The Supersonic Turbine: A Design and Cascade Study

1971 ◽  
Author(s):  
Irving Fruchtman
Keyword(s):  
Rotor Blade ◽  
Leading Edge ◽  
Rotor Blades ◽  
Minimum Length ◽  
Two Dimensional ◽  
Turbine Stage ◽  
Low Loss ◽  
Free Vortex ◽  
Cooling Flows ◽  
Mach Numbers

Fundamental concepts are given for the design of a turbine stage with supersonic gas velocities relative to the blading. Minimum-length nozzles (stators) and free-vortex-type rotor blades are specified and a correlation of their published performance is given. A blade selection chart is given to provide a method for obtaining appropriate low-loss rotor blade configurations. A series of two-dimensional cascade experiments are described in which the performance of film-cooled, blunted leading-edge rotor blades were measured. Blade performance is given over a range of inlet Mach numbers and cooling flows.

Film-Cooling Prediction on Rotor Blade Leading Edge in 1-1/2 Turbine Stage

2008 ◽  
Vol 22 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Huitao Yang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han ◽  
Hee-Koo Moon
Keyword(s):  
Film Cooling ◽  
Rotor Blade ◽  
Leading Edge ◽  
Turbine Stage ◽  
Blade Leading Edge

Influence of Rotor Blade Fillets on Aerodynamic Performance of Turbine Stage

2010 ◽  
Author(s):  
Yan Shi ◽  
Jun Li ◽  
Zhenping Feng
Keyword(s):  
Secondary Flow ◽  
Rotor Blade ◽  
Stokes Equations ◽  
Leading Edge ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
Main Stream ◽  
Shape Parameters ◽  
Turbine Stage ◽  
A Minor

In this paper, steady and unsteady flow simulations were performed to investigate the influence of rotor fillet on the performance of turbine stage, based on 3D compressible Navier-Stokes equations closed with the Spalart-Allmaras turbulence model. The profile of Aachen turbine was employed and the fillet modeled by two shape parameters was placed at the junctions between the rotor blade and the endwalls (at both tip and hub). Based on the comparisons of the efficiency and the flow rate of turbine stage among the cases with different fillet shapes, the roles of two shape parameters were evaluated. To understand the mechanism of the rotor fillet influence on the flow field, the aerodynamic load, secondary flow and loss were analyzed and compared between the cases with and without the rotor fillet. It is found that the fillet is capable of restraining the flow separation near the leading edge of the rotor blade while inducing the displacement of the flow from the endwalls towards the mid-span, which enhances the loss generated by the interaction between the secondary flow and the main stream. Consequently, associated with the distribution of the loss at the outlet of the turbine stage, the best clocking position near the endwalls for the downstream blade moves about 10%∼20% of rotor pitch in the direction of rotor rotation. Therefore, the shape of the fillet in the rotor blade should be especially controlled in the process of the rotor design and manufacture, even though it is a minor part in the turbomachine.

A CFD Approach to Fluid Dynamic Optimum Design of Steam Turbine Stages With Stator and Rotor Blades

2010 ◽  
Author(s):  
Xin Yuan ◽  
Tadashi Tanuma ◽  
Xiaofeng Zhu ◽  
Zhirong Lin ◽  
Daisuke Nomura
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Optimum Design ◽  
Rotor Blade ◽  
Fluid Dynamic ◽  
Rotor Blades ◽  
Turbine Stage ◽  
Tip Leakage ◽  
Pressure Steam ◽  
End Wall

An advanced aerodynamic design optimization system for steam turbine stages considering rotor blade tip leakage and blade end-wall non-axis-symmetric contouring has been developed. Using this system, fluid dynamic optimizations were carried out for a steam turbine stage with stator and rotor blades. The system includes parametric modeling of blade and end-wall contouring, evaluation system with in-house or package CFD software and optimization strategy module. The designs of rotor blade and hub end-wall surface in a typical large-scale high-pressure steam turbine stage were optimized in order to know this design optimization impact on enhancing the stage efficiency. Results show that: from the current well designed high pressure steam turbine stage, the demonstrated efficiency enhancement with the present optimum design is around 0.2% under consideration of rotor tip leakage. Design cycle could be greatly shortened by parallel optimization algorithm and cluster PC, and especially four days could be sufficient for an optimization with one thousand iterations on 20 CPUs of 2.0G cluster PC.

