scholarly journals Transonic Probe Blockage Effects in a Calibration Wind–Tunnel and Stator Blade Passage

1996 ◽  
Author(s):  
Frank Truckenmüller ◽  
Martin Renner ◽  
Heinz Stetter ◽  
Hans–Georg Hosenfeld
Keyword(s):  
Wind Tunnel ◽  
Static Pressure ◽  
Guide Vane ◽  
Calibration Procedure ◽  
Wind Tunnels ◽  
Pressure Probe ◽  
Blade Passage ◽  
Stator Blade ◽  
Flow Through ◽  
Transonic Turbine

Probe blockage effects are presented for transonic flow through a calibration wind–tunnel as well as through a guide vane row in a three–stage model turbine. Accurate experimental data from measurements in a transonic turbine are needed for the verification of CFD results. The accuracy of etatic pressure measurements in transonic turbine stages is severely affected by the pressure probe stem disturbing the surrounding flow–field. These disturbance effects are present during calibration procedures in wind–tunnels, as well as during measurements in–between turbomachinery blade rows. Therefore, the phenomenon associated with this blockage effect must be investigated for both procedures. The influence of the blockage ratios on the static pressure readings of the four–hole wedge probe during the calibration procedure is investigated for two different wind–tunnels. The aim is to measure the blockage effects on the blade passage flow which are produced by a pneumatic pressure probe immersed in the flow between two adjacent blade rows. In order to measure these effects, two stator blades are instrumented with static pressure taps along the blade chord, as well as along the blade span. During the investigations, the radial and circumferential positions of the probes relative to the blade channel are varied. Pressure probe readings of two four–hole wedge probes with different stem diameters are compared as well as correlated to the static pressure readings of the stator blade pressure taps. The apparent deviations of the different readings are discussed.

Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage

2000 ◽  
Author(s):  
P. Giangiacomo ◽  
V. Michelassi ◽  
F. Martelli
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Turbine Stage ◽  
Flow Rates ◽  
Tip Leakage ◽  
Mass Flow Rates ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Rotor Mass

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.

Aero-Thermal Performance of a Two-Dimensional Highly Loaded Transonic Turbine Nozzle Guide Vane: A Test Case for Inviscid and Viscous Flow Computations

1992 ◽  
Vol 114 (1) ◽  
pp. 147-154 ◽  
Author(s):  
T. Arts ◽  
M. Lambert de Rouvroit
Keyword(s):  
Heat Transfer ◽  
Turbulence Intensity ◽  
Static Pressure ◽  
Free Stream ◽  
Guide Vane ◽  
Free Stream Turbulence ◽  
Nozzle Guide Vane ◽  
Transonic Turbine ◽  
Nozzle Guide ◽  
Highly Loaded

This contribution deals with an experimental aero-thermal investigation around a highly loaded transonic turbine nozzle guide vane mounted in a linear cascade arrangement. The measurements were performed in the von Karman Institute short duration Isentropic Light Piston Compression Tube facility allowing a correct simulation of Mach and Reynolds numbers as well as of the gas to wall temperature ratio compared to the values currently observed in modern aero engines. The experimental program consisted of flow periodicity checks by means of wall static pressure measurements and Schlieren flow visualizations, blade velocity distribution measurements by means of static pressure tappings, blade convective heat transfer measurements by means of platinum thin films, downstream loss coefficient and exit flow angle determinations by using a new fast traversing mechanism, and free-stream turbulence intensity and spectrum measurements. These different measurements were performed for several combinations of the free-stream flow parameters looking at the relative effects on the aerodynamic blade performance and blade convective heat transfer of Mach number, Reynolds number, and free-stream turbulence intensity.

scholarly journals Aero-Thermal Performance of a Two Dimensional Highly Loaded Transonic Turbine Nozzle Guide Vane: A Test Case for Inviscid and Viscous Flow Computations

1990 ◽  
Author(s):  
Tony Arts ◽  
Muriel Lambert De Rouvroit
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Turbulence Intensity ◽  
Static Pressure ◽  
Guide Vane ◽  
Nozzle Guide Vane ◽  
Transonic Turbine ◽  
Nozzle Guide ◽  
Highly Loaded

This contribution deals with an experimental aero-thermal investigation around a highly loaded transonic turbine nozzle guide vane mounted in a linear cascade arrangement. The measurements were performed in the von Karman Institute short duration Isentropic Light Piston Compression Tube facility allowing a correct simulation of Mach and Reynolds numbers as well as of the gas to wall temperature ratio compared to the values currently observed in modern aero engines. The experimental programme consisted of flow periodicity checks by means of wall static pressure measurements and Schlieren flow visualizations, blade velocity distribution measurements by means of static pressure tappings, blade convective heat transfer measurements by means of platinum thin films, downstream loss coefficient and exit flow angle determinations by using a new fast traversing mechanism and freestream turbulence intensity and spectrum measurements. These different measurements were performed for several combinations of the freestream flow parameters looking at the relative effects on the aerodynamic blade performance and blade convective heat transfer of Mach number, Reynolds number and freestream turbulence intensity.

