齿轮泵的结构改进设计【带UG三维】【16张图纸】【优秀】
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编号无锡太湖学院毕业设计(论文)相关资料题目: 齿轮泵的结构改进设计 信机 系 机械工程及自动化专业学 号: 0923807 学生姓名: 陈 浩 指导教师:何雪明(职称:副教授 ) (职称: )2013年5月25日目 录一、毕业设计(论文)开题报告二、毕业设计(论文)外文资料翻译及原文三、毕业论文(论文)计划、进度、检查及落实表四、实习鉴定表无锡太湖学院毕业设计(论文)开题报告题目: 齿轮泵结构改进设计 信机 系 机械工程及自动化 专业学 号: 0923807 学生姓名: 陈 浩 指导教师: 何雪明(职称:副教授 ) (职称 ) 2012年11月10日 课题来源课题来源于工程生产实际。齿轮传动因其具有传动功率大、效率比较高、结构相当紧凑、传动比稳定精确等优点而应用在化工、汽车、船舶、航空、能源等国民经济的重要领域中。齿轮泵是液压传动中一种广泛应用的液压机构。在液压传动与控制技术中占有很大比重,其主要特点是结构简单、体积小、重量轻、自吸性好、耐污染、使用可靠、寿命较长、制造容易、维修方便、价格便宜。但渐开线型齿轮泵也有不少缺点,主要是流量和困油引起的压力脉动较大、噪声较大、排量不可变、高温效率低等。这些缺点在某些结构经过改进的齿轮泵上己得到了很大的改善。近年来,齿轮泵的工作压力有了很大提高,额定压力可达到25Mpa,最高压力可达31.5Mpa。另外,产品结构也有不少改进,特别是三联、四联齿轮泵的问世,部分地弥补了齿轮泵不能变量的缺点。而复合齿轮泵的出现使齿轮泵的流量均匀性得到了很大的改善。其使用领域也在不断扩大,许多过去使用柱塞泵的液压设备也已改用齿轮泵(如工程起重机等)。科学依据(包括课题的科学意义;国内外研究概况、水平和发展趋势;应用前景等)由于齿轮泵在液压传动系统中应用广泛, 因此, 吸引了大量学者对其进行研究。目前, 国内外学者关于齿轮泵的研究主要集中在以下方面: ( 1)齿轮参数及泵体结构的优化设计; ( 2) 齿轮泵间隙优化及补偿技术 ; ( 3) 困油冲击及卸荷措施 ; ( 4) 齿轮泵流量品质研究 ; ( 5) 齿轮泵的噪声控制技术; ( 6) 轮齿表面涂覆技术; ( 7) 齿轮泵的变量方法研究; ( 8) 齿轮泵的寿命及其影响因素研究 ; ( 9) 齿轮泵液压力分析及其高压化的途径 ; ( 10) 水介质齿轮泵基础理论研究。提高齿轮泵的工作压力是齿轮泵的一个发展方向, 而提高工作压力所带来的问题是: ( 1) 轴承寿命大大缩短; ( 2) 泵泄漏加剧, 容积效率下降。产生这2 个问题的根本原因在于齿轮上作用了不平衡的径向液压力, 并且工作压力越高, 径向液压力越大。目前, 国内外学者针对以上2 个问题所进行的研究是: ( 1) 对齿轮泵的径向间隙进行补偿; ( 2)减小齿轮泵的径向液压力, 如优化齿轮参数、缩小排液口尺寸等; ( 3) 提高轴承承载能力, 如采用复合材料滑动轴承代替滚针轴承等。但这些措施都没从根本上解决问题。目前液压传动系统的发展目标是:缩小体积、快速响应、降低噪音。因此要想达到这个目的,齿轮泵除了要稳住其在润滑系统、中低压定量系统的绝对优势地位,另外还需要向以下几个方面纵深发展:(1)高压化 (2)低流量脉动 (3)低噪音 (4)大排量 (5)变排量。研究内容1、收集齿轮泵的相关资料,确定方案。2、完成齿轮泵的三维结构模型建模,并制作成二维图。3、根据收集的资料,制作不同齿廓的齿轮4、借助有限元分析对不同齿廓的齿轮泵进行流体力学分析。5、利用流体力学软件fluent分析各类型齿轮泵的流体力学性能的优劣。6、选取综合性能最好的齿轮泵,并提出优化方案,拟采取的研究方法、技术路线、实验方案及可行性分析查阅各种资料,了解齿轮泵的工作原理、结构、流量计算方法和优化设计方法。学会熟悉UG软件对产品结构的设计,并了解齿轮泵的运动特性,对其不同齿廓进行有限元分析,比较不同齿廓的优劣,在综合性性能较好的齿轮泵上提出优化方案。研究计划及预期成果研究计划:2012年11月1日-2012年12月25日:按照任务书要求查阅论文相关参考资料,填写毕业设计开题报告书。2013年1月11日-2013年3月5日:填写毕业实习报告。2013年3月8日-2013年3月14日:按照要求修改毕业设计开题报告。2013年3月15日-2013年3月21日:学习并翻译一篇与毕业设计相关的英文材料。2013年3月22日-2013年4月11日:齿轮泵建模、有限元分析、比较优劣。2013年4月12日-2013年4月25日:齿廓设计、装配图和说明书。2013年4月26日-2013年5月21日:毕业论文撰写和修改工作。预期成果:工艺规程:有限元分析资料,齿轮泵总图及主要零件图,设计说明书特色或创新之处运用UG对产品完成三维建模,制作完成二维图形,通过对二维图形有限元结构分析,尽早发现产品设计的缺陷,及时更改问题和缺陷,并对其优化,以提高齿轮泵的性能已具备的条件和尚需解决的问题在比较熟悉运用UG的基础上制作齿轮泵的二维图,能运用Gambit和Fluent软件对不同齿轮泵的齿廓分析比较,总结出不同齿廓的优劣,尚需解决的是,如果在硬件条件允许下,可以尝试对三维的软件进行流体分析,更能准确的了解不同齿轮泵的优劣。指导教师意见 指导教师签名:2012年11月10日教研室(学科组、研究所)意见 教研室主任签名: 年 月 日系意见 主管领导签名: 年 月 日无锡太湖学院毕业设计(论文)外文资料翻译 信机 系 机械工程及自动化 专业院 (系): 信 机 系 专 业: 机械工程及自动化 班 级: 机械97 姓 名: 陈 浩 学 号: 0923807 外文出处: 机械专业英语教程 附 件: 1.译文;2.原文;3.评分表 2013年5月20日 英文原文4.3 Flow in an Oil Injected Screw CompressorFigure 4-27 Comparison of pressure change for turbulent and laminar flow calculationsThe difference in the compressor flow obtained from laminar and turbulent calcu-lations is presented in Figure 4-28. The mass flows at suction and discharge are given as functions of the shaft angle. On average, 4% higher low is calculated with the turbulent model. The difference was greater at the discharge end of the compressor, both in the mean value and in the amplitude. This agrees with the re-sults obtained from the approximate calculations where turbulent transport through clearances is significant. The difference in flow obtained at the suction end is, on average, less than 3%. This shows that a compressor with a large suc-tion opening has no significant dynamical losses, although turbulence exists in the compressor low pressure