Numerical Investigation on Unsteady Effects of Hot Streak on Flow and Heat Transfer in a Turbine Stage

2008 ◽  
Author(s):  
Bai-Tao An ◽  
Jian-Jun Liu ◽  
Hong-De Jiang
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Heat Load ◽  
Leading Edge ◽  
Turbine Stage ◽  
Characteristic Analysis ◽  
Flow And Heat Transfer ◽  
Total Temperature ◽  
Inlet Conditions ◽  
Hot Streak

This paper presents a detailed flow and heat transfer characteristic analysis on gas turbine first stage turbine under hot streak inlet conditions. Two kinds of inlet total temperature conditions are specified at the turbine stage inlet. The first is uniform inlet total temperature, and the second is hot streak 2D total temperature contour. The two kinds of inlet conditions have the same mass-averaged total temperature, and the same uniform inlet total pressure. The hot streak total temperature contours are obtained according to the exit shape of an annular-can combustor. The ratio of the highest total temperature in the hot streak to the mass-averaged total temperature is about 1.23, and one hot streak corresponds to two vane passages and four blade passages. Six hot streak circumferential positions relative to the vane 1 leading edge varied from −2% to 81% pitch are computed and analyzed. Results show that hot streak obviously increases the non-uniform degree of vane heat load in comparison with the uniform total temperature inlet condition. The change of hot streak circumferential position leads to the circumferential parameter variation at stator exit, and also leads to different transient periodic fluctuating characteristics of heat load and pressure on rotor blade surface. The hot streak of relative pitch at 65% obtains similar heat load for the two vanes corresponding to one hot streak and small fluctuation of the averaged heat load on rotor blade.

Using the Similarity Theory in the Design of Gas Turbine Engines

2021 ◽  
pp. 48-57
Author(s):  
V.D. Molyakov ◽  
B.A. Kunikeev
Keyword(s):  
Gas Turbine ◽  
Rotor Blade ◽  
Similarity Theory ◽  
Rotor Blades ◽  
Design Flow ◽  
Fourth Generation ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Temperature ◽  
Turbine Stage

At present, in the promising development of gas turbine engines compared to at least the fourth generation products, there have been significant changes in the approaches to the design of engine. First of all, it is an increase in maximum values of temperature, gas pressure and circumferential flow speeds, an increase in power of the turbine stage, as well as improvement of the turbine manufacturing technology. All these factors lead to the fact that when designing the flow parts of the gas turbine, it is necessary at the fixed design flow rate of the working medium in the engine, i.e. at the fixed diameters, lengths of the nozzle and rotor blades forming the outline of the inter-blade channels, to increase the blade chords with the corresponding reduction of the number of blades in the row. The increase in turbine stage power associated with the increase in temperature, pressure (density), and circumferential velocity increases the bending stresses leading to the need to increase chords at a fixed blade length. Significant reduction of number of blades in stages, simplifies technology of blades manufacturing. A substantial increase in the maximum gas temperature, in the perspective of more than 2000 K, also leads to the need to increase the blade chords, due to the need to place cooling cavities in the blades. As a result, contradictions arise with the use of similarity theory in the design of stages of turbines of different purpose, as some of the main requirements of similarity are violated — geometric similarity of blade channels of the flow part and then the use of the generally accepted number Re by the chord of blades loses meaning. Therefore, it is necessary to carry out detailed investigations of all flow parameters in four stages of turbines with detection of influence of change of rotor blade chords at equal length of blades. And justify the effect of change of rotor blade chords on physical processes in flow parts of turbines in engines of various purpose.

