Numerical Investigation of Unsteady Flow Phenomena in an HP Axial Flow Compressor Incorporating Stator Shroud Cavities'

The paper presents the results of large-scale numerical simulations which were conducted for better understanding of unsteady flow phenomena in a multi-stage axial flow compressor at off-design condition. The compressor is a test rig compressor which was used for development of the industrial gas turbine, Kawasaki L30A. The compressor consists of 14 stages, the front two stages and the front half stages of which were investigated in the present study. The final goal of this study is to elucidate the flow mechanism of the rotating stall inception in the multi-stage axial compressor for actual gas turbines, and according to the test data it is considered that the 2nd stage and the 5th or 6th stage are suspected of leading to the stall. In order to capture precise flow physics in the compressor, a computational mesh for the simulation was generated to have at least several million cells per passage, which amounted to 650 million cells for the front 2-stage simulation and two billion cells for the front 7-stage simulation (about three hundred million cells for each stage). Since these were still not enough for the large-eddy simulation (LES), the detached-eddy simulation (DES) was employed, which can calculate flow fields except near-wall region by LES. The required computational resources were quite large for such simulations, so the computations were conducted on the K computer (RIKEN AICS in Japan). The simulations were well validated, showing good agreement with the measurement results obtained in the test. In the validation, the effect of the boundary condition for the casing wall was also investigated by comparing the results between the adiabatic boundary condition and the isothermal boundary condition. As for the unsteady effect, the wake/blade interaction was investigated in detail. In addition, unsteady flow phenomena in the present compressor at off-design condition were analyzed by using data mining techniques such as vortex identification and limiting streamline drawing with the LIC (line integral convolution) method. The simulation showed that they could be caused by the corner separation on the hub side.

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A Study on Unsteady Flow Phenomena at Near-Stall in a Multi-Stage Axial Flow Compressor by Large-Scale DES with K Computer

International Journal of Gas Turbine, Propulsion and Power Systems ◽

10.38036/jgpp.9.1_18 ◽

2017 ◽

Vol 9 (1) ◽

pp. 18-26

Author(s):

Kazutoyo Yamada ◽

Masato Furukawa ◽

Satoshi Nakakido ◽

Yuki Tamura ◽

Akinori Matsuoka ◽

...

Keyword(s):

Unsteady Flow ◽

Large Scale ◽

Axial Flow ◽

Axial Flow Compressor ◽

Multi Stage ◽

Flow Phenomena ◽

Flow Compressor

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1628 Numerical Analysis of Unsteady Flow Phenomena in an Axial Flow Compressor Rotor at Near Stall Condition

The proceedings of the JSME annual meeting ◽

10.1299/jsmemecjo.2007.7.0_125 ◽

2007 ◽

Vol 2007.7 (0) ◽

pp. 125-126

Author(s):

Ken-ichiro IWAKIRI ◽

Sho BONKOHARA ◽

Masato FURUKAWA

Keyword(s):

Numerical Analysis ◽

Unsteady Flow ◽

Axial Flow ◽

Axial Flow Compressor ◽

Compressor Rotor ◽

Flow Phenomena ◽

Flow Compressor

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A New Approach to the Experimental Study of Turbomachinery Flow Phenomena

Journal of Engineering for Power ◽

10.1115/1.3446259 ◽

1977 ◽

Vol 99 (1) ◽

pp. 97-105 ◽

Cited By ~ 20

Author(s):

J. P. Gostelow

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Axial Flow ◽

Centrifugal Pumps ◽

New Approach ◽

Static Pressure Distribution ◽

Compressor Rotor ◽

Flow Phenomena ◽

On Line ◽

Flow Compressor

Measurements of the unsteady flow field over a rotor and within its wake are needed in the development of most turbomachines. The technique advocated is that of data acquisition by on-line computer, using the periodic passing of a blade as a phase reference. The phase-lock averaging process is described as is its use in reducing the noise of raw data traces. Measurements of the unsteady flow over a cascade and of the resulting boundary layer behavior are presented. The approach was used in interpreting the unsteady flow field of an axial-flow compressor rotor and the static pressure distribution over the rotor tip. Finally the application to centrifugal pumps is discussed, enabling the designer to obtain information on the suction pressures and the extent of any separated region.

