The Transonic Flow Through a Plane Turbine Cascade as Measured in Four European Wind Tunnels

1986 ◽  
Vol 108 (2) ◽  
pp. 277-284 ◽  
Author(s):  
R. Kiock ◽  
F. Lehthaus ◽  
N. C. Baines ◽  
C. H. Sieverding
Keyword(s):  
Transonic Flow ◽  
High Speed ◽  
Turbine Rotor ◽  
Wind Tunnels ◽  
Test Results ◽  
Turbine Rotor Blade ◽  
Pressure Distributions ◽  
Order Of Magnitude ◽  
Blade Section ◽  
Flow Through

Reliable cascade data are esssential to the development of high-speed turbomachinery, but it has long been suspected that the tunnel environment influences the test results. This has now been investigated by testing one plane gas turbine rotor blade section in four European wind tunnels of different test sections and instrumentation. The Reynolds number of the transonic flow tests was Re2 = 8 × 105 based on exit flow conditions. The turbulence was not increased artificially. A comparison of results from blade pressure distributions and wake traverse measurements reveals the order of magnitude of tunnel effects.

The Transonic Flow Through a Plane Turbine Cascade as Measured in Four European Wind Tunnels

1985 ◽  
Author(s):  
R. Kiock ◽  
F. Lehthaus ◽  
N. C. Baines ◽  
C. H. Sieverding
Keyword(s):  
Transonic Flow ◽  
Turbine Rotor ◽  
Wind Tunnels ◽  
Test Results ◽  
Turbine Rotor Blade ◽  
Pressure Distributions ◽  
Order Of Magnitude ◽  
Blade Section ◽  
Flow Through ◽  
Tunnel Effects

Reliable cascade data are essential to the development of highspeed turbomachinery, but it has long been suspected that the tunnel environment influences the test results. This has now been investigated by testing one plane gas turbine rotor blade section in four European wind tunnels of different test sections and instrumentation. The Reynolds number of the transonic flow tests was Re2 = 8 · 105 based on exit flow conditions. The turbulence was not increased artificially. A comparison of results from blade pressure distributions and wake traverse measurements reveals the order of magnitude of tunnel effects.

Unsteady and Calming Effects Investigation on a Very High Lift LP Turbine Blade: Part I — Experimental Analysis

2002 ◽  
Author(s):  
Thomas Coton ◽  
Tony Arts ◽  
Michae¨l Lefebvre ◽  
Nicolas Liamis
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Numerical Study ◽  
Turbine Rotor ◽  
High Lift ◽  
Turbine Rotor Blade ◽  
Pressure Loss Coefficient ◽  
Lp Turbine ◽  
Exit Mach Number ◽  
Very High

An experimental and numerical study was performed about the influence of incoming wakes and the calming effect on a very high lift low pressure turbine rotor blade. The first part of the paper describes the experimental determination of the pressure loss coefficient and the heat transfer around the blade mounted in a high speed linear cascade. The cascade is exposed to incoming wakes generated by high speed rotating bars. Their aim is to act upon the transition/separation phenomena. The measurements were conducted at a constant exit Mach number equal to 0.8 and at three Reynolds number values, namely 190000, 350000 and 650000. The inlet turbulence level was fixed at 0.8%. An additional feature of this work is to identify the boundary layer status through heat transfer measurements. Compared to the traditionally used hot films, thin film heat flux gages provide fully quantitative data required for code validation. Numerical computations are presented in the second part of the paper.

Measurement of Turbine Rotor Blade Flows

1981 ◽  
Vol 103 (2) ◽  
pp. 400-405 ◽  
Author(s):  
R. P. Dring ◽  
H. D. Joslyn
Keyword(s):  
Rotor Blade ◽  
Static Pressure ◽  
Turbine Rotor ◽  
Measurement Methods ◽  
Incident Flow ◽  
Airfoil Surface ◽  
Turbine Rotor Blade ◽  
Pressure Distributions ◽  
Different Types ◽  
Flow Phenomena

Measurement methods for obtaining various types of experimental data on a turbine rotor blade are discussed in this paper. A variety of different types of measurements have been taken in the rotating frame of reference, including: airfoil surface static pressure distributions, the radial distribution of total pressure in the incident flow, flow visualization of surface streamlines, and radial-circumferential traversing of a pneumatic probe aft of the rotor. Typical results are presented/showing interesting flow phenomena present on the rotor. In particular, results are shown which demonstrate the various viscous and inviscid mechanisms that give rise to strong radial flows.

