The Influence of Blade Number Ratio and Blade Row Spacing on Axial-Flow Compressor Stator Blade Dynamic Load and Stage Sound Pressure Level

Abstract

In axial-flow turbomachines considerable dynamic blade loads and noise production occur as a result of the unsteady blade row interaction between rotor and stator blades. This paper presents results of midspan measurements of the dynamic pressure distribution on the stator blade surface (fixed number of blades) for various rotor-blade numbers and various axial clearances between rotor and stator. For this purpose, one stator blade had been provided with eleven semiconductor pressure transducers in the midspan section. Simultaneously, the sound pressure level was measured at two axial distances downstream of the stator by four condensator microphones distributed along the circumference in each of the two sections and mounted flush with the wall surface. The wake-flow distribution downstream of the rotor could be obtained by a rotating three-hole pressure probe. The results of the corresponding dynamic pressure-measurements and noise measurements are discussed and compared with results from theory.

Reduction of Unsteady Blade Loading by Beneficial Use of Vortical and Potential Disturbances in an Axial Compressor With Rotor Clocking

“…The vortical contribution essentially represents the total (prior to decomposition) transverse gust, since the potential contribution is small even at 10% chord gap between blade rows. Figure 7 thus provides further justification for using wake/blade calculation to model the unsteady effect from the upstream blade on the downstream blade (e.g., Giles, 1988 andHall andCrawley, 1989). Moreover, the distinct difference in time scale between the vortical and potential gusts -the vortical gust on the order of passing of the wake width and the potential gust being blade-to-blade period -can be clearly seen.…”

“…Forced response had been studied by many researchers. Theoretical work on unsteady disturbances includes Goldstein and Atassi (1976) and Goldstein (1978). Excellent series of experiments Fleeter, 1993a &1993b;Feiereisen et at, 1993;Weaver and Fleeter, 1994) were conducted by Professor Fleeter and his students on illuminating the physics of vortical and potential disturbances.…”

“…Excellent series of experiments Fleeter, 1993a &1993b;Feiereisen et at, 1993;Weaver and Fleeter, 1994) were conducted by Professor Fleeter and his students on illuminating the physics of vortical and potential disturbances. Gallus et al (1982) also studied potential and wake interactions experimentally. The work by Manwaring and Wisler (1993) provided extensive comparison between the state-of-the-art analysis methods and data.…”

Study on the Effect of Asymmetric Vane Spacing on Vibratory Stress of Blade

“…Traditionally, the blade designer has adopted the following methods to reduce the probability of failure: (1) Avoid the resonance by detuning the blade frequency or altering the vane count [1]. (2) Reduce the excitation force by expanding the spacing between the vane and the blade [2,3] or by use of clocking [4,5]. (3) Increase the blade damping by adopting the friction damper, etc.…”

Experimental and Numerical Study of Gust and Gust Response in a Rotor/Stator Axial Compressor

“…The work of Valkov and Tan provided exceptional physical insight into the cause of unsteady blade loading due to moving wakes. Experimental studies which focus on the unsteady blade loading include Fleeter et al (1981), Capece and Fleeter (1987), Gallus et al (1982), Manwaring and Wisler (1993), and others. The work of Manwaring and Wisler emphasized the importance of properly accounting both vortical and potential contributions to calculate the total unsteady response.…”