R410A小型制冷螺杆压缩机与涡旋压缩机的理论性能比较

Theoretical performance comparison of R410A small refrigeration screw compressors and scroll compressors

为了探究螺杆制冷压缩机小型化的潜力与优劣,选择相同理论排气量与转速的螺杆与涡旋压缩机进行理论设计。通过归一化分析,建立了螺杆压缩机与涡旋压缩机几何性能的量化评价标准。并采用㶲分析模型,分析了螺杆与涡旋压缩机的泄漏㶲损失。通过建立统一的热力学模型,分析了内容积比、间隙及转速对热力学性能的影响。研究发现,内容积比设计对涡旋压缩机绝热指示效率影响显著,而对螺杆压缩机效率的影响不显著;涡旋压缩机排气孔口面积远小于螺杆压缩机排气孔口,其排气功率损失高于螺杆压缩机。相同间隙下,螺杆压缩机的相对泄漏量与泄漏㶲损失高于涡旋压缩机,每增加0.01 mm的间隙,涡旋压缩机的绝热效率下降6%,螺杆压缩机的绝热效率下降11%。在额定转速3000 r/min时,螺杆压缩机的绝热效率与容积效率分别低于涡旋压缩机6%,13.6%。在2250,1500,750 r/min的转速下,螺杆压缩机绝热效率较涡旋压缩机分别减少9%,13%,26%,为提高小型螺杆制冷压缩机性能,应将其进行高速化设计。

In order to explore the potential,advantages and disadvantages of the miniaturization of screw refrigeration compressors,a scroll compressor with the same theoretical displacement and speed was selected for theoretical design.Through normalization analysis,the quantitative evaluation standard of the geometric performance of screw compressor and scroll compressor was established.And the exergy analysis model was used to analyze the leakage exergy loss of screw and scroll compressors.A unified thermodynamic model was established to analyze the effects of clearance,internal volume ratio and speed on thermodynamic performance.The study shows that the influence of the internal volume ratio design on the adiabatic efficiency of the scroll compressor is significant,while the influence on the screw compressor efficiency is not significant.The area of the exhaust orifice of the scroll compressor is much smaller than that of the screw compressor,and its exhaust power loss is higher than that of the screw compressor.Under the same clearance,the relative leakage amount and leakage exergy loss of the screw compressor is higher than that of scroll compressor.For every 0.01 mm increase in clearance,the adiabatic efficiency of scroll compressor decreases by 6%,and the adiabatic efficiency of screw compressor decreases by 11%.When the rated speed is 3000 r/min at the same speed,the adiabatic efficiency and volumetric efficiency of the screw compressor are 6%and 13.6%lower than those of the scroll compressor,respectively.When the rotating speed is 2250,1500 and 750 r/min,the adiabatic efficiency of the screw compressor is 9%,13%and 26%lower than that of the scroll compressor.In order to improve the performance of the small screw refrigeration compressor,it 72 FLUID MACHINERY Vol.51,No.12,2023 should be designed for high speed.