Verification of a ground-based method for simulating high-altitude, supersonic flight conditions

2018 ◽  
Vol 07 (01n02) ◽  
pp. 1850005
Author(s):  
Xuewen Zhou ◽  
Jian Xu ◽  
Shuiyan Lv
Keyword(s):  
High Altitude ◽  
High Speed ◽  
Test Method ◽  
Wind Tunnels ◽  
Test Results ◽  
Atmospheric Conditions ◽  
Test Bed ◽  
Supersonic Flight ◽  
Important Research Topic ◽  
Sled System

Ground-based methods for accurately representing high-altitude, high-speed flight conditions have been an important research topic in the aerospace field. Based on an analysis of the requirements for high-altitude supersonic flight tests, a ground-based test bed was designed combining Laval nozzle, which is often found in wind tunnels, with a rocket sled system. Sled tests were used to verify the performance of the test bed. The test results indicated that the test bed produced a uniform-flow field with a static pressure and density equivalent to atmospheric conditions at an altitude of 13–15[Formula: see text]km and at a flow velocity of approximately M 2.4. This test method has the advantages of accuracy, fewer experimental limitations, and reusability.

Wind Tunnel Investigations on Rotating Blades of Aerofoil Section

1952 ◽  
Vol 166 (1) ◽  
pp. 419-428 ◽  
Author(s):  
K. H. Khalil
Keyword(s):  
Wind Tunnel ◽  
Direct Observation ◽  
Wind Tunnels ◽  
Test Results ◽  
Static Tests ◽  
Rotating Blades ◽  
Spin Factor ◽  
Pressure Distributions ◽  
Static Conditions ◽  
Experimental Difficulty

The results are presented in this paper of investigations on the pressure distributions around aerofoil section blades while rotating in a wind tunnel. The experimental difficulty of obtaining pressures during rotation was overcome by the use of a special gauge attached to the hubs and illuminated by “Strobo-flood” for direct observation. Pressure diagrams and lift coefficients were obtained along the radius of a double-blade set, arranged as a windmill, for various angles of incidence. Static tests were conducted also in all cases to find values for comparison. As the purpose of the work was to contrast rotating and static conditions, two main facts are emphasized: the similarity in the pressure diagram shapes and the significance of the spin factor. It therefore becomes possible to correct ordinary test results obtained when using stationary aerofoil blades in wind tunnels by adding the effect of a vortex of rotation of uniform strength.

An Experimental and Computational Study of Transonic Three-Dimensional Flow in a Turbine Cascade

1984 ◽  
Vol 106 (2) ◽  
pp. 414-420 ◽  
Author(s):  
J.-J. Camus ◽  
J. D. Denton ◽  
J. V. Soulis ◽  
C. T. J. Scrivener
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Turbine Rotor Blade ◽  
Dimensional Effects ◽  
Blade Section ◽  
Exit Mach Number ◽  
End Wall

Detailed experimental measurements of the flow in a cascade of turbine rotor blades with a nonplanar end wall are reported. The cascade geometry was chosen to model as closely as possible that of a H.P. gas turbine rotor blade. The blade section is designed for supersonic flow with an exit Mach number of 1.15 and the experiments covered a range of exit Mach numbers from 0.7–1.2. Significant three-dimensional effects were observed and the origin of these is discussed. The measurements are compared with data for the same blade section in a two-dimensional cascade and also with the predictions of two different fully three-dimensional inviscid flow calculation methods. It is found that both these calculations predict the major three-dimensional effects on the flow correctly.

The Computation of Transonic Flow Through Two-Dimensional Gas Turbine Cascades

1971 ◽  
Author(s):  
P. W. McDonald
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Transonic Flow ◽  
Equations Of Motion ◽  
Two Dimensional ◽  
Airfoil Surface ◽  
Pressure Distributions ◽  
Flow Through ◽  
Turbine Cascades ◽  
Definition Of

Steady transonic flow through two-dimensional gas turbine cascades is efficiently predicted using a time-dependent formulation of the equations of motion. An integral representation of the equations has been used in which subsonic and supersonic regions of the flow field receive identical treatment. Mild shock structures are permitted to develop naturally without prior knowledge of their exact strength or position. Although the solutions yield a complete definition of the flow field, the primary aim is to produce airfoil surface pressure distributions for the design of aerodynamically efficient turbine blade contours. In order to demonstrate the accuracy of this method, computed airfoil pressure distributions have been compared to experimental results.

