scholarly journals Experimental and Numerical Flow Analysis of an Engine-Realistic State-of-the-Art Turbine Rear Structure

2021 ◽  
Author(s):  
Valentin Vikhorev ◽  
Pär Nylander ◽  
Valery Chernoray ◽  
Jonas Larsson ◽  
Oskar Thulin
Keyword(s):  
Static Pressure ◽  
State Of The Art ◽  
Flow Analysis ◽  
Surface Flow ◽  
Secondary Flows ◽  
Test Facility ◽  
Turbofan Engine ◽  
Pressure Distributions ◽  
Outlet Flow ◽  
Engine Mount

Abstract This paper presents experimental and numerical CFD studies of the aerodynamics of a turbine rear structure (TRS). The TRS test geometry is an engine-realistic state-of-the-art design with a polygonal outer case, recessed engine mount bumps, and three different vane types: regular vanes, bump vanes in bump sectors, and thick vanes. Using three different sector types simultaneously was found to be crucial for the inlet boundary conditions. Experiments were performed in a modern rotating test facility with an LPT stage upstream of the TRS. A Reynolds number of 350,000 was used, representative of a TRS in a narrow-body geared turbofan engine. The TRS performance was analyzed both at on- and off-design conditions and a thorough side-by-side comparison of CFD and experiments was performed. Static-pressure-distributions, turning and outlet flow-angles, wakes and losses, and surface-flow visualizations and outlet total pressure contours are presented. The thick vane showed good aerodynamic performance, similar to the regular vane. For the bump vane, the mount bumps were found to generate additional local separations and secondary flows, resulting in extra losses. In the regions with strong secondary flows CFD over-predicts the wakes, whereas the wakes around midspan, where secondary flows have a smaller influence, are predicted well.

Centrifugal Compressor Impeller Aerodynamics: An Experimental Investigation

1991 ◽  
Vol 113 (4) ◽  
pp. 660-669 ◽  
Author(s):  
H. D. Joslyn ◽  
J. J. Brasz ◽  
R. P. Dring
Keyword(s):  
Experimental Investigation ◽  
Flow Visualization ◽  
Centrifugal Compressor ◽  
Static Pressure ◽  
Flow Analysis ◽  
Surface Flow ◽  
Pressure Distributions ◽  
Compressor Impeller ◽  
New Facility ◽  
Surface Flow Visualization

The ability to acquire blade loadings (surface pressure distributions) and surface flow visualization on an unshrouded centrifugal compressor impeller is demonstrated. Circumferential and streamwise static pressure distributions acquired on the stationary shroud are also presented. Data were acquired in a new facility designed for centrifugal compressor aerodynamic research. Blade loadings calculated with a blade-to-blade potential flow analysis are compared with the measured results. Surface flow visualization reveals some complex aspects of the flow on the surface of the impeller blading and hub.

Experimental and Computational Analyses of Pressure Differentials in Flexible Ducts With Different Bent Angles

2007 ◽  
Author(s):  
Ray R. Taghavi ◽  
Wonjin Jin ◽  
Mario A. Medina
Keyword(s):  
Pressure Drop ◽  
Static Pressure ◽  
Complex Geometry ◽  
Analysis Data ◽  
Secondary Flows ◽  
Low Flow ◽  
Pressure Drops ◽  
Pressure Distributions ◽  
Geometrical Effects ◽  
Cfd Analyses

A set of experimental analyses was conducted to determine static pressure drops inside non-metallic flexible, spiral wire helix core ducts, with different bent angles. In addition, Computational Fluid Dynamics (CFD) solutions were performed and verified by comparing them to the experimental data. The CFD computations were carried out to produce more systematic pressure drop information through these complex-geometry ducts. The experimental setup was constructed according to ASHRAE Standard 120-1999. Five different bent angles (0, 30, 45, 60, and 90 degrees) were tested at relatively low flow rates (11 to 89 CFM). Also, two different bent radii and duct lengths were tested to study flexible duct geometrical effects on static pressure drops. FLUENT 6.2, using RANS based two equations - RNG k-ε model, was used for the CFD analyses. The experimental and CFD results showed that larger bent angles produced larger static pressure drops in the flexible ducts. CFD analysis data were found to be in relatively good agreement with the experimental results for all bent angle cases. However, the deviations became slightly larger at higher velocity regimes and at the longer test sections. Overall, static pressure drop for longer length cases were approximately 0.01in.H2O higher when compared to shorter cases because of the increase in resistance to the flow. Also, the CFD simulations captured more pronounced static pressure drops that were produced along the sharper turns. The stronger secondary flows, which resulted from higher and lower static pressure distributions in the outer and inner surfaces, respectively, contributed to these higher pressure drops.

