Simulation of Particle Trajectories and Erosion in a Centrifugal Compressor

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Particle Size ◽  
Centrifugal Compressor ◽  
Equations Of Motion ◽  
Leading Edge ◽  
Lagrangian Model ◽  
Sand Particle ◽  
Pressure Side ◽  
Particle Trajectories ◽  
Erosion Rates ◽  
Severe Erosion

Turbocompressors manipulating particle-laden airflows suffer from severe erosion damages which affect their operating performance and lifetime. This paper presents the results of a numerical investigation of the dynamics of sand particles and the subsequent erosion in a centrifugal compressor. The particle trajectories simulations used a developed code based on a stochastic Lagrangian model, which solves the equations of motion separately from the airflow, whereas the tracking of particles in different computational cells used the finite element method. The number of particles, sizes, and initial positions were specified, conformed to a sand particle size distribution AC_coarse (0–200 μm), and a given concentration profile. The obtained results show that the speed of rotation and particle size strongly affect the trajectories of particles and their locations of impact. Erosion is spreading over the pressure side of the main blade. Regions of high erosion rates are seen over the leading edge, at the inducer top corner and along the blade tip. Over the splitter pressure side erosion wear is much less than the main blade. The suction sides are almost without erosion except near the leading edge, and the casing is mainly affected over the inducer and tips of the blades.

Study of Sand Particle Trajectories and Erosion Into the First Compression Stage of a Turbofan

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Equations Of Motion ◽  
Leading Edge ◽  
Sand Particle ◽  
The Finite Element Method ◽  
Particle Trajectories ◽  
Compression Stage ◽  
Trailing Edges ◽  
Blade Tip ◽  
Lagrangian Tracking ◽  
Aero Engines

Aero-engines operating in dusty environments are subject to ingestion of erodent particles leading to erosion damage of blades and a permanent drop in performance. This work concerns the study of particle dynamics and erosion of the front compression stage of a commercial turbofan. Particle trajectories simulations used a stochastic Lagrangian tracking code that solves the equations of motion separately from the airflow in a stepwise manner, while the tracking of particles in different cells is based on the finite element method. As the locations of impacts and rates of erosion were predicted, the subsequent geometry deteriorations were assessed. The number of particles, sizes, and initial positions were specified conformed to sand particle distribution (MIL-E5007E, 0-1000 micrometers) and concentrations 50–700 mg/m3. The results show that the IGV blade is mainly eroded over the leading edge and near hub and shroud; also the rotor blade has a noticeable erosion of the leading and trailing edges and a rounding of the blade tip corners, whereas in the diffuser, erosion is shown to spread over the blade surfaces in addition to the leading edge and trailing edge.

Simulation of Particle Trajectories and Erosion Through a Centrifugal Compressor

2010 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Particle Size ◽  
Numerical Study ◽  
Leading Edge ◽  
Suction Side ◽  
Particle Trajectories ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Erosion Rates ◽  
Air Stream ◽  
Lagrangian Tracking Approach

Under particulate environments, turbocompressors suffer from erosion which is of serious concern to both manufacturers and users of these equipments. In this paper, the results of a numerical study of particle laden air flows through a radial compressor ‘Schwitzer’ are presented. Particle trajectories used an updated version of our in-house code based on a stochastic Lagrangian tracking approach, where equations of particle motion are solved separately from the air-stream. This latter considers the effects of turbulence on particles, initial locations of particles and random particle size and rebound. The tracking of particles in different computational cells and theirs corresponding impacts used the finite element method. The number of particles, their sizes and initial positions were specified according to a concentration profile and an AC coarse (0–200 micron) size distribution. The simulations results are depicting that the impeller rotating speed and particle size strongly affect the trajectories, locations of impacts and erosion rates. For a high rotational speed, erosion is spreading over the pressure side of the main blade and splitter. Regions of high erosion rates are seen on the blades leading edges and towards the upper corner at blade exit. However, the main blade is highly eroded than the splitter. The suction side is almost without erosion except near the leading edge. Furthermore, the casing is mainly affected over the inducer and along the tips of blades.

