湿压缩过程中水滴的运动分析

Motion analysis of water droplets during wet compression

湿压缩过程中水滴的喷入对压气机性能具有显著影响。为了研究水滴在压气机内的运动情况,对单级轴流压气机的湿压缩过程进行了数值分析。结果表明,水滴在压气机内主要受气流拖拽力的作用,雷诺数与韦伯数整体较小,发生振荡破碎的可能性较大,并且集中于转子叶前缘附近;湿压缩过程中会有水滴撞击叶片,不仅对水滴的运动破碎产生影响,还会造成叶片的附加载荷;较小的水滴颗粒传热传质效果较好,湍流波动强度较弱,对气流造成的粘性损失较小。所以,湿压缩效果需要综合考虑水滴产生的蒸发冷却、阻力损失与撞击作用的影响,选取较小的水滴颗粒和适当的喷雾量。

Water injection exerts an obvious influence on the performance of compressors during wet compression. Wet compression was numerically simulated using a single-stage axial compressor to study the motion of water drop-lets in a compressor. Results showed that water droplets in a compressor are mainly controlled by drag forces and that the Reynolds and Weber numbers of these droplets are low. Water droplets are most likely to break up in a model of vibrational breakup,and the break-up phen o m e n o n mainly occurs around the leading edge of rotor blades. Some water droplets impact the blade during wet compression. Impingement of water droplets on the blade not only influences the motion and breakup of water droplets but also increases the load on the blade. T he mass and heat transfer effects generated by smaller water droplets are better than those produced by larger ones,and the intensity of turbulent fluctuation is w e aker, leading to lower viscosity loss. Considering the evaporation cooling, resistance loss,and impact effects produced by water droplets,small droplets and the proper amount of water injection should be chosen to minimize negative effects during wet compression.