Aerodynamic Design of Exo-Skeletal Engine Fan Blades

2005 ◽  
Author(s):  
Galib H. Abumeri ◽  
James F. Schmidt ◽  
Christos C. Chamis
Keyword(s):  
Rotor Blade ◽  
Subsonic Flow ◽  
Computational Simulation ◽  
Leading Edge ◽  
Boundary Layer Separation ◽  
Rotor Blades ◽  
Aerodynamic Design ◽  
Design Code ◽  
Performance Map ◽  
Fan Blade

The aerodynamic feasibility of fan rotor blades for the revolutionary Exo-Skeletal Engine (ESE) is assessed for a subsonic mission using the NASA Engine Structures Technology Benefit Estimator (EST/BEST) computational simulation system. The ESE calls for the elimination of the shafts and disks completely from the engine center, and places the attachment of the rotor blades in spanwise compression to a rotating casing. The preliminary aerodynamic design of the fan rotor blade estimated an overall adiabatic efficiency of 91.8%. The flow is supersonic near the blade leading edge but quickly transitions into a subsonic flow without any turbulent boundary layer separation on the blade. The performance map for the fan rotor blade is calculated using a 2D off-design code. The results show that the ESE fan blade has reasonable stall and choke margins. It will be demonstrated in this paper that a computational simulation capability is readily available to evaluate new and revolutionary technology such as the ESE.

Experimental and Numerical Investigation of Interactions Between Axial Turbine and Non-Axisymmetric Exhaust Hood

2008 ◽  
Author(s):  
Jing-Lun Fu ◽  
Si-Jing Zhou ◽  
Jian-Jun Liu
Keyword(s):  
Total Pressure ◽  
Rotor Blade ◽  
Aerodynamic Force ◽  
Exhaust System ◽  
Rotor Blades ◽  
Exhaust Hood ◽  
Turbine Stage ◽  
Coupled Flow ◽  
Local Flow ◽  
Numerical Predictions

This paper describes experimental and numerical studies on the coupled flow field in a single turbine stage and exhaust hood model. The turbine stage with 22 stator blades and 30 rotor blades is especially designed for the hood model, which is a typical design for Westinghouse model 300/600 MW steam turbine. Unsteady pressure at the rotor blade, hood outer casing, unsteady total pressure at the stage outlet and velocity distributions at the turbine outlet and hood exit, in addition to static pressure distributions at the diffuser tip and hub end-walls and at hood outer casing, are measured and compared with numerical predictions. The flow details in the exhaust system with the whole annulus stator and rotor blade rows are simulated by employing CFD software CFX-5. It is found that the swirl angle profile and total pressure profile caused by the upstream turbine at the diffuser inlet have an unfavorable effect on the exhaust hood performance. The non-axisymmetric back-pressure generated by the downstream exhaust hood leads to the local flow varying for each stator and rotor blades and low frequency fluctuation in the aerodynamic force on the blade.

scholarly journals Active Thermography for the Detection of Sub-Surface Defects on a Curved and Coated GFRP-Structure

2021 ◽  
Vol 11 (20) ◽  
pp. 9545
Author(s):  
Friederike Jensen ◽  
Marina Terlau ◽  
Michael Sorg ◽  
Andreas Fischer
Keyword(s):  
Rotor Blade ◽  
Test Specimen ◽  
Surface Defects ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Contactless Measurement ◽  
Viewing Angle ◽  
Pulse Thermography ◽  
Long Pulse