Experimental and CFD Investigations to Evaluate the Effects of Fluid Viscosity and Particle Size on Erosion Damage in Oil and Gas Production Equipment

2010 ◽  
Author(s):  
Risa Okita ◽  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Edmund F. Rybicki
Keyword(s):  
Particle Size ◽  
Oil And Gas ◽  
Production Equipment ◽  
Gas Production ◽  
Inconel 625 ◽  
Sand Particle ◽  
Fluid Viscosity ◽  
Particle Sizes ◽  
Erosion Rates ◽  
Particle Speed

Zhang et al (2006) utilized CFD to examine the validity of erosion models that have been implemented into CFD codes to predict solid particle erosion in air and water for Inconel 625. This work is an extension of Zhang’s work and is presented as a step toward obtaining a better understanding of the effects of fluid viscosity and sand particle size on measured and calculated erosion rates. The erosion rates of Aluminum 6061-T6 were measured for direct impingement conditions of a submerged jet. Fluid viscosities of 1, 10, 25, and 50 cP and sand particle sizes of 20, 150, and 300 μm were tested. The average fluid speed of the jet was maintained at 10 m/s. Erosion data show that erosion rates for the 20 and 150 μm particles are reduced as the viscosity is increased, while surprisingly the erosion rates for the 300 μm particles do not seem to change much for the higher viscosities. For all viscosities considered, larger particles produced higher erosion rates, for the same mass of sand, than smaller particles. Concurrently, an erosion equation has been generated based on erosion testing of the same material in air. The new erosion model has been compared to available models and has been implemented into a commercially available CFD code to predict erosion rates for a variety of flow conditions, flow geometries, and particle sizes. Since particle speed and impact angle greatly influence erosion rates of the material, calculated particle speeds were compared with measurements. Comparisons reveal that, as the particles penetrate the near wall shear layer, particles in the higher viscosity liquids tend to slow down more rapidly than particles in the lower viscosity liquids. In addition, CFD predictions and particle speed measurements are used to explain why the erosion data for larger particles is less sensitive to the increased viscosities.

A Second Order Lagrangian Model for Irregular Ocean Waves

2005 ◽  
Vol 128 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Sébastien Fouques ◽  
Harald E. Krogstad ◽  
Dag Myrhaug
Keyword(s):  
Specular Reflection ◽  
Fluid Velocity ◽  
Equations Of Motion ◽  
Wave Theory ◽  
Ocean Waves ◽  
Second Order ◽  
Lagrangian Model ◽  
Lagrangian Description ◽  
Linear Wave ◽  
Irregular Solution

Synthetic aperture radar (SAR) imaging of ocean waves involves both the geometry and the kinematics of the sea surface. However, the traditional linear wave theory fails to describe steep waves, which are likely to bring about specular reflection of the radar beam, and it may overestimate the surface fluid velocity that causes the so-called velocity bunching effect. Recently, the interest for a Lagrangian description of ocean gravity waves has increased. Such an approach considers the motion of individual labeled fluid particles and the free surface elevation is derived from the surface particles positions. The first order regular solution to the Lagrangian equations of motion for an inviscid and incompressible fluid is the so-called Gerstner wave. It shows realistic features such as sharper crests and broader troughs as the wave steepness increases. This paper proposes a second order irregular solution to these equations. The general features of the first and second order waves are described, and some statistical properties of various surface parameters such as the orbital velocity, slope, and mean curvature are studied.

scholarly journals Aerothermal Investigations of Mixing Flow Phenomena in Case of Radially Inclined Ejection Holes at the Leading Edge

1999 ◽  
Author(s):  
Dieter E. Bohn ◽  
Karsten A. Kusterer
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Gas Turbines ◽  
Leading Edge ◽  
Suction Side ◽  
Pressure Side ◽  
Blade Surface ◽  
Cooling Fluid ◽  
Flow Phenomena ◽  
Vortex Systems

