Numerical Study of Droplet Erosion in the First-Stage Rotor of an Axial Flow Compressor

2021 ◽  
Author(s):  
Giuliano Agati ◽  
Domenico Borello ◽  
Francesca Di Gruttola ◽  
Franco Rispoli ◽  
Paolo Venturini ◽  
...  
Keyword(s):  
Numerical Study ◽  
Axial Flow ◽  
Leading Edge ◽  
Point Of View ◽  
Rotor Blades ◽  
Process Efficiency ◽  
Computational Grids ◽  
Axial Flow Compressor ◽  
Washing Process ◽  
Flow Compressor

Abstract In the present paper, a procedure for the study of the water washing in axial flow compressors is presented. The study is part of an ongoing partnership between Baker Hughes and Sapienza University of Rome aiming at maximizing the washing of the compressor blades while maintaining the erosion under specific thresholds. A computational analysis in the first part of an axial flow compressor (i.e. up to the first rotor) was carried out by using Ansys Fluent for the solution of multi-phase flow, while the water droplet erosion mechanism was modeled by the authors by using a properly developed methodology implemented in Fluent though the use of User Defined Functions. The washing process efficiency as well as the erosion rate are evaluated by introducing appropriate indexes. A parametric analysis was carried out by varying the mass flow rate of injected water. Two different computational grids were considered aiming at simulating two different configurations. In the first one the rotor blades leading edge (LE) is placed in the wake released by IGVs trailing edge (TE). In the second configuration, the rotor blades LE is located in a circumferential position corresponding to the mid-pitch between two successive IGVs. These two configurations simulate the situations of minimum and maximum water impact on the rotor blade surfaces. For all the injection conditions here considered, the configuration where IGVs trailing edges were aligned with the rotor blades LEs resulted in higher impacts and erosion on the blade pressure sides. When rotating rotor blades LEs in the middle of the IGVs vanes, rotor LEs were found to be the mostly washed regions but also the most subject to erosion phenomena. The computed indexes show the not optimal distribution of the injectors from the washing efficiency point of view.

Flow Studies on a Single Stage Transonic Axial Flow Compressor Retrofitted With Circumferential Grooves and Varied Rotor-Stator Axial Gap

2017 ◽  
Author(s):  
Anand P. Darji ◽  
Dilipkumar Bhanudasji Alone ◽  
Chetan S. Mistry
Keyword(s):  
Numerical Study ◽  
Computational Study ◽  
Axial Flow ◽  
Single Stage ◽  
Experimental Results ◽  
Stall Margin ◽  
Axial Flow Compressor ◽  
Transonic Compressor ◽  
Stall Margin Improvement ◽  
Flow Compressor

A transonic axial flow compressor undergoes severe vibrations due to instabilities like stall and surge when it operates at lower mass flow rate in the absence of any control devices. In present study, the attempt was made to understand the combine impact of circumferential casing grooves (CCG) of constant aspect ratio and different axial spacing between rotor and stator on the operating stability of single stage transonic axial compressor and that of rotor alone using numerical simulation. The optimum rotor-stator gap in the presence of grooved casing treatment was identified. The steady state numerical analysis was performed by using three-dimensional Reynolds Average Navier-Stokes equation adapting shear stress transport (SST) k-ω turbulence model. The study is reported in two sections. First section includes the detailed numerical study on baseline case having smooth casing wall (SCW). The computational results were validated with the experimental results available at Propulsion Division of CSIR-NAL, Bangalore. The computational study shows good agreement with experimental results. The second section comprises the effects of optimum designs of CCG and various axial spacing on the stall margin improvement of transonic compressor. Current computational study shows that the axial spacing between rotor and stator is an important parameter for improvement in stall margin not only for SCW but also for CCG. Therefore, the highest stall margin improvement of 9% has achieved for 75% axial spacing.

Numerical Simulation of Steady Air Injection Flow Control Effects on a Transonic Axial Flow Compressor

2012 ◽  
Vol 224 ◽  
pp. 352-357
Author(s):  
Islem Benhegouga ◽  
Ce Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Leading Edge ◽  
Air Injection ◽  
Axial Flow Compressor ◽  
Blade Tip ◽  
Flow Compressor

In this work, steady air injection upstream of the blade leading edge was used in a transonic axial flow compressor, NASA rotor 37. The injectors were placed at 27 % upstream of the axial chord length at blade tip, the injection mass flow rate is 3% of the chock mass flow rate, and 3 yaw angles were used, respectively -20°, -30°, and -40°. Negative yaw angles were measured relative to the compressor face in opposite direction of rotational speeds. To reveal the mechanism, steady numerical simulations were performed using FINE/TURBO software package. The results show that the stall mass flow can be decreased about 2.5 %, and an increase in the total pressure ratio up to 0.5%.

