The Design and Performance of a High Work Research Turbine

1995 ◽  
Author(s):  
E. P. Vlasic ◽  
S. Girgis ◽  
S. H. Moustapha
Keyword(s):  
Pressure Ratio ◽  
Limit Load ◽  
Gas Generator ◽  
Part Load ◽  
Cold Flow ◽  
Turbine Efficiency ◽  
Load Pattern ◽  
Design Speed ◽  
And Performance ◽  
High Work

This paper describes the design and performance of a high work single stage research turbine with a pressure ratio of 5.0, a stage loading of 2.2 and cooled stator and rotor. Tests were carried out in a cold flow rig and as part of a gas generator facility. The performance of the turbine was assessed, through measurements of reaction, rotor exit conditions and efficiency, with and without airfoil cooling. The measured cooled efficiency in the cold rig was 79.9%, which, after correcting for temperature and measuring plane location, matched reasonably well the efficiency of 81.5% in the gas generator test. The effect of cooling, as measured in the cold rig, was to reduce the turbine efficiency by 2.1%. A part load turbine map was obtained at 100, 110 and 118% design speed and at 3.9, 5.0 and 6.0 pressure ratio. The influence of speed and the limit load pattern for transonic turbines are discussed. The effect of the downstream measuring distance on the calculated efficiency was determined using three different locations. An efficiency drop of 3.2% was measured between the rotor trailing edge plane and a distance four chords downstream.

The Design and Performance of a High Work Research Turbine

1996 ◽  
Vol 118 (4) ◽  
pp. 792-799 ◽  
Author(s):  
E. P. Vlasic ◽  
S. Girgis ◽  
S. H. Moustapha
Keyword(s):  
Pressure Ratio ◽  
Limit Load ◽  
Gas Generator ◽  
Part Load ◽  
Cold Flow ◽  
Turbine Efficiency ◽  
Load Pattern ◽  
Design Speed ◽  
And Performance ◽  
High Work

This paper describes the design and performance of a high work single-stage research turbine with a pressure ratio of 5.0, a stage loading of 2.2, and cooled stator and rotor. Tests were carried out in a cold flow rig and as part of a gas generator facility. The performance of the turbine was assessed, through measurements of reaction, rotor exit conditions and efficiency, with and without airfoil cooling. The measured cooled efficiency in the cold rig was 79.9 percent, which, after correcting for temperature and measuring plane location, matched reasonably well the efficiency of 81.5 percent in the gas generator test. The effect of cooling, as measured in the cold rig, was to reduce the turbine efficiency by 2.1 percent. A part-load turbine map was obtained at 100, 110, and 118 percent design speed and at 3.9, 5.0, and 6.0 pressure ratio. The influence of speed and the limit load pattern for transonic turbines are discussed. The effect of the downstream measuring distance on the calculated efficiency was determined using three different locations. An efficiency drop of 3.2 percent was measured between the rotor trailing edge plane and a distance four chords downstream.

Improving Efficiency of a High Work Turbine Using Non-Axisymmetric Endwalls: Part I—Endwall Design and Performance

2008 ◽  
Author(s):  
T. Germain ◽  
M. Nagel ◽  
I. Raab ◽  
P. Schuepbach ◽  
R. S. Abhari ◽  
...  
Keyword(s):  
Numerical Optimization ◽  
Axial Flow ◽  
Loss Reduction ◽  
Numerical Investigations ◽  
Turbine Efficiency ◽  
Transition Modeling ◽  
And Performance ◽  
High Work ◽  
Stage Efficiency ◽  
Probe Measurements

This paper is the first part of a two part paper reporting the improvement of efficiency of a one-and-half stage high work axial flow turbine by non-axisymmetric endwall contouring. In this first paper the design of the endwall contours is described and the CFD flow predictions are compared to five-hole-probe measurements. The endwalls have been designed using automatic numerical optimization by means of an Sequential Quadratic Programming (SQP) algorithm, the flow being computed with the 3D RANS solver TRACE. The aim of the design was to reduce the secondary kinetic energy and secondary losses. The experimental results confirm the improvement of turbine efficiency, showing a stage efficiency benefit of 1%±0.4%, revealing that the improvement is underestimated by CFD. The secondary flow and loss have been significantly reduced in the vane, but improvement of the midspan flow is also observed. Mainly this loss reduction in the first row and the more homogeneous flow is responsible for the overall improvement. Numerical investigations indicate that the transition modeling on the airfoil strongly influences the secondary loss predictions. The results confirm that non-axisymmetric endwall profiling is an effective method to improve turbine efficiency, but that further modeling work is needed to achieve a good predictability.

