轴承是用来支撑轴及其它回转零件的一种重要部件，因其本身具有一些独特的优点：轴颈轴瓦间所特有的润滑油膜具有缓冲吸振作用，使用寿命长，结构紧凑，回转速度高等，这些优点使它在某些场合占有重要地位。因此滑动轴承在金属切削机床、内燃机、铁路机及车辆、轧钢机、雷达、卫星通信地面站及天文望远镜等方面的应用十分广泛。为了帮助大学学生更加深入、细致地了解和研究滑动轴承，各种滑动轴承实验台应运而生，但在实验的效率、效果方面都还有不足。现有的滑动轴承试验台不能满足我们需要的要求，因此，我们需要为了测试专门的改进。
本论文主要对液体动压滑动轴承进行分析、设计，使得其能够更好的工作，测得各种实验数据。对电机、温度传感器、加热装置进行解析、选择，可以测量及仿真径向油膜压力分布、油膜温度变化、油槽温度变化等各种参数。在基于流体力润滑理论的基础上，以雷诺方程的建立和求解过程，揭示了影响油膜压力的因素和其变化规律。可以通过改变各种参数揭示影响油膜压力的因素及其变化规律，从而能够更加深刻的理解和掌握滑动轴承的原理。如此一来，不仅完成了滑动轴承实验，并且加深了对油膜承载机理的理解，同时还提高了对滑动轴承的设计能力。

关键词：液体动压滑动轴;油膜压力;油膜温度

Abstract
Sliding bearing is used to support shaft and other rotating parts is an important part，Because of its itself has some unique advantages：Between the journal bearing of lubricating oil film vibration cushioning、Long service life、Compact structure、Rotation speed is higher and so on，These advantages make it occupies an important position in some occasions.So the sliding bearing in the metal cutting machine tools, internal combustion engines, railway and vehicle, rolling mill, radar, satellite communication earth station and astronomical telescope are widely used, etc.In order to help college students more in-depth and meticulous understanding of and research on the sliding bearing, all kinds of sliding bearing experimental platform arises at the historic moment, but in the experimental efficiency, effect and inadequacy. Existing sliding bearing test rig can not meet the requirements of we need, therefore, we need to test the specific improvements.
This thesis mainly analyze the fluid dynamic pressure sliding bearing, the design, make it can work better, measured a variety of experimental data.Motor, temperature sensors, heating device for parsing, choice, can be measured and simulation of radial oil film pressure distribution, oil film temperature, oil temperature and other parameters.Based on flow, on the basis of manual lubrication theory, with the establishment of the Reynolds equation and the solving process, reveals the factors that affect the oil film pressure and its change rule.Can by changing various parameters that influences factors of oil film pressure and variation law, to be able to more deeply understand and master the principle of sliding bearing.As a result, not only completed the sliding bearing experimental, and deepen the understanding of the mechanism of oil film bearing, also raised the design capability of sliding bearing.

Key words: Liquid dynamic pressure sliding bearing; The oil film pressure；The oil film temperature

目录
摘要 III
Abstract IV
第一章绪论 6
1.1 国内外研究现状和发展趋势 1
1.1.1 液体动压滑动轴承试验台国内外研究现状 1
1.1.2 液体动压滑动轴承试验台发展趋势 2
1.2 液体动压滑动轴承试验台的研究目的和意义 2
1.3 课题研究的主要内容 2
第2章液体动压滑动轴承的理论基础 4
2.1 滑动轴承 4
2.1.1 滑动轴承的主要类型和结构 4
2.2 液体动压润滑的基本原理和基本关系 5
2.2.1 液体动压油膜的形成原理 5
2.2.2 液体动压润滑的基本方程 6
2.2.3 油楔承载机理 8
2.3 径向滑动轴承液体动压基本原理 9
2.3.1 径向滑动轴承液体动压润滑的建立过程 9
2.3.2 径向滑动轴承的主要几何关系和承载能力 10
2.3.3 径向滑动轴承的参数选择 11
第3章液体动压滑动轴承油膜特性分析 13
3.1 径向滑动轴承油膜压力分布的理论基础 13
3.1.1液体动压润滑的基本方程 13
3.1.2 雷诺方程的简化 13
3.1.3 雷诺方程的无量纲形式 14
3.1.4 雷诺方程的无量边界条件 15
3.1.5 开设油槽时油膜压力的计算 16
第4章液体动压滑动轴承试验台的实现 17
4.1 试验台的简介 17

4.1.1 液体动压滑动轴承试验台的结构简图 17
4.1.2 关于电机的选择 18
4.1.3 关于热敏电阻传感器的选择 20
4.1.4 关于加热装置的选择 22
4.2 液体摩擦径向滑动轴承的计算 25
4.2.1 主要技术指标 25
4.2.2 选择轴承材料和结构 25
4.2.3 润滑剂和润滑方法的选择 26
4.2.4 承载能力计算 26
4.2.5 层流校核 27
4.2.6 流量计算 27
4.2.7 功耗计算 28
4.2.8 热平衡计算 28
4.2.9 安全度计算 29
4.3 滑动轴承内轴瓦、油温、油压的关系 29
第五章总结 33
参考文献 34
致谢 35

第一章绪论
滑动轴承是用来支撑轴及其它回转零件的一种重要部件，因其本身具有一些独特的优点：轴颈轴瓦间所特有的润滑油膜具有缓冲吸振作用，使用寿命长，结构紧凑，回转速度高等，这些优点使它在某些场合占有重要地位。因此滑动轴承在金属切削机床、内燃机、铁路机及车辆、轧钢机、雷达、卫星通信地面站及天文望远镜等方面的应用十分广泛。为了帮助大学学生更加深入、细致地了解和研究滑动轴承，各种滑动轴承实验台应运而生，但在实验的效率、效果方面都还有不足。

