【作者】 刘兴旺；

【导师】 齐学义；

【作者基本信息】 兰州理工大学 ， 流体机械及工程， 2011， 博士

【摘要】 涡旋压缩机具有结构简单、体积小、重量轻、振动小、噪声低、吸排气平稳、调节流量方便等优点,已广泛应用于制冷、空调、燃气机组等领域,并由定转速涡旋压缩机向变频涡旋压缩机领域发展。但实践表明,变频涡旋压缩机在低转速下的压缩性能较差。本课题针对这一问题进行了一些研究。首先,从理论上分析了转速对变频涡旋压缩机单位曲柄转角下的排气量、压缩终了内压力、单位质量有效气体获得的多变压缩能量头及多变效率等表示压缩性能的参数的影响规律,并利用实验测试得出了单位曲柄转角下的排气量和转速的关系曲线、压缩终了内压力和转速的关系曲线、单位质量有效气体获得的多变压缩能量头和转速的关系曲线及多变效率和转速的关系曲线。研究表明,由转速降低引起的泄漏的增大是导致变频涡旋压缩机压缩性能降低的主要原因。然后,针对变频涡旋压缩机的泄漏问题进行了三个方面的研究工作通过分析涡旋压缩机动静涡旋齿间的切向密封机理,探寻了变频涡旋压缩机动静涡旋齿间切向泄漏的根源,提出了一种新型切向密封机构(弹力衬套机构)。该机构既能保证变频涡旋压缩机在低转速下具有良好的切向密封性能,又能实现动涡旋盘的径向退让,可避免动涡旋盘发生阻转现象,同时可降低动静涡旋盘及与其相配合的零件的加工、装配精度。为进一步提高变频涡旋压缩机的切向密封性能,提出并设计了迷宫式切向密封结构。分析了该结构的迷宫综合效应,根据切向泄漏的流动特点,推导得出了无迷宫切向密封结构和迷宫式切向密封结构泄漏量的计算式,计算了两种切向密封结构的泄漏量。设计并建立了测定切向密封结构泄漏量的实验台,测定了无迷宫切向密封结构和迷宫式切向密封结构的切向泄漏量。通过对比两种切向密封结构泄漏量的实测值和理论计算值表明,理论推导得出的计算无迷宫切向密封结构和迷宫式切向密封结构泄漏量的算法正确,两种切向密封结构的泄漏量均随相邻压缩腔压差的增大而增大,迷宫式切向密封结构的泄漏量占无迷宫切向密封结构泄漏量的比例基本恒定,本研究的算例中,该比例为58.9%,说明迷宫式切向密封结构的密封性能明显优于无迷宫切向密封结构的密封性能。为提高涡旋压缩机的径向密封性能,提出并设计了迷宫式径向密封结构。分析了该结构的迷宫综合效应,根据径向泄漏的特点,推导得出了无迷宫径向密封结构和迷宫式径向密封结构泄漏量的计算式,计算了两种径向密封结构的泄漏量。设计并建立了测定径向密封结构泄漏量的实验台,测定了无迷宫径向密封结构和迷宫式径向密封结构的径向泄漏量。对比两种径向密封结构泄漏量的实测值和理论计算值表明,理论推导得出的计算无迷宫径向密封结构和迷宫式径向密封结构的泄漏量的算法正确,两种径向密封结构的泄漏量均随相邻压缩腔压差的增大而增大迷宫式径向密封结构的泄漏量占无迷宫径向密封结构泄漏量的比例基本恒定,本算例中该比例为79%,说明迷宫式径向密封结构的密封性能优于无迷宫径向密封结构的密封性能。本研究的主要成果及创新在于,通过理论分析和实验测试得出,导致变频涡旋压缩机在低转速下压缩性能变差的主要原因是低转速下泄漏的增大,提出了减小泄漏、提高变频涡旋压缩机压缩性能的三种方法,即弹力衬套机构、迷宫式切向密封结构和迷宫式径向密封结构,通过理论计算和实验测试证明了这三种方法可减小泄漏,从而可提高变频涡旋压缩机的压缩性能,并可拓宽变频涡旋压缩机的频率适用范围。更多还原

