UG软件在真空泵涡旋盘建模与仿真中的应用

涡旋真空泵型线主要有圆渐开线、线段渐开线、正多边形渐开线、螺旋线、包络型线以及通用集成型线等.由于圆渐开线理论成熟且易于加工,一般用圆渐开线作为涡旋齿壁型线.但单一型线涡旋齿难以实现完全啮合,需对涡旋机械性能影响较大的涡旋齿齿头型线进行修正,以确保涡旋型线光滑连续,从而实现涡旋齿的正确啮合.介绍了基于圆渐开线参数方程和刘振全教授的图解修正法,通过UG软件平台对涡旋真空泵零部件进行参数化建模仿真,为涡旋真空泵涡旋盘的设计和生产提供有效方案.     

涡旋齿端型线的三角函数类修正研究

在深入研究涡旋压缩机型线包络啮合原理的基础上,提出了涡旋齿端型线的三角函数类修正几何理论,给出了齿端型线的通用修正方程并探讨了各种可能的修正形式.采用等距线法导出了任意封闭压缩腔容积的通用解析表达式和内容积比计算公式.系统地分析了各修正参数对涡旋齿端形状、压缩机内容积比和气体载荷特性的影响,精确地给出了它们之间的定量关系,总结了修正参数变化与容积效率、摩擦泄漏损失变化之间的规律,指出了三角函数类修正与圆弧类修正的转化条件.上述结论同样适用于其他涡旋型机械的型线修正.     

严格密封型螺杆真空泵转子型线研究

结合现有干式螺杆真空泵螺杆转子型线的特点,提出了一种严格密封的单头螺杆转子端面新型线,其端面型线依次由齿顶圆、齿顶圆弧过渡曲线、渐开线、齿根圆过渡曲线、齿根圆、长幅外摆线顺序相接组成;采用该型线螺杆转子的主要特征是:两段圆弧、两段过渡曲线和渐开线相切过渡,严格密封且没有滞留区,不会形成泄露三角,从而提高泵的抽速和极限真空度。文中通过啮合理论给出了端面型线推导过程和曲线参数方程,可供设计人员参考借鉴;从实际应用角度出发,采用螺旋面等距面法设计啮合间隙均匀的成对螺杆,从而得到带啮合间隙的端面型线。     

一种等齿顶宽的螺杆真空泵单头变螺距转子型线

一种适用于无油螺杆真空泵的单头变螺距螺杆转子新型线,其端面型线依次由齿根圆、摆线、齿顶圆和渐开线线顺序相接组成;该型线的主要特征是:当端面型线沿轴向作变螺距螺旋展开过程中,转子螺旋导程由排气端向吸气端逐渐增大,同时其渐开线的发生圆半径则逐渐变小,使转子齿形面的齿顶宽可以保持不变,因此能够增大吸气端的吸气容积,降低排气端的气体返流泄漏,从而提高泵的抽速和极限真空度.文章中给出了端面型线的极坐标方程、轴向展开方程和渐开线发生圆半径的计算方程,可供设计人员参考借鉴。     

高形转子基于渐开线齿廓的型线构造方法研究

为进一步提升渐开线转子的最大形状系数以实现泵的轻量化和降低径向泄漏。基于渐开线齿廓的构造方法,提出了具有渐开线齿廓的转子型线。先后构建了高形转子的渐开线型线方程,给出了其最大形状系数的计算方法,分析了转子间的型线干涉与改善。结果表明:顶圆弧能有效降低径向泄漏,提高泵的容积效率;0°～5°齿顶半角下的最大形状系数提升了2叶下的9.3%～4.3%,3叶下的13%～6.2%,4叶下的13.9%～5.8%;峰渐开线型线包括过渡用和共轭用两部分,过渡段与配对转子的型线基点存在干涉;替代的凹圆弧型线段既可避免型线干涉,也利于缓解转子系统的动不平衡,且加工简单。     

对称圆弧加直线修正型线涡旋压缩机脱啮角与排气角研究

在采用对称圆弧加直线修正型线涡旋压缩机设计计算中,形成中心压缩腔时的转角与压缩机排气时主轴的转角完全不同.针对这两种情形下的主轴转角,由于没有完整而清晰的阐述,导致计算涡旋压缩机各压缩腔容积时容易产生较大误差.对此,通过研究采用对称圆弧加直线修正涡旋压缩机涡盘始端型线的几何特性,定义了脱啮角与实际排气角,阐明了二者之间相互区别,详细推导了脱啮角计算公式并分析了影响脱啮角的因素,且根据涡盘始端壁厚增加造成修正后中心压缩腔容积减少的本质特点,提供了修正后涡盘始端壁厚增加容积和实际排气角的计算方法.通过运算实例验证了脱啮角与实际排气角相差很大的结论,指出实际排气角将影响排气孔的设计.     