Experimental Observation of Cavitating Squeeze-Film Dampers

1987 ◽  
Vol 109 (2) ◽  
pp. 290-294 ◽  
Author(s):  
J. F. Walton ◽  
J. A. Walowit ◽  
E. S. Zorzi ◽  
J. Schrand
Keyword(s):  
High Speed ◽  
Axial Flow ◽  
Squeeze Film ◽  
Test Results ◽  
Film Rupture ◽  
Video Recordings ◽  
Order Of Magnitude ◽  
Circumferential Extent ◽  
The Right ◽  
Right Order

This paper presents the results of an experimental investigation intended to observe cavitation in squeeze-film bearing dampers representative of those commonly found in aircraft gas turbine engines. Two different squeeze-film damper geometries were tested with both high-speed motion pictures and stroboscopic video recordings acquired at speeds up to 20,000 r/min. The results presented are limited to 8000 r/min due to the increased clarity of the photos acquired at the lower speeds and the similarity of trends at the higher speeds. Comparisons are also made with analysis formulated to handle the dynamics of the film rupture for the “short” damper case. The test results confirmed several of the commonly held “short” bearing assumptions (i.e., predominant axial flow and the effect of supply pressure and eccentricity on the cavitation zone). However, the test results demonstrated that significant flow reversals and film rupture were experienced in the feed/drain grooves in contradiction to the assumed boundary conditions. While agreement between analysis and test is of the right order of magnitude in predicting the cavitation zone shape and circumferential extent, current analyses do not adequately account for the observed variations in the boundaries and change in shape of the cavitation zone.

Blade Tip Carving Effects on the Aero-Thermal Performance of a Transonic Turbine

2013 ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua
Keyword(s):  
High Speed ◽  
Thermal Stresses ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Geometrical Parameters ◽  
Complex Flow ◽  
Turbine Rotor Blade ◽  
Blade Tip ◽  
Transonic Turbine

Tip leakage flows in unshrouded high speed turbines cause large aerodynamic penalties, induce significant thermal loads and give rise to intense thermal stresses onto the blade tip and casing endwalls. In the pursuit of superior engine reliability and efficiency, the turbine blade tip design is of paramount importance and still poses an exceptional challenge to turbine designers. The ever-increasing rotational speeds and pressure loadings tend to accelerate the tip flow velocities beyond the transonic regime. Overtip supersonic flows are characterized by complex flow patterns, which determine the heat transfer signature. Hence, the physics of the overtip flow structures and the influence of the geometrical parameters on the overtip flow require further understanding to develop innovative tip designs. Conventional blade tip shapes are not adequate for such high speed flows and hence, potential for enhanced performances lays in appropriate tip shaping. The present research aims to quantify the prospective gain offered by a fully contoured blade tip shape against conventional geometries such as a flat and squealer tip. A detailed numerical study was conducted on a modern transonic turbine rotor blade (Reynolds number is 5.5 × 105, relative exit Mach number is 0.9) by means of three-dimensional Reynolds-Averaged Navier-Stokes calculations. The novel contoured tip geometry was designed based on a 2D tip shape optimization in which only the upper 2% of the blade span was modified. This study yields a deeper insight into the application of blade tip carving in high speed turbines and provides guidelines for future tip designs with enhanced aerothermal performances.

scholarly journals Negative Incidence Flow Over a Turbine Rotor Blade

1983 ◽  
Author(s):  
H. David Joslyn ◽  
Robert P. Dring
Keyword(s):  
Gas Turbines ◽  
Large Scale ◽  
Three Dimensional ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Surface Flow ◽  
Separated Flows ◽  
Turbine Rotor Blade ◽  
Pressure Surface ◽  
Pressure Distributions

The operation of variable cycle gas turbines at negative incidence can result in highly three dimensional separated flows on the turbine rotor pressure surface. These flows can impact both performance and durability. The present program was conducted to experimentally study the behavior of surface flow on a large scale axial flow turbine rotor with incidence varying up to and including negative incidence separation. Fullspan pressure distributions and surface flow visualization were acquired over a range of incidence. The data indicate that at large negative incidence, pressure surface separation occurred and extended to 60 percent chord at midspan. These separated flows were simulated at midspan by applying potential flow theory to match the measured pressure distributions.

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