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内容简介：: 浙江理工大学本科毕业设计（论文）任务书丁建峰同学（专业 / 班级：机械设计制造及其自动化09（4）班）现下达毕业设计（论文）课题任务书，望能保质保量地认真按时完成。课题名称液体动压滑动轴承试验台主要任务与目标滑动轴承是用来支撑轴及其它回转零件的一种重要部件，因其本身具有一些独特的优点：轴颈轴瓦间所特有的润滑油膜具有缓冲吸振作用，使用寿命长，结构紧凑，回转速度高等，这些优点使它在某些场合占有重要地位。因此滑动轴承在金属切削机床、内燃机、铁路机及车辆、轧钢机、雷达、卫星通信地面站及天文望远镜等方面的应用十分广泛。为了帮助大学学生更加深入、细致地了解和研究滑动轴承，各种滑动轴承实验台应运而生，但在实验的效率、效果方面都还有不足。主要任务：本课题重点完成实验台传动电机及调速方法选择、相应传感器的选择，其主要内容有：1、了解液体动压滑动轴承实验台研制研究目的。理解液体动压滑动轴承结构及其特点。确定完整实验系统总体方案。2、相关测试用传感器型号、电机选定。3、进行油温测试，对油膜进行加热，测得油温与压力的关系（这是以前所不具有的，是本试验台最大的创新）4、对油膜形成过程进行三维仿真。目标：设计一个试验台，了解到温度变化与油膜压力、粘度的关系。主要内容与基本要求（这个是别人做好的试验台，我拿过来做参考）。1、电机2、皮带3、摩擦力传感器4、压力传感器：测量轴承表面油膜压力，共7个F1 F7，5、轴瓦6、加载传感器：测量外加载荷值7、主轴9、油槽10、底座11、面板12、调速旋钮：控制电机转速试验台启动后，由电机1通过皮带带动主轴7在油槽9中转动，在油膜粘力作用下通过摩擦力传感器3测出主轴旋转时受到的摩擦力矩；当润滑油充满整个轴瓦内壁后轴瓦上的7个压力传感器可分别测出分布在其上的油膜压力值；待稳定工作后由温度传感器t1测出入油口的油温，t2测出出油口的油温。主要参考资料及文献阅读任务1 张直明，谢友柏.滑动轴承的流体动力润滑理论M.北京:高等教育出版社，19862 西北工业大学机械原理及机械零件教研组.机械设计.人民教育出版社，1979,13 许尚贤.液体静压和动静压滑动轴承设计.东南大学出版社，19894 Sun Meili, Zhang Zhiming. /benkekaiti/ Experimental Study of the Film Distribution of Statically and Dynamically Loaded Cylinder Journal Bearing J . Journal of Shanghai University: Natural Science Edition, 1997, 3 (5) : 500 - 5075 刘诗海.教学仪器的现状与发展.教学仪器与实验,2003 ,(5):256 杨可桢，程光蕴，李仲生.机械设计基础M. 北京:高等教育出版社，1986，253-2657 wang wen, ZhangZhiming.Calculation of journal dynamic locus aided by database of non一stationary oil film force of single bush segment C.Asia-Pacific Vibration Conference93, Japan, 1993,365-3698 费业泰.论文代写误差理沦与数据处理.北京:机械工业出版社，2000，59濮良贵，纪名刚.机械设计（第八版）M.北京：高等教育出版社，2012：22.10孙恒，陈作模，葛文杰.机械原理（第七版）M.北京：高等教育出版社，2006：77.外文翻译任务原文1：Research on the reliability of sliding bearing support in a swash-plate type axial piston water hydraulic pump译文1：研究的可靠性,滑动轴承支撑斜盘式轴向柱塞泵型水液压原文2：Application of computational fluid dynamic to model the hydraulic performance of subsurface flow wetlands 译文2：应用计算流体动力学模型来模拟地下水流水力性能的湿地阅读了10000字以上的外文，并且翻译了5000字英译汉。计划进度：起止时间内容负责人2012.9.20分管院领导作毕业设计动员（教师）分管院长2012.9.20-2012.10.08毕业设计相关文件及规定学习、优秀毕业设计（论文）交流；确定教师所带人数、完成选题表、所级题目审核各系系主任2012.10.09-2012.10.15教学委员会题目审核、按专业毕业设计动员（学生）分管院长、学生线2012.10.16-2012.10.22学生选题各系系主任、各班班长2012.10.23-2012.10.29各所根据学生选题情况进行平衡调整，确定指导教师及各课题学生，上交毕业设计（论文）信息表。各系系主任2012.10.30-2012.11.06教师填写毕业设计任务书、确定外文阅读与翻译资料，并下达毕业设计任务指导教师2012.11.07-2012.12.27学生毕业设计调研，完成开题报告、文献综述、外文资料阅读、翻译任务指导教师2012.12.28-2013.01.03学生提交开题报告、文献综述及外文翻译初稿，指导教师审阅，提出修改意见指导教师2013.01.04-2013.01.11各系进行开题报告答辩各系系主任2013.01.12-2013.02.11指导教师布置具体设计任务，利用假期完成指导教师2013.02.12-2013.02.19本周开始，指导教师应对所指导的每位学生进行考核登记毕业设计前期检查：任务书、综述报告、开题报告、外文翻译院教学委员会、院督导组2013.02.20-2013.04.04按毕业设计任务书要求进行毕业设计指导教师2013.04.05-2013.04.11毕业设计中期检查：教师指导情况、学生完成情况、表格与记录的填写情况院教学委员会、院督导组2013.04.12-2013.05.09学生完成课题设计，提交毕业设计（论文）指导教师2013.05.10-2013.05.15指导教师完成所指导学生的毕业设计（论文）的审阅，写出评语，评出成绩；评议小组分组审阅，写出评语，评定成绩指导教师、各系评议组2013.05.20-2013.05.22学院分组进行答辩，由答辩小组给出评语及成绩答辩小组2013.05.27-2013.05.28二次答辩答辩小组2013.05.30-2013.05.31进行成绩综合评定，上报学生毕业设计（论文）成绩教学委员会实习地点指导教师签名年月日系意见系主任签名：年月日学院盖章主管院长签名：年月日外文翻译毕业设计题目：液体动压滑动轴承试验台原文1：Research on the reliability of sliding bearing support in a swash-plate type axial piston water hydraulic pump译文1：研究的可靠性,滑动轴承支撑斜盘式轴向柱塞泵型水液压原文2：Application of computational fluid dynamic to model the hydraulic performance of subsurface flow wetlands 译文2：应用计算流体动力学模型来模拟地下水流水力性能的湿地Research on the reliability of sliding bearing support in a swash-plate type axial piston water hydraulic pumpYin F.L., Nie S.L. College of Mechanical Engineering and AppliedElectronicsTechnologyRuan J.Logistics department of the 92962th armyPeoples Liberation Army of ChinaBeijing University of TechnologyBeijing 100124, CRuan J.Logistics department of the 92962th armyPeoples Liberation Army of ChinaBeijing University of TechnologyBeijing 100124, CGuangzhou 510700, CAbstractIn this paper, two kinds of different sliding bearing support structure including a traditional cross-shaft and a semi-shaft are designed for a water hydraulic pump.The characteristics of the two sliding bearings in each structure are calculated. By comparison, it is found that the working conditions of the two sliding bearings, especially the pv value, in the semi-shaft support