scispace - formally typeset
Search or ask a question
Topic

Axial compressor

About: Axial compressor is a research topic. Over the lifetime, 12035 publications have been published within this topic receiving 127766 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a spectral and modal analysis of axial rotor configurations was performed using a spectral decomposition based on cross-spectral matrices, and a time-resolved analysis based on a spatial Discrete Fourier Transform was applied to clarify the temporal characteristics of the RI modes and their potential interrelations.
Abstract: Rotating Instability (RI) occurs at off-design conditions in axial compressors, predominantly in rotor configurations with large tip clearances. Characteristic spectral signatures with side-by-side peaks below the blade passing frequency are typically referred to RI located in the clearance region next to the leading edge (LE). Each peak can be assigned to a dominant circumferential mode. RI is the source of the clearance noise and an indicator for critical operating conditions. Earlier studies at an annular cascade pointed out that RI modes of different circumferential orders occur stochastically distributed in time and independently from each other, which is contradictory to existing explanations of the RI. Purpose of the present study is to verify the generality with regard to axial rotor configurations.Experiments were conducted on a laboratory axial fan stage mainly using unsteady pressure measurements in a sensor ring near the rotor LE. A mode decomposition based on cross spectral matrices was used to analyze the spectral and modal RI patterns upstream of the rotor. Additionally, a time-resolved analysis based on a spatial Discrete-Fourier-Transform was applied to clarify the temporal characteristics of the RI modes and their potential interrelations. The results and a comparison with the previous findings on the annular cascade corroborate a new hypothesis about the basic RI mechanism. This hypothesis implies that instability waves of different wavelengths are generated stochastically in a shear layer resulting from a backflow in the tip clearance region.Copyright © 2014 by ASME

39 citations

01 Jan 1972
TL;DR: In this article, the results of testing a single-stage axial flow compressor with a solid-wall casing and with grooved casings are presented, and the greatest reduction in the near-stall weight flow was noted for the configuration with five grooves located over the blade midchord region.
Abstract: Comparisons of the results of testing a single-stage axial-flow compressor with a solid-wall casing and with grooved casings are presented. The depth, location, and number of circumferential grooves in the casing over the casing over the rotor tip were varied. The near-stall weight flow was lower than that with the solid-wall casing for all but one grooved configuration indicating an improvement in the stall margin. The greatest reduction in the near-stall weight flow was noted for the configuration with five grooves located over the blade midchord region.

39 citations

Patent
26 Nov 2002
TL;DR: In this article, an exhaust-gas turbocharger for an internal combustion engine includes an auxiliary-air feed device, which is assigned to the compressor region and has an auxiliary air passage in the compressor housing for supplying auxiliary air.
Abstract: An exhaust-gas turbocharger for an internal combustion engine includes an exhaust-gas turbine in the exhaust section and a compressor in the intake tract. The compressor includes a compressor impeller in an inflow passage in the compressor housing. Furthermore, there is an auxiliary-air feed device, which is assigned to the compressor region and has an auxiliary-air passage, in the compressor housing for supplying auxiliary air, which can be introduced via an injection opening in the wall of the inflow passage of the compressor into the flow-facing region of the compressor impeller.

39 citations

Journal ArticleDOI
TL;DR: In this paper, the second part of a two part paper that reports on the improvement of efficiency of a one-and-half stage high-work axial flow turbine is presented.
Abstract: This paper is the second part of a two part paper that reports on the improvement of efficiency of a one-and-half stage high work axial flow turbine. The first part covered the design of the endwall profiling as well as a comparison with steady probe data, this part covers the analysis of the time-resolved flow physics. The focus is on the time-resolved flow physics that lead to a total-to-total stage efficiency improvement of Δη tt = 1.0% ± 0.4% . The investigated geometry is a model of a high work (Δ h/ U2 = 2.36 ), axial shroudless HP turbine. The time-resolved measurements have been acquired upstream and downstream of the rotor using a Fast Response Aerodynamic Probe (FRAP). The paper contains a detailed analysis of the secondary flow field that is changed between the axisymmetric and the non-axisymmetric endwall profiling cases. The flowfield at exit of the first stator is improved considerably due to non-axisymmetric endwall profiling and results in reduced secondary flow and a reduction of loss at both hub and tip, as well as a reduced trailing shed vorticity. The rotor has reduced losses and a reduction of secondary flows mainly at the hub. At the rotor exit the flow field with non-axisymmetric endwalls is more homogenous due to the reduction of secondary flows in the two rows upstream of the measurement plane. This confirms that non-axisymmetric endwall profiling is an effective tool for reducing secondary losses in axial turbines. Using a frozen flow assumption the time-resolved data is used to estimate the axial velocity gradients, which are then used to evaluate the streamwise vorticity and dissipation. The non-axisymmetric endwall profiling of the first nozzle guide vane show reductions of dissipation and streamwise vorticity due to reduced trailing shed vorticity. This smaller vorticity explains the reduction of loss at mid-span, which is shown in the first part of the two part paper. This leads to the conclusion that non-axisymmetric endwall profiling also has the potential of reducing trailing shed vorticity.Copyright © 2008 by ASME

39 citations

F. K. Moore1
01 Jul 1983
TL;DR: In this paper, a theoretical analysis was made of rotating stall in axial compressors of many stages, finding conditions for a permanent straight-through traveling disturbance, with the steady compressor characteristic assumed known, and with simple lag processes ascribed to the flows in the inlet, blade passages, and exit regions.
Abstract: A theoretical analysis was made of rotating stall in axial compressors of many stages, finding conditions for a permanent, straight-through traveling disturbance, with the steady compressor characteristic assumed known, and with simple lag processes ascribed to the flows in the inlet, blade passages, and exit regions. For weak disturbances, predicted stall propagation speeds agree well with experimental results. For a locally-parabolic compressor characteristic, an exact nonlinear solution is found and discussed. For deep stall, the stall-zone boundary is most abrupt at the trailing edge, as expected. When a complete characteristic having unstalling and reverse-flow features is adopted, limit cycles governed by a Lienard's equation are found. Analysis of these cycles yields predictions of recovery from rotating stall; a relaxation oscillation is found at some limiting flow coefficient, above which no solution exists. Recovery is apparently independent of lag processes in the blade passages, but instead depends on the lags originating in the inlet and exit flows, and also on the shape of the given characteristic diagram. Small external lags and tall diagrams favor early recovery. Implications for future research are discussed.

39 citations


Network Information
Related Topics (5)
Reynolds number
68.4K papers, 1.6M citations
87% related
Laminar flow
56K papers, 1.2M citations
86% related
Heat exchanger
184.2K papers, 1M citations
82% related
Turbulence
112.1K papers, 2.7M citations
82% related
Heat transfer
181.7K papers, 2.9M citations
82% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202398
2022304
2021217
2020288
2019316
2018353