涡旋式压缩机涡旋齿线型修正的图解法和修正角的研究

线型修正在涡旋式压缩机的理论研究和设计中是一个十分关键和重要的问题。本文在分析切削加工过程中刀具对渐开线型涡旋齿的干涉现象及其对排气角和压缩比的影响的基础上,作者提出了一种新的线型修正的图解方法,并且首次提出了修正角的概念。采用这种修正方法,当取修正角值为零时,涡旋压缩机的排气角可达2π,实现了零余隙压缩。一组由此方法所得到的加工要素在产品试制中被采用,样机实验结果表明涡旋齿合状况良好。     

无油涡旋压缩机涡旋齿齿顶密封结构的研究

本文对无油涡旋压缩机涡旋齿齿顶密封结构进行优化,提出一种新型径向组合密封结构,利用几何和工程流体力学的方法,推导出基圆渐开线无油涡旋压缩机齿顶光滑间隙密封、齿顶迷宫密封、齿顶组合密封泄漏量的算法,建立了无油涡旋压缩机相邻压缩腔实验台,分别测量了3种密封结构在相同压差条件下的气体泄漏量,并研究了无油涡旋压缩机动涡旋盘转速对泄漏量的影响。对比实验与理论计算结果可得：理论计算结果与实验结果基本相近,光滑密封与迷宫密封泄漏量随压差的增大而增大,而组合密封泄漏量与压差成反比,但密封条磨损量增加。迷宫密封泄漏量实测值约为光滑密封实测值的80%,组合密封泄漏量实测值约为光滑密封实测值的63%,且3种密封结构的径向泄漏量随动涡旋盘转速的提高而降低,当动涡旋盘转速超过4 000 m/s时趋于平稳。     

驱动轴承内嵌式涡旋压缩机特性分析

对驱动轴承内嵌于动涡旋齿中的涡旋式压缩机的几何特性进行了研究分析，引入了涡旋型线始端展角和终端展角，使吸气容积、吸气角、排气容积、排气角、内容积比等几何参数计算式的应用更为方便，它不仅适用于涡旋型线为整数圈的情况，而且也适用于涡旋型线为非整数圈的情况。将动涡旋的驱动轴承安置于涡旋齿中，可以在结构设计上达到减少气体力和动涡旋离心惯性力对动涡旋产生的倾覆力矩的目的，从而改善了驱动轴承的受力状况。延长了使用寿命。     

新型分段圆弧型罗茨转子几何理论与性能研究

提出一种分段圆弧型罗茨转子,在转子齿峰部分采用3段圆弧式设计。运用啮合原理求解了与齿峰分段圆弧共轭的齿谷曲线,建立了转子型线的数学模型。分析并求解了分段圆弧型转子不发生根切、无余隙容积的条件。研究了转子型线参数对面积利用系数的影响,结果表明:在转子外圆半径、节圆半径一定的情况下,随着圆心角的增大,转子面积利用系数增大;分段圆弧型罗茨转子的面积利用系数明显高于常见的圆弧型罗茨转子。     

The effect of scroll wraps on the performance of scroll compressors

A number of geometrical curves have been used to form the wraps of scroll compressors. When the suction pressure, pressure ratio, scroll wrap height and thickness, and suction volume are constant, the effect of the involute curves of a cricle, square and line segment on the performances of the scroll compressor, such as geometrical parameters, leakage line length and various gas forces acting on the orbiting scroll are analysed in this paper. The effects of these scroll wraps on the performance of the scroll compressor vary as the suction volume changes. The results in this paper should be considered in scroll compressor design.     