structure are near to be identical in the cross-shaft one, which will be helpful to prolong their service life. Based on the Stress-strength interference theory, a reliability calculation model of the friction pair between the shaft and sliding bearings is proposed. The analysis results indicate that the semi-shaft sliding bearing support is beneficial to largely raise the inherent reliability of the water hydraulic pump as well as the service life of the pump.Keywordswater hydraulic pump; sliding bearing; pv value;Reliability.IntroductionWater hydraulic system is operated with raw water(pure tap water) substituting for mineral oil. Such systems are becoming more and more popular, especially in the fields of steel and glass production, nuclear power generation, coal and gold mining, food and medicine processing, ocean exploration, and underwater robotics.Compared with conventional mineral oil, raw water that acts as hydraulic fluid has several inherent advantages,including low operating cost, sound environmental compatibility, non-flammability, and low pollution potential to products 1-2.Water hydraulic axial piston pump (WHAP) is one of key power components in water hydraulic systems. There are several challenging issues associated with the pump,such as conflicts between lubrication and wear, and between sealing and leakage. Especially, shaft and bearings form key friction pairs, which will result in significant influences on the pumps performance.Generally, the hydrodynamic sliding bearing is extensively used for supporting the water hydraulic pumps shaft. Therefore, in order to improve the pumps efficiency and reliability, it is crucial to study the force distribution of sliding bearings thoroughly. According to hydrodynamic lubrication theory, the critical points,which satisfies the wear resistance for sliding bearing and shaft of WHAP includes: (1) An optimal load distributed strategy should be used to determine optimal dimensions for achieving the even distributing of the load. (2) Several suitable materials should be selected to meet the water lubrication working conditions and to ensure a long life with lower friction losses 3.The concepts of both stress and strength relating to reliability design are generalized. In this paper, thereliability of sliding bearing support will be investigated using Stress-strength interference model to calculate the reliability value of the sliding bearings, which will include the effect of the flow fluctuation in WHAP. II. Description of sliding bearing supportFigure (a) shows a schematic of a typical cross-shaft supporting structure. The cylinder block is supported on the shaft. Two sliding bearings are located on the cylinders left and right ends to support the shaft. Figure (b) shows a schematic of a novel design, where a semi-shaft supporting structure is employed. The front sliding bearing is used to support the input shaft (spline shaft). And the rear sliding bearing inside the cylinder is used to support the cylinder block. In the semi-shaft support structure, the spline shaft and cylinder are interference fit, and they are combined by a spline.During pump running, the motor drives input shaft rotating, bringing along the rotation of the cylinder.Because of the presence of the angle of swash plate, the whirling motion of the cylinder is translated into straight reciprocating motion of the pistons. When the cylinder rotated a period, the pistons reciprocate a round-trip to complete a process of suction and discharge of the pump.(a) cross-shaft support(b) semi-shaft supportFig. 