domains. It is expected that the difference between the laminar and turbulent flow calculations will be smaller for higher discharge pres-sures and lower compressor speeds.Figure 4-28 Comparison of fluid flow at inlet and exit of screw compressorThe integral parameters obtained from both the laminar and turbulent numerical models are presented in Table 4-2. According to these results, it can be concluded that turbulence has some influence on the screw compressor. Its effect is greater at lower pressure ratios and low compressor speeds.More detailed insights into the results obtained from the k-model of turbulence can be found in the following four figures; Figure 4-29 shows the kinetic energy of turbulence. The dissipation rate is presented in Figure 4-30, the turbulent vis-cosity in Figure 4-31 and the dimensionless distance from wall y+ is given in Figure 4-32.Figure 4-29 Kinetic energy of turbulence within the screw compressor4.3 Flow in an Oil Injected Screw Compressor Figure 4-30 Dissipation rate within the screw compressorFigure 4-31 Turbulent viscosity within the screw compressorFigure 4-32 Dimensionless distances from the wall within the compressorThe results in all these diagrams are presented in horizontal sections through the blow hole areas on the suction and discharge side of the compressor, in vertical sections through the rotor axes and in cross sections at suction and discharge. The kinetic energy of turbulence, dissipation, turbulent viscosity and y+ are all high for the lobes exposed to the suction domains. All these gradually die out towards discharge. The dissipation rate is extremely high in the clearance gaps between the rotors, as shown in Figure 4-30, while in the other domains it is significantly lower. On the other hand, y+ is small in the clearance gaps while in the main do-mains at suction it has higher values, as shown in Figure 4-32.4.3.5 The Influence of the Mesh Size on Calculation AccuracyMost calculations in this book are presented for numerical meshes with an average number of 30 cells along one interlobe and a similar number of time steps selected for the rotor to rotate between two interlobe positions. The numerical mesh for thecompressor in this example consists of about 450,000 cells of which About 322,000 numerical cells define the rotor domains. This was a convenient numberof cells to use with a PC computer with an ATHLON 800 processor and 1GB of RAM, which was used for this study. Although the results obtained on that mesh appeared to be satisfactory and agreed well with the experimental data, an investi-gation of the influence of the mesh size on the calculation accuracy had to be con-ducted. For that reason, two additional meshes were generated for the same com-pressor. A smaller one was generated with 20 points along the rotor interlobe, which gave 190,000 cells on both rotors while the other compressor parts were mapped with almost the same number of cells as originally. The overall number of numerical cells was about 353,000. A lower number of cells on the rotors results in a geometry, which does not follow the rotor shape precisely, and the intercon-nection between rotors would possibly become inappropriate. This number of nu-merical cells is probably the lowest for which reliable results can be obtained. Thelargest numerical mesh generated for this