LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

1991 ◽  
Vol 113 (4) ◽  
pp. 660-667
Author(s):  
Hasan Eroglu ◽  
Widen Tabakoff
Keyword(s):  
Flow Field ◽  
Flow Direction ◽  
Mean Flow ◽  
Flow Rates ◽  
Radial Turbine ◽  
Contour Plots ◽  
Mass Flow Rates ◽  
Flow Turbulence ◽  
Downstream Flow ◽  
Nozzle Blade

The results of LDV measurements and investigation of the detailed flow field in a radial inflow turbine nozzle are presented. The flow velocities were measured at upstream, inside and downstream of the nozzle blades for two different mass flow rates, using a three-component LDV system. Results are presented as contour plots of mean velocities, flow angles, and turbulence intensities. The flow field inside the nozzle blade passages was found to be influenced by the upstream scroll geometry. The flow turbulence increased in the downstream flow direction. The LDV mean flow results on the blade-to-blade midspan plane which is parallel to the end walls were also compared with an inviscid, “panel method” solution.

scholarly journals LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

1989 ◽  
Author(s):  
Hasan Eroglu ◽  
Widen Tabakoff
Keyword(s):  
Flow Field ◽  
Flow Direction ◽  
Mean Flow ◽  
Flow Mixing ◽  
Contour Plots ◽  
Mass Flow Rates ◽  
Flow Turbulence ◽  
Downstream Flow ◽  
End Wall ◽  
Nozzle Blade

The results of LDV measurements and investigation of the detailed flow field in a radial inflow turbine nozzle are presented. The flow velocities were measured at upstream, inside and downstream of the nozzle blades for two different mass flow rates, using a three-component LDV system. Results are presented as contour plots of mean velocities, flow angles and turbulence intensities. The flow field inside the nozzle blade passages were found to be strongly influenced by the upstream scroll geometry. Significant end wall cross flows and flow mixing were observed. The flow turbulence increased in the downstream flow direction. The LDV mean flow results on the blade-to-blade plane at midspan location were also compared with an inviscid, “panel method” solution.

LDV Measurements of Turbulent Stresses in Radial Turbine Guide Vanes

1990 ◽  
Author(s):  
Hasan Eroglu ◽  
Widen Tabakoff
Keyword(s):  
Flow Direction ◽  
Suction Surface ◽  
Guide Vanes ◽  
Numerical Predictions ◽  
Radial Turbine ◽  
Flow Mixing ◽  
Contour Plots ◽  
Mass Flow Rates ◽  
Ion Laser ◽  
End Wall

The results of Laser Doppler Velocimetry (LDV) measurements, in particular, turbulent stresses in radial turbine guide vanes are presented in this paper, in order to provide experimental data for the numerical predictions. The flow velocities were measured at upstream, inside and downstream of the guide vanes for two different mass flow rates (0.2 lb/s “0.0907 kg/s” and 0.3 lb/s “0.1361 kg/s”) using a two-component LDV system. The results are presented as contour plots of turbulent stresses. The LDV system consists of a 5 watt argon-ion laser, the seeding particle atomizer, the optical and the data acquisition systems. The optical components were arranged in the backward scatter mode to measure two orthogonal velocity components simultaneously. Frequency shifts were used on both components to determine the flow direction. The results indicate a significant transport of higher turbulence fluid into the suction surface-end wall corner by the end wall cross flows inside the passage. High turbulent stress gradients show that there is considerable flow mixing downstream of the flow passages. Turbulence was found to be locally anisotropic everywhere.