1 Schematic diagram of sliding bearing supportIII. Theoretical analysesA. Load characteristics of the bearings.As shown in Figure 1, the reaction component force that act on a single slipper along X-axis and Z-axis can be respectively described as follows: In terms of the axial piston pump, the hydraulic pressure in each piston hole can be represented as: Then the radial resultant force is located in point O (as shown in Figure 1), and the radial resultant force can be expressed as: Furthermore, with the radial force equilibrium along the X-axis of the supporting structure, we have: The torque equilibrium along the X-axis can be written as: Through solving Eqs. (4) (6), the supporting force of the front and rear bearings can be obtained, respectively: B. PV value of the bearingsFor the valve plate distribution of axial piston pump,the number of pistons within the discharge pressure area (Zg) during one operating period is variably along with the reciprocating motion of the pistons. Ignoring the influence of the pressure pulsation in the pre-loading and pre-unloading areas, and the cylinder weight, affected by the alternative vibration of the number of piston in the discharge pressure area, the sliding bearing is subjected to periodic unstable loads. Water is characterized by very low dynamical viscosity, which is regarded as poor lubricating properties affecting the performance of sliding and rolling contacts 4. Here it appears that it is impossible to obtain an acceptable film thickness in water lubricated sliding bearings. Consequently, in practical work, the sliding bearings in WHAP are usually working under the condition of an incomplete liquid lubrication. Especially, at the points of turn on / off, the direct contacts between the matching pairs of the shaft and sliding bearings may take place. Moreover, since it is necessary for the sliding bearings the surface hardness should be as high as possible in order to sustain contacting pressure, and thus, the abrasion between the shaft and bearings would be as low as possible in order to improve the sliding bearings reliability.It is essential to select several suitable materials and matching pair. The siding bearings in this paper are made of WR525, which is a thermoplastic composite consisting of carbon fiber in a PEEK matrix. Due to its unique thermal expansion properties, WR525 is ideal for use as impeller wear rings, bushings and case wear rings.WR525 allows the pump user to increase pump efficiency by running tighter wear ring clearances, while decreasing potential pump damage when pumps are cavitated or experience down-line bearing failures. WR525 bearings are specified as standard material on all HGM/HGM-RO boiler feed pumps.As it is known, the critical pv value is a very important parameter for polymers or their composites in tribological applications, and has been widely used in investigation of ploymers sliding wear behaviors. Besides, pv limits are affected by variations in temperature, speed,loading,lubrication and surface finish. Exceeding pv limits will result in accelerated wear and premature bearing failure, where p is the intensity of pressure applied to a bearing surface and v is the relative velocity 5. Furthermore, the pv value is proportional to bearings wear, friction power loss and friction heat 6. Wear, friction power loss and temperature conditions are the three key index of the service life of the bearings. Therefore, the pv value can be used to preliminarily evaluate the sliding bearingsworking life in a WHAP. Generally speaking, in order to guarantee the boundary lubricated bearing running reliably, it is necessary to meet the following three conditions 7: Bearings average working specific pressure is: Substituting Eqs. (7) and (8) into Eq. (10), average working specific pressure of the front bearing can be obtained as: And average working specific pressure of the rear bearing can be represented as: Radial circumferential velocity of the shaft is: The friction specific work rate of sliding bearing can be