Part Load Behavior of the LP Part of an Industrial Gas Turbine

2017 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann ◽  
Srecko M. Nedeljkovic ◽  
Milan Banjac
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Solution Procedure ◽  
Turbine Efficiency ◽  
Through Flow ◽  
Wide Range ◽  
Design Speed ◽  
Industrial Gas Turbine

The operation under off-design conditions of a two-stage LP part of a 6.5 MW industrial gas turbine was analyzed in this work. Since the turbine is able to vary the rotation speed in a wide range from 40 to 140% of the design speed, a flow with extremely large positive and negative incidence angle appears. The flow field was calculated applying 2D through-flow code for the analysis of axial multistage turbines with cooling by air from compressor bleed. The code was developed by the authors and validated by calculation of a number of test cases with different configurations. The method is based on a stream function approach and a finite element solution procedure. In parallel, the flow in the turbine was calculated using a commercial CFD code. Based on the calculated flow field, the turbine efficiency and pressure ratio and also different stage parameters were determined for the design point and for a wide range of off-design conditions. Comparison of the predicted results and measured test data for a number of parameters showed good agreement.

New FORTRAN meanline code for investigating the volute to rotor interspace effect on mixed flow turbine performance

2021 ◽  
pp. 095440892110070
Author(s):  
Ahmed Ketata ◽  
Zied Driss
Keyword(s):  
Test Data ◽  
Expansion Ratio ◽  
Industrial Applications ◽  
Electricity Production ◽  
Mixed Flow ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Fortran Language ◽  
Design Speed ◽  
And Performance

Mixed flow turbines are widely used in several industrial applications covering turbomachinery, automotive engineering and electricity production. For decades, it is well known that mixed flow turbines are a seat of several loss phenomena such as the volute to rotor interspace loss, subject of this paper. Commonly, the meanline approach is the first step solution for building a preliminary design of such turbines and estimating subsequent losses. The accuracy of the code used in the meanline modeling is crucial for building an optimized turbine design with a minimized loss generation. This paper presents an improved validated meanline code, written in the newest object-oriented version of the FORTRAN language, for turbomachinery performance prediction. Unlike commercially available codes, the code allows the calculation of the rotor passage loss coefficient given the turbine expansion ratio without the need for additional test data. The standard deviation value between the code and test data is less than 10%, for all studied cases which ensure the validity of the developed model. Then, the developed code is exploited to investigate the effect of the volute to rotor interspace geometry on the loss generation and performance of a mixed flow turbine. Indeed, a performance distribution over a wide range of rotational speed and an energy loss breakdown are depicted and discussed showing a significant impact of the volute to rotor interspace. The results revealed an improvement in the turbine efficiency up to 2.9% with a volute to rotor interspace radii ratio of 0.59 at 80% of the design speed.

Improving Efficiency of a High Work Turbine Using Nonaxisymmetric Endwalls— Part I: Endwall Design and Performance

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
T. Germain ◽  
M. Nagel ◽  
I. Raab ◽  
P. Schüpbach ◽  
R. S. Abhari ◽  
...  
Keyword(s):  
Axial Flow ◽  
Programming Algorithm ◽  
Navier Stokes ◽  
Turbine Efficiency ◽  
Computational Fluid Dynamics Cfd ◽  
Transition Modeling ◽  
And Performance ◽  
High Work ◽  
Sequential Quadratic Programming Algorithm ◽  
Probe Measurements

This paper is the first part of a two part paper reporting the improvement of efficiency of a one-and-half stage high work axial flow turbine by nonaxisymmetric endwall contouring. In this first paper the design of the endwall contours is described, and the computational fluid dynamics (CFD) flow predictions are compared with five-hole-probe measurements. The endwalls have been designed using automatic numerical optimization by means of a sequential quadratic programming algorithm, the flow being computed with the 3D Reynolds averaged Navier-Stokes (RANS) solver TRACE. The aim of the design was to reduce the secondary kinetic energy and secondary losses. The experimental results confirm the improvement of turbine efficiency, showing a stage efficiency benefit of 1%±0.4%, revealing that the improvement is underestimated by CFD. The secondary flow and loss have been significantly reduced in the vane, but improvement of the midspan flow is also observed. Mainly this loss reduction in the first row and the more homogeneous flow is responsible for the overall improvement. Numerical investigations indicate that the transition modeling on the airfoil strongly influences the secondary loss predictions. The results confirm that nonaxisymmetric endwall profiling is an effective method to improve turbine efficiency but that further modeling work is needed to achieve a good predictability.