【Abstract】 Scroll compressor have advantages of simple structure, small volume, light weight, small vibration, low noise, smoothly suction and exhausting, and flow adjusting convenience etc, it has been widely used in refrigeration, air conditioning, gas units and other fields, and developed from the constant speed scroll compressor into inverter scroll compressor. But the practice showed that the compression performance of inverter scroll compressor at low revolution is poor. The research is based on this question.Firstly, theoretically analyses on the influence of revolution to discharge capacity under one angle, eventual compression, polytropic energy head gained by the effective gas and polytropic efficiency is made. Relation curves of discharge capacity-revolution, eventual compression-revolution, polytropic energy head-revolution and polytropic efficiency-revolution are gained by experimental tests. The study showed that increase of leakage with reducing of revolution was the main factor that made the compression performance poor. So it is very necessary to reduce leakage to improve compression performance. Then, three aspects of the research work based on the leakage problem of inverter scroll compressor were made.Tangential sealing mechanism of the scroll compressor between fixed scroll teeth and orbiting scroll teeth was analyzed in this paper, the root of the tangential leakage of inverter scroll compressor is explored, and a new kind of tangential sealing mechanism is put forward, it is called elastic bushing, this mechanism guarantee that inverter scroll compressor has good sealing performance at low revolution, and also could make the orbiting scroll plate move toward the centre of fixed scroll, so orbiting scroll plate could not be hold up, meanwhile, it could reduce processing and assembling accuracy of orbiting scroll plate and parts combined with the orbiting scroll plate.To enhance the tangential seal performance of scroll compressor, the labyrinth tangential seal structure are put forward and designed. The comprehensive effect of the labyrinth structure is analyzed, according to the flow characteristics of the tangential leakage, calculation formula for tangential leakage of the labyrinth tangential seal structure and that of the structure without labyrinth were given, and the leakages of these two tangential seal structures are calculated. The test bench to determine the leakage of tangential seal structure is designed and built, and tangential leakages of the labyrinth tangential seal structure and that of the structure without labyrinth were determined. By comparing the leakages of these two kinds of tangential seal structure, which were got by theoretical calculation and experimental determination, showed that the algorithms for tangential leakage of the tangential labyrinth seal and that of the structure without labyrinth were accurate, leakages of the two tangential seal structure were increasing with the increasing of the adjoining compression chambers’ pressure difference, the ratios of the leakages of labyrinth tangential seal accounted for those of the structure without labyrinth are fundamentally constant, only58.9%. This showed that the sealing ability of the tangential labyrinth seal is greater than that of the sealing structure without labyrinth.To improve the radial seal performance of scroll compressor, the labyrinth radial seal structure is put forward and designed. The comprehensive effect of the labyrinth structure is analyzed, according to the flow characteristics of the radial leakage, calculation formula for radial leakage of the labyrinth radial seal structure and that of the structure without labyrinth were given, and the leakages of these two radial sealing structure are calculated. The test bench to determine the leakage of radial seal structure are designed and built, and radial leakages of the labyrinth radial seal structure and that of the structure without labyrinth were determined. By comparing the leakages of these two kinds of radial seal structure, which were got by theoretical calculation and experimental determination, showed that the algorithms for radial leakage of the radial labyrinth seal and that of the structure without labyrinth were accurate, leakages of the two radial seal structures were increasing with the increasing of the adjoining compression chambers’pressure difference, the ratios of the leakages of labyrinth radial seal accounted for those of the structure without labyrinth are fundamentally constant, only79%. This showed that the sealing ability of the radial labyrinth seal is greater than that of the sealing structure without labyrinth.The main findings and innovations of this study are as follows, the main root that made the compression performance poor is the increasing of leakage at low revolution. Three methods to improve the compression performance of inverter scroll compressor were put forward. They are elastic bushing institutions, labyrinth tangential seal structure and labyrinth radial seal structure. These innovations have superiority for improving the compression performance, and opened up a vast range of prospects.更多还原