Experimental investigation on stall characteristics of contra-rotating compressor with variable speed ratios

对转压气机变转速比失速特性试验研究

¹ School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China
² Aerospace Technology Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China

Received: 6 April 2021

Abstract

By experiment at a low-speed large-scale axial contra-rotating compressor, the near stall points of 19 speed configurations were captured and the stall characteristics under different speed ratios were obtained successfully. The results show that the compressor with speed ratio greater than 1 are more likely to stall than the compressor with speed ratio less than 1 and the flow rate at the starting point of stall is at least 18% earlier, the pressurization capacity is at least 5.5% higher when speed values of the front and rear rotors are interchanged. At the same speed ratio, the dimensionless characteristic lines of pressure rise coefficient-flow coefficient almost coincide. With the decrease of speed ratio, the dimensionless characteristic line of contra-compressor moves upward. Through summing up all speed configurations' stall types and stall initial disturbance frequency, it can be found that: there is a critical speed ratio between 1.125 and 1.167 in the contra-rotating compressor studied in this paper. When the speed ratio is less than the critical value, the stall disturbance has the characteristic like spike stall. At this time, the initial stall disturbance frequency is higher with the speed ratio is smaller. And at the same speed ratio, the initial stall disturbance frequency increases with the increase of the average speed of the front and rear rotors. When the speed ratio is greater than the critical value, the stall disturbance doesn't rotate circumferentially.

摘要

以1台低速大尺寸轴流对转压气机为研究对象，应用试验手段成功捕捉到了19组不同转速配置下的失速边界及失速过程动态特征，进而得到不同转速比条件下失速特性。结果表明：当前/后转子转速值互换时，转速比大于1的压气机相比于转速比小于1的情况更容易失速，失速起始点流量至少提前18%，增压能力至少高出5.5%；在相同的转速比下，压气机压升系数-流量系数无量纲特性线几乎重合，随转速比减小，压气机无量纲特性线向上移动。通过对所有转速配置下的失速类型及失速初始扰动频率进行归纳可以发现：所研究的对转压气机存在一个位于1.125~1.167之间的临界转速比值，当转速比小于该临界值时，失速扰动为类突尖波特征，此时转速比越小，失速初始扰动频率越高，且在同一转速比下，失速扰动初始频率随前后转子平均转速的增大而增大；当转速比大于该临界值时，失速扰动不沿周向旋转。