Initial defects, for example, those occurring during the production of a rotor blade, encourage early damages such as rain erosion at the leading edge of wind turbine rotor blades. To investigate the potential that initial defects have for early damage, long-pulse thermography as a non-destructive and contactless measurement technique is applied to a strongly curved and coated test specimen for the first time. This specimen is similar in structural size and design to a rotor blade leading edge and introduced with sub-surface defects whose diameters range between 2mm and 3.5mm at depths between 1.5mm and 2.5mm below the surface. On the curved and coated test specimen, sub-surface defects with a depth-to-diameter ratio of up to 1.04 are successfully detected. In particular, defects are also detectable when being observed from a non-perpendicular viewing angle, where the intensity of the defects decreases with increasing viewing angle due to the strong surface curvature. In conclusion, long-pulse thermography is suitable for the detection of sub-surface defects on coated and curved components and is therefore a promising technique for the on-site application during inspection of rotor blade leading edges.

Numerical Investigation on Unsteady Effects of Hot Streak on Flow and Heat Transfer in a Turbine Stage

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Bai-Tao An ◽  
Jian-Jun Liu ◽  
Hong-De Jiang
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Heat Load ◽  
Leading Edge ◽  
Turbine Stage ◽  
Characteristic Analysis ◽  
Flow And Heat Transfer ◽  
Total Temperature ◽  
Inlet Conditions ◽  
Hot Streak

This paper presents a detailed flow and heat transfer characteristic analysis on gas turbine first-stage turbine under hot streak inlet conditions. Two kinds of inlet total temperature conditions are specified at the turbine stage inlet. The first is uniform inlet total temperature, and the second is hot streak 2D total temperature contour. The two kinds of inlet conditions have the same mass-averaged total temperature and the same uniform inlet total pressure. The hot streak total temperature contours are obtained according to the exit shape of an annular-can combustor. The ratio of the highest total temperature in the hot streak to the mass-averaged total temperature is about 1.23, and one hot streak corresponds to two vane passages and four blade passages. Six hot streak circumferential positions relative to the Vane 1 leading edge varied from −2% to 81% pitch are computed and analyzed. The results show that hot streak obviously increases the nonuniform degree of vane heat load in comparison with the uniform total temperature inlet condition. The change in hot streak circumferential position leads to the circumferential parameter variation at stator exit and also leads to different transient periodic fluctuating characteristics of heat load and pressure on the rotor blade surface. The hot streak of relative pitch at 65% obtains a similar heat load for the two vanes corresponding to one hot streak and small fluctuation in the averaged heat load on the rotor blade.

Time-Accurate Euler Simulation of Interaction of Nozzle Wake and Secondary Flow With Rotor Blade in an Axial Turbine Stage Using Nonreflecting Boundary Conditions

1996 ◽  
Vol 118 (4) ◽  
pp. 663-678 ◽  
Author(s):  
S. Fan ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Unsteady Flow ◽  
Secondary Flow ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Turbine Stage ◽  
Unsteady Pressure ◽  
Nonreflecting Boundary Conditions

The objective of this paper is to investigate the three-dimensional unsteady flow interactions in a turbomachine stage. A three-dimensional time-accurate Euler code has been developed using an explicit four-stage Runge–Kutta scheme. Three-dimensional unsteady nonreflecting boundary conditions are formulated at the inlet and the outlet of the computational domain to remove the spurious numerical reflections. The three-dimensional code is first validated for two-dimensional and three-dimensional cascades with harmonic vortical inlet distortions. The effectiveness of the nonreflecting boundary conditions is demonstrated. The unsteady Euler solver is then used to simulate the propagation of nozzle wake and secondary flow through the rotor and the resulting unsteady pressure field in an axial turbine stage. The three-dimensional and time-dependent propagation of nozzle wakes in the rotor blade row and the effects of nozzle secondary flow on the rotor unsteady surface pressure and passage flow field are studied. It was found that the unsteady flow field in the rotor is highly three dimensional and the nozzle secondary flow has significant contribution to the unsteady pressure on the blade surfaces. Even though the steady flow at the midspan is nearly two dimensional, the unsteady flow is three dimensional and the unsteady pressure distribution cannot be predicted by a two-dimensional analysis.

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