Three-Dimensional Analysis of Hot Streak Attenuation in a High Pressure Turbine Stage

2002 ◽  
Author(s):  
Hakan Aksoy ◽  
Jong-Shang Liu ◽  
Paul Couey ◽  
Victor Reyes
Keyword(s):  
High Pressure ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Hot Streak

Three Dimensional Heat Transfer Analysis of High Pressure Turbine Blade

2009 ◽  
Author(s):  
A. Sipatov ◽  
L. Gomzikov ◽  
V. Latyshev ◽  
N. Gladysheva
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
High Pressure ◽  
Rotor Blade ◽  
Computational Analysis ◽  
Three Dimensional ◽  
Heat Transfer Analysis ◽  
Aircraft Engines ◽  
Turbine Stage ◽  
High Pressure Turbine

The present tendency of creating new aircraft engines with a higher level of fuel efficiency leads to the necessity to increase gas temperature at a high pressure turbine (HPT) inlet. To design such type of engines, the improvement of accuracy of the computational analysis is required. According to this the numerical analysis methods are constantly developing worldwide. The leading firms in designing aircraft engines carry out investigations in this field. However, this problem has not been resolved completely yet because there are many different factors affecting HPT blade heat conditions. In addition in some cases the numerical methods and approaches require tuning (for example to predict laminar-turbulent transition region or to describe the interaction of boundary layer and shock wave). In this work our advanced approach of blade heat condition numerical estimation based on the three-dimensional computational analysis is presented. The object of investigation is an advanced aircraft engine HPT first stage blade. The given analysis consists of two interrelated parts. The first part is a stator-rotor interaction modeling of the investigated turbine stage (unsteady approach). Solving this task we devoted much attention to modeling unsteady effects of stator-rotor interaction and to describing an influence of applied inlet boundary conditions on the blade heat conditions. In particular, to determine the total pressure, flow angle and total temperature distributions at the stage inlet we performed a numerical modeling of the combustor chamber of the investigated engine. The second part is a flow modeling in the turbine stage using flow parameters averaging on the stator-rotor interface (steady approach). Here we used sufficiently finer grid discretization to model all perforation holes on the stator vane and rotor blade, endwalls films in detail and to apply conjugate heat transfer approach for the rotor blade. Final results were obtained applying the results of steady and unsteady approaches. Experimental data of the investigated blade heat conditions are presented in the paper. These data were obtained during full size experimental testing the core of the engine and were collected using two different type of experimental equipment: thermocouples and thermo-crystals. The comparison of experimental data and final results meets the requirements of our investigation.

scholarly journals Calculation and Correlation of the Unsteady Flowfield in a High Pressure Turbine

2002 ◽  
Author(s):  
Milind A. Bakhle ◽  
Jong S. Liu ◽  
Josef Panovsky ◽  
Theo G. Keith ◽  
Oral Mehmed
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Test Facility ◽  
Navier Stokes ◽  
Turbine Stage ◽  
High Pressure Turbine

Forced vibrations in turbomachinery components can cause blades to crack or fail due to high-cycle fatigue. Such forced response problems will become more pronounced in newer engines with higher pressure ratios and smaller axial gap between blade rows. An accurate numerical prediction of the unsteady aerodynamics phenomena that cause resonant forced vibrations is increasingly important to designers. Validation of the computational fluid dynamics (CFD) codes used to model the unsteady aerodynamic excitations is necessary before these codes can be used with confidence. Recently published benchmark data, including unsteady pressures and vibratory strains, for a high-pressure turbine stage makes such code validation possible. In the present work, a three dimensional, unsteady, multi blade-row, Reynolds-Averaged Navier Stokes code is applied to a turbine stage that was recently tested in a short duration test facility. Two configurations with three operating conditions corresponding to modes 2, 3, and 4 crossings on the Campbell diagram are analyzed. Unsteady pressures on the rotor surface are compared with data.

Mainstream Aerodynamic Effects due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part II — Aerodynamic Measurements in the Rotational Frame

2001 ◽  
Author(s):  
Christopher McLean ◽  
Cengiz Camci ◽  
Boris Glezer
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Axial Flow ◽  
Main Stream ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Coolant Injection ◽  
Cooling Air

The current paper deals with the aerodynamic measurements in the rotational frame of reference of the Axial Flow Turbine Research Facility (AFTRF) at the Pennsylvania State University. Stationary frame measurements of “Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High Pressure Turbine Stage” were presented in part-I of this paper. The relative aerodynamic effects associated with rotor – nozzle guide vane (NGV) gap coolant injections were investigated in the rotating frame. Three-dimensional velocity vectors including exit flow angles were measured at the rotor exit. This study quantifies the secondary effects of the coolant injection on the aerodynamic and performance character of the stage main stream flow for root injection, radial cooling and impingement cooling. Current measurements show that even a small quantity (1%) of cooling air can have significant effects on the performance and exit conditions of the high pressure turbine stage. Parameters such as the total pressure coefficient, wake width, and three-dimensional velocity field show significant local changes. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions. Effects are the strongest from the hub to midspan. Negligible effect of the cooling flow can be seen in the tip region.

