An Advanced Usage of Meanline Loss Systems for Axial Turbine Design Optimisation

2013 ◽  
Author(s):  
Ivan Zhdanov ◽  
Stephan Staudacher ◽  
Sergey Falaleev
Keyword(s):  
Parameter Space ◽  
Design Parameter ◽  
Global Optimum ◽  
Axial Turbine ◽  
Turbine Performance ◽  
Framework Model ◽  
Optimal Values ◽  
Loss Systems ◽  
Turbine Design ◽  
The Impact

A comprehensive axial turbine framework model has been developed at the Institute of Aircraft Propulsion Systems, University of Stuttgart. It discovers the principles of a meanline optimisation and shows its advantages for quick prediction of optimal meanline parameters considering manufacturing, mechanical and aerodynamic requirements. The framework model can incorporate different loss correlations and compare their results for one and the same multi-dimensional design parameter space. A special attention is paid to the influence of loss correlations on optimal values of meanline parameters. It is shown that, although all loss correlation has their own global optimum of turbine performance in the multi-dimensional design parameter space, they are going to coincide if the requirements addressed to a turbine are considered and the turbine design constraints, e.g. a specified rotational speed, inlet diameter and etc., are applied. Thus, the more constraints in the design parameter space exist, the lower the impact of a loss correlation on optimal values of meanline parameters.

Impact of Time-Resolved Entropy Measurement on a One-and-One-Half-Stage Axial Turbine Performance

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
M. Mansour ◽  
N. Chokani ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Fast Response ◽  
Loss Coefficient ◽  
Time Resolved ◽  
Axial Turbine ◽  
Pressure Loss Coefficient ◽  
Entropy Measurement ◽  
High Pressure Stage ◽  
Turbine Design ◽  
The Impact ◽  
Loss Mechanisms

An accurate assessment of unsteady interactions in turbines is required, so that this may be taken into account in the design of the turbine. This assessment is required since the efficiency of the turbine is directly related to the contribution of unsteady loss mechanisms. This paper presents unsteady entropy measurements in an axial turbine. The measurements are conducted at the rotor exit of a one–and-one-half-stage unshrouded turbine that is representative of a highly loaded, high-pressure stage of an aero-engine. The unsteady entropy measurements are obtained using a novel miniature fast-response probe, which has been developed at ETH Zurich. The entropy probe has two components: a one-sensor fast-response aerodynamic probe and a pair of thin-film gauges. The probe allows the simultaneous measurement of the total temperature and the total pressure from which the time-resolved entropy field can be derived. The measurements of the time-resolved entropy provide a new insight into the unsteady loss mechanisms that are associated with the unsteady interaction between rotor and stator blade rows. A particular attention is paid to the interaction effects of the stator wake interaction, the secondary flow interaction, and the potential field interaction on the unsteady loss generation at the rotor exit. Furthermore, the impact on the turbine design of quantifying the loss in terms of the entropy loss coefficient, rather than the more familiar pressure loss coefficient, is discussed in detail.

Impact of Time-Resolved Entropy Measurement on a One-and-1/2-Stage Axial Turbine Performance

2008 ◽  
Author(s):  
M. Mansour ◽  
N. Chokani ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Fast Response ◽  
Loss Coefficient ◽  
Time Resolved ◽  
Axial Turbine ◽  
Pressure Loss Coefficient ◽  
Entropy Measurement ◽  
High Pressure Stage ◽  
Turbine Design ◽  
The Impact ◽  
Loss Mechanisms

An accurate assessment of unsteady interactions in turbines is required, so that this may be taken into account in the design of the turbine. This assessment is required since the efficiency of the turbine is directly related to the contribution of unsteady loss mechanisms. This paper presents unsteady entropy measurements in an axial turbine. The measurements are conducted at the rotor exit of a one-and-1/2-stage, unshrouded turbine that is representative of a highly loaded, high-pressure stage of an aero-engine. The unsteady entropy measurements are obtained using a novel miniature fast-response probe, which has been developed at ETH Zurich. The entropy probe has two components: a one-sensor fast response aerodynamic probe and a pair of thin-film gauges. The probe allows the simultaneous measurement of total temperature and total pressure from which the time-resolved entropy field can be derived. The measurements of the time resolved entropy provide a new insight into the unsteady loss mechanisms that are associated with the unsteady interaction between rotor and stator blade rows. A particular attention is paid to the interaction effects of the stator wake interaction, the secondary flow interaction and the potential field interaction on the unsteady loss generation at the rotor exit. Furthermore, the impact on turbine design of quantifying the loss in terms of the entropy loss coefficient, rather than the more familiar pressure loss coefficient, is discussed in detail.

