CP型单螺杆压缩机关键技术研究及内流场模拟

发布时间：2018-06-22 06:55

本文选题：CP型单螺杆压缩机 + 啮合副　；参考：《湘潭大学》2012年硕士论文

【摘要】：CP型单螺杆压缩机是上世纪70年代研制的第三代高档压缩机，依靠星轮与螺杆的啮合来实现气体的压缩过程，广泛应用于工业众多领域。目前国内只有少数压缩机生产商能批量生产单螺杆压缩机，但还有不少理论和加工问题任然有待于解决。研究单螺杆压缩机内部流动对改良压缩机性能意义重大，应用CFD模拟可以很大程度缩短单螺杆压缩机相关机械的设计、优化以及生产周期。本文借助MATLAB、UG和FLUENT等软件对CP型单螺杆压缩机的型线设计及内流场进行了研究，主要内容如下：在微分几何原理和经典啮合理论的基础上分析了CP型单螺杆压缩机动态啮合过程以及螺杆和星轮的空间运动关系，运用坐标变换建立了以圆柱为包络母面的螺旋槽数学模型并推导出螺槽两侧面的型线方程和一次包络啮合条件，同时利用反包络求解方法，推导出星轮齿廓的二次包络型线方程和啮合条件。分析平面二次包络星轮齿面的组成，并运用截面法将二次包络星轮片齿面离散成曲线，运用MATLAB编程计算了离散曲线上的点建立了星轮齿面的离散点云模型。在UG软件中将离散的点云拟合成三维曲面并建立单螺杆压缩机螺杆和二次包络星轮的三维实体模型。运用快速成型机制造了单螺杆压缩机螺杆、二次包络星轮和机壳的塑料模型，随后应用片体修型完成星轮特性面的建模—第三条接触线。抽取单螺杆压缩机的内部流场模型，考虑整个内流场模型的边界条件相当复杂以及网格数量超出了电脑内存的计算范围，本文将几何模型分两步计算：螺旋槽内流场的计算和出流管道的模拟。应用动网格和滑移网格分别模拟螺旋槽的压缩过程及出流管道的排气，同时模拟了出流管道在螺杆四个不同转速下的压力、温度、体积流量等参数，，并细致分析单螺杆压缩机的螺槽和排气管道的分布特性。搭建单螺杆压缩机试验台，测量单螺杆压缩机在螺杆不同转速的四种工况下的压力、速度、体积流量等数据，同时应用绝热压缩过程计算了螺旋槽内气体的压缩情况，比较实验数据、理论计算结果和模拟结果的误差，确定了FLUENT模拟的合理性。
[Abstract]:CP type single-screw compressor is the third generation of high-grade compressor developed in the 1970s. The gas compression process is realized by the meshing of star wheel and screw. It is widely used in many fields of industry. At present, only a few compressor manufacturers in China can produce single screw compressor in batches, but there are still many theoretical and processing problems to be solved. It is of great significance to study the internal flow of single screw compressor to improve the performance of the compressor. CFD simulation can greatly shorten the design, optimization and production cycle of the single screw compressor related machinery. In this paper, the profile design and internal flow field of CP single screw compressor are studied by MATLAB UG and fluent. The main contents are as follows: on the basis of differential geometry principle and classical meshing theory, the dynamic meshing process of CP type single screw compressor and the spatial motion relationship between screw and star wheel are analyzed. The mathematical model of spiral groove with cylinder as envelope bus surface is established by using coordinate transformation. The profile equation and primary envelop meshing condition of both sides of spiral groove are derived, and the inverse envelope solution method is used at the same time. The quadratic envelope profile equation and meshing condition of star gear tooth profile are derived. The composition of the planar quadratic enveloping star wheel tooth surface is analyzed, and the tooth surface of the quadratic envelope star wheel is discretized into a curve by using the section method. The discrete point cloud model of the star wheel tooth surface is established by using MATLAB programming to calculate the points on the discrete curve. In UG software, the discrete point cloud is used to synthesize the 3D surface and the three-dimensional solid model of the screw and the secondary enveloping star wheel of the single screw compressor is established. The plastic model of single screw compressor screw, secondary enveloping star wheel and casing was manufactured by using rapid prototyping machine. Then, the model of star wheel characteristic surface was built by using slice body modification, and the third contact line was completed. The internal flow field model of a single screw compressor is extracted. The boundary conditions of the whole internal flow field model are considered to be quite complex and the number of meshes is beyond the calculation range of computer memory. In this paper, the geometric model is divided into two steps: the calculation of the flow field in the spiral groove and the simulation of the outlet pipe. Dynamic mesh and slip grid are used to simulate the compression process of spiral grooves and the exhaust of outlet pipes respectively. At the same time, the parameters of pressure, temperature and volume flow of the outlet pipe at four different screw speeds are simulated. The distribution characteristics of screw groove and exhaust pipe of single screw compressor are analyzed in detail. A single screw compressor test rig was built to measure the pressure, velocity and volume flow of the single screw compressor under four working conditions with different screw speeds. At the same time, the gas compression in the spiral groove was calculated by the adiabatic compression process. The rationality of fluent simulation is determined by comparing the experimental data, theoretical calculation results and simulation results.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH45

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