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Endwall Effects at Two Tip Clearances in a Multistage Axial Flow Compressor With Controlled Diffusion Blading

Journal of Turbomachinery ◽

10.1115/1.2929454 ◽

1994 ◽

Vol 116 (4) ◽

pp. 635-645 ◽

Cited By ~ 14

Author(s):

M. A. Howard ◽

P. C. Ivey ◽

J. P. Barton ◽

K. F. Young

Keyword(s):

Unsteady Flow ◽

Axial Flow ◽

Tip Clearance ◽

Exit Angle ◽

Controlled Diffusion ◽

The Third ◽

Flow Phenomena ◽

Multistage Compressor ◽

Flow Compressor ◽

Stage Efficiency

Effects of tip clearance, secondary flow, skew, and corner stall on the performance of a multistage compressor with controlled diffusion blading have been studied experimentally. Measurements between 1 and 99 percent annulus height were carried out in both the first and the third stages of a four-stage low-speed compressor with repeating-stage blading. Measurements were obtained at a datum rotor tip clearance and at a more aerodynamically desirable lower clearance. The consequences of the modified rotor tip clearance on both rotor and stator performance are examined in terms of loss coefficient and gas exit angle. Stator losses close to the casing are found to increase significantly when the clearance of an upstream rotor is increased. These increased stator losses cause 30 percent of the stage efficiency reduction that arises with increased rotor tip clearance. The deviation angles due to tip clearance from the multistage measurements are found to be similar to data from single-stage machines with conventional blading, which suggests that the unsteady flow phenomena associated with the multistage environment do not dominate the physics of the flow.

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Unsteady flow field under surge and rotating stall in a three-stage axial flow compressor

Journal of Thermal Science ◽

10.1007/s11630-011-0427-z ◽

2011 ◽

Vol 20 (1) ◽

pp. 6-12 ◽

Cited By ~ 4

Author(s):

Takayuki Hara ◽

Daisuke Morita ◽

Yutaka Ohta ◽

Eisuke Outa

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Axial Flow ◽

Rotating Stall ◽

Axial Flow Compressor ◽

Flow Compressor

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Effects of tip clearance size on the unsteady flow behaviors and performance in a counter-rotating axial flow compressor

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410017745901 ◽

2017 ◽

Vol 233 (3) ◽

pp. 1059-1070 ◽

Cited By ~ 2

Author(s):

Xiaochen Mao ◽

Bo Liu ◽

Hang Zhao

Keyword(s):

Unsteady Flow ◽

Incidence Angle ◽

Axial Flow ◽

Leading Edge ◽

Tip Clearance ◽

Leakage Flow ◽

Tip Leakage Flow ◽

Tip Leakage ◽

Axial Flow Compressor ◽

Flow Compressor

This paper presents the studies performed to better understand the effects of increased tip clearance size on the unsteady flow behaviors and overall performance under the rotor–rotor interaction environment in a counter-rotating axial flow compressor. The investigation method is based on the three-dimensional unsteady Reynolds-averaged Navier–Stokes simulations. The results show that the intensified tip leakage flow in front rotor (R1) caused by the increased tip clearance size will lead to the growth of incoming incidence angle near the tip of the rear rotor (R2). The increasing of double leakage flow range plays a significant role in the sensitivity of the efficiency to tip clearance size and its extent is enlarged gradually with the increase of tip clearance size. As the tip clearance size is increased to 1.5τ (τ represents the designed tip clearance size) from 0.5τ, the results of the fast Fourier transform for the static pressure near blade tip show that two other new fluctuating frequency components appear due to the happening of tip leakage flow self-unsteadiness in R1 and R2, respectively. Additionally, the fluctuating strength near the tip in R2 is significantly increased. However, both the overall fluctuation in R1 caused by the potential effect from downstream and the oscillation in the hub corner on the pressure side of R2 are decreased obviously. The relative inflow angle tends to increase when the incoming wakes and tip leakage flow from R1 encounter the blade leading edge of R2, which leads to the result that the trajectory of tip leakage flow is shifted more upstream.

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