Detection of a Rotating Stall Precursor in Isolated Axial Flow Compressor Rotors

1991 ◽  
Vol 113 (2) ◽  
pp. 281-287 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru ◽  
T. Iwamoto ◽  
Y. Ando
Keyword(s):  
Pressure Sensor ◽  
Pressure Fluctuation ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Statistical Characteristics ◽  
Flow Passage ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Stall Precursor

Statistical characteristics of pressure fluctuation on the casing wall of two axial flow compressor rotors have been investigated experimentally to find a precursor of rotating stall. Near stall, the casing wall pressure across a flow passage near the leading edge is characterized by a highly unsteady region where low-momentum fluid accumulates. The periodicity of the pressure fluctuation with blade spacing disappears and an alternative phenomenon comes into existence, which supports the disturbance propagating at a different speed from the rotor revolution. The precursor of rotating stall can be detected by monitoring collapse of the periodicity in the pressure fluctuation. To represent the periodicity qualitatively, a practical detection parameter has been proposed, which is easily obtained from signals of a single pressure sensor installed at an appropriate position on the casing wall during operation of a compressor.

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

2017 ◽  
Vol 233 (3) ◽  
pp. 1059-1070 ◽  
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.

Numerical Studies on Effect of Stepped Tip Clearance Height on the Performance of Single Stage Transonic Axial Flow Compressor

2013 ◽  
Author(s):  
Pritam Batabyal ◽  
Dilipkumar B. Alone ◽  
S. K. Maharana
Keyword(s):  
Numerical Study ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Flow ◽  
Single Stage ◽  
Tip Clearance ◽  
Baseline Model ◽  
Axial Flow Compressor ◽  
Design Speed ◽  
Flow Compressor

This paper presents a numerical case study of various stepped tip clearances and their effect on the performance of a single stage transonic axial flow compressor, using commercially available software ANSYS FLUENT 14.0. A steady state, implicit, three dimensional, pressure based flow solver with SST k-Ω turbulence model has been selected for the numerical study. The stepped tip clearances have been compared with the baseline model of zero tip clearance at 70% and 100 % design speed. It has been observed that the compressor peak stage efficiency and maximum stage pressure ratio decreases as the tip clearances in the rear part are increased. The stall margin also increases with increase in tip clearance compared to the baseline model. An ‘optimum’ value of stepped tip clearance has been obtained giving peak stage compressor performance. The CFD results have been validated with the earlier published experimental data on the same compressor at 70% design speed.

scholarly journals Causes for Turbomachinery Performance Deterioration

1988 ◽  
Author(s):  
W. Tabakoff
Keyword(s):  
Gas Turbine ◽  
Axial Flow ◽  
Leading Edge ◽  
Solid Particles ◽  
Two Stage ◽  
Axial Flow Compressor ◽  
Polluted Atmosphere ◽  
Performance Deterioration ◽  
Flow Compressor ◽  
Blunt Leading Edge

Turbines and compressors operating in polluted atmosphere with solid particles are subjected to performance deterioration. This paper presents an investigation carried out on two-stage gas turbine with blunt leading edge blades and on a single-stage axial flow compressor to study the effects of particulates and erosion on performance deterioration.

Stator Endwall Leading-Edge Sweep and Hub Shroud Influence on Compressor Performance

1986 ◽  
Vol 108 (2) ◽  
pp. 224-232 ◽  
Author(s):  
D. L. Tweedt ◽  
T. H. Okiishi ◽  
M. D. Hathaway
Keyword(s):  
Axial Flow ◽  
Leading Edge ◽  
Outer Diameter ◽  
Loss Reduction ◽  
Local Loss ◽  
Axial Flow Compressor ◽  
Stator Blade ◽  
Inner Diameter ◽  
Compressor Performance ◽  
Flow Compressor

The use of stator endwall leading-edge sweep to improve axial-flow compressor stator row performance was examined experimentally. The aerodynamics of three stator hub (inner diameter) conditions, namely, a running clearance, a stationary clearance, and a shroud, were also investigated. Leading-edge sweep in the endwall regions of a stator blade can be beneficial in terms of loss reduction on the casing (outer diameter) end of a stator blade. It can also help at the hub end of a stator blade when either a stationary hub clearance or a hub shroud is used. A leading-edge sweep is detrimental (local loss increase) on the hub end of a stator blade when a running hub clearance is used. A running clearance is aerodynamically preferable to a stationary clearance.

