Effect of manufacturing tolerance in flow past a compressor blade

Abstract

This paper presents the effect of manufacturing tolerance on performance and stability boundaries of a transonic fan using a RANS simulation. The effect of tip gap and stagger angle was analysed through a series of single passage and double passage simulation; based on which an optimal arrangement was proposed for random tip gap and random stagger angle in case of a whole annulus rotor. All simulations were carried out using NASA rotor 67 as a test case and AU3D an in-house CFD solver. Results illustrate that the stagger angle mainly affects efficiency and hence its circumferential variation must be as smooth as possible. Furthermore, the tip gap affects the stability boundaries, pressure ratio and efficiency. Hence its optimal configuration mandates that the blades be configured in a zigzag arrangement around the annulus i.e. larger tip gap between two smaller ones.

Development of a surrogate model for uncertainty quantification of compressor performance due to manufacturing tolerance

“…To represent stagger angle manufacturing tolerances, a twist is imposed to the blade by using mesh morphing. Fol lowing previous work (Suriyanarayanan et al, 2022), the variation of stagger angle is in the range of ±1.5°. The tip gap variations do not impact the performances of the wide chord fan which is not tiploaded (see Fig.…”

“…This is due to the average effect of geometrical tolerances and to the variation between adjacent blades. In other words, the order in which the blades are arranged influences the performances, as shown in previous work (Suriyanarayanan et al, 2022).…”

“…Previous work (Suriyanarayanan et al, 2022) has shown that tip gap variations affect both stall margin and performance whereas stagger angle variations mostly affect the latter. While relying on the same strategy, two independent surrogate models are needed to compute the characteristic curve of equivalent compressors (see the middlepart of Fig.…”

“…Previous work (Suriyanarayanan et al, 2022) showed that stagger angle variations create a change in passage geometry and incidence angle which induce a displacement of the shockwave. The maximal efficiency is obtained, by design, for a specific shockwave position which is, by symmetry, the same for all passages.…”

“…Hence, to maximize compressor performance, one needs to maximize adjacent tipgap variations (which is referred as zigzag pattern). More details on these two mechanisms can be found in (Suriyanarayanan et al, 2022).…”