Measurements of Secondary Losses in a Turbine Cascade With the Implementation of Nonaxisymmetric Endwall Contouring

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
D. C. Knezevici ◽  
S. A. Sjolander ◽  
T. J. Praisner ◽  
E. Allen-Bradley ◽  
E. A. Grover
Keyword(s):  
Kinetic Energy ◽  
Axial Flow ◽  
Surface Flow ◽  
Secondary Flows ◽  
Test Facility ◽  
Suction Surface ◽  
Blade Passage ◽  
Low Pressure Turbine ◽  
Endwall Contouring ◽  
Pressure And Velocity Measurements

An approach to endwall contouring has been developed with the goal of reducing secondary losses in highly loaded axial flow turbines. The present paper describes an experimental assessment of the performance of the contouring approach implemented in a low-speed linear cascade test facility. The study examines the secondary flows of a cascade composed of Pratt & Whitney PAKB airfoils. This airfoil has been used extensively in low-pressure turbine research, and the present work adds intrapassage pressure and velocity measurements to the existing database. The cascade was tested at design incidence and at an inlet Reynolds number of 126,000 based on inlet midspan velocity and axial chord. Quantitative results include seven-hole pneumatic probe pressure measurements downstream of the cascade to assess blade row losses and detailed seven-hole probe measurements within the blade passage to track the progression of flow structures. Qualitative results take the form of oil surface flow visualization on the endwall and blade suction surface. The application of endwall contouring resulted in lower secondary losses and a reduction in secondary kinetic energy associated with pitchwise flow near the endwall and spanwise flow up the suction surface within the blade passage. The mechanism of loss reduction is discussed in regard to the reduction in secondary kinetic energy.

An Advanced Single-Stage Turbine Facility for Investigating Non-Axisymmetric Contoured Endwalls in the Presence of Purge Flow

2019 ◽  
Author(s):  
Robin R. Jones ◽  
Oliver J. Pountney ◽  
Bjorn L. Cleton ◽  
Liam E. Wood ◽  
B. Deneys J. Schreiner ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Static Pressure ◽  
Optical Measurement ◽  
Guide Vane ◽  
Single Stage ◽  
Test Facility ◽  
Pressure Distributions ◽  
Mainstream Flow ◽  
Purge Flow ◽  
Nozzle Guide

Abstract In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimise the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream-egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile and EWC on the rotor endwall. This paper presents the design of, and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress-mainstream flow interactions. To the authors’ knowledge this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry and planar laser induced fluorescence are also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seals geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes at three different spanwise locations; pitchwise static pressure distributions downstream of the nozzle guide vane at four axial locations on the stator platform.

Centrifugal Compressor Impeller Aerodynamics: An Experimental Investigation

1990 ◽  
Author(s):  
H. David Joslyn ◽  
Joost J. Brasz ◽  
Robert P. Dring
Keyword(s):  
Flow Visualization ◽  
Centrifugal Compressor ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Companion Paper ◽  
Surface Flow ◽  
Navier Stokes ◽  
Pressure Distributions ◽  
Compressor Impeller ◽  
Surface Flow Visualization

The ability to acquire blade loadings (surface pressure distributions) and surface flow visualization on an unshrouded centrifugal compressor impeller is demonstrated. Circumferential and streamwise static pressure distributions acquired on the stationary shroud are also presented. Data was acquired in a new facility designed for centrifugal compressor aerodynamic research. Blade loadings calculated with a blade–to–blade potential flow analysis are compared with the measured results. Surface flow visualization reveals some complex aspects of the flow on the surface of the impeller blading and hub. In a companion paper, Dorney and Davis (1990), a state–of–the–art, three–dimensional, time–accurate, Navier Stokes prediction of the flow through the impeller is presented.

APR+ Core Flow and Pressure Distributions Under the 4 Pump Unbalanced Flow Condition

2013 ◽  
Author(s):  
K. Kim ◽  
D. J. Euh ◽  
Y. J. Youn ◽  
I. C. Chu ◽  
H. S. Choi ◽  
...  
Keyword(s):  
Flow Condition ◽  
Static Pressure ◽  
Flow Path ◽  
Test Facility ◽  
Hydraulic Characteristics ◽  
Ensemble Averaging ◽  
Core Flow ◽  
Pressure Distributions ◽  
Fuel Assemblies ◽  
Reduced Scale

The core inlet flow rates and exit pressure distributions of an APR+ (Advanced Power Reactor Plus) reactor were evaluated experimentally in this study. The tests were performed in the ACOP (APR+ Core Flow & Pressure) test facility constructed with a linear reduced scale of 1/5 referring to the prototype plant. The major flow path inside the reactor vessel was designed with a preservation of a geometrically similar flow without hindering the dynamic similarity. The 257 core simulators with 771 pressure impulse lines were installed in the ACOP facility to measure the hydraulic characteristics at the inlet and outlet of the fuel assemblies. The pressure distributions along the major flow path were obtained by measuring the static pressure and differential pressures at 584 points. The hydraulic characteristics of the reactor flow under an unbalanced cold leg flow condition were investigated by using an ensemble averaging process of 5 independent tests. The details of these experiments and a data analysis were described in this paper.

Effect of Swirl on Pressure Recovery in Annular Diffusers

1980 ◽  
Vol 22 (6) ◽  
pp. 305-313 ◽  
Author(s):  
D. S. Kumar ◽  
K. L. Kumar
Keyword(s):  
Cross Sections ◽  
Static Pressure ◽  
Tangential Velocity ◽  
Pressure Recovery ◽  
Test Facility ◽  
Pressure Loss Coefficient ◽  
Pressure Distributions ◽  
Inlet Swirl ◽  
Total Pressure Loss Coefficient ◽  
Different Levels

Annular diffusers are likely to operate with varying amounts of swirl at the inlet. The work described in this paper is concerned mainly with an experimental investigation of subsonic turbulent swirling flows through annular diffusers having diverging hub and casing boundaries. The test facility was designed SO as to peImit different levels of inlet swirl. The static pressure distributions and the axial and tangential velocity profiles were measured with the help of a three-hole cobra probe suitably mounted at different cross sections along the diffuser length. The diffuser performance parameters such as static-pressure recovery, effectiveness, and the total pressure loss coefficient were then computed from the experimental observations. The behaviour of these parameters has been discussed to establish the effect of swirl. The presence of inlet swirl was found to increase the overall static-pressure recovery. A substantial increase in the pressure recovery occurred over the initial stages of diffusion and the gain was maintained thereafter. Improvement in effectiveness was more significant for otherwise stalled diffusers. Introduction of swirl was found to substantially reduce the chances of separation at the casing and to shift the stall from the casing to the hub for the stalled diffusers.

The Effect of Blade Curving on Flow Characteristics in Rectangular Turbine Stator Cascades With Different Incidences

1991 ◽  
Author(s):  
Zhongqi Wang ◽  
Wanjin Han ◽  
Wenyuan Xu
Keyword(s):  
Static Pressure ◽  
Flow Characteristics ◽  
Streamwise Vortices ◽  
Flow Losses ◽  
Aerodynamic Loading ◽  
Turbine Stator ◽  
Pressure Distributions ◽  
Outlet Flow ◽  
Inlet Conditions ◽  
Negative Gradient

In a low speed plane cascade tunnel, the outlet flow fields and the static pressure distributions on blade surfaces of the turbine rectangular stator cascades with a small aspect ratio (s=0.68) were measured in detail. The experimental results show that the blade curving can form the negative gradient of static pressure along the blade height in the lower region of the cascade and the positive one in the upper region. This can lead to the reduction of the intensity of the streamwise vortices and the aerodynamic loading on both sides of the blades and the endwalls. Therefore, the end crosswise secondary flow losses are decreased considerably. The use of the curvilinear leaned blades can not only improve the flow characteristics in the stator cascades, but also provide good inlet conditions for rotor cascades.

An Advanced Single-Stage Turbine Facility for Investigating Nonaxisymmetric Contoured Endwalls in the Presence of Purge Flow

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Robin R. Jones ◽  
Oliver J. Pountney ◽  
Bjorn L. Cleton ◽  
Liam E. Wood ◽  
B. Deneys J. Schreiner ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Static Pressure ◽  
Optical Measurement ◽  
Single Stage ◽  
Test Facility ◽  
Pressure Distributions ◽  
Mainstream Flow ◽  
Planar Laser ◽  
Flow Interactions ◽  
Purge Flow

Abstract In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimize the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream–egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile, and EWC on the rotor endwall. This paper presents the design of and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress–mainstream flow interactions. To the authors' knowledge, this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals, and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry (VV) and planar laser-induced fluorescence (PLIF), is also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seal geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes (NGV) at three different spanwise locations; pitchwise static pressure distributions downstream of the NGV at four axial locations on the stator platform.

Regulating Effect of Asymmetrical Impeller on the Flow Distributions of Double-sided Centrifugal Compressor

2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Ce Yang ◽  
Yixiong Liu ◽  
Dengfeng Yang ◽  
Benjiang Wang
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Static Pressure ◽  
Mode Conversion ◽  
Work Capacity ◽  
Conversion Process ◽  
Impeller Blade ◽  
Pressure Distributions ◽  
Conversion Mode ◽  
Outlet Flow

AbstractTo achieve the rebalance of flow distributions of double-sided impellers, a method of improving the radius of rear impeller is presented in this paper. It is found that the flow distributions of front and rear impeller can be adjusted effectively by increasing the radius of rear impeller, thus improves the balance of flow distributions of front and rear impeller. Meanwhile, the working conversion mode process of double-sided centrifugal compressor is also changed. Further analysis shows that the flowrates of blade channels in front impeller are mainly influenced by the circumferential distributions of static pressure in the volute. But the flowrates of rear impeller blade channels are influenced by the outlet flow field of bent duct besides the effects of static pressure distributions in the volute. In the airflow interaction area downstream, the flowrate of blade channel is obviously smaller. By increasing the radius of rear impeller, the work capacity of rear impeller is enhanced, the working mode conversion process from parallel working mode of double-sided impeller to the single impeller working mode is delayed, and the stable working range of double-sided compressor is broadened.

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