Computational Analysis of a Compressor Rotor With Enhanced Airfoil

2012 ◽  
Author(s):  
Shervin Sammak ◽  
Masoud Boroomand
Keyword(s):  
Rotor Blade ◽  
Computational Analysis ◽  
Leading Edge ◽  
Numerical Data ◽  
Suction Side ◽  
Aerodynamic Characteristics ◽  
Test Case ◽  
Experimental Measurements ◽  
Unstable Zone ◽  
Compressor Rotor

In this article, a compressor rotor blade is numerically modeled and solved by a CFD code. A stepped blade with higher aerodynamic characteristics is used to investigate unstable zone and improve operational limit and compressor stall. To validate numerical data original test case compared with experimental measurements. In this study, several locations of step on suction side of blades are tried, finally the results are compared with the case with no step on blades. It is shown that, by moving the step towards the leading edge, surge is delayed due to the reattachment of flow after the step. Efficiency is also decreased but lower than previous case.

Numerical Simulation of Effects of Tip Geometry on the Performance of an Axial Compressor

2012 ◽  
Author(s):  
Hongwei Ma ◽  
Jun Zhang
Keyword(s):  
Mass Flow ◽  
Tangential Force ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Leading Edge ◽  
Suction Side ◽  
Leakage Flow ◽  
Base Line ◽  
Compressor Rotor ◽  
Blade Tip

The purpose of this paper is to investigate numerically the effects of the tip geometry on the performance of an axial compressor rotor. There are three case studies which are compared with the base line tip geometry. 1) baseline (flat tip); 2) Cavity (tip with a cavity); 3) SSQA (suction side squealer tip) and 4) SSQB (modified suction side squealer tip). The case of SSQB is a combination of suction side squealer tip and the cavity tip. From leading edge to 10% chord, the tip has a cavity. From 10% chord to trailing edge, the tip has a suction side squealer. The numerical results of 2) show that the cavity tip leads to lower leakage mass flow and greater loss in tip gap and the rotor passage. The loading near the blade tip is lower than the baseline, thus the tangential force of the blade is lower. It leads to lower pressure rise than the baseline. The performance of the compressor for the tip with cavity is worse than the baseline. The results of 3) show that the higher curvature of the suction side squealer increases the loading of the blade and the tangential blade force. With the suction side squealer tip, the leakage flow experiences two vena contractor thus the mass of the leakage flow is reduced which is benefit for the performance of the compressor. The loss in the tip gap is lower than baseline. The performance is better than the baseline with greater pressure rise of the rotor, smaller leakage mass flow and lower averaged loss. For the case the SSQB, the leakage mass flow is lower than the SSQA and the loss in the tip gap and the rotor passage is greater than SSQA. The performance of the case of the SSQB is worse than the case of SSQA.

scholarly journals Investigation and Improvement of Stall Characteristic of High-Lift Configuration without Slats

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Zhao Yang ◽  
Jie Li ◽  
Jing Jin ◽  
Heng Zhang ◽  
Youxu Jiang
Keyword(s):  
Evaluation Method ◽  
Leading Edge ◽  
Suction Side ◽  
Aerodynamic Characteristics ◽  
Angle Distribution ◽  
Detached Eddy Simulation ◽  
High Lift ◽  
Eddy Simulation ◽  
Business Jet ◽  
Delayed Detached Eddy Simulation

In order to simplify the manufacturing process or because of the limitation of the propulsion system, business jet, small civil airplane, and turboprop aircraft are always designed without leading-edge slats, which poses a great challenge to the flight safety during takeoff and landing. Focusing on the low-speed stall and poststall conditions, we investigated the aerodynamic characteristics and flow mechanism of high-lift configuration without slats using an improved delayed detached eddy simulation (IDDES) model which is validated by numerical simulations of the Common Research Model (CRM). Based on the analysis of the calculated results, conclusion can be made that the stall behavior of the configurations is directly related to the onset and evaluation of flow separation on the suction side. And through further research, an efficient evaluation method that is capable of qualitatively predicting the stall performance of two-element high-lift configuration by stall angle distribution of wing sections is proposed. By using the evaluation method, together with design rules summarized from the present study, high-lift configuration with mild-stall characteristic can be obtained in the preliminary stage of design.

