scholarly journals Investigation of Sound Generation and Transmission Effects Through the ACAT1 Fan Stage using Compressed Sensing-based Mode Analysis

2019 ◽  
Author(s):  
Maximilian Behn ◽  
Ulf Tapken
Keyword(s):  
Compressed Sensing ◽  
Mode Analysis ◽  
Sound Generation

Azimuthal Mode Characteristics of Rotating Instability in Axial Compressor Using Compressed Sensing Method

2021 ◽  
pp. 1-53
Author(s):  
Jie Tian ◽  
Zonghan Sun ◽  
Xiaopu Zhang ◽  
Hua Ouyang
Keyword(s):  
Compressed Sensing ◽  
Dynamic Pressure ◽  
Robustness Analysis ◽  
Axial Compressor ◽  
Mode Analysis ◽  
Reconstruction Method ◽  
Sampling Point ◽  
Complex Flow ◽  
Azimuthal Mode ◽  
Rotating Instability

Abstract A signal reconstruction algorithm based on the compressed sensing (CS) theory with dual-uniform sampling point (DUSP) distribution is developed and applied to identify the circumferential mode of axial compressor. A regular failure signal pattern is found and the corresponding explanation is presented with validation. Circumferential mode analysis is applied to both numerical and experimental pressure fluctuation signals of rotating instability in the axial compressor tip region. For numerical calculations, the signal in the circumferential mode domain is reconstructed by the CS with random measurement points and DUSP respectively. The success rates and the reconstruction errors are discussed in details. It is shown that the circumferential mode reconstruction method based on CS combined with DUSP is capable to identify the complex flow modes in tip region of axial compressor. For the experimental results, high circumferential mode numbers are reconstructed based on dynamic pressure signals measured by DUSP. Circumferential mode analysis efficiency is thereby significantly improved. The time-resolved characteristics of the rotating instability (RI) is discussed. Moreover, a robustness analysis is conducted, demonstrating the ability of the CS-based method with DUSP to address fault sensor problems.

Sound Power Measurements at Radial Compressors Using Compressed Sensing Based Signal Processing Methods

2019 ◽  
Author(s):  
Jakob Hurst ◽  
Maximilian Behn ◽  
Ulf Tapken ◽  
Lars Enghardt
Keyword(s):  
Signal Processing ◽  
Compressed Sensing ◽  
Matching Pursuit ◽  
Orthogonal Matching Pursuit ◽  
Radial Mode ◽  
Mode Analysis ◽  
Sound Power ◽  
Test Rig ◽  
Azimuthal Mode ◽  
Radial Compressor

Abstract Two sound power measurement approaches were developped that are easy to install and have the ability to detect the dominant modal content by applying the modern signal processing method, Compressed Sensing. In general Compressed Sensing requires only few measurement positions for an exact reconstruction of sparse acoustic mode fields. For a current study we have chosen two Compressed Sensing algorithms. Each require separate sensor array arrangements and deliver different modal contents, from which the sound power can be derived. Firstly, an Azimuthal Mode Analysis is conducted by applying the Enhanced Orthogonal Matching Pursuit (EOMP) algorithm to a sound pressure measurement vector. The measurements are obtained by using a sensor ring array with optimized positions. In a subsequent step, the sound power is calculated by referring the detected azimuthal mode spectrum to a model describing the energy distribution over the radial mode content. Secondly, using the Block Orthogonal Matching Pursuit (BOMP) algorithm, the radial mode amplitudes are determined directly. This algorithm requires the sensors to be placed at optimized azimuthal and axial positions and reconstructs a set of dominant radial modes that occur in groups. With the objective to verify both methods, the newly designed and optimized arrays in combination with the aforementioned mode reconstruction algorithms are applied to a numerical data set. This data was provided by URANS simulations of a radial compressor set-up, which is an exact replication of an actual test rig located at the RWTH Aachen University. The introduced estimation methods perform well as shown by comparison with an exact and high resolution Radial Mode Analysis Method. In the near future, the presented measurement approaches will be applied in an experimental study performed at the radial compressor test rig.

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