expressed as Substituting Eqs. (11) (13) into Eq. (14), the friction specific work rate of the front bearing can be obtained as follows: And the friction specific work rate of the rear bearing is calculated as follows: Based on the structure parameters of the WHAP, taking the peak number of pistons in the discharge pressure area (Zg), the working conditions of the bearings under the two different structures are calculated in Table1.C. Scale factorActually, analyzing Eqs. (10), (11), (14) and (15), it is found that the dz, B andinfluence the match of the two bearings working conditions. Define the bearingslinear velocity ratio asaverage specific work rate ratio asThen we have: The three parameters mentioned above can be calculated (as shown in Table 2).D. Reliability model and evaluationIn terms of a WHAP, design of the sliding bearing is an important part for raising its reliability. In this paper, the pv value is defined as the stress between the sliding bearing friction pair-Y, and it is a random variable. The allowable pv value pv can be defined as the strength-X.Generally speaking, the contact stress p between the friction pair and the relative linear velocity v are mutually independent random variables, and they are all distributed normally, so the product pv is also distributed normally.Thus, according to the formula when the stress and strength are all distributed normally, the reliability coefficientcan be determined by means of the equation: In fact, the pv or allowable pv value can be expressed by the two random variables Pd and ： K is constant coefficient. Pd is the working pressure of the pump and is the relative angular velocity. Based on probability theory, the average value and the standard deviation can be obtained, respectively: Through solving Eqs. (22) and (23), we have: The rated pressure of the WHAP can be allowed for fluctuating within 5%. According to the definition of mean value and the principle of3 , we have: The allowable pv value pv of WR 525 is 8.89MPam/s, and its standard deviation pv s is 0.315.Substituting Eqs. (24) (28) and their corresponding data into Eq. (20), the reliability coefficient R u of the two kinds of structure can be calculated respectively. Hence, the corresponding reliability R for each structure can be obtained, as listed in Table 3.IV. DiscussionIn terms of the WHAP, the failure of any sliding bearing could destroy the pumps supporting and balance to cause severe noise and vibration. It also could lead to the invalidation of the flow distribution and make the volumetric efficiency decrease sharply. Thus, service life of WHAP is determined by the bearing which has the severe working condition.Table 1 presents the calculated results of the key parameters in two different sliding bearings distribution structure. It indicates that the working conditions of the sliding bearings in each distribution structure are different.Firstly, the center distance L2 in the semi-shaft structure is smaller than the cross-shaft one. This means that the rear bearing in the semi-shaft structure is closer to the center point of the resultant force, and the distance between the front and bearing is also smaller. Thus it is favorable to balance the torque of F1 and F2 so that making the sliding bearings work smoothly. Secondly, the loads on the sliding bearings in each structure are different. In the cross-shaft structure, the loads on the front bearing are much larger than on the rear one. However, in the semi-shaft structure, the loads on the front bearing reduced, while the loads on the rear bearing increased, so as to make the bearings supported load condition in the front and rear location closely and their loads distributed evenly. Additionally, the front bearings average working specific pressure (pz) and its pv value in the