Aerodynamic Design of High Endwall Angle Turbine Stages: Part 2—Experimental Verification

2012 ◽  
Author(s):  
A. W. Cranstone ◽  
G. Pullan ◽  
E. M. Curtis ◽  
S. Bather
Keyword(s):  
Test Results ◽  
Aerodynamic Design ◽  
Turbine Stage ◽  
Suction Surface ◽  
Satisfactory Performance ◽  
The Difference ◽  
And Performance ◽  
Turbine Design ◽  
Stage Efficiency ◽  
Very High

An experimental investigation of a turbine stage featuring very high endwall angles is presented. The initial turbine design did not achieve a satisfactory performance and the difference between the design predictions and the test results was traced to a large separated region on the rear suction-surface. To improve the agreement between CFD and experiment, it was found necessary to modify the turbulence modelling employed. The modified CFD code was then used to redesign the vane, and the changes made are described. When tested, the performance of the redesigned vane was found to have much closer agreement with the predictions than the initial vane. Finally, the flowfield and performance of the redesigned stage are compared to a similar turbine, designed to perform the same duty, which lies in an annulus of moderate endwall angles. A reduction in stage efficiency of at least 2.4% was estimated for the very high endwall angle design.

Aerodynamic Design of High End Wall Angle Turbine Stages—Part II: Experimental Verification

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
A. W. Cranstone ◽  
G. Pullan ◽  
E. M. Curtis ◽  
S. Bather
Keyword(s):  
Turbulence Modeling ◽  
Test Results ◽  
Suction Surface ◽  
Wall Angle ◽  
Computational Fluid Dynamics Cfd ◽  
The Difference ◽  
And Performance ◽  
Turbine Design ◽  
End Wall ◽  
Very High

An experimental investigation of a turbine stage featuring very high end wall angles is presented. The initial turbine design did not achieve a satisfactory performance and the difference between the design predictions and the test results was traced to a large separated region on the rear suction-surface. To improve the agreement between computational fluid dynamics (CFD) and experiment, it was found necessary to modify the turbulence modeling employed. The modified CFD code was then used to redesign the vane, and the changes made are described. When tested, the performance of the redesigned vane was found to have much closer agreement with the predictions than the initial vane. Finally, the flowfield and performance of the redesigned stage are compared to a similar turbine, designed to perform the same duty, which lies in an annulus of moderate end wall angles. A reduction in stage efficiency of at least 2.4% was estimated for the very high end wall angle design.

scholarly journals Turbine Passage Design Methodology to Minimize Entropy Production—A Two-Step Optimization Strategy

Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 604 ◽  
Author(s):  
Paht Juangphanich ◽  
Cis De Maesschalck ◽  
Guillermo Paniagua
Keyword(s):  
Pareto Front ◽  
Correction Term ◽  
Optimization Strategy ◽  
Aerodynamic Design ◽  
Turbine Stage ◽  
Aerodynamic Optimization ◽  
Design And Optimization ◽  
And Performance ◽  
Definition Of ◽  
Line Design

Rapid aerodynamic design and optimization is essential for the development of future turbomachinery. The objective of this work is to demonstrate a methodology from 1D mean-line-design to a full 3D aerodynamic optimization of the turbine stage using a parameterization strategy that requires few parameters. The methodology is tested by designing a highly loaded and efficient turbine for the Purdue Experimental Turbine Aerothermal Laboratory. This manuscript describes the entire design process including the 2D/3D parameterization strategy in detail. The objective of the design is to maximize the entropy definition of efficiency while simultaneously maximizing the stage loading. Optimal design trends are highlighted for both the stator and rotor for several turbine characteristics in terms of pitch-to-chord ratio as well as the blades metal and stagger angles. Additionally, a correction term is proposed for the Horlock efficiency equation to maximize the accuracy based on the measured blade kinetic losses. Finally, the design and performance of optimal profiles along the Pareto front are summarized, featuring the highest aerodynamic performance and stage loading.

