Effects of uniform profile tolerance on aerodynamic performance eligibility of high subsonic cascade

Abstract

In this paper, the concept of “aerodynamic performance tolerance”, which is used to measure the aerodynamic performance eligibility of the cascade, is proposed by analogy with the concept of profile tolerance which is used to constrain profile geometry. Then, the mathematical model of profile with random machining error is established based on random process. After that, taking a high subsonic cascade as the research object, the influence of uniform profile tolerance on aerodynamic performance eligibility under i = 0°, i = 2.4° and i = 4° at Ma=0.8 by SG-NIPC(Sparse Grid -Non Instrusive Polynomial Chaos) uncertainty quantification method. The mechanism analysis of the reasons for the change of aerodynamic eligibility is carried out. The results show that the aerodynamic performance eligibility is the lowest under i = 4°, and the aerodynamic performance eligibility shows a nonlinear decreasing trend with the increase of uniform profile tolerance. With the increase of uniform profile tolerance, the fluctuation of boundary layer loss in the first 10 % arc length of the suction surface will be aggravated, which will affect the downstream flow field, resulting in the increase of the fluctuation of separation loss, and ultimately the qualification of the overall aerodynamic parameters, like total pressure loss coefficient, will be reduced.