Process Optimization of an Integrated Combined Cycle — The Impact and Benefit of Sequential Combustion

1997 ◽  
Author(s):  
Walter Jury ◽  
David E. Searles
Keyword(s):  
Gas Turbine ◽  
Optimal Solution ◽  
Combined Cycle ◽  
Exhaust Temperature ◽  
Turbine Performance ◽  
Rapid Pace ◽  
Exhaust Energy ◽  
And Performance ◽  
Turbine Design ◽  
The Impact

Advanced gas turbine designs require revisiting the optimization process to provide maximum competitiveness of new generating installations. This counts specifically for those designs created for combined cycle applications. Gas turbine performance and its associated exhaust temperature has been increasing at a rapid pace over recent years. The conventional method of selecting a GT based upon price and performance, and then designing a complex bottoming cycle does not provide sufficient solutions for power generation in an open access marketplace. The optimal solution takes into account the interrelation between the GT and WS cycle, leading to a more efficient, simplified and flexible power plant. This analysis shows how different levels of GT exhaust energy lead to different optimum cycle solutions. It shows, as postulated above, that considering the WS cycle demands in gas turbine design leads to a simpler cycle with inherent advantages in efficiency, reliability and flexibility.

Axial-Radial Diffuser With Integrated Exhaust Hood for An Automotive Turbocharger With Axial Turbine

2021 ◽  
Author(s):  
Christoph Kuestner ◽  
Joerg R. Seume
Keyword(s):  
Preliminary Design ◽  
Steam Turbines ◽  
Exhaust Hood ◽  
Design Guideline ◽  
Axial Turbine ◽  
Turbine Efficiency ◽  
Turbine Performance ◽  
Turbine Design ◽  
Inflow Conditions ◽  
Turbine Exhaust

Abstract Exhaust hoods with an integrated axial-radial diffuser use the kinetic energy downstream of a turbine for static pressure recovery. This is especially useful in applications with limited axial space behind the turbine. So far, such exhaust hoods have been used almost exclusively in larger turbomachinery such as maritime turbochargers and steam turbines, where an axial turbine is typically installed. In combination with an axial turbine, an exhaust hood can result in a very powerful and space-efficient turbine design, especially under highly pulsating inflow conditions. Both are important requirements for automotive turbochargers. Therefore, the application of such an exhaust hood in a small automotive turbocharger is investigated in this paper; this turbocharger also uses an axial turbine. In the first step, a preliminary design is developed, based on a design approach for steam turbine exhaust hoods. The resulting design is examined with a 3D CFD model to determine efficiency and turbine performance. Subsequently, the design is improved by modifying the exhaust hood geometry such as to further improve the overall efficiency of the turbine. Finally, the CFD evaluation for the operating point investigated reveals an increased power output and a higher overall turbine efficiency compared to the initial design. A resulting design guideline for exhaust hoods with an integrated axial-radial diffuser is included.