Efficiency Prediction for Axial-Flow Turbines Operating with Nonconventional Fluids

1981 ◽  
Vol 103 (4) ◽  
pp. 718-724 ◽  
Author(s):  
E. Macchi ◽  
A. Perdichizzi
Keyword(s):  
Specific Volume ◽  
Reliable Method ◽  
Axial Flow ◽  
Expansion Ratio ◽  
Aerodynamic Design ◽  
Turbine Stage ◽  
Dimensional Parameter ◽  
Optimization Study ◽  
Specific Speed ◽  
Stage Efficiency

The need for a simple and reliable method for predicting the efficiency of a turbine stage without carrying out a detailed aerodynamic design is enhanced. The results of an optimization study carried on a large number of turbine stages are presented. The turbine stage efficiency is found to be a function of three main parameters: the expansion ratio, defined as the specific volume variation across the turbine in an isentropic process; the dimensional parameter V˙out/Δhis1/4, which accounts for actual turbine dimensions, and the specific speed. The presented method is believed to be useful mainly for nonconventional turbine stages, the efficiency of which cannot be anticipated on previous machines experience.

A Novel Centrifugal Flow Gas Turbine Design

2004 ◽  
Author(s):  
Klaus Brun ◽  
Robert J. McKee ◽  
Anthony J. Smalley ◽  
Justin R. Hollingsworth ◽  
Ryan S. Gernentz
Keyword(s):  
Gas Turbine ◽  
Radial Flow ◽  
Axial Flow ◽  
Major Elements ◽  
Aerodynamic Design ◽  
Electric Generator ◽  
Rotor Disk ◽  
The Difference ◽  
Turbine Design ◽  
Novel Design

A centrifugal gas turbine is developed based on a straight radial flow design with no axial flow turning. The geometry contains only two major elements — a rotor disk and a stator shroud. The rotor consists of a centrifugal compressor and high impulse radial outward-flow turbine connected to an electric generator. The stator shroud contains the combustor and nozzles. Fuel lines are attached to the shroud, ducted directly into the combustor. The difference between this novel design and conventional radial gas turbine is that the compressor and turbine section are installed on the same side of the rotating wheel, while the combustor and nozzle are mounted on the stationary shroud. Thus, the entire assembly consists of two components. Technical advantages are: • Single Rotating Component; • Short Axial Span; • Compact Two-Piece Construction; • Ease of Maintenance/Repair Access. Aerodynamic design, performance, and structural analysis of this design are discussed.

Improvement of Steam Turbine Stage Efficiency by Controlling Rotor Shroud Leakage Flows—Part II: Effect of Axial Distance Between a Swirl Breaker and a Rotor Shroud on Efficiency Improvement

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Chongfei Duan ◽  
Hisataka Fukushima ◽  
Kiyoshi Segewa ◽  
Takanori Shibata ◽  
Hidetoshi Fujii
Keyword(s):  
Structural Reliability ◽  
Tangential Velocity ◽  
Maximum Pressure ◽  
Leakage Flow ◽  
Axial Distance ◽  
Steam Turbines ◽  
Turbine Stage ◽  
Entire Flow ◽  
The Difference ◽  
Stage Efficiency

The basic principle of a distinct idea to reduce an aerodynamic mixing loss induced by the difference in tangential velocity between mainstream flow and rotor shroud leakage flow is presented in “Part I: Design Concept and Typical Performance of a Swirl Breaker.” When the swirl breaker is installed in the circulating region of leakage flow at the rotor shroud exit cavity, the axial distance between the swirl breaker and the rotor shroud is a crucial factor to trap the leakage flow into the swirl breaker cavity. In Part II, five cases of geometry with different axial distances between the swirl breaker and the rotor shroud, which covered a range for the stage axial distance of actual high and intermediate pressure (HIP) steam turbines, were investigated using a single-rotor computational fluid dynamics (CFD) analysis and verification tests in a 1.5-stage air model turbine. By decreasing the axial distance between the swirl breaker and the rotor shroud, the tangential velocity and the mixing region in the tip side which is influenced by the rotor shroud leakage flow were decreased and the stage efficiency was increased. The case of the shortest axial distance between the swirl breaker and the rotor shroud increased turbine stage efficiency by 0.7% compared to the conventional cavity geometry. In addition, the measured maximum pressure fluctuation in the swirl breaker cavity was only 0.7% of the entire flow pressure. Consequently, both performance characteristics and structural reliability of swirl breaker were verified for application to real steam turbines.