涡旋压缩机涡旋型线的研究现状及展望

涡旋压缩机作为第三代容积式压缩机,具有效率高、能耗低、噪声低、结构紧凑等诸多优点,被广泛应用于制冷空调与气体压缩等方面。由于涡旋压缩机的寿命、加工性能、效率和功耗等都受到涡旋型线的制约,所以涡旋型线的研究是开展涡旋压缩机其他研究的基础和关键。本文总结了国内外相关的研究成果,从型线类型和型线修正两个方面出发,对现有涡旋型线的研究现状进行综述分析,并对未来涡旋型线发展方向和趋势进行预测和展望,对于今后涡旋压缩机型线的研究与工程应用具有指导和借鉴作用。     

A lumped-parameter thermal model for scroll compressors including the solution for the temperature distribution along the scroll wraps

A lumped-parameter thermal model is presented to predict the temperature in different chambers and components inside scroll compressors with particular attention to gas superheating in the suction process. Thermal resistances between the components are based on global heat transfer conductances, whereas conduction heat transfer through the scroll wraps is solved via a one-dimensional finite volume method. The thermal model was coupled to a thermodynamic model of the compression cycle and then applied to simulate the compressor performance under different conditions of speed and pressure ratio. The model was able to correctly predict the compressor temperature for operating conditions within the range of those adopted for its calibration. The results showed a strong coupling between the compressor thermal profile and the temperatures of the motor and lubricating oil. It has also been found that heat conduction through the scroll wraps reduces slightly the discharge temperature.     

涡旋压缩机的并联使用

结合并联涡旋压缩机组的结构特点，介绍涡旋压缩机并联使用的优点，着重分析其使用过程中的回油问题，并根据试验结果客观分析比较目前市场中两种并联结构一高压内部供油机组和低压均油均气机组的优缺点。     

On the profile design of a scroll compressor

The scroll configuration plays a very important role in the design of a scroll compressor. Therefore, in the present paper, a general design process for the profile of a scroll compressor is proposed. The design process is developed based on geometric as well as kinematic considerations. It is general enough that not only a perfect meshing profile (PMP) but other profiles can be designed and constructed. The latter includes meshes with clearance and meshes with interference. A correction angle is introduced such that the discharge angle of the compressor can be varied from a negative value to a positive value, which in turn results in different shapes of scroll profile. The geometric boundary conditions for all profiles are maintained continuous up to the first order. Easier manufacture and better performance of scroll compressors may be predicted based on this condition. Computer simulations are provided to show that applicability and versatility of the proposed design process.     

R32涡旋式压缩机开发

R32是一种具有巨大应用潜力的制冷剂,但其适用的涡旋式压缩机的开发尚不成熟,尤其是排气温度过高的问题严重影响R32制冷剂的应用。本文指出R32涡旋式压缩机开发的重点与难点,并探讨R32涡旋式压缩机未来的开发方向。     

Modelling of reciprocating and scroll compressors

This paper presents simple and thermodynamically realistic models of two types of compressors widely used in domestic heat pumps (reciprocating and scroll compressors). These models calculate the mass flow rate of refrigerant and the power consumption from the knowledge of operating conditions and parameters. Some of these parameters may be found in the technical datasheets of compressors whereas others are determined in such a way that the calculated mass flow rate and electrical power match those given in these datasheets.The two models have been tested on five reciprocating compressors and five scroll compressors. This study has been limited to compressors with a maximum electrical power of 10 kW and for the following operating conditions: evaporating temperatures ranging from −20 to 15 °C and condensing temperatures ranging from 15 to 60 °C.The average discrepancies on mass flow rate and power for reciprocating compressors are 1.10 and 1.69% (for different refrigerants: R134a, R404A, R22, R12 and R407C). For scroll compressors, the average discrepancies on mass flow rate and power are 2.42 and 1.04% (for different refrigerants: R134a, R404A, R407C and R22).     

并联式涡旋压缩机应用实例分析

介绍并联式涡旋压缩机的技术优势，针对并联式涡旋压缩机的特点分析应用实例，提出相关建议。     

Mathematical modeling of scroll compressors — part II: overall scroll compressor modeling

This paper presents the development of a comprehensive simulation model of a horizontal scroll compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of scroll compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall compressor model. In the overall model, compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different compressor chambers, the temperature distributions in the scroll wraps, and the temperatures of the other compressor elements can be obtained. Thereafter, power consumption and efficiency of the compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall compressor model, a parametric study of the scroll compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive scroll compressor model is capable of predicting real compressor behavior and useful to the design and optimization of scroll compressors.     

涡旋式压缩机中间补气技术

对带有中间补气功能的涡旋式压缩机理论循环进行分析,针对在不同蒸发温度下采用中间补气对涡旋式压缩机的能力、功率、排气温度及能效比的影响进行试验研究与分析。结果显示,与普通涡旋式压缩机相比,带有中间补气功能的压缩机在蒸发温度由-5℃到-20℃之间变化时,其能力提升约15%～30%,能效比提升约9%～19%,功耗仅上升约10%。