cross-shaft structure, are much larger than the rear one. However, in the semi-shaft structure, the front bearings pz and pv value reduced slightly, for which the rear bearing increases a little. Comparing the results listed in Table 2, it can be seen that thevalue of the semi-shaft structure are smaller than which are in the cross-shaft structure. Moreover, these values are close to 1. It is revealed that in the semi-shaft structure, the working conditions of the two sliding bearings are near to be identical.From Table 3, the reliability value of the siding bearings support in the semi-shaft structure are higher. It is indicated that the sliding bearings of the semi-shaft have longer service life than those in the cross-shaft.Consequently, it can be concluded that the distribution of sliding bearings in the semi-shaft structure is beneficial to make the bearings working conditions equilibrium and to improve the reliability of the pump.V. ConclusionIn this research, two sliding bearings of the WHAP which have the same size work in the same water medium in same time. So the change law of loads on the bearings similar. Besides, they are made of the same material:WR525. Hence, the life of the two sliding bearing support structure depends on the bearing which has higher working conditions especially the pv value. So it is important to design a rational structure arrangement to make the two bearings working conditions as equal as possible. Consequently, for the sake of raising the sliding bearings life in the WHAP, the scale factorsmust be close to 1. Additionally, the degree of reliability is a main indicator for the reliability of the sliding bearing support structure. So the reliability value of the sliding bearing support structure should be as large as possible for improving the WHAPs reliability.By comparing the working conditions of the sliding bearings in each structure, it is found that the pv value of the two sliding bearings in the semi-shaft structure are closer than in the cross-shaft one. And the scale factorof the semi-shaft structure are closer to 1, compared to the cross-shaft one. Additionally, the reliability value of the sliding bearings in the semi-shaft structure is higher than which in the cross-shaft one.Obviously, all the comparisons mentioned above show that the arrangement of sliding bearings in the semi-shaft structure does a better job in achieve the purpose of distributing the load averagely and raising the service life of the sliding bearings in the water hydraulic piston pump as well as improving the reliability of WHAP. ACKNOWLEDGMENTThis research was funded by Natural Science Foundations of China (s 50675074 and 51075007), NCET of State Education Ministry ( NCET-07-0330), and PHR (IHLB) 20090203.REFERENCESNomenclature The author;Yin F.L. Nie S.L. Ruan J.Nationality:ChinaSource:The 2011 International Conference on Fluid Power and Mechatronics, Beijing, August 16-17, 2011, 282-286.研究的可靠性,滑动轴承支撑斜盘式轴向柱塞泵型水液压Yin F.L., Nie S.L. 大学的机械工程和应用ElectronicsTechnologyRuan J.中国北京北京科技大学中国人民解放军物流部门的92962部队 100124Y中国广州 510700文摘-在本文中,两种不同的滑动轴承支撑结构包括一个传统的十字轴和半轴,被设计为-水液压泵。滑动轴承在每个结构计算。相比之下,特别是两个根据应力-强度干涉理论,一个可靠性计算模型之间的摩擦副轴和提出了滑动轴承。分析结果表明,半轴滑动轴承的支持是有益的,很大程度上提高固有可靠性的水液压泵以及泵的使用寿命。滑动轴承pv值,在半轴支撑结构都是相同的附近的十字轴,这将有助于延长其使用寿命。关键词水液压泵;滑动轴承;pv值;可靠性介绍水液压系统的原始水(纯自来水)取代了矿物油。这种系统正变得越来越流行,尤其是在田野的钢铁和玻璃生产、核电、煤炭、黄金矿业、食品和医药处理、海洋探险,水下机器人。与传统的矿物油,原水,充当液压流体有几个固有优势,包括更低的运营成本、合理的环境兼容性、耐燃性、低污染潜力产品1-2。水液压轴向柱塞泵(重击)是一个关键的动力组件在水液压系统。有几个挑战性问题相关的泵,如冲突之间,润滑和穿密封和泄漏。特别是,轴和轴承形式主要摩擦副,这将导致显著影响泵性能。通常,水动力滑动轴承是广泛用于支持水液压泵的轴。因此,为了提高泵的效率和可靠性,这是至关重要的,研究了滑动轴承力分布的彻底。根据流体动力润滑理论,关键的点,这满足了耐磨性的滑动轴承和轴的重击包括:(1)一个最佳负载分布策略应该用于确定最优尺寸对实现甚至分发的负载。(2)几个应该选择合适的材料,以满足水润滑的工作条件,确保一个长寿命和低摩擦损失3。二者的概念的应力和强度可靠性设计有关的推广。在本文中,可信度的滑动轴承的支持将被采用了应力-强度干涉模型来计算可靠性价值的滑动轴承,这将包括流动的影响波动。描述的滑动轴承的支持图(a)展示了一个示意性的一个典型的十字轴支承结构。缸体的轴上的支持。