Measurement of the Mean Flow Field in a Smooth Rotating Channel With Coriolis and Buoyancy Effects

2017 ◽  
Author(s):  
Ruquan You ◽  
Haiwang Li ◽  
Zhi Tao ◽  
Kuan Wei
Keyword(s):  
Flow Field ◽  
Coriolis Force ◽  
Indium Tin Oxide ◽  
Buoyancy Force ◽  
Flow Direction ◽  
Density Ratio ◽  
Mean Flow ◽  
The Mean ◽  
Static Conditions ◽  
Rotating Channel

The mean flow field in a smooth rotating channel was measured by particle image velocimetry under the effect of buoyancy force. In the experiments, the Reynolds number, based on the channel hydraulic diameter (D) and the bulk mean velocity (Um), is 10000, and the rotation numbers are 0, 0.13, 0.26, 0.39, 0.52, respectively. The four channel walls are heated with Indium Tin Oxide (ITO) heater glass, making the density ratio (d.r.) about 0.1 and the maximum value of buoyancy number up to 0.27. The mean flow field was simulated on a 3D reconstruction at the position of 3.5<X/D<6.5, where X is along the mean flow direction. The effect of Coriolis force and buoyancy force on the mean flow was taken into consideration in the current work. The results show that the Coriolis force pushes the mean flow to the trailing side, making the asymmetry of the mean flow with that in the static conditions. On the leading surface, due to the effect of buoyancy force, the mean flow field changes considerably. Comparing with the case without buoyancy force, separated flow was captured by PIV on the leading side in the case with buoyancy force. More details of the flow field will be presented in this work.

Experimental Investigation of a Tandem Cylinder System With a Yawed Upstream Cylinder

2011 ◽  
Author(s):  
Stephen J. Wilkins ◽  
Joseph W. Hall
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Unsteady Flow ◽  
Surface Pressure ◽  
Vortex Shedding ◽  
Flow Direction ◽  
Pressure Fluctuations ◽  
Mean Flow ◽  
The Mean ◽  
Velocity Spectra

The unsteady flow field produced by a tandem cylinder system with the upstream cylinder yawed to the mean flow direction is investigated for upstream cylinder yaw angles from α = 60° to α = 90°. Multi-point fluctuating surface pressure and hotwire measurements were conducted at various spanwise positions on both the upstream and downstream cylinders. The results indicate that yawing the front cylinder to the mean flow direction causes the pressure and velocity spectra on the upstream and downstream cylinders to become more broadband than for a regular tandem cylinder system, and reduces the magnitude of the peak associated with the vortex-shedding. However, span-wise correlation and coherence measurements indicate that the vortex-shedding is still present and was being obscured by the enhanced three-dimensionality that the upstream yawed cylinder caused and was still present and correlated from front to back, at least for the larger yaw angles investigated. When the cylinder was yawed to α = 60°, the pressure fluctuations became extremely broadband and exhibited shorter spanwise correlation.

On strong blowing into an incompressible airstream

1973 ◽  
Vol 60 (2) ◽  
pp. 241-255 ◽  
Author(s):  
F. T. Smith
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Velocity Profile ◽  
Air Injection ◽  
Relative Mass ◽  
Pressure Measurements ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Strong Injection ◽  
Steady Laminar

An experimental study of distributed air-injection from a porous section of a flat plate into a uniform incompressible airflow is described. The relative mass flow rates of the injection varied between 0·008 and 0·053 (strong injection) and the blowing was fairly uniformly distributed. In the resulting flow field, which was predominantly laminar except near the dividing streamline, where unsteadiness prevailed, velocity profile and pressure measurements were taken and the position of the dividing streamline thereby estimated. Overall the results agree fairly well with the steady laminar theory for strong normal blowing, outlined in §2, although for the strongest blow some signs of separation some way upstream of the blow are apparent.

LDV Measurements of the Flow Field in the Nozzle Region of a Confined Double Annular Burner

2001 ◽  
Vol 123 (2) ◽  
pp. 228-236 ◽  
Author(s):  
Francois Schmitt ◽  
Birinchi K. Hazarika ◽  
Charles Hirsch
Keyword(s):  
Flow Field ◽  
Turbulent Flow ◽  
Turbulence Intensity ◽  
Meridional Plane ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Fine Grid ◽  
Contour Plots ◽  
The Mean ◽  
Grid Points

A database for the complex turbulent flow of a confined double annular burner in cold conditions is presented here. In the region close to the exit of the annular nozzles LDV measurements at 5515 grid points in the meridional plane were conducted. At each measurement position, validated data for 3000–16,000 particles were recorded, and the mean axial and radial velocities, axial and radial turbulence intensity and Reynolds stresses were computed. The resulting mean flow field is axisymmetric within an uncertainty of 2 percent. The contour plots of turbulent quantities on the fine grid, as well as the streamlines based on the mean flow field, are presented for the flow.