Assessment of Unsteady Flows in Turbines

1992 ◽  
Vol 114 (1) ◽  
pp. 79-90 ◽  
Author(s):  
O. P. Sharma ◽  
G. F. Pickett ◽  
R. H. Ni
Keyword(s):  
Unsteady Flow ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Experimental Investigations ◽  
Flow Parameters ◽  
Research Activities ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
The Impact

The impacts of unsteady flow research activities on flow simulation methods used in the turbine design process are assessed. Results from experimental investigations that identify the impact of periodic unsteadiness on the time-averaged flows in turbines and results from numerical simulations obtained by using three-dimensional unsteady Computational Fluid Dynamics (CFD) codes indicate that some of the unsteady flow features can be fairly accurately predicted. Flow parameters that can be modeled with existing steady CFD codes are distinguished from those that require unsteady codes.

scholarly journals Sensitivity of Supersonic ORC Turbine Injector Designs to Fluctuating Operating Conditions

2015 ◽  
Author(s):  
Elio A. Bufi ◽  
Paola Cinnella ◽  
Xavier Merle
Keyword(s):  
Method Of Characteristics ◽  
Organic Rankine Cycle ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Real Gas ◽  
Real Gas Effects ◽  
Nozzle Shape ◽  
Turbine Design ◽  
The Impact

The design of an efficient organic rankine cycle (ORC) expander needs to take properly into account strong real gas effects that may occur in given ranges of operating conditions, which can also be highly variable. In this work, we first design ORC turbine geometries by means of a fast 2-D design procedure based on the method of characteristics (MOC) for supersonic nozzles characterized by strong real gas effects. Thanks to a geometric post-processing procedure, the resulting nozzle shape is then adapted to generate an axial ORC blade vane geometry. Subsequently, the impact of uncertain operating conditions on turbine design is investigated by coupling the MOC algorithm with a Probabilistic Collocation Method (PCM) algorithm. Besides, the injector geometry generated at nominal operating conditions is simulated by means of an in-house CFD solver. The code is coupled to the PCM algorithm and a performance sensitivity analysis, in terms of adiabatic efficiency and power output, to variations of the operating conditions is carried out.

scholarly journals The perceived impact of downsizing and organisational transformation on survivors

2005 ◽  
Vol 31 (2) ◽  
Author(s):  
N. Ndlovu ◽  
S. Brijball Parumasur
Keyword(s):  
Change Implementation ◽  
Way Of Life ◽  
Advancement Opportunities ◽  
Survivor Syndrome ◽  
Framework Model ◽  
Key Factor ◽  
Major Transformation ◽  
Perceived Impact ◽  
The Impact ◽  
Implementation Factors

Change is a way of life and the ability to manage change is a key factor in organisational survival and effectiveness. This article evaluates the ‘survivor syndrome’ and assesses the impact of the process of downsizing and transformation on communication, trust, survivor commitment and loyalty, morale and career advancement opportunities. The study was conducted using a stratified random sample of 361 employees/survivors in a branch of a motor manufacturer that had undergone major transformation. Data was collected using a self-developed questionnaire and analysed using descriptive and inferential statistics. The study generates a framework/model of critical change implementation factors and recommendations that will enable change managers to sense, adjust, respond and implement change timeously so as to gain strategic and competitive advantage. Opsomming Verandering is ’n lewenswyse en die vermoë om te verander is ’n kernaspek in organisasieverandering en -oorlewing. In hierdie artikel word die ‘oorlewingsindroom’ beoordeel en word die impak van die afskalingsproses en transformasie op kommunikasie, vertroue, ‘oorlewende’ toewyding en lojaliteit, moraal en loopbaanvorderingsgeleenthede takseer. Die studie is uitgevoer, met die gebruik van ’n gestratifiseerde ewekansige steekproef van 361 werknemers/’oorlewendes’ in ’n afdeling van ’n motorvervaardiger wat ingrypende transformasie ondergaan het. Data is ingesamel by wyse van ’n selfontwikkelde vraelys en ontleed aan die hand van beskrywende en inferensiële statistiek. Die studie het ’n raamwerk/model van kritieke veranderingsimplementeringsfaktore en aanbevelings gegenereer wat veranderingsbestuurders in staat sal stel om die gewaarwording, aanpassing, reaksie en implementering van verandering tydig te doen sodat strategiese en mededingingsvoordeel behaal kan word.

