Stall Inception in a High-Speed Centrifugal Compressor

Abstract

Stall inception in a high-speed centrifugal compressor has been examined. The main objective was to find stall precursor and to develop a reliable stall warning method. Eight equally spaced fast-response pressure transducers in the inducer detected the spatial structure of small amplitude perturbations, via spatial Fourier transform, as stall is approached. Near the stall inception point, the phase of spatial Fourier coefficients increased linearly with the speed of impeller rotation for several impeller revolutions at all test speeds, and the spectrum at impeller frequency increased as stall is approached. This is the clear evidence that the impeller frequency participates in the stalling process. For stall warning, a method which uses the spectrum at impeller frequency is suggested. The use of spectrum at impeller frequency as a stall warning method showed a warning time of about two hundreds impeller revolutions. This method uses only one sensor that it has made the stall warning method more useful. And the well-known traveling wave energy method proved to be a good method for stall warning also in a high-speed centrifugal compressor. The warning time was about one hundred impeller revolutions at lower speeds, and about one thousand impeller revolutions at higher speeds. The stall warning methods used here were found to be robust and reliable. Therefore, it seems to be promising to set up a reliable stall avoidance control based on this analysis.

Unstable Flow Structures Present at Different Rotational Velocities of the Centrifugal Compressor

“…Many researchers have analyzed the spectral structure of the signals at the surge and prior to it. This kind of analysis was conducted, among others, by Oakes et al [17,24], Brown et al [26], Lawless and Fleeter [27], Kang and Kang [28], Horodko [29] or Liskiewicz et al [14,30].…”

“…Galindo et al investigated the influence of inlet pulsation on the compressor surge line at different rotational speeds [32]. Kang and Kang investigated different algorithms for stall warning based on the pressure spectrum change observed at different rotational speeds of the high-speed centrifugal compressor [28].…”

Analysis of biogas compression system dynamics

“…For these reasons, different strategies to avoid compressor operation beyond the surge line have been developed and can be grouped into three categories: surge detection, through the precursors of instabilities, which requires large control forces and very fast actuators [6][7][8][9]; surge avoidance, based on the definition of a surge avoidance line, which is conservative if compared to the surge line. The definition of the surge avoidance line does not allow the compressor to operate close to the surge line, i.e.…”

Numerical simulation of rotating stall in a centrifugal compressor with vaned diffuser

“…While the successful control of rotating stall to improve compressor stability is based on the detection of early precursors to stall, Lawless [1] experimentally studied the rotating stall acoustic signatures in a low speed centrifugal compressor with vaneless and vaned diffusers. Recently Kang et al [2][3][4] examined the stall inception in a high speed centrifugal compressor through a series of experiments. Both of them wanted to find stall precursors and develop reliable stall warning method.…”