Parametrical Investigation of Turbine Stages With Open Tip Clearance for the Purpose of Stage Efficiency Increase

2010 ◽  
Author(s):  
Andrei Granovskiy ◽  
Mikhail Kostege ◽  
Nikolay Lomakin
Keyword(s):  
Pressure Ratio ◽  
Axial Flow ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Turbine Stage ◽  
Suction Surface ◽  
Tip Leakage ◽  
Degree Of Reaction ◽  
Blade Tip ◽  
Stage Efficiency

The aerodynamic loss due to tip leakage vortex of rotor blades represents a significant part of viscous losses in axial flow turbines. The mixing of leakage flow with the main rotor passage flow causes losses and reduces turbine stage efficiency. Many measures have been proposed to reduce the loss in the tip clearance area. In this paper the reduction of the tip clearance loss due to changes made to the blade tip section profile is presented. The blade tip profile was modified to decrease the pressure gradient between pressure surface and suction surface. This approach allows the reduction of tip leakage and tip vortex strength and consequently the reduction of tip clearance losses. A 3D Navier-Stokes solver with q-ω turbulence model is used to analyze the flow in the turbine with various tip section profiles. Test data of three single-stage experimental turbines have been used to validate analytical predictions: • Highly loaded turbine stage with a pressure ratio π0T = 3.2 and reaction degree ρmean = 0.5. • Two turbines with a pressure ratio π0T = 3.9. (One with high degree of reaction ρmean = 0.55; the other with low degree of reaction ρmean = 0.26). The numerical investigation of the influence of various tip section profiles on stage efficiency was carried out in the range of relative tip clearance 0.5%–2.4% with the objective of a decreasing the influence of the tip clearance on the stage efficiency.

scholarly journals Methods of enlarging material to the concentration table

2019 ◽  
Vol 2 (1) ◽  
pp. 59-68
Author(s):  
Jacek Feliks ◽  
Magdalena Krawczyk
Keyword(s):  
Air Pollution ◽  
Theoretical Analysis ◽  
Perforated Plate ◽  
High Water ◽  
Test Results ◽  
Air Concentration ◽  
Enrichment Method ◽  
The Difference ◽  
Concentration Table ◽  
Very High

Abstract Concentration tables are one of the oldest oscillatory enrichments with over 100 years of tradition. On this type of distribution tables are made according to material mass in many recurring cycles induced by appropriate drives. So-called wet tables are the devices most often used for coal enrichment in Polish mines because this process generates very high costs, high water consumption and pollution of the environment, as well as the need for, among others, water and mud management is increasingly being replaced mainly in areas poor in water by the modern model of the air concentration table – FGX produced in China. The process of enrichment on this type of table itself runs in a manner comparable to the method of wet enrichment with the difference that the FGX is distributed on a perforated plate, in this case we deal with air pollution. Department of Machinery Engineering and Transport's attempts to use the differences in coefficients of friction in over-resonance screens have shown that it is possible effective separation of grains with different coefficients of friction. The article presents a theoretical analysis and presents the results of performed dry enrichment trials using different coefficients of friction. The summary presents the advantages of using the enrichment method using the differences in friction coefficients and test results.

A Modification of the Payne-Jones Method of Identifying Abnormal Differences in WISC-R Performance and Verbal IQ's

1996 ◽  
Vol 12 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Louis M. Hsu
Keyword(s):  
Full Scale ◽  
True Score ◽  
Verbal Iq ◽  
Score Difference ◽  
The Difference ◽  
And Performance

The difference (D) between a person's Verbal IQ (VIQ) and Performance IQ (PIQ) has for some time been considered clinically meaningful ( Kaufman, 1976 , 1979 ; Matarazzo, 1990 , 1991 ; Matarazzo & Herman, 1985 ; Sattler, 1982 ; Wechsler, 1984 ). Particularly useful is information about the degree to which a difference (D) between scores is “abnormal” (i.e., deviant in a standardization group) as opposed to simply “reliable” (i.e., indicative of a true score difference) ( Mittenberg, Thompson, & Schwartz, 1991 ; Silverstein, 1981 ; Payne & Jones, 1957 ). Payne and Jones (1957) proposed a formula to identify “abnormal” differences, which has been used extensively in the literature, and which has generally yielded good approximations to empirically determined “abnormal” differences ( Silverstein, 1985 ; Matarazzo & Herman, 1985 ). However applications of this formula have not taken into account the dependence (demonstrated by Kaufman, 1976 , 1979 , and Matarazzo & Herman, 1985 ) of Ds on Full Scale IQs (FSIQs). This has led to overestimation of “abnormality” of Ds of high FSIQ children, and underestimation of “abnormality” of Ds of low FSIQ children. This article presents a formula for identification of abnormal WISC-R Ds, which overcomes these problems, by explicitly taking into account the dependence of Ds on FSIQs.

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