Effect of Inflow Circumferential Distortion on a Transonic Axial Compressor

2017 ◽  
Author(s):  
Yuyun Li ◽  
Zhiheng Wang ◽  
Guang Xi
Keyword(s):  
Total Pressure ◽  
Rotor Blade ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Leading Edge ◽  
Inlet Distortion ◽  
Compressor Rotor ◽  
Structure Changes ◽  
Transonic Axial Compressor

The Inlet distortion, which may lead to the stability reduction or structure failure, is often non-ignorable in an axial compressor. In the paper, the three-dimensional unsteady numerical simulations on the flow in NASA rotor 67 are carried out to investigate the effect of inlet distortion on the performance and flow structure in a transonic axial compressor rotor. A sinusoidal circumferential total pressure distortion with eleven periods per revolution is adopted to study the interaction between the transonic rotor and inlet circumferential distortion. Concerning the computational expense, the flow in two rotor blade passages is calculated. Various intensities of the total pressure distortion are discussed, and the detailed flow structures under different rotating speeds near the peak efficiency condition are analyzed. It is found that the distortion has a positive effect on the flow near the hub. Even though there is no apparent decrease in the rotor efficiency or total pressure ratio, an obvious periodic loading exists over the whole blade. The blade loadings are concentrated in the region near the leading edge of the rotor blade or regions affected by the oscillating shocks near the pressure side. The time averaged location of shock structure changes little with the distortion, and the motion of shocks and the interactions between the shock and the boundary layer make a great contribution to the instability of the blade structure.

The Effect of Inlet Guide Vanes Wake Impingement on the Flow Structure and Turbulence Around a Rotor Blade

2005 ◽  
Vol 128 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Francesco Soranna ◽  
Yi-Chih Chow ◽  
Oguz Uzol ◽  
Joseph Katz
Keyword(s):  
Flow Structure ◽  
Rotor Blade ◽  
Normal Component ◽  
Leading Edge ◽  
Suction Side ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Entire Flow ◽  
Turbulence Production ◽  
Wall Blockage

The flow structure and turbulence around the leading and trailing edges of a rotor blade operating downstream of a row of inlet guide vanes (IGV) are investigated experimentally. Particle image velocimetry (PIV) measurements are performed in a refractive index matched facility that provides unobstructed view of the entire flow field. Data obtained at several rotor blade phases focus on modification to the flow structure and turbulence in the IGV wake as it propagates along the blade. The phase-averaged velocity distributions demonstrate that wake impingement significantly modifies the wall-parallel velocity component and its gradients along the blade. Due to spatially non-uniform velocity distribution, especially on the suction side, the wake deforms while propagating along the blade, expanding near the leading edge and shrinking near the trailing edge. While being exposed to the nonuniform strain field within the rotor passage, the turbulence within the IGV wake becomes spatially nonuniform and highly anisotropic. Several mechanisms, which are consistent with rapid distortion theory (RDT) and distribution of turbulence production rate, contribute to the observed trends. For example, streamwise (in rotor frame reference) diffusion in the aft part of the rotor passage enhances the streamwise fluctuations. Compression also enhances the turbulence production very near the leading edge. However, along the suction side, rapid changes to the direction of compression and extension cause negative production. The so-called wall blockage effect reduces the wall-normal component.