A leading edge cooling configuration is investigated numerically by application of a 3-D conjugate fluid flow and heat transfer solver, CHT-Flow. The code has been developed at the Institute of Steam and Gas Turbines, Aachen University of Technology. It works on the basis of an implicit finite volume method combined with a multi-block technique. The cooling configuration is an axial turbine blade cascade with leading edge ejection through two rows of cooling holes. The rows are located in the vicinity of the stagnation line, one row is on the suction side, the other row is on the pressure side. The cooling holes have a radial ejection angle of 45°. This configuration has been investigated experimentally by other authors and the results have been documented as a test case for numerical calculations of ejection flow phenomena. The numerical domain includes the internal cooling fluid supply, the radially inclined holes and the complete external flow field of the turbine vane in a high resolution grid. Periodic boundary conditions have been used in the radial direction. Thus, end wall effects have been excluded. The numerical investigations focus on the aerothermal mixing process in the cooling jets and the impact on the temperature distribution on the blade surface. The radial ejection angles lead to a fully three dimensional and asymmetric jet flow field. Within a secondary flow analysis it can be shown that complex vortex systems are formed in the ejection holes and in the cooling fluid jets. The secondary flow fields include asymmetric kidney vortex systems with one dominating vortex on the back side of the jets. The numerical and experimental data show a good agreement concerning the vortex development. The phenomena on the suction side and the pressure side are principally the same. It can be found that the jets are barely touching the blade surface as the dominating vortex transports hot gas under the jets. Thus, the cooling efficiency is reduced.

Effects of Diffuser Vane Geometries on Compressor Performance and Noise Characteristics in a Centrifugal Compressor

2013 ◽  
Author(s):  
Yohei Morita ◽  
Nobumichi Fujisawa ◽  
Takashi Goto ◽  
Yutaka Ohta
Keyword(s):  
Centrifugal Compressor ◽  
Noise Level ◽  
Leading Edge ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Numerical Techniques ◽  
Vaned Diffuser ◽  
Noise Characteristics ◽  
Edge Vortex ◽  
Compressor Performance

The effects of the diffuser vane geometries on the compressor performance and noise characteristics of a centrifugal compressor equipped with vaned diffusers were investigated by experiments and numerical techniques. Because we were focusing attention on the geometries of the diffuser vane’s leading edge, diffuser vanes with various leading edge geometries were installed in a vaned diffuser. A tapered diffuser vane with the tapered portion near the leading edge of the diffuser’s hub-side could remarkably reduce both the discrete frequency noise level and broadband noise level. In particular, a hub-side tapered diffuser vane with a taper on only the hub-side could suppress the development of the leading edge vortex (LEV) near the shroud side of the diffuser vane and effectively enhanced the compressor performance.

Generation Mechanism of Broadband Whoosh Noise in an Automotive Turbocharger Centrifugal Compressor

2021 ◽  
pp. 1-35
Author(s):  
Rick Dehner ◽  
Pranav Sriganesh ◽  
Ahmet Selamet ◽  
Keith Miazgowicz
Keyword(s):  
Centrifugal Compressor ◽  
Combustion Engine ◽  
Three Dimensional ◽  
Leading Edge ◽  
Broadband Noise ◽  
Rotor Blades ◽  
Generation Mechanism ◽  
Primary Concern ◽  
Frequency Range ◽  
Modal Decomposition