Experimental Investigation of Turbine Leakage Flows on the Three-Dimensional Flow Field and Endwall Heat Transfer

2006 ◽  
Vol 129 (3) ◽  
pp. 608-618 ◽  
Author(s):  
Hans-Jürgen Rehder ◽  
Axel Dannhauer
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Secondary Flow ◽  
Mass Flow ◽  
Test Section ◽  
Flow Behavior ◽  
Leakage Flow ◽  
Flow Rates ◽  
Low Pressure Turbine ◽  
Mass Flow Rates

Within a European research project, the tip endwall region of low pressure turbine guide vanes with leakage ejection was investigated at DLR in Göttingen. For this purpose a new cascade wind tunnel with three large profiles in the test section and a contoured endwall was designed and built, representing 50% height of a real low pressure turbine stator and simulating the casing flow field of shrouded vanes. The effect of tip leakage flow was simulated by blowing air through a small leakage gap in the endwall just upstream of the vane leading edges. Engine relevant turbulence intensities were adjusted by an active turbulence generator mounted in the test section inlet plane. The experiments were performed with tangential and perpendicular leakage ejection and varying leakage mass flow rates up to 2%. Aerodynamic and thermodynamic measurement techniques were employed. Pressure distribution measurements provided information about the endwall and vane surface pressure field and its variation with leakage flow. Additionally streamline patterns (local shear stress directions) on the walls were detected by oil flow visualization. Downstream traverses with five-hole pyramid type probes allow a survey of the secondary flow behavior in the cascade exit plane. The flow field in the near endwall area downstream of the leakage gap and around the vane leading edges was investigated using a 2D particle image velocimetry system. In order to determine endwall heat transfer distributions, the wall temperatures were measured by an infrared camera system, while heat fluxes at the surfaces were generated with electric operating heating foils. It turned out from the experiments that distinct changes in the secondary flow behavior and endwall heat transfer occur mainly when the leakage mass flow rate is increased from 1% to 2%. Leakage ejection perpendicular to the main flow direction amplifies the secondary flow, in particular the horseshoe vortex, whereas tangential leakage ejection causes a significant reduction of this vortex system. For high leakage mass flow rates the boundary layer flow at the endwall is strongly affected and seems to be highly turbulent, resulting in entirely different heat transfer distributions.

Measurement of the Mean Flow Field in a Smooth Rotating Channel With Coriolis and Buoyancy Effects

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Ruquan You ◽  
Haiwang Li ◽  
Zhi Tao ◽  
Kuan Wei
Keyword(s):  
Flow Field ◽  
Coriolis Force ◽  
Indium Tin Oxide ◽  
Buoyancy Force ◽  
Flow Direction ◽  
Density Ratio ◽  
Mean Flow ◽  
The Mean ◽  
Static Conditions ◽  
Rotating Channel

The mean flow field in a smooth rotating channel was measured by particle image velocimetry (PIV) under the effect of buoyancy force. In the experiments, the Reynolds number, based on the channel hydraulic diameter (D) and the bulk mean velocity (Um), is 10,000, and the rotation numbers are 0, 0.13, 0.26, 0.39, and 0.52, respectively. The four channel walls are heated with indium tin oxide (ITO) heater glass, making the density ratio (d.r.) about 0.1 and the maximum value of buoyancy number up to 0.27. The mean flow field was simulated on a three-dimensional (3D) reconstruction at the position of 3.5 < X/D < 6.5, where X is along the mean flow direction. The effect of Coriolis force and buoyancy force on the mean flow was taken into consideration in the current work. The results show that the Coriolis force pushes the mean flow to the trailing side, making the asymmetry of the mean flow with that in the static conditions. On the leading surface, due to the effect of buoyancy force, the mean flow field changes considerably. Comparing with the case without buoyancy force, separated flow was captured by PIV on the leading side in the case with buoyancy force. More details of the flow field will be presented in this work.