investigation consists of 45 numerical cells along the rotor interlobe. That gave 515,520 cell on the rotors and 637,000 cells for the entire compressor domain. This was the biggest numerical mesh that could be loaded into the available computer memory without disc swapping dur-ing the solution. These three numerical meshes are presented in Figure 4-33 in the cross section perpendicular to the rotor axes.Figure 4-33 Three different mesh sizes for the same compressorThe results of the calculations are presented in Figure 4-34 in the form of a pres-sure-angle diagram, and in Figure 4-36 as a discharge flow-angle diagram. The first diagram shows how the calculated working pressures for all three investi-gated mesh sizes agree with the measurements. The lowest number of cells gives the highest pressure in the working chamber and vice versa. As a result of that, the consumed power is changed slightly, from 42 kW obtained with the smallest mesh to slightly less then 41 kW for the largest mesh. The difference between the two is less then 3%. This situation is shown in Figure 4-35. The diagram shows the larg-est difference within the cycle to be in the discharge area of the compressor. Some difference is also visible in the middle area of the diagram which seems to be a consequence of the leakage flows obtained with smaller meshes between the ro-tors. In that area, the mesh is probably too coarse to capture all the oscillations which appear in the flow.Figure 4-34 P-alpha diagrams for three different mesh sizesFigure 4-35 Compressor power calculated with three different mesh sizes4.3 Flow in an Oil Injected Screw CompressorFigure 4-36 Discharge flow rates for different mesh sizesFigure 4-37 Integral flow rate and Specific power obtained with different mesh sizesDiagrams of discharge flow as a function of rotation angle are given in Figure4-36. The coarser mesh shows less oscillation in the flow then the finer meshes. However, the mean value of the flow remained the same for all three mesh sizes, as shown in Figure 4-37. Specific power is calculated from the values obtained previously. It shows a slight fall in value as the number of computational cells is increased.The results obtained with the three different mesh sizes for the compressor in-vestigated here give the impression that the calculation conducted for the com-pressor on an average size of the mesh with 25 to 30 numerical cells along the ro-tor interlobe is sufficiently accurate.中文译文4.3 喷油螺杆压缩机的流量图4-27计算比较湍流和层流压力变化如图4-28为在计算吸气和排气的质量流量功能轴角中获得的压缩机流从层流和湍流差异。总体而言,湍流模型比流从层流高4%,无论是在平均值和振幅,压缩机的排出端是最大的,通过计算近似结果获得间隙显着的湍流输送的重。在吸入端获得的流量差异的平均值,小于3。这表明,具有大的吸入端的压缩机吸气开口没有任何显着的动力损失,虽然在压缩机低压域存在湍流。这是预期的层流和湍流之间的差异计算将提高排气压力和减小压缩机速度。图4-28根据流体的流动比较螺杆式压缩机的入口和出口从层流和湍流数值模型的积分获得的参数,如表4-2中。根据这些结果,可以得出结论,在湍流的螺杆式压缩机上有一定的影响。其效果是在压力越小,流速越大。从第k湍流模型获得的结果的更详细的分析,可以发现在以下四个数字,如图4-29的湍流的动能。图4-30,图4-31动荡对粘度和无量纲距离墙Y +耗散率,如图4-32。图4-29螺杆压缩机内的湍流动能图4-30螺杆式压缩机内的损耗率图4-31螺杆压缩机内的湍流粘度图4-32从墙壁内压缩机的量纲距离通过吸入阀和排出侧的压缩机的结果列于所有这些图中,在通过转子轴的吸入阀和排出的横截面的垂直剖面上的吹孔区域的水平部分。动荡,耗散,湍流粘度和y+的动能都是高暴露在吸域叶上,所有这些逐渐消亡走向放电。耗散率非常高,转子之间的间隙差距,如图4-30所示,而在其他领域,它是显着较低。另一方面,如图4-32所示,+小的间隙中,在主电源处于吸入它具有较高的值。 4.3.5 网格大小对计算精度的影响在计算这本书中的大部分平均30个细胞的数量沿一个和类似用于转子之间旋转两位置的数量的选择步骤啮合。在这个例子中包括约45万个细胞数值网格,其中约322,000数字单元格定义转子域。这是用于这项研究为了方便使用的细胞数量与PC电脑的Athlon800处理器和1GB的RAM,虽然网格上,得到的结果似乎是令人满意的
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