变负荷下单螺杆制冷压缩机复合滑阀能量调节机构特性

Characteristics of Compound Slide Valve Capacity Control Mechanism in Single Screw Refrigeration Compressor Under Variable Load Conditions

为了解决不同环境工况下单螺杆制冷压缩机内外压比不等的问题,以提高运行效率,提出采用复合滑阀新型能量调节机构.复合滑阀能量调节机构可同时实现气量和内容积比调节.基于单螺杆制冷压缩机的工作特点,确定了某单螺杆制冷压缩机复合滑阀的结构参数;分析了旁通口起始位置和串气槽对不同负荷下内容积比的影响;建立了有效旁通面积的计算模型,得到不同负荷及滑阀起始位置对有效旁通面积的影响,为部分负荷工作特性研究奠定了基础.研究表明:复合滑阀可以实现满负荷内容积比较大范围调节,部分负荷时,随着气量的减小,内容积比随之增大,串气槽可以有效缓和其增大,滑阀起始位置越靠近排气端,内容积比和气量突跳量越大;有效旁通面积和持续时间随着负荷减小而增大,旁通口起始位置在不越过封闭螺旋线的条件下应尽量靠近进气端,以提高部分负荷压缩机的工作性能.

In order to solve the problem of the unequal between internal and external pressure ratio in single screw refrigeration compressor under different environmental conditions and improve the efficiency, compound slide valve capacity control mechanism was proposed in this paper. The compound slide valve capacity control mechanism can achieve capacity and internal volume ratio regulation simultaneously. On the basis of the operating feature of single screw compressor,the structural parameters of a single screw refrigeration compressor were determined,and then the influences of the starting position of the by-pass and string gas groove on internal volume ratio under different load conditions were analyzed. A model was established to calculate the effective by-pass area,which laid the foundation for the study of the part-load working characteristics, and the influences of different part-load conditions and slide valve starting position on effective by-pass area under different load conditions were obtained. Results show that the compound slide valve can achieve internal volume ratio regulation under full-load condition, and internal volume ratio increases with the decrease of capacity under part-load conditions. String gas groove can ease its increase effectively. Jumping value increases with the closer of slide valve starting position to exhaust end. Effective by-pass area and duration increase with the decrease of load. In order to increase the performance of part-load conditions, the starting position of by-pass should be as close as possible to inlet end,but the starting position of by-pass can’t cross the closed helix.