Development of the Unsteady Flow on a Turbine Rotor Platform Downstream of a Rim Seal

2004 ◽  
Author(s):  
Kirk D. Gallier ◽  
Patrick B. Lawless ◽  
Sanford Fleeter
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Thermal Design ◽  
Flow Rates ◽  
Image Velocimetry ◽  
Downstream Flow

In high temperature turbines, air from disk cavities is forced through the vane-rotor seal to prevent hot gas ingress into these cavities. This emergent seal air can play a significant role in the formation of secondary flows which emanate from the hub region near the rotor blade leading edge. The formation of these structures is also dependent on the inherently unsteady flow field driven by the vane-rotor interaction. As these secondary flows play an important role in both blade performance and heat transfer, the physics that governs them is of significant interest in turbine aero and thermal design. This work investigates and characterizes the aerodynamic signature of the interaction between an emergent seal flow and the hub flow approaching the downstream rotor including the effects of vane-rotor interaction. This is accomplished by means of an experimental investigation performed on the first stage of the Purdue Research Turbine using Particle Image Velocimetry (PIV). The flow field is interrogated in the near-hub region of the intra-stage space, downstream of the first vane row. Purge air is introduced through a planar seal at two different flow rates which characterize typical high and low boundaries for the range of dimensionless seal flow rates encountered in practice. Two-dimensional (radial and axial) velocity data from four measurement planes spaced from vane pressure side to mid-passage are acquired. These data are phase-locked to rotor position. The ensemble-averaged vorticity data from each of ten rotor positions provide a characterization of the effect of the rotor potential field on the emergent seal flow. Vane wake affects on purge strength and downstream flow development are captured at each of two seal flow rates.

Experimental Investigation of Turbine Leakage Flows on the 3D Flow Field and End Wall Heat Transfer

2006 ◽  
Author(s):  
Hans-Ju¨rgen Rehder ◽  
Axel Dannhauer
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Secondary Flow ◽  
Mass Flow ◽  
Flow Behavior ◽  
Leakage Flow ◽  
Wall Heat Transfer ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
End Wall

Within a European research project the tip end wall region of LP turbine guide vanes with leakage ejection was investigated at DLR in Go¨ttingen. For this purpose a new cascade wind tunnel with three large profiles in the test section and a contoured end wall was designed and built up, representing 50% height of a real low pressure turbine (LPT) stator and simulating the casing flow field of shrouded vanes. The effect of tip leakage flow was simulated by blowing air through a small leakage gap in the end wall just upstream of the vane leading edges. Engine relevant turbulence intensities were adjusted by an active turbulence generator mounted in the test section inlet plane. The experiments were performed with tangential and perpendicular leakage ejection and varying leakage mass flow rates up to 2%. Aerodynamic and thermodynamic measurement techniques were employed. Pressure distribution measurements provided information about the end wall and vane surface pressure field and its variation with leakage flow. Additionally streamline pattern (local shear stress directions) on the walls were detected by oil flow visualization. Downstream traverses with 5-hole pyramid type probes allow a survey of the secondary flow behavior in the cascade exit plane. The flow field in the near end wall area downstream of the leakage gap and around the vane leading edges was investigated using a 2D Particle Image Velocimetry (PIV) system. In order to determine end wall heat transfer distributions, the wall temperatures were measured by an infra-red camera system, while heat fluxes at the surfaces were generated with electric operating heating foils. It turned out from the experiments that distinct changes in the secondary flow behavior and end wall heat transfer mainly occur when the leakage mass flow rate is increased from 1% to 2%. Leakage ejection perpendicular to the main flow direction amplifies the secondary flow, in particular the horse-shoe vortex, whereas tangential leakage ejection causes a significant reduction of this vortex system. For high leakage mass flow rates the boundary layer flow at the end wall is strongly affected and seems to be highly turbulent, resulting in entirely different heat transfer distributions.

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