A Comparative Aerodynamic and Performance Study of a Three-Stage High Pressure Turbine With 3-D Bowed Blades and Cylindrical Blades

2004 ◽  
Author(s):  
M. T. Schobeiri ◽  
A. Suryanarayanan ◽  
C. Jermann ◽  
T. Neuenschwander
Keyword(s):  
High Pressure ◽  
Initial Conditions ◽  
Pressure Ratio ◽  
Experimental Investigations ◽  
Performance Study ◽  
Pressure Loss Coefficient ◽  
Design Speed ◽  
And Performance ◽  
Turbine Design ◽  
Total Pressure Loss Coefficient

To investigate the effect of the blade geometry on blade total pressure loss coefficient, efficiency, and performance, a comparative study is presented that deals with the aerodynamic and performance behavior of three-stage high pressure research turbine utilizing two different blade types. Keeping the initial conditions and the pressure ratio the same, two different rotors with the same hub and tip diameters are experimentally investigated. The first rotor incorporates 3-D convexly bowed blades, where as the second one utilizes a set of fully cylindrical blades. Using shrouded rotors and stators, the stator rings are correspondingly configured. The research turbine incorporates six rows beginning with a stator row. Interstage aerodynamic measurements are performed at design speeds at three stations, namely downstream of the first rotor row, the second stator row, and the second rotor row. For both rotors, the interstage radial and circumferential traversing present detailed flow pictures of the middle stage. Aerodynamic measurements were carried out at the turbine design speed. The experimental investigations have been carried out on a HP 3-stage gas turbine research facility at the Turbomachinery Performance and Flow Research Laboratory of Texas A&M University.

scholarly journals Genetic Algorithm Optimization of the Volute Shape of a Centrifugal Compressor

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Martin Heinrich ◽  
Rüdiger Schwarze
Keyword(s):  
Numerical Model ◽  
Centrifugal Compressor ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Algorithm Optimization ◽  
Cross Sectional ◽  
Design Variables ◽  
Design Speed

A numerical model for the genetic optimization of the volute of a centrifugal compressor for light commercial vehicles is presented. The volute cross-sectional shape is represented by cubic B-splines and its control points are used as design variables. The goal of the global optimization is to maximize the average compressor isentropic efficiency and total pressure ratio at design speed and four operating points. The numerical model consists of a density-based solver in combination with the SSTk-ωturbulence model with rotation/curvature correction and the multiple reference frame approach. The initial validation shows a good agreement between the numerical model and test bench measurements. As a result of the optimization, the average total pressure rise and efficiency are increased by over1.0%compared to the initial designs of the optimization, while the maximum efficiency rise is nearly 2.5% atm˙corr=0.19 kg/s.

Characterisation of Static Strip Seal Flow

2007 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Flow ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Main Stream ◽  
Cfd Modelling ◽  
Height Range ◽  
And Performance ◽  
Nozzle Guide ◽  
The Cost ◽  
Cooling Air

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

A Compact External Combustion Engine With High Part-Load Efficiency

2010 ◽  
Author(s):  
Robert Bourque
Keyword(s):  
Combustion Engine ◽  
Front Wheel ◽  
Good Efficiency ◽  
Complete Combustion ◽  
Part Load ◽  
Gasoline Engines ◽  
Full Power ◽  
And Performance ◽  
External Combustion ◽  
External Combustion Engine

An external combustion engine design using steam is described which has good efficiency at full power and even better efficiency at the low power settings common for passenger vehicles. The engine is compact with low weight per unit power. All of its components fit in the engine compartment of a front-wheel drive vehicle despite the space occupied by the transaxle. It readily fits in a rear-drive vehicle. Calculated net efficiencies, after accounting for all losses, range, depending on engine size, from 28–32% at full power increasing to 33–36% at normal road power settings. A two-stage burner, 100% excess air, and combustion temperature below 1500°C assure complete combustion of the fuel and negligible NOx. The engine can burn a variety of fuels and fuel mixes, which should encourage the development of new fuels. Extensive software has been written that calculates full power and part-load energy balances, structural analysis and heat transfer, and performance in specified vehicles including using SAE driving cycles. Engines have been sized from 30 to 3200 hp. In general, fuel consumption should be at least 1.5 times lower than gasoline engines and about the same as diesels operating at low to moderate load settings. Due to this analysis, a prototype, when built, should perform as expected.

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