喷油螺杆压缩机指示图的试验研究

Experimental Study on the Indicating Diagram of an Oil-Injected Twin Screw Compressor

为了深入了解压缩机内部的微观工作过程 ,从而给压缩机参数的优化设计提供可靠的试验依据 ,通过安装在阴转子齿根处的压力传感器 ,测出从吸气过程中段至排气过程完毕时基元容积中压力的变化 ,得到了压缩机的一个基元容积内气体工作过程的指示图 .通过比较不同工况下的指示图及相应的热力性能 ,分析了排气压力、转速及喷油量等设计参数对喷油螺杆压缩机热力性能的影响 .研究结果表明 :在较宽广的排气压力范围内 ,指示图上并未出现明显的等容压缩 ;转速对指示图及热力性能的影响不大 ;喷油量控制在压缩机容积流量的 1%～ 2 %时 ,压缩机性能较优 ;为了避免排气过程末期明显的压力突升现象 。

Through experimental study on the indicating diagram, the working process of an oil-injected twin screw compressor can be understood thoroughly and this is beneficial to advanced optimum design. A small pressure sensor built into the tooth root of the discharge side of the female rotor was used to measure the pressure changes in the groove, ranging from the midpoint of the suction process to the completion of the discharge. By comparing the indicating diagrams at various working conditions, the influence of the parameters such as discharge pressure, rotating speed and oil-gas ratio on performance was analyzed. It is shown that the great change in discharge pressures has not caused evident iso-volumetric compression, and the indicating diagram and the corresponding performance have changed a littler in a wide range of rotating speeds. However, the oil-gas ratio seems to have a great influence. About 1%-2% of oil-gas volume ratio can provide a comparatively good performance. Furthermore, a rapid pressure rise at the end of discharge stage has been found in the indiating diagram and a flow-guided slot should be designed to avoid it.