Quantitative Computational Fluid Dynamics Analyses of Particle Deposition on a Transonic Axial Compressor Blade—Part I: Particle Zones Impact

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Alessio Suman ◽  
Rainer Kurz ◽  
Nicola Aldi ◽  
Mirko Morini ◽  
Klaus Brun ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Particle Deposition ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Numerical Data ◽  
Suction Side ◽  
Continuous Phase ◽  
Industrial Applications ◽  
Compressor Rotor ◽  
The Impact

Solid particle ingestion is one of the principal degradation mechanisms in the turbine and compressor sections of gas turbines. In particular, in industrial applications, the microparticles that are not captured by the air filtration system cause fouling and, consequently, a performance drop of the compressor. This paper presents three-dimensional numerical simulations of the microparticle ingestion (0 μm–2 μm) on an axial compressor rotor carried out by means of a commercial computational fluid dynamic (CFD) code. Particles of this size can follow the main air flow with relatively little slip, while being impacted by flow turbulence. It is of great interest to the industry to determine which areas of the compressor airfoils are impacted by these small particles. Particle trajectory simulations use a stochastic Lagrangian tracking method that solves the equations of motion separate from the continuous phase. Then, the NASA Rotor 37 is considered as a case study for the numerical investigation. The compressor rotor numerical model and the discrete phase treatment have been validated against the experimental and numerical data available in literature. The number of particles, sizes, and concentrations are specified in order to perform a quantitative analysis of the particle impact on the blade surface. The results show that microparticles tend to follow the flow by impacting at full span with a higher impact concentration on the pressure side (PS). The suction side (SS) is affected only by the impact of the smaller particles (up to 1 μm). Particular fluid dynamic phenomena, such as separation, stagnation point, and tip leakage vortex, strongly influence the impact location of the particles.

The Effect of IGV Wake Impingement on the Flow Structure and Turbulence Around a Rotor Blade

2005 ◽  
Author(s):  
Francesco Soranna ◽  
Yi-Chih Chow ◽  
Oguz Uzol ◽  
Joseph Katz
Keyword(s):  
Flow Structure ◽  
Rotor Blade ◽  
Normal Component ◽  
Leading Edge ◽  
Suction Side ◽  
Image Velocimetry ◽  
Trailing Edges ◽  
Entire Flow ◽  
Turbulence Production ◽  
Wall Blockage

The flow structure and turbulence around the leading and trailing edges of a rotor blade operating downstream of a row of Inlet Guide Vanes (IGV) are investigated experimentally. Particle Image Velocimetry (PIV) measurements are performed in a refractive index matched facility that provides unobstructed view of the entire flow field. Data obtained at several rotor blade phases focus on modification to the flow structure and turbulence in the IGV wake as it propagates along the blade. The phase-averaged velocity distributions demonstrate that wake impingement significantly modifies the wall-parallel velocity component and its gradients along the blade. Due to spatially non-uniform velocity distribution, especially on the suction side, the wake deforms while propagating along the blade, expanding near the leading edge and shrinking near the trailing edge. While being exposed to the non-uniform strain field within the rotor passage, the turbulence within the IGV wake becomes spatially non-uniform and highly anisotropic. Several mechanisms, which are consistent with rapid distortion theory (RDT) and distribution of turbulence production rate, contribute to the observed trends. For example, streamwise (in rotor frame reference) diffusion in the aft part of the rotor passage enhances the streamwise fluctuations. Compression also enhances the turbulence production very near the leading edge. However, along the suction side, rapid changes to the direction of compression and extension cause negative production. The so-called wall blockage effect reduces the wall-normal component.

Effects of Solid Particle Ingestion Through an HP Turbine

2012 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Gas Turbines ◽  
Rotor Blade ◽  
Leading Edge ◽  
Suction Side ◽  
Operating Conditions ◽  
Pressure Side ◽  
Trailing Edge ◽  
Premature Failure ◽  
Narrow Strip ◽  
Tracking Model

