无油双螺杆空压机的运行性能

Operating characteristics of oil-free twin-screw air compressor

为了提高两级压缩无油双螺杆空压机的运行效率,研究两级压缩无油双螺杆空压机的运行特性。采用试验测试和理论推导的方法,研究两级压缩无油双螺杆空压机的多变指数、最佳中间压力、排气温度和排气压力等参数的变化规律。结果表明,空压机的一级压缩多变指数比二级低,两者均高于等熵指数,且随电动机负载率的增加先减小后稳定;将中间冷却器考虑在内后,一级多变指数略高于二级,两者均小于等熵指数,且随电动机负载率的增加略微上升。空压机的最佳中间压力较为复杂,不能简单的认为是压缩后的压力和初始压力乘积的根方。随电动机负载率的增大,一级压缩排气温度逐步下降,二级压缩排气温度逐渐增加,一级排气压力略有下降,二级排气压力略有上升。研究结果为更好的设计和使用无油双螺杆空压机奠定基础。

In order to improve the operating efficiency of the oil-free twin-screw air compressor, the operating characteristics of the compressor were studied. Polytropic exponent, optimal intermediate pressure, exhausted-air pressure and temperature of the oil-free twin-screw air compressor during the operating processes were systematically studied. The theoretical analyses and experimental measurements were carried out. Results showed that the first-stage compression polytropic index was slightly lower than the second stage, both were higher than the iso-entropy exponent. With the increase of motor load rate, they firstly decreased gradually and then tended to be stabilized. If the intermediate cooler were taken into account, the first-stage compression polytropic index was slightly higher than the second stage. Both were lower than the iso-entropy exponent and increased slightly with the increase in the motor load rate. The optimal intermediate pressure of the oil-free twin-screw air compressor was quite complex, and it could not be simply considered as square root of the product of the compressed and the initial pressure. With the increase in motor load rate, the first-stage compression exhausted-air temperature gradually decreased, the second-stage compression exhausted-air temperature gradually increased, the first-stage exhausted-air pressure slightly decreased and the second-stage exhausted-air pressure slightly increased. Results of this work laid the foundation for better design and use of the oil-free twin-screw air compressor.