The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Filippo Rubechini ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Massimiliano Maritano ◽  
Stefano Cecchi
Keyword(s):  
Gas Turbine ◽  
Flow Direction ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Ratio Distribution ◽  
Real Gas ◽  
Turbine Performance ◽  
Wall Boundary Conditions ◽  
Heavy Duty Gas Turbine ◽  
The Impact

In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows, and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp, and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel∕air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at the inlet∕outlet of each row and total temperature at the turbine exit.

scholarly journals Design of advanced airfoil for stall-regulated wind turbines

2017 ◽  
Vol 2 (2) ◽  
pp. 403-413
Author(s):  
Francesco Grasso ◽  
Domenico Coiro ◽  
Nadia Bizzarrini ◽  
Giuseppe Calise
Keyword(s):  
Wind Turbines ◽  
Design Strategy ◽  
High Wind ◽  
Pitch Control ◽  
Turbine Performance ◽  
Gradient Based ◽  
Machine Control ◽  
And Control ◽  
The Impact ◽  
Numerical Optimisation

Abstract. Nowadays, all the modern megawatt-class wind turbines make use of pitch control to optimise the rotor performance and control the turbine. However, for kilowatt-range machines, stall-regulated solutions are still attractive and largely used for their simplicity and robustness. In the design phase, the aerodynamics plays a crucial role, especially concerning the selection/design of the necessary airfoils. This is because the airfoil performance is supposed to guarantee high wind turbine performance but also the necessary machine control capabilities. In the present work, the design of a new airfoil dedicated to stall machines is discussed. The design strategy makes use of a numerical optimisation scheme, where a gradient-based algorithm is coupled with the RFOIL code and an original Bezier-curves-based parameterisation to describe the airfoil shape. The performances of the new airfoil are compared in free- and fixed-transition conditions. In addition, the performance of the rotor is analysed, comparing the impact of the new geometry with alternative candidates. The results show that the new airfoil offers better performance and control than existing candidates do.

Axial Turbine Design for a Twin-Turbine Heavy-Duty Turbocharger Concept

2018 ◽  
Author(s):  
Nicholas Anton ◽  
Magnus Genrup ◽  
Carl Fredriksson ◽  
Per-Inge Larsson ◽  
Anders Christiansen-Erlandsson
Keyword(s):  
Engine Performance ◽  
Operating Conditions ◽  
Single Stage ◽  
Flow Coefficient ◽  
Speed Ratio ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Radial Turbine ◽  
Turbine Design

In the process of evaluating a parallel twin-turbine pulse-turbocharged concept, the results considering the turbine operation clearly pointed towards an axial type of turbine. The radial turbine design first analyzed was seen to suffer from sub-optimum values of flow coefficient, stage loading and blade-speed-ratio. Modifying the radial turbine by both assessing the influence of “trim” and inlet tip diameter all concluded that this type of turbine is limited for the concept. Mainly, the turbine stage was experiencing high values of flow coefficient, requiring a more high flowing type of turbine. Therefore, an axial turbine stage could be feasible as this type of turbine can handle significantly higher flow rates very efficiently. Also, the design spectrum is broader as the shape of the turbine blades is not restricted by a radially fibred geometry as in the radial turbine case. In this paper, a single stage axial turbine design is presented. As most turbocharger concepts for automotive and heavy-duty applications are dominated by radial turbines, the axial turbine is an interesting option to be evaluated for pulse-charged concepts. Values of crank-angle-resolved turbine and flow parameters from engine simulations are used as input to the design and subsequent analysis. The data provides a valuable insight into the fluctuating turbine operating conditions and is a necessity for matching a pulse-turbocharged system. Starting on a 1D-basis, the design process is followed through, resulting in a fully defined 3D-geometry. The 3D-design is evaluated both with respect to FEA and CFD as to confirm high performance and durability. Turbine maps were used as input to the engine simulation in order to assess this design with respect to “on-engine” conditions and to engine performance. The axial design shows clear advantages with regards to turbine parameters, efficiency and tip speed levels compared to a reference radial design. Improvement in turbine efficiency enhanced the engine performance significantly. The study concludes that the proposed single stage axial turbine stage design is viable for a pulse-turbocharged six-cylinder heavy-duty engine. Taking into account both turbine performance and durability aspects, validation in engine simulations, a highly efficient engine with a practical and realizable turbocharger concept resulted.

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