亚临界气体喷射器的设计计算

Design and calculation of sub-critical gas ejector

计算气体压缩喷射器可达到喷射系数的研究已很成熟,但对亚临界气体喷射器可达到喷射系数,大多采用气体喷射压缩器的方法进行计算。针对亚临界气体喷射器的特性,给出了3种计算方法:气体喷射压缩器计算方法;喷射泵计算方法;气体喷射器计算方法。研究表明:对膨胀比和压缩比都小于临界压力比的亚临界气体喷射器,膨胀比较大时,工作介质的弹性影响不能忽略;压缩比较小时,引射介质的弹性影响应该忽略;进而得出在膨胀比和压缩比都接近临界压力比时,适宜采用把工作介质视为弹性,引射介质视为非弹性的气体喷射器计算方法;而在膨胀比和压缩比都非常小且接近于1时,应该采用把工作介质和引射介质都视为非弹性的喷射泵计算方法。

Study on calculation for entrainment ratio of gas ejecting compressor has been done perfectly. As for subcritical gas ejector, the same method is taken into account for most of researchers. Aiming at the characteristics of sub-critical gas ejector, three methods of calculation, such as calculation methods for gas ejecting compressor, jet pump and gas ejector, are presented. The research reveals respectively appropriate computation programs of subcritical gas ejector. With ejector which expansion ratio and compression ratio both are less than critical pressure ratio, elastic influence of the working media can not be ignored when the expansion ratio is a bit large, while the elastic influence of media should be ignored when the compression ratio is a bit small. Based on this, working media can be considered as elastic and ejecting media can be treated as non-elastic when expansion ratio and compression ratio both are close to the critical pressure ratio. Working media and ejecting media should be treated as non-elastic for jet pump calculation when expansion ratio and compression ratio both are close to 1.