涡旋式压缩机内泄漏机理研究

发布时间：2018-06-05 03:45

本文选题：涡旋式压缩机 + 泄漏机理　；参考：《兰州理工大学》2017年硕士论文

【摘要】：涡旋式压缩机是一种新型的容积式流体机械,与旋转式压缩机、往复式压缩机相比较,具有内部结构简单、工作性能平稳、气流波动小、效率高、噪音低等优点,目前已广泛应用于动力、制冷空调及医药等领域。涡旋式压缩机内部部件主要包括静涡旋盘、动涡旋盘、支架体、平衡铁、曲轴、防自转机构件等。动涡旋盘作回转平动运动与静涡旋盘相互啮合,形成多个封闭压缩腔,实现气体的吸入、压缩和排出。由于工作腔内部存有非定常可压缩流动的泄漏问题,泄漏使得压缩机的内部流场和压缩机性能发生改变。为了研究泄漏对涡旋式压缩机工作腔流场的影响及流场变化规律,在分析和总结涡旋式压缩机工作腔内部泄漏模型的基础上,采用理论计算方法和数值模拟方法分别对涡旋式压缩机单个工作腔的切向泄漏机理、径向泄漏机理进行研究。首先,针对某一型号的涡旋式压缩机,通过理论分析和运用MATLAB编程计算,获得模拟仿真所需的几何参数和热力参数,并对涡旋式压缩机六种类型的内泄漏模型的特点和适用性进行了比较分析。第二,基于涡旋式压缩机的基本几何设计参数和热力参数,建立了单个工作腔的结构化和非结构化网格模型。采用不同的数值模拟方法,获得涡旋式压缩机工作过程中相邻工作腔压差变化、轴向间隙、转速发生变化时对切向泄漏的影响以及内部流场的分布规律。对比分析不同转速下结构化、非结构化网格模型,网格质量对数值模拟精度的影响。第三,研究涡旋式压缩机轴向啮合间隙的径向泄漏机理。针对涡旋式压缩机动旋涡盘受到倾覆力矩作用影响,使得动静涡旋盘轴向间隙形成楔形角的泄漏问题,基于气体动力学理论,建立了楔形平板间径向泄漏模型。通过数值模拟得到单个工作腔的压力场、速度场、温度场的分布规律。考虑气体可压缩性和摩擦损失的影响,将理论计算、数值模拟和实验结果进行了比较分析,验证楔形平板间泄漏模型的准确性。综合上述研究表明:涡旋式压缩机工作腔泄漏通道比较复杂,为提高效率减小泄漏,应该综合考虑不同工况下的影响因素。对于复杂流场分布规律实验无法直接测得,可通过建立合理的仿真模型,应用数值模拟方法进行计算分析。
[Abstract]:Scroll compressor is a new type of volumetric fluid machinery. Compared with rotary compressor and reciprocating compressor, scroll compressor has the advantages of simple internal structure, stable working performance, low air flow fluctuation, high efficiency, low noise and so on. At present, it has been widely used in power, refrigeration, air conditioning, medicine and other fields. The internal components of scroll compressor mainly include static scroll disk, moving scroll disk, support body, balance iron, crankshaft, anti-rotation mechanism and so on. The rotating and translational motion of the moving vortex disk intermeshed with the static vortex disk to form a number of closed compressing cavities to realize the inhalation, compression and discharge of gases. Due to the leakage of unsteady compressible flow in the working chamber, the internal flow field and compressor performance of the compressor are changed by the leakage. In order to study the effect of leakage on the flow field of the working cavity of the scroll compressor and the variation law of the flow field, the leakage model of the working cavity of the scroll compressor is analyzed and summarized. The tangential leakage mechanism and radial leakage mechanism of a single working chamber of a scroll compressor are studied by theoretical calculation method and numerical simulation method respectively. First of all, for a certain type of scroll compressor, through theoretical analysis and MATLAB programming calculation, the geometric parameters and thermodynamic parameters needed for simulation are obtained. The characteristics and applicability of six types of internal leakage models for scroll compressors are compared and analyzed. Secondly, based on the basic geometric design parameters and thermodynamic parameters of a scroll compressor, a structured and unstructured grid model of a single working cavity is established. By using different numerical simulation methods, the influence of pressure difference, axial clearance and rotational speed on tangential leakage and the distribution of internal flow field in the working process of scroll compressor are obtained. The effects of structured and unstructured mesh models and mesh quality on the accuracy of numerical simulation are compared and analyzed. Thirdly, the radial leakage mechanism of axial meshing clearance of scroll compressor is studied. Aiming at the leakage of axial clearance of vortex compressor due to the effect of overturning moment, a radial leakage model between wedge plates is established based on the theory of gas dynamics. The distribution of pressure field, velocity field and temperature field in a single working cavity is obtained by numerical simulation. Considering the effects of gas compressibility and friction loss, the theoretical calculation, numerical simulation and experimental results are compared to verify the accuracy of the wedge plate leakage model. The results show that the leakage channel of the working chamber of the scroll compressor is more complex. In order to improve the efficiency and reduce the leakage the factors affecting the leakage under different working conditions should be considered comprehensively. The distribution law of complex flow field can not be measured directly in the experiment. The numerical simulation method can be used to calculate and analyze the complex flow field by establishing a reasonable simulation model.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH45

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