Investigation on the influence of the structure parameters of blade tip recess on the performance of axial flow compressor

2021 ◽  
pp. 095441002199810
Author(s):  
Song Yan ◽  
WuLi Chu
Keyword(s):  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Field Analysis ◽  
Structure Parameters ◽  
Two Dimensional ◽  
Axial Flow Compressor ◽  
Aero Engine ◽  
Blade Tip ◽  
Flow Compressor

As one of the important components of an aero engine, the compressor plays an important role in improving the performance of the aero engine. The blade tip recess (BTR) has great potential and advantages in improving the performance of the compressor. It is very important to clarify the influence of the structure parameters of the BTR on the performance of the compressor. In this study, the two-dimensional results of the BTR were analyzed by using the method of variance analysis, and the two-dimensional calculation results of the BTR were used to guide the design of the BTR of axial flow compressor rotor. In the NASA Rotor 35, the influence rules of the structure parameters of BTR on the recess effect that was basically the same as the two-dimensional conditions. The optimization of the rotor BTR structure parameters may be achieved by the two-dimensional calculation. The flow field analysis showed the BTR can retard the growth rate of the blockage area of the leading edge of blade tip by weakening the tip clearance leakage flow intensity that delayed the occurrence of blade tip blockage and improved the aerodynamic stability of the rotor.

Aerodynamic Design and Testing of an Axial Flow Compressor for the GT24/26 Gas Turbines

2013 ◽  
Author(s):  
Damir Novak ◽  
Michael Loetzerich ◽  
Matthias Boese
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Leading Edge ◽  
Advanced Technology ◽  
Aerodynamic Design ◽  
3D Design ◽  
Axial Flow Compressor ◽  
Stage Matching ◽  
Flow Compressor

A 22-stage axial flow compressor with a pressure ratio 35:1 has been designed, built and successfully tested for a heavy-duty gas turbine application. Advanced technology and aero engine design tools have been used. The compressor has been designed using an “arbitrary” airfoil blading including 3D design features, like leading edge re-camber, lean, sweep and flowpath contouring. The compressor performance and part load behavior have been improved by accurate stage matching based on whole compressor 3D analyses. The new compressor has been tested in a scaled down rig and validated in the Alstom Test Power Plant (ATPP).The compressor met all design objectives and demonstrated excellent performance. This paper describes the aerodynamic design and test results.

scholarly journals Water washing of axial flow compressors: numerical study on the fate of injected droplets

2020 ◽  
Vol 197 ◽  
pp. 11015
Author(s):  
Giuliano Agati ◽  
Francesca Di Gruttola ◽  
Serena Gabriele ◽  
Domenico Simone ◽  
Paolo Venturini ◽  
...  
Keyword(s):  
Numerical Study ◽  
Axial Flow ◽  
Rotor Blades ◽  
Injection System ◽  
Asymmetric Distribution ◽  
Wall Functions ◽  
Erosion Risk ◽  
Water Washing ◽  
Washing Process ◽  
The Impact

In turbomachinery applications blade fouling represents a main cause of performance degradation. Among the different techniques currently available, online water washing is one of the most effective in removing deposit from the blades. Since this kind of washing is applied when the machine is close to design conditions, injected droplets are strongly accelerated when they reach the rotor blades and the understanding of their interaction with the blades is not straightforward. Moreover, undesirable phenomena like blades erosion or liquid film formation can occur. The present study aims at assessing droplets dragging from the injection system placed at the compressor inlet till the first stage rotor blades, with a focus on droplets impact locations, on the washing process and the associated risk of erosion. 3D numerical simulations of the whole compressor geometry (up to the first rotor stage) are performed by using Ansys Fluent to account for the asymmetric distribution of the sprays around of the machine struts, IGV and rotor blades. The simulations are carried out by adopting the k-ε realizable turbulence model with standard wall functions, coupled with the discretephase model to track injected droplets motion. Droplets-wall interaction is also accounted for by adopting the Stanton-Rutland model which define a droplet impact outcome depending on the impact conditions. The induced erosion is evaluated by adopting an erosion model previously developed by some of the authors and implemented in Fluent through the use of a User Defined Function (UDF). Two sets of simulations are performed, by considering the rotor still and rotating, representative of off-line and on-line water washing conditions, respectively. In the rotating simulation, the Multiple Reference Frame Model is used. The obtained results demonstrate that the washing process differs substantially between the fixed and the rotating case. Moreover, to quantify the water washing effectiveness and the erosion risk, new indices were introduced and computed for the main components of the machine. These indices can be considered as useful prescriptions in the optimization process of water washing systems.

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