scholarly journals Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design

1999 ◽  
Vol 122 (2) ◽  
pp. 189-217 ◽  
Author(s):  
John J. Adamczyk
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Design Environment ◽  
Cfd Simulations ◽  
Flow Models ◽  
Flow Processes ◽  
Design Systems ◽  
Future Work

This paper summarizes the state of 3D CFD based models of the time-averaged flow field within axial flow multistage turbomachines. Emphasis is placed on models that are compatible with the industrial design environment and those models that offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models free of aerodynamic input from semiempirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures that can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines that help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time-averaged flow models. [S0889-504X(00)02002-X]

scholarly journals Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design

1999 ◽  
Author(s):  
John J. Adamczyk
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Environment ◽  
Cfd Simulations ◽  
Average Flow ◽  
Flow Models ◽  
Time Average ◽  
Semi Empirical ◽  
Future Work

This paper summarizes the state of 3D CFD based models of the time average flow field within axial flow multistage turbomachines. Emphasis is placed on models which are compatible with the industrial design environment and those models which offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models which are free of aerodynamic input from semi-empirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures which can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines which help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time average flow models.

An Investigation of Steady and Unsteady Flow through a Napier Turboblower Turbine under Conditions of Full and Partial Admission

1968 ◽  
Vol 183 (1) ◽  
pp. 615-630 ◽  
Author(s):  
H. R. M. Craig ◽  
K. J. Edwards ◽  
J. H. Horlock ◽  
M. Janota ◽  
R. Shaw ◽  
...  
Keyword(s):  
Unsteady Flow ◽  
Mass Flow ◽  
Power Output ◽  
Axial Flow ◽  
Limited Range ◽  
Expansion Ratio ◽  
Operating Conditions ◽  
Turbine Efficiency ◽  
Cyclic Operation ◽  
Partial Admission

The paper presents the results of tests on an axial-flow turbine and describes how they are obtained, in steady and unsteady flow. An analysis of turbine-test results obtained under the unsteady operating conditions is then given. It is shown that over a limited range of cyclic operation the mass flow and power output may be predicted by assuming that the turbine operates instantaneously as it would under steady-flow conditions (at the same expansion ratio and the same non-dimensional rotational speed) and integrating over the engine cycle. At high pressure ratios, pulse frequencies and rotational speeds, this ‘quasi-steady’ analysis gives a slight overestimate of mass flow and power output but the error in turbine efficiency is very small.

Modern Trends in CFD Simulations: Application to GTL Technology

2006 ◽  
Vol 1 (1) ◽  
Author(s):  
Abid Akhtar ◽  
Vishnu K Pareek ◽  
Moses O Tade
Keyword(s):  
Multiphase Flow ◽  
Bubble Column ◽  
Fluid Dynamic ◽  
Scale Up ◽  
Operating Conditions ◽  
Special Focus ◽  
Cfd Simulations ◽  
Multiphase Reactors ◽  
Flow Processes ◽  
Gas To Liquid

Multiphase flow processes are frequently observed in several important reactor technologies. These technologies are found in diverse applications such as in manufacture of petroleum-based fuels and products, conversion of synthesis gas into liquid hydrocarbons (Gas-to-liquid technology), production of commodity chemicals, pharmaceuticals, herbicides, pesticides, polymers etc. Due to the inherent complexity of these processes, the knowledge of fluid dynamic and transport parameters is necessary for development of appropriate reactor models and scale-up rules. It is, therefore, of paramount importance to develop understanding and predictive tools to simulate multiphase flow processes for better and economically viable