两个滑动轴承位于汽缸的左和右端支持轴。图(b)显示了一个新颖的设计原理,在那里一个半轴支承结构采用。前面的滑动轴承是用来支持输入轴(花键轴)。和后方滑动轴承在气缸内用于支持缸体。在半轴支撑结构、花键轴和圆柱干涉配合,他们结合的花键。在泵运行时,马达驱动器输入轴旋转,带上的旋转圆筒。因为存在的防波板的角度,旋转运动的缸是翻译成直线往复运动的活塞。当缸旋转一个时期,活塞往复运动的往返来完成一个过程的入口及出口的泵。（a）十字轴的支持（b）半轴的支持图1示意图的滑动轴承的支持理论分析 a的负荷特性轴承。如图1所示,反应分力,作用于一个滑块沿着x轴和z轴可以分别描述如下: 在术语的轴向柱塞泵、液压在每个活塞孔可以表示为: 然后径向合力位于点O(如图1),和径向合力可以表述为: 此外,由于径向力平衡沿着x轴的支承结构,我们有: 沿着x轴的扭矩平衡可以写成: 通过求解方程式。(4)-(6),支持力量的前后轴承可以分别获得:B PV值的轴承对于阀板分布的轴向柱塞泵,活塞的数量在放电压力区(Zg)在一个操作周期是不定地随着活塞的往复运动。忽略压力脉动的影响在预加载和pre卸货区,汽缸重量,受替代振动的数量活塞在放电压力区,滑动轴承受到周期性不稳定的负载。水具有非常低的动力粘度,它被认为是贫穷的润滑性能影响性能的滑动和滚动接触4。这里似乎是不可能获得一个可接受的膜厚度在水润滑滑动轴承。因此,在实际工作,滑动轴承在打败通常工作条件下的一个不完整的液体润滑。特别是,在点开/关,直接接触摩擦副之间的滑动轴承的轴和可能发生。此外,因为它是必要的滑动轴承表面硬度应该尽可能高的为了维持接触压力,因此,磨损的轴和轴承之间会尽可能低为了提高滑动轴承的可靠性。它是必要的选择几个合适的材料和匹配的一对。外墙轴承在本文是由WR525,这是一种热塑性复合构成的碳纤维在PEEK矩阵。由于其独特的热膨胀性能,非常适合用作WR525叶轮磨损环、衬套和案例穿环。WR525允许泵用户增加泵效率进行更严格的穿环间隙,同时减少潜在的泵损坏当泵cavitated或经验的下线轴承故障。WR525轴承被指定为标准物质在所有HGM / HGM-RO锅炉给水泵。众所周知,关键的pv值是一个非常重要的参数对聚合物或他们的复合材料在摩擦学的应用程序,并已广泛应用于调查ploymers“滑动磨损行为。此外,pv极限温度变化的影响、速度、加载,润滑和表面光洁度。超过光伏限制将导致加速磨损和过早轴承故障,p是压力强度应用于轴承表面,v是相对速度5。此外,pv值成正比轴承的磨损、摩擦功率损耗和摩擦热6。穿,摩擦功率损耗和温度条件下的三个关键指标的轴承的使用寿命。因此,pv值可用于初步评估滑动轴承的工作生活在一个重击。一般来说,为了保证边界润滑轴承运行可靠,必须满足以下三个条件7:轴承的平均工作特定压力是:取代方程式。(7)和(8)到Eq。(10),平均单位压力的工作前轴承可以得到:和平均单位压力的工作后轴承可以表示为:径向圆周速度的轴是:具体工作率的摩擦滑动轴承可以表达为取代方程式。(11)-(13)到Eq。(14),摩擦具体工作率的前轴承可以得到如下:和摩擦率的具体工作后轴承是计算方式如下:基于结构参数的重击,采取的峰值活塞在放电压力区(Zg),工作条件下的轴承的两个不同的结构计算中。C 比例因子实际上,分析方程式。(10),(11),(14)和(15),它是发现dz,B 和比赛的两个轴承工作条件。定义轴承linear速度比特定工作率比我们有:上面提到的三个参数可以计算(如表2所示)。D 可靠性模型和评价从一个重击,滑动轴承的设计是一个重要的部分为提高其可靠性。摘要pv值定义为应力之间的滑动轴承摩擦副y,它是一个随机变量。允许的pv值(pv)可以被定义为强度x。一般来说,接触应力p之间的摩擦副和相对线速度v是相互独立的随机变量,并且他们都是正态分布,所以产品pv也正态分布。因此,根据公式当压力和强度都是分布式通常可靠性系数可以确定通过方程:事实上,pv或容许pv值可以表示为两个随机变量Pd和:K是常数系数。Pd是工作压力的泵和角速度是相对的。基于概率理论,平均值和标准偏差分别可以得到:通过求解方程式。(22)和(23日),我们有: 额定压力的重击可以被允许在5%的波动。根据定义的平均值和of3原则,我们有:允许的pv值(pv)的525年是8.89 mpam WR / s,其标准偏差(pv)年代是0.315。取代方程式。(24)-(28)和相应的数据转换成Eq。(20),可靠性系数R u的两种结构可以分别计算。因此,相应的可靠性R可以得到每一个结构,如表3所示。讨论在术语的重击,任何一个失败的滑动轴承可以摧毁泵的支持和平衡造成严重的噪音和振动。它还可能导致的失效流分布和使容积效率大幅下降。因此,使用寿命的重击是由轴承具有严重的工作条件。表1给出了计算结果的关键参数在两个不同的滑动轴承分布结构。它表明,滑动轴承的工作条件在每个分布结构是不同的。首先,该中心距离L2在半轴结构是小于十字轴一。这意味着后轴承在半轴结构接近中心点的合力,之间的距离也变小前和轴承。因此它有利于平衡扭矩的F1和F2,以便使滑动轴承工作顺利。其次,对滑动轴承载荷在每个结构是不同的。在十字轴结构、负载前轴承是远远大于背面的一个。然而,在半轴结构、负载前轴承,而负载减少背面轴承增加,使轴承的支持负载情况在前方和后方位置密切和它们的负荷均匀分布。此外,前轴承的平均工作特定的压力(pz)和它的pv值在十字轴结构、远后一个。然而,在半轴结构,前轴承的pz和pv值略有减少,后轴承略有提高。比较结果列在表2中,可以看出,在半轴结构的价值小于在十字轴结构。此外,这些值接近1。研究结果表明,在半轴的结构设计、工作条件的两个附近滑动轴承是相同的。从表3,可靠性价值的支持在半轴轴承支撑结构更高。结果表明,滑动轴承的半轴具有更长的使用寿命比十字轴。因此,可以认为分布的滑动轴承在半轴结构有利于使轴承工作条件平衡和提高可靠性的泵。结论在本研究中,两名滑动轴承的重击,有同样大小的工作在同一个水介质在同一时间。所以变化规律,对轴承载荷相似。此外,他们是由相同的材料:WR525。因此,生命的两个滑动轴承支撑结构取决于轴承具有更高的工作条件特别是pv值。因此,重要的是要设计一个合理的结构安排,使两个轴承工作条件尽可能作为平等。因此,为了提高滑动轴承的生活突然摔倒,规模和接近1。此外,程度的可靠性是一个主要指标的可靠性滑动轴承支撑结构。所以可靠性价值的滑动轴承支撑结构应该尽可能大为提高可靠性的重击。通过对比工作条件的滑动轴承在每个结构,发现pv值的两个滑动轴承在半轴结构更接近比在十字轴一。和规模的半轴结构更接近到1,而交叉轴一。此外,可靠性价值的滑动轴承在半轴结构是高于在十字轴一。显然,所有上面提到的比较表明,滑动轴承的安排在半轴结构并更好地达到目的,分配负载平均地和提高使用寿命的滑动轴承在水水力活塞泵,以及提高可靠性的重击。承认这项研究是由自然科学基金会的中国(年代50675074和51075007),NCET国家教育部(NCET - 07 - 0330),和PHR(IHLB)20090203。引用命名法反应力单滑块在x轴(N); 压力在高压力室的活塞(MPa);反应力单滑块(N); 供应压力泵(MPa);角的防波板(度); 合力支持(N);反应力单滑块在z轴(N); 承载力的滑动轴承(N);长度,请参考图1(mm); 平均容许pv值(MPam / s);轴直径(mm); 平均pv值(MPam / s);轴承宽度(mm); 标准偏差的pv值;径向速度输入轴(m / s); 标准偏差的容许pv值;许用压力的滑动轴承; 工作压力的泵(MPa);容许速度(m / s); 平均工作压力的泵(MPa);容许pv值(MPam / s); 标准偏差的工作压力的泵;平均工作具体的压力轴承(MPa); 标准偏差的转动角速度的输入轴摩擦特定工作率的轴承; 旋转角速度的输入轴(rad / s);线速度比率的轴承; 平均旋转角速度的输入轴(rad / s)。平均工作具体的压力比;具体工作的平均比率;可靠性系数;可靠性价值；作者：聂松林宋晓菲阮俊国籍：中国出处：2011年国际会议上流体动力和机电一体化,北京,8月16 - 17日,2011年,282 - 286。