Modern gas turbines operate in severe dusty environments, and because of such harsh operating conditions, their blades experience significant degradation in service. This paper presents a numerical study of particle dynamics and erosion in an hp axial turbine stage. The flow field is solved separately from the solid phase and constitutes the necessary data in the particle trajectories simulations using a Lagrangian tracking model based on the finite element method. Several parameters consider a statistical description such as particle size, shape and rebound, in addition to the turbulence effect. A semi empirical erosion correlation is used to estimate erosion contours and blades deteriorations, knowing the locations and conditions of impacts. The trajectory and erosion results show high erosion rates over the pressure side of NGV near trailing edge, in addition to extreme erosion observed toward the root corner, due to high number of particles impacting with high velocities. On the suction side, erosion is mainly over a narrow strip from leading edge. Erosion in the rotor blade is shown along the leading edge and spreading over the fore of the blade suction side, owing to a flux of particles entering at high velocities and incidence. On the pressure side, regions of dense erosion are observed near the leading edge and trailing edge as well as the tip corner. Critical erosion spots seen over NGV and rotor blade are signs of a premature failure.

Entropy Generation Maps of a Low-Specific Speed Radial Compressor Rotor

2000 ◽  
Author(s):  
Carmine Luca Iandoli ◽  
Enrico Sciubba
Keyword(s):  
Flow Field ◽  
Entropy Generation ◽  
Leading Edge ◽  
Suction Side ◽  
Detailed Knowledge ◽  
Radial Compressor ◽  
Compressor Rotor ◽  
Entire Flow ◽  
Low Specific Speed ◽  
Specific Speed

Abstract The flow field in the rotor of a low-specific speed radial compressor is computed in a fully 3-D simulation and the irreversible entropy generation rates directly calculated from the local velocity- and temperature values. The code used for the simulation is a commercial CFD-finite volumes package, FLUENT™, augmented by an novel entropy generation routine adapted from the original formulation due to Bejan [1]. The model provides the designer with exact and detailed knowledge of the local values of the irreversibility production, allowing for a separate accounting of viscous- and thermal effects and thus resulting in a valuable tool for the search of design improvements. These local entropy generation rates can of course be integrated over the entire flow field to obtain the global irreversibility production, directly linked with the rotor efficiency: but more important is the possibility of obtaining an exact “mapping” of these local values in some particularly “critical” design areas (leading edge of the blade at the inlet, first portion of the channel on the pressure side, last portion of the channel on the suction side, rotor exit). By direct comparison of repeated simulations, the designer can then easily assess the relative performance of different blade arrangements and rotor configurations. In particular, it is possible to compute, via a direct application of the Gouy-Stodola lost work formula, the isentropic efficiency of the rotor. The possibility is discussed of developing a “configuration optimisation procedure” based on the systematic, iterative and automatic application of this type of analysis.

Investigation of the Flowfield in the Transonic VKI BRITE EURAM Turbine Stage With 3D Steady and Unsteady N-S Computations

2000 ◽  
Author(s):  
Björn Laumert ◽  
Hans Mårtensson ◽  
Torsten H. Fransson
Keyword(s):  
Rotor Blade ◽  
Three Dimensional ◽  
Leading Edge ◽  
Weak Shock ◽  
Suction Side ◽  
Navier Stokes ◽  
Turbine Stage ◽  
Trailing Edge ◽  
Measured Pressure ◽  
Good Agreement

This paper presents the results from three-dimensional (3D) steady and unsteady Navier-Stokes computations, performed on the transonic VKI BRITE EURAM test turbine stage. The work aimed at giving deeper insight in the aerodynamics of the turbine stage. The analysis has been carried out with the nominal stator trailing edge ejection slot geometry and cooling flow ejection. Additionally a simplified rounded stator trailing edge was employed. The results from the unsteady computations were compared with measured pressure perturbation traces at 22 locations around the rotor blade at midspan. Computations with both the ejection slot and the rounded stator trailing edge geometry were in good agreement with the measurements on the pressure side and half chord of the rotor blade’s suction side. Measurements and computations showed less good agreement downstream a weak shock on the suction side of the rotor blade. The measured pressure double peak in the rotor blade leading edge region is only observed in the computations with the ejection slot geometry.

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