Abstract: A method of optimizing probe placement in a turbomachine is disclosed which includes establishing a design matrix A of size m×(2N+1) utilized in developing flow properties around an annulus of a turbomachine, where m represents the number of datapoints at different circumferential locations around the annulus, and N represents dominant wavelets generated by upstream and downstream stators and blade row interactions formed around an annulus, wherein m is greater or equal to 2N+1, and optimizing probe positioning by iteratively modifying probe positions placed around the annulus and for each iteration determining a condition number of the design matrix A for each set of probe positions until a predetermined threshold is achieved for the condition number representing an optimal probe layout.

Abstract: A method of optimizing probe placement in a turbomachine is disclosed which includes establishing a design matrix A of size m×(2N+1) utilized in developing flow properties around an annulus of a turbomachine, where m represents the number of datapoints at different circumferential locations around the annulus, and N represents dominant wavelets generated by upstream and downstream stators and blade row interactions formed around an annulus, wherein m is greater or equal to 2N+1, and optimizing probe positioning by iteratively modifying probe positions placed around the annulus and for each iteration determining a condition number of the design matrix A for each set of probe positions until a predetermined threshold is achieved for the condition number representing an optimal probe layout.

Abstract: A method of optimizing probe placement in a turbomachine is disclosed which includes determining wavenumber (Wn) of N dominant wavelets generated by upstream and downstream stators and blade row interactions formed around an annulus, establishing a design matrix A utilized in developing flow properties around the annulus having a dimension of m×(2N+1), iteratively modifying probe positions placed around the annulus and determining a condition number of the design matrix A for each set of probe positions until a predetermined threshold is achieved for the condition number representing optimal probe position, wherein the condition number is defined as norm A·norm A+, wherein A+ represents inverse of A for a square matrix and a Moore-Penrose pseudoinverse of A for a rectangular matrix.

Abstract: The present disclosure relates to a novel method to detect an imminent compressor stall by using nonlinear feature extraction algorithms. The present disclosure focuses on the small nonlinear disturbances prior to deep surge and introduces a novel approach to identify these disturbances using nonlinear feature extraction algorithms including phase-reconstruction of time-serial signals and evaluation of a parameter called approximate entropy. The technique is applied to stall data sets from a high-speed centrifugal compressor that unexpectedly entered rotating stall during a speed transient and a multi-stage axial compressor with both modal- and spike-type stall inception. In both cases, nonlinear disturbances appear, in terms of spikes in approximate entropy, prior to surge. The presence of these pre-surge spikes indicates imminent compressor stall.

Abstract: A method for reconstructing nonuniform circumferential flow in a turbomachine is disclosed which includes receiving one or more wavenumbers of interest, receiving positional information for a plurality of circumferential positions of a plurality of instrumentation probes, receiving signals from the plurality of instrumentation probes to generate a spatially under-sampled data, and from the spatially under-sampled data determining a multi-wavelet approximation reconstructing circumferential flow field.

Abstract: A method of optimizing probe placement in a turbomachine is disclosed which includes determining wavenumber (Wn) of N dominant wavelets generated by upstream and downstream stators and blade row interactions formed around an annulus, establishing a design matrix A utilized in developing flow properties around the annulus having a dimension of m×(2N+1), iteratively modifying probe positions placed around the annulus and determining a condition number of the design matrix A for each set of probe positions until a predetermined threshold is achieved for the condition number representing optimal probe position, wherein the condition number is defined as norm A·norm A+, wherein A+ represents inverse of A for a square matrix and a Moore-Penrose pseudoinverse of A for a rectangular matrix.

Abstract: The present disclosure relates to a novel method to detect an imminent compressor stall by using nonlinear feature extraction algorithms. The present disclosure focuses on the small nonlinear disturbances prior to deep surge and introduces a novel approach to identify these disturbances using nonlinear feature extraction algorithms including phase-reconstruction of time-serial signals and evaluation of a parameter called approximate entropy. The technique is applied to stall data sets from a high-speed centrifugal compressor that unexpectedly entered rotating stall during a speed transient and a multi-stage axial compressor with both modal- and spike-type stall inception. In both cases, nonlinear disturbances appear, in terms of spikes in approximate entropy, prior to surge. The presence of these pre-surge spikes indicates imminent compressor stall.

Abstract: A method to monitor rotor blade vibration using unsteady casing pressure. The method applies a non-intrusive blade vibration monitoring technique by using an array of unsteady pressure sensors which may be flush-mounted in the casing of a compressor. The method comprises using spinning mode theory and temporal-spatial analysis to obtain frequency and nodal diameter information of spinning pressure waves associated with the rotor blade vibration. An example of the compressor can be a multistage axial compressor.

Abstract: The present disclosure relates to a novel method to monitor rotor blade vibration using unsteady casing pressure. The novel method applies a non-intrusive blade vibration monitoring technique by using an array of unsteady pressure sensors flush-mounted in the casing of a multistage axial compressor. The novel method comprises using spinning mode theory to obtain frequency and nodal diameter information for all pressure waves that can be identified and determining any of the pressure waves that is associated with blade vibration.