Influence of Hot Streak/Airfoil Count Ratios on High Pressure Stage of a Vaneless Counter-Rotating Turbine

2008 ◽  
Author(s):  
Qingjun Zhao ◽  
Huishe Wang ◽  
Fei Tang ◽  
Xiaolu Zhao ◽  
Jianzhong Xu
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Peak Temperature ◽  
Combined Effects ◽  
High Pressure Turbine ◽  
Flow Angle ◽  
Count Ratio ◽  
Hot Streak

In order to reveal the effects of the hot streak/airfoil count ratio on the heating patterns of high pressure turbine rotor blades in a Vaneless Counter-Rotating Turbine, three-dimensional unsteady Navier-Stokes simulations have been performed. In these simulations, the ratio of the number of hot streaks to the number of the high pressure turbine vanes and rotors is 1:3:3, 1:2:2, 2:3:3 and 1:1:1, respectively. The numerical results show that the migration characteristics of the hot streak in the high pressure turbine rotor are predominated by the combined effects of secondary flow and buoyancy. The combined effects induce the high temperature fluid migrate towards the hub in the high pressure turbine rotor. And the combined effects become more intensified when the hot streak/airfoil count ratio increases. The results also indicate that the peak temperature of the hot streak is dissipated as the hot streak goes through the high pressure turbine vane or the rotor. The dissipated extent of the peak temperature in the high pressure turbine stator and the rotor is increased as the hot streak-to-airfoil ratio increases. And the increase of the hot streak/airfoil count ratio trends to increase the relative Mach number at the high pressure turbine outlet. The relative flow angle from 23% to 73% span at the high pressure turbine outlet decreases as the hot streak-to-airfoil ratio increases. The results also indicate that the isentropic efficiency of the Vaneless Counter-Rotating Turbine is decreased as the hot streak/airfoil count ratio increases.

Heat-Transfer Measurements and Predictions for the Vane and Blade of a Rotating High-Pressure Turbine Stage

2004 ◽  
Vol 126 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Charles W. Haldeman ◽  
Michael G. Dunn
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Three Dimensional ◽  
Experimental Results ◽  
Thermal Barrier ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Transfer Data ◽  
Commercial Code ◽  
Blade Tip

This paper describes heat-transfer measurements and predictions obtained for the vane and blade of a rotating high-pressure turbine stage. The measurements were obtained with the stage operating at design corrected conditions. A previous paper described the aerodynamics and the blade midspan location heat-transfer data and compared these experimental results with predictions. The intent of the current paper is to concentrate on the measurements and predictions for the 20%, 50%, and 80% span locations on the vane, the vane inner and outer endwall, the 20% and 96% span location on the blade, the blade tip (flat tip), and the stationary blade shroud. Heat-transfer data obtained at midspan for three different thermal-barrier-coated vanes (fine, medium, and coarse) are also presented. Boundary-layer heat-transfer predictions at the off-midspan locations are compared with the measurements for both the vane and the blade. The results of a STAR-CD (a commercial code) three-dimensional prediction are compared with the 20% and 96% span results for the blade surface. Predictions are not available for comparison with the tip and shroud experimental results.

Study of Hot Streak Effects in a Counter-Rotating Turbine

2001 ◽  
Author(s):  
L. C. Ji ◽  
J. Z. Xu ◽  
J. Chen
Keyword(s):  
High Pressure ◽  
Heat Load ◽  
Three Dimensional ◽  
High Pressure Turbine ◽  
Design And Optimization ◽  
Low Pressure Turbine ◽  
Second Stage ◽  
Euler Solver ◽  
Hot Streak ◽  
Turbine Design

Based on its convection nature, some influences of the hot streak on a 1+1 (with inter-blade vane) counter-rotating turbine are studied by using a three-dimensional (3D) unsteady Euler solver. Emphasis is laid on the hot streak effect to the blade heat load and the clocking effects between hot streak and blade rows. One temperature distortion magnitude, two spanwise and four tangential positions, four clocking locations between vanes of first and second stage are examined. Results show that the effect of the hot streak on a counter-rotating turbine is nearly the same as a conventional turbine. However, clocking between the hot streak and the vane of the high pressure turbine (HPT) exerts significant influences on the heat load of the whole HPT stage. Also, clocking between the HPT vane and the vane of the low pressure turbine (LPT) affects the heat load of the LPT greatly. These effects cannot be captured with the steady flow assumption. So time accurate simulation about the hot streak/blade interaction must be used as a basis for the turbine design and optimization.

Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part II—Aerodynamic Measurements in the Rotational Frame

2001 ◽  
Vol 123 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Christopher McLean ◽  
Cengiz Camci ◽  
Boris Glezer
Keyword(s):  
High Pressure ◽  
Guide Vane ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Axial Flow ◽  
Main Stream ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Coolant Injection ◽  
Cooling Air

The current paper deals with the aerodynamic measurements in the rotational frame of reference of the Axial Flow Turbine Research Facility (AFTRF) at the Pennsylvania State University. Stationary frame measurements of “Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High Pressure Turbine Stage” were presented in Part I of this paper. The relative aerodynamic effects associated with rotor–nozzle guide vane (NGV) gap coolant injections were investigated in the rotating frame. Three-dimensional velocity vectors including exit flow angles were measured at the rotor exit. This study quantifies the secondary effects of the coolant injection on the aerodynamic and performance character of the stage main stream flow for root injection, radial cooling, and impingement cooling. Current measurements show that even a small quantity (1 percent) of cooling air can have significant effects on the performance and exit conditions of the high-pressure turbine stage. Parameters such as the total pressure coefficient, wake width, and three-dimensional velocity field show significant local changes. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions. Effects are the strongest from the hub to midspan. Negligible effect of the cooling flow can be seen in the tip region.

Investigation of the Flow Field in a High-Pressure Turbine Stage for Two Stator-Rotor Axial Gaps—Part I: Three-Dimensional Time-Averaged Flow Field

2006 ◽  
Vol 129 (3) ◽  
pp. 572-579 ◽  
Author(s):  
P. Gaetani ◽  
G. Persico ◽  
V. Dossena ◽  
C. Osnaghi
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Three Dimensional ◽  
Flow Fields ◽  
Secondary Flows ◽  
Point Of View ◽  
Flow Structures ◽  
Axial Distance ◽  
Turbine Stage ◽  
High Pressure Turbine

An extensive experimental analysis on the subject of unsteady flow field in high-pressure turbine stages was carried out at the Laboratorio di Fluidodinamica delle Macchine (LFM) of Politecnico di Milano. The research stage represents a typical modern HP gas turbine stage designed by means of three-dimensional (3D) techniques, characterized by a leaned stator and a bowed rotor and operating in high subsonic regime. The first part of the program concerns the analysis of the steady flow field in the stator-rotor axial gap by means of a conventional five-hole probe and a temperature sensor. Measurements were carried out on eight planes located at different axial positions, allowing the complete definition of the three-dimensional flow field both in absolute and relative frame of reference. The evolution of the main flow structures, such as secondary flows and vane wakes, downstream of the stator are here presented and discussed in order to evidence the stator aerodynamic performance and, in particular, the different flow field approaching the rotor blade row for the two axial gaps. This results set will support the discussion of the unsteady stator-rotor effects presented in Part II (Gaetani, P., Persico, G., Dossena, V., and Osnaghi, C., 2007, ASME J. Turbomach., 129(3), pp. 580–590). Furthermore, 3D time-averaged measurements downstream of the rotor were carried out at one axial distance and for two stator-rotor axial gaps. The position of the probe with respect to the stator blades is changed by rotating the stator in circumferential direction, in order to describe possible effects of the nonuniformity of the stator exit flow field downstream of the stage. Both flow fields, measured for the nominal and for a very large stator-rotor axial gap, are discussed, and results show the persistence of some stator flow structures downstream of the rotor, in particular, for the minimum axial gap. Finally, the flow fields are compared to evidence the effect of the stator-rotor axial gap on the stage performance from a time-averaged point of view.

Influence of Hot Streak Temperature Ratio on Low Pressure Stage of a Vaneless Counter-Rotating Turbine

2007 ◽  
Author(s):  
Qingjun Zhao ◽  
Fei Tang ◽  
Huishe Wang ◽  
Jianyi Du ◽  
Xiaolu Zhao ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Secondary Flow ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Pressure Stage ◽  
Low Pressure Turbine ◽  
Hot Streak

In order to explore the influence of hot streak temperature ratio on low pressure stage of a Vaneless Counter-Rotating Turbine, three-dimensional multiblade row unsteady Navier-Stokes simulations have been performed. The predicted results show that hot streaks are not mixed out by the time they reach the exit of the high pressure turbine rotor. The separation of colder and hotter fluids is observed at the inlet of the low pressure turbine rotor. After making interactions with the inner-extending shock wave and outer-extending shock wave in the high pressure turbine rotor, the hotter fluid migrates towards the pressure surface of the low pressure turbine rotor, and the most of colder fluid migrates to the suction surface of the low pressure turbine rotor. The migrating characteristics of the hot streaks are predominated by the secondary flow in the low pressure turbine rotor. The effect of buoyancy on the hotter fluid is very weak in the low pressure turbine rotor. The results also indicate that the secondary flow intensifies in the low pressure turbine rotor when the hot streak temperature ratio is increased. The effects of the hot streak temperature ratio on the relative Mach number and the relative flow angle at the inlet of the low pressure turbine rotor are very remarkable. The isentropic efficiency of the Vaneless Counter-Rotating Turbine decreases as the hot streak temperature ratio is increased.

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