Abstract The present study focuses on the acoustics of a turbocharger centrifugal compressor from a spark-ignition internal combustion engine. Whoosh noise is typically the primary concern for this type of compressor, which is loosely characterized by broadband sound elevation in the 4 to 13 kHz range. To identify the generation mechanism of broadband whoosh noise, the present study combines three approaches: three-dimensional (3D) computational fluid dynamics (CFD) predictions, experiments, and modal decomposition of 3D CFD results. After establishing the accuracy of predictions, flow structures and time-resolved pressures are closely examined in the vicinity of the main blade leading edge. This reveals the presence of rotating instabilities that may interact with the rotor blades to generate noise. An azimuthal modal decomposition is performed on the predicted pressure field to determine the number of cells and the frequency content of these rotating instabilities. The strength of the rotating instabilities and the frequency range in which noise is generated as a consequence of the rotor-rotating instability interaction, is found to correspond well with the qualitative trend of the whoosh noise that is measured several duct diameters upstream of the rotor blades. The variation of whoosh frequency range between low and high rotational speeds is interpreted through this analysis. It is also found that the whoosh noise primarily propagates along the duct as acoustic azimuthal modes. Hence, the inlet duct diameter, which governs the cut-off frequency for multi-dimensional acoustic modes, determines the lower frequency bound of the broadband noise.

Tip Leakage Flow Instability in a Centrifugal Compressor

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Teng Cao ◽  
Tadashi Kanzaka ◽  
Liping Xu ◽  
Tobias Brandvik
Keyword(s):  
Shear Layer ◽  
Centrifugal Compressor ◽  
Large Scale ◽  
Flow Instability ◽  
Leading Edge ◽  
Main Stream ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Unstable Flow ◽  
Tip Leakage

Abstract In this paper, an unsteady tip leakage flow phenomenon is identified and investigated in a centrifugal compressor with a vaneless diffuser at near-stall conditions. This phenomenon is associated with the inception of a rotating instability in the compressor. The study is based on numerical simulations that are supported by experimental measurements. The study confirms that the unstable flow is governed by a Kelvin–Helmholtz type instability of the shear layer formed between the main-stream flow and the tip leakage flow. The shear layer instability induces large-scale vortex roll-up and forms vortex tubes, which propagate circumferentially, resulting in measured pressure fluctuations with short wavelength and high amplitude which rotate at about half of the blade speed. The 3D vortex tube is also found to interact with the main blade leading edge, causing the reduction of the blade loading identified in the experiment. The paper also reveals that the downstream volute imposes a once-per-rev circumferential nonuniform back pressure at the impeller exit, inducing circumferential loading variation at the impeller inducer, and causing circumferential variation in the unsteady tip leakage flow.

A Numerical Model for Simulating Liquid Particles Deposition on Surface

2018 ◽  
Author(s):  
Zhenxia Liu ◽  
Fei Zhang ◽  
Zhengang Liu
Keyword(s):  
Particle Size ◽  
Numerical Model ◽  
Particle Deposition ◽  
Surface Profile ◽  
Leading Edge ◽  
Solid Particles ◽  
Liquid Particle ◽  
Aircraft Icing ◽  
Turbine Vane ◽  
Deposition Thickness

The deposition of liquid particles, which may be converted from solid particles due to high temperature gas heating, makes much more harm on turbine vane blades compared to solid particles, since it may block film-cooling holes, worsen the cooling efficiency and aerodynamic performance of the turbine vane blades. Due to the similarity between the deposition of liquid particles on a surface and the icing on a surface, a numerical model for simulating particles deposition was developed based on the Myers icing model, an extension of the Messinger model, which has been applied in predicting aircraft icing or aero-engine icing. Compared to the conventional liquid particle deposition model, the numerical model in this paper considers the heat transfer and the flow of liquid particles during the particles phase transition from liquid state to solid state. In this model, the change of the surface profile due to the particles deposition was also considered, which was implemented with dynamic mesh technique. To test this model, deposition distribution and thickness obtained from the numerical simulations were compared to the experimental results. Additionally, a numerical simulation was conducted for liquid particle deposition on a flat plate. The result showed that the deposition thickness at the leading edge was much larger than that on the upper surface where the deposition appeared mainly at the middle and rear of the plate. The deposition mass and thickness increased with the increasing in the particle size. The effect of the particle size on the deposition thickness was more notable on the upper surface compared to that at the leading edge.

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