Application of computational fluid dynamic to model the hydraulic performance of subsurface flow wetlandsFAN Liwei1, Hai Reti1, WANG Wenxing1;, LU Zexiang2, YANG Zhiming31. Center of Resources and Environment, Beijing University of Chemical Technology, Beijing 100029, China. E-mail: 2. State Key Laboratory of Chemical Resources Engineering, Beijing University of Chemical Technology, Beijing 100029, China3. Department of Agriculture and Natural Resources, Delaware State University, Dover, DE 19901, USAReceived 10 January 2008; revised 18 February 2008; accepted 23 May 2008AbstractA subsurface flow wetland (SSFW) was simulated using a commercial computational fluid dynamic (CFD) code.The constructed media was simulated using porous media and the liquid resident time distribution (RTD) in the SSFW was obtained using the particle trajectory model.The effect of wetland configuration and operating conditions on the hydraulic performance of the SSFW were investigated. The results indicated that the hydraulic performance of the SSFW was predominantly affected by the wetland configuration.The hydraulic efficiency of the SSFW with an inlet at the middle edge of the upper media was 0.584 and the best among the SSFWs with an inlet at the top, the middle, and the bottom edge of the upper media.The constructed media affected the hydraulic performance by the ratio (K) of the upper and lower media resistance. The selection of appropriate media resistance in the protection layer can improve the hydraulic eciency.When the viscous resistance coefficient of the media in the protection layer changed from 2.315 105 to 1.200 108, the hydraulic efficiency of the SSFW increased from 0.301 to 0.751. However, the effect of operating conditions on the hydraulic eciency of the SSFW was slight.Key words: subsurface flow wetland; computational fluid dynamic; resident time distribution; hydraulic performance IntroductionThe wastewater treatment technology by subsurface flow wetland (SSFW) relies on the functions of media-microorganism-vegetable to achieve efficient removal of pollutants by a combination of physical, chemical, and biological processes. The processes of physical, chemical,and biological treatment in a wetland system depend on the flow of the water. Therefore, the hydraulic characteristics within the system have a significant effect on the efficiency of the wetland as a water treatment device (Hu, 1991;Feng and Molz, 1997; Chazarenc et al., 2003). Many wetland management problems can be attributed to poor hydrodynamic characteristics within the wetland system(Persson et al., 1999). An appropriate hydraulic design not only can improve the pollutant removal eciency but also can reduce the cost and achieve optimal benefits of treatment and engineering (Badkoubi et al., 1998; Garca et al., 2004a; Garca et al., 2005).Good engineering design demands a detailed understanding of the hydraulic characteristics within a system.Some studies have been devoted to evaluate the impact parameters of the hydrodynamic behavior of constructed wetlands，including the vegetation（Kadlec，1990；Jain and Harindra，1995；serra et al., 2004），flow parameters(Kadlec, 1994), wind (Kadlec and Knight, 1996),temperature(Torres et al., 1997), inlet and outlet location(Persson et al., 1999; Suliman et al., 2006), water depth(USEPA, 2000; Huang et al., 2005), aspect ratio, and medium (William et al., 1995; Garca et al., 2004b;Worman and Kronnas, 2005; Molle, 2006; Suliman et al.,2007). However, the hydraulics of the wetland in the above publications was studied by physical tracer experiment that is expensive, time-consuming, and even impossible to perform in the majority of practical cases. Hence, using mathematical models as design tools can contribute to a better understanding of the flow patterns in wetlands.Computational fluid dynamics (CFD) is a sophisticated design and analysis tool to simulate the flow of mass and momentum throughout a fluid continuum. It is an advantage method to study the hydraulics and reaction in a constructed wetland because it is low cost, can be used to analyze the full flow field and

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