A Modular Wing-Tail Airplane Configuration for the Educational Wind Tunnel Laboratory

2004 ◽  
Author(s):  
B. Terry Beck
Keyword(s):  
Wind Tunnel ◽  
Rapid Prototyping ◽  
Calibration Procedure ◽  
Aerodynamic Characteristics ◽  
Wind Tunnels ◽  
Small Scale ◽  
Pitching Moment ◽  
Gravity Effects ◽  
Basic Parameters ◽  
Rapid Prototyping System

An innovative modular airplane configuration has been developed for use in small-scale educational wind tunnels. The “airplane” consists of an interchangeable wing and horizontal tail configuration that mounts on a conventional wind tunnel electronic balance (“sting”) to facilitate measurements of normal force, axial force and longitudinal pitching moment. From these basic parameters, the total lift, total drag, and resultant airplane pitching moment can be deduced, along with the location of the aerodynamic center of the total airplane. Using known wing planform and airfoil shapes facilitates comparison of the total airplane aerodynamic characteristics with those predicted from the known characteristics of the separate wing and horizontal tail. In particular, the aerodynamic center of the simplified airplane configuration can be determined, along with the effect that downwash on the tail has on longitudinal stability of the airplane. Included in the paper is a description of the calibration procedure for the modular “sting” mount. This procedure accounts for an offset “line of action” for aerodynamic forces, as well as offset center of gravity effects. In conjunction with this same test setup, an available Rapid Prototyping system has been used to manufacture the test sections (separate wing and tail) for use in the wind tunnel, and in particular, in the modular wing-tail assembly. This provides tremendous flexibility in the types of wing-tail assemblies that can be investigated experimentally using the same module. The relatively inexpensive prototyping procedure also provides the capability for students to design and test their own configurations. Furthermore, the precision manufacturing capability of the Rapid Prototyping system guarantees reliable reproduction of virtually any desired aerodynamic planform and airfoil shape.

An Investigation of the Swirl in an S-Duct

1982 ◽  
Vol 33 (1) ◽  
pp. 25-58 ◽  
Author(s):  
R.W. Guo ◽  
J. Seddon
Keyword(s):  
Wind Tunnel ◽  
Total Pressure ◽  
Static Pressure ◽  
Three Dimensional ◽  
Rectangular Duct ◽  
Large Vortex ◽  
High Incidence ◽  
Air Intake ◽  
Flow Through ◽  
Pressure Swirl

SummaryMeasurements are presented of the static pressure, total pressure, swirl and three-dimensional turbulence in the flow through an S-curved rectangular duct mounted in a wind tunnel at different incidences, yaw angles and mass flow ratios. The results show that at high incidence there is a large vortex around an area of flow separation after the first bend and a pair of contra-rotating vortices in the flow after the second bend. The distortion of total pressure at the exit of the S-duct is significantly high, and the corresponding three-dimensional turbulence is up to 16.7%. Appreciation of the existence of this type of flow is important in the field of air intake design for jet aircraft.

Three Dimensional Aerodynamic Optimization for an Ultra-Low Aspect Ratio Transonic Turbine Stator Blade

2005 ◽  
Author(s):  
Martina Hasenja¨ger ◽  
Bernhard Sendhoff ◽  
Toyotaka Sonoda ◽  
Toshiyuki Arima
Keyword(s):  
Aspect Ratio ◽  
Static Pressure ◽  
Multi Objective Optimization ◽  
Aerodynamic Loss ◽  
Low Aspect Ratio ◽  
Turbine Stator ◽  
Static Pressure Distribution ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Single Objective

A modern numerical stochastic optimization method, namely the evolution strategy (ES), was applied to an ultra-low aspect ratio transonic turbine stator blade in order to seek a new aerodynamic design concept for lower secondary flow losses. The low stator blade count is selected to avoid the direct viscous interaction of the stator wake with the downstream rotor blade. This led to the ultra-low aspect ratio stator blade. In the optimization, two kinds of objective functions were used, that is, (1) minimization of the “aerodynamic loss” (a single objective), (2) minimization of the “aerodynamic loss” and of the “variation of circumferential static pressure distribution” downstream of the stator blade (multi-objective optimization). In the case of the single objective, the aerodynamic loss is improved by an extreme aft-loaded airfoil with a noticeable bent part near the trailing edge, although the circumferential static distribution is slightly worse than that of the baseline. In the case of the multi-objective optimization, we observe a trade-off relation between aerodynamic loss and variation of static pressure distribution which is not easily resolved. A new design concept to achieve lower aerodynamic loss for ultra-low aspect ratio transonic turbine stator blades is discussed.

scholarly journals A preliminary study on static pressure probe mobile measurement method for flow field in transonic wind tunnel

2021 ◽  
Vol 39 (4) ◽  
pp. 786-793
Author(s):  
Haijun Deng ◽  
Bo Xiong ◽  
Xinfu Luo ◽  
Shaozun Hong ◽  
Qi Liu ◽  
...  
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Static Pressure ◽  
Wind Tunnel Test ◽  
Flow Characteristics ◽  
Pressure Probe ◽  
Number Distribution ◽  
Mach Number Distribution ◽  
Transonic Wind Tunnel

The axial Mach number distribution of the core flow for model in a transonic wind tunnel is an important index to evaluate the performance of the flow field, which is usually measured by the centerline probe. In order to simulate the incoming flow characteristics without interference, the probe will extend from the support section to the shrinkage section, so the probe usually must has longer inches, more static pressure measuring points and smaller blockage requirements. In order to study the influence of the points of the centerline probe on the uniformity distribution of flow field, a new static pressure probe is designed, which is smaller and shorter than the centerline probe. On the basis of the stability of the flow field, the Mach number distribution of the flow field measured by the static pressure probe which is driven by the moving measuring mechanism. The characteristics of the measured values are studied by wind tunnel test. The results show that: when Ma ≤ 0.95, the overall distribution and value of Mach number obtained by the static pressure probe is basically the same as those obtained by the centerline probe, but some flow field details, which mainly shows that Mach number of the static pressure probe has smaller fluctuation, higher accuracy and better uniformity index.

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