scholarly journals Numerical and Experimental Analysis of Secondary Flow in Modern State-of-the-Art Low Pressure Guide Vane Rows

1995 ◽  
Author(s):  
Ernst Lindner
Keyword(s):  
Aspect Ratio ◽  
Secondary Flow ◽  
Total Pressure ◽  
Guide Vane ◽  
Numerical Results ◽  
Flow Behaviour ◽  
Inlet Guide Vane ◽  
Streamwise Vorticity ◽  
Pressure Losses ◽  
Turbine Guide Vane

To enhance the performance of the inlet guide vane and the annular duct of a jet engine, a detailed investigation of annular cascades with two different types of turbine guide vane rows is made. The first one is a leaned guide vane with an aspect ratio of two and a half and a transition duct ahead of the vane. To avoid the losses associated to the decelerating transition duct an alternative vane is designed and investigated with the same inlet and exit conditions. In this case the chord of the vane is increased to the effect that the vane begins immediately at the enterance of the diverging annulus and so a continuously accelerated flow is achieved. To maintain a good performance for this configuration a bowed-type vane with an aspect ratio of one is designed. The aim of the investigation is to obtain detailed informations on the secondary flow behaviour with particular regard to the development of the total pressure losses and the streamwise vorticity of the vortices inside and behind the blade rows. In the first step a three-dimensional, structured, explicit finite-volume flow-solver with a k–ε turbulence model is validated against the measurements, which were made in cross-sections behind the blades. Having proved that the numerical results are very close to the experimental ones, the secondary flow behaviour inside and behind the blade rows is analysed in the second step. By calculating the streamwise vorticity from the numerical results the formation of horse-shoe vortex, passage-vortex and the trailing edge vortex shed is investigated. The differences of the vortical motion and the formation of the total pressure losses between the two configurations of turbine guide vane rows are discussed.

CFD Simulation of the Losses in an Inlet Guide Vane of a Transonic Test Turbine

2004 ◽  
Author(s):  
W. Sanz ◽  
P. Pieringer ◽  
W. Baumgartner ◽  
W. Edelbauer ◽  
C. Pilz ◽  
...  
Keyword(s):  
Total Pressure ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Measurement Data ◽  
Secondary Flows ◽  
Inlet Guide Vane ◽  
Commercial Code ◽  
Turbine Guide Vane ◽  
Gap Height ◽  
Generation Mechanisms

In this work the flow through a pre-swirl turbine guide vane was calculated using two different flow solvers and compared with total pressure measurements in a downstream plane. The flow is transonic and strongly influenced by secondary flows. A special feature of this cascade is that the gap height at the hub is varying. Flow separation and leakage vortex flow dominate the loss generation. The flow is simulated using an in-house CFD code as well as the commercially available code FLUENT. The flow is carefully analysed and the loss generation mechanisms are presented in detail. The comparison with the measured total pressure distribution shows that the overall loss scheme is well predicted by both codes, but there are still large deficiencies in the quantitative results. The commercial code FLUENT is closer to the measurement data. Further investigations are performed to find out the differences between both codes.

Growth of Secondary Flow Losses Downstream of a Turbine Blade Cascade

1986 ◽  
Vol 108 (2) ◽  
pp. 270-276 ◽  
Author(s):  
L. D. Chen ◽  
S. L. Dixon
Keyword(s):  
Boundary Layer ◽  
Aspect Ratio ◽  
Secondary Flow ◽  
Total Pressure ◽  
Turbine Cascade ◽  
Pressure Losses ◽  
Flow Losses ◽  
Blade Cascade ◽  
Flow Loss ◽  
Loss Coefficients

Endwall total pressure losses downstream of a low-speed turbine cascade have been measured at several planes in order to determine the changes in secondary flow loss coefficients and the growth of the mixing loss with distance downstream. The results obtained are compared with various published secondary flow loss correlations in an attempt to explain some of the anomalies which presently exist. The paper includes some new correlations including one for the important gross secondary loss coefficient YSG with loading and aspect ratio parameters as well as the upstream boundary layer parameters.

Production and Development of Secondary Flows and Losses in Two Types of Straight Turbine Cascades: Part 1—A Stator Case

1987 ◽  
Vol 109 (2) ◽  
pp. 186-193 ◽  
Author(s):  
A. Yamamoto
Keyword(s):  
Secondary Flow ◽  
Total Pressure ◽  
Experimental Information ◽  
Secondary Flows ◽  
Accumulation Process ◽  
Flow Angle ◽  
Turning Angle ◽  
Pressure Losses ◽  
Flow Vectors ◽  
Turbine Cascades

The present study intends to give some experimental information on secondary flows and on the associated total pressure losses occurring within turbine cascades. Part 1 of the paper describes the mechanism of production and development of the loss caused by secondary flows in a straight stator cascade with a turning angle of about 65 deg. A full representation of superimposed secondary flow vectors and loss contours is given at fourteen serial traverse planes located throughout the cascade. The presentation shows the mechanism clearly. Distributions of static pressures and of the loss on various planes close to blade surfaces and close to an endwall surface are given to show the loss accumulation process over the surfaces of the cascade passage. Variation of mass-averaged flow angle, velocity and loss through the cascade, and evolution of overall loss from upstream to downstream of the cascade are also given. Part 2 of the paper describes the mechanism in a straight rotor cascade with a turning angle of about 102 deg.

scholarly journals Flow Measurements Behind the Inlet Guide Vane of a Centrifugal Compressor

1998 ◽  
Author(s):  
I. Kassens ◽  
M. Rautenberg
Keyword(s):  
Centrifugal Compressor ◽  
Total Pressure ◽  
Guide Vane ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Inlet Guide Vane ◽  
Flow Measurements ◽  
Flow Angle ◽  
Partial Load ◽  
Measurement Location

In a centrifugal compressor adjustable inlet guide vanes (IGV) in front of the impeller are used to regulate the pressure ratio and the mass flow. The stationary measurement of the velocity profile in front of the impeller with different angles of the IGV displays shock losses at the inlet edge of blade of the impeller. In the partial-load region (e.g. partial-load efficiency) the radial distribution of the flow influences considerably the performance of the impeller. The tested compressor consists of an adjustable IGV with straight vanes, a shrouded impeller and a vaneless, parallel diffuser. In the first measurement location, behind the IGV, total pressure, static pressure and flow angle were measured with a 5-hole cylinder probe. In the second measurement location, in front of the impeller, the measurement of the total pressure was carried out with a Kiel probe and the flow angle with a Cobra probe accordingly the static wall pressure was measured. Taking into consideration the fundamental thermodynamical equations it was possible to determine the velocity profiles because of the measured distributions of the flow angle in these two measurement locations. For different angles of the IGV and with various mass flows the distributions of the deflection defect behind the IGV are described. Starting with the measured distributions of the flow in front of the impeller the flow angles at the impeller inlet are calculated and the distributions of the incidence angle at the impeller inlet are figured out.

scholarly journals Experimental Investigation of Rotor-Stator Interaction in Axial-Flow Turbines and Compressors

1998 ◽  
Vol 4 (4) ◽  
pp. 217-231
Author(s):  
Heinz E. Gallus
Keyword(s):  
Unsteady Flow ◽  
Total Pressure ◽  
Vector Fields ◽  
Guide Vane ◽  
Axial Flow ◽  
Tip Clearance ◽  
Inlet Guide Vane ◽  
Flow Measurements ◽  
Rotor Stator Interaction ◽  
Flow Compressor

Detailed results of unsteady flow measurements in a stator-rotor-stator assembly of an axial-flow turbine as well as an inlet guide vane-rotor-stator formation of an axial-flow compressor are presented in this paper.The measurements include the time-dependent 3-D velocity vector fields in the axial gaps between the blade rows by means of triple-hot wire-technique, furthermore the total pressure field downstream of the blade rows by means of semiconductor total pressure probes and the unsteady flow field determination in the rotor passages by LDV-technique. Special semiconductor pressure measurements along the casing all over the rotor tip clearance permit detailed discussion of the rotor tip clearance flows.The conclusion of the measured data provides a new and very instructive view of the physics of the unsteady blade-row interaction in axial-flow turbines and compressors.

Investigation of Nonaxisymmetric Endwall Contouring and Three-Dimensional Airfoil Design in a 1.5 Stage Axial Turbine—Part II: Experimental Validation

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Jens Niewoehner ◽  
Thorsten Poehler ◽  
Peter Jeschke ◽  
Yavuz Guendogdu
Keyword(s):  
Experimental Validation ◽  
Guide Vane ◽  
Radial Profile ◽  
Three Dimensional ◽  
Mechanical Efficiency ◽  
Fast Response ◽  
Numerical Results ◽  
Inlet Guide Vane ◽  
Computational Fluid Dynamics Cfd ◽  
Yaw Angle

This paper is the second part of a two-part paper reporting on the increase in efficiency of a 1.5 stage axial test rig turbine with the use of nonaxisymmetric endwalls and 3D airfoil design. Contoured endwalls were developed for the inlet guide vane separately, as well as in combination with a bowed radial profile stacking. In addition, a contour endwall was applied to the hub of the unshrouded rotor. In Part I, the design of the profiled endwalls and 3D airfoils is presented, as well as a detailed analysis of the steady and unsteady computational fluid dynamics (CFD) results. Part II reports on the experimental validation of the numerical results. A distinct increase in mechanical efficiency for both new configurations in good agreement with the numerical results is observed. Additionally, performance map measurements demonstrate that the new designs are also beneficial under off-design conditions. Five- and three-hole-probes as well as fast-response total pressure probes are used to investigate the new designs. The main effect is the homogenization of the yaw angle behind the first stator.

scholarly journals DEVELOPMENT OF AERODYNAMIC DIAGRAMS OF HIGH-LOADED REVERSE AXIAL FANS

2020 ◽  
Vol 2 ◽  
pp. 72-81
Author(s):  
Pavel V. Kosykh
Keyword(s):  
Flow Rate ◽  
Total Pressure ◽  
High Speed ◽  
Guide Vane ◽  
Pressure Coefficient ◽  
Aerodynamic Characteristics ◽  
Inlet Guide Vane ◽  
Ansys Software ◽  
Axial Fans ◽  
Limiting Values

Present-day achievements in the field of strength calculation and structural optimization allow creating main mine fans with higher tip speed than in currently used machines. The paper considers the features of calculating the aerodynamic diagrams of mine reverse axial fans with a tip speed over 200 m/s. It is shown that at such speed it is possible to obtain high-flow fans with significantly smaller dimensions than their existing counterparts. Aerodynamic diagrams with high reverse characteristics (flow rate of more than 0.7 from the direct mode for the network of the same aerodynamic characteristics as in direct mode) are developed. The aerodynamic characteristics of the developed diagrams are calculated in the ANSYS software package. It is shown that an increase in the tip speed contributes to an increase in reverse properties of fans compared to less high-speed machines designed for the same total pressure. The limiting values of axial velocity coefficient and pressure coefficient are determined, at which it is possible to obtain a fan without an inlet guide vane, with a monotonic dependence of total pressure on flow rate.

scholarly journals Measurements of the Flow Field Within a Compressor Outlet Guide Vane Passage

1993 ◽  
Author(s):  
J. F. Carrotte ◽  
K. F. Young ◽  
S. J. Stevens
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Guide Vane ◽  
Pressure Probe ◽  
Streamwise Vorticity ◽  
Measured Velocity ◽  
Tip Leakage ◽  
Blade Row ◽  
Flow Features ◽  
Novel Design

A series of tests have been carried out to investigate the flow in a Compressor Outlet Guide Vane (OGV) blade row downstream of a single stage rotor. The subsequent flow field that developed within an OGV passage was measured, at intervals of 10% axial chord, using a novel design of miniature 5 hole pressure probe. In addition to indicating overall pressure levels and the growth of regions containing low energy fluid, secondary flow features were identified from calculated axial vorticity contours and flow vectors. Close to each casing the development of classical secondary flow was observed, but towards the centre of the annulus large well defined regions of opposite rotation were measured. These latter flows were due to the streamwise vorticity at inlet to the blade row associated with the skewed inlet profile. Surface static pressures were also measured and used to obtain the blade pressure force at 3 spanwise locations. These values were compared with the local changes in flow momentum calculated from the measured velocity distributions. With the exception of the flow close to the outer casing, which is affected by rotor tip leakage, good agreement was found between these quantities indicating relatively weak radial mixing.

Effects of axial length and integrated design on the aggressive intermediate turbine duct

2018 ◽  
Vol 233 (4) ◽  
pp. 443-456 ◽  
Author(s):  
Qingzong Xu ◽  
Pei Wang ◽  
Qiang Du ◽  
Jun Liu ◽  
Guang Liu
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Secondary Flow ◽  
Axial Length ◽  
Pressure Loss ◽  
Total Pressure ◽  
Guide Vane ◽  
Three Dimensional ◽  
Intermediate Turbine Duct ◽  
Aero Engine

With the increasing demand of high bypass ratio and thrust-to-weight ratio in civil aero-engine, the intermediate turbine duct between the high pressure and low pressure turbines of a modern gas turbine tends to shorter axial length, larger outlet-to-inlet area ratio and high pressure-to-low pressure radial offset. This paper experimentally and numerically investigated the three-dimensional flow characteristics of traditional (ITD1) and aggressive intermediate turbine duct (ITD2) at low Reynolds number. The baseline case of ITD1 is representative of a traditional intermediate turbine duct of aero-engine design with non-dimensional length of L/dR = 2.79 and middle angle of 20.12°. The detailed flow fields inside ITD1 and flow visualization were measured. Results showed the migration of boundary layer and a pair of counter-rotating vortexes were formed due to the radial migration of low momentum fluid. With the decreasing axial length of intermediate turbine duct, the radial and streamwise reverse pressure gradient in aggressive intermediate turbine duct (ITD2) were increased resulting in severe three-dimensional separation of boundary layer near casing surface and higher total pressure loss. The secondary flow and separation of boundary layer near the endwall were deeply analyzed to figure out the main source of high total pressure loss in the aggressive intermediate turbine duct (ITD2). Based on that, employing wide-chord guide vane to substitute “strut + guide vane”, this paper designed the super-aggressive intermediate turbine duct and realized the suppression of the three-dimensional separation and secondary flow.

Measurements of the Flow Field Within a Compressor Outlet Guide Vane Passage

1995 ◽  
Vol 117 (1) ◽  
pp. 29-37 ◽  
Author(s):  
J. F. Carrotte ◽  
K. F. Young ◽  
S. J. Stevens
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Guide Vane ◽  
Pressure Probe ◽  
Streamwise Vorticity ◽  
Measured Velocity ◽  
Tip Leakage ◽  
Blade Row ◽  
Flow Features ◽  
Novel Design

A series of tests have been carried out to investigate the flow in a Compressor Outlet Guide Vane (OGV) blade row downstream of a single-stage rotor. The subsequent flow field that developed within an OGV passage was measured, at intervals of 10 percent axial chord, using a novel design of miniature five-hole pressure probe. In addition to indicating overall pressure levels and the growth of regions containing low-energy fluid, secondary flow features were identified from calculated axial vorticity contours and flow vectors. Close to each casing the development of classical secondary flow was observed, but toward the center of the annulus large well-defined regions of opposite rotation were measured. These latter flows were due to the streamwise vorticity at inlet to the blade row associated with the skewed inlet profile. Surface static pressures were also measured and used to obtain the blade pressure force at three spanwise locations. These values were compared with the local changes in flow momentum calculated from the measured velocity distributions. With the exception of the flow close to the outer casing, which is affected by rotor tip leakage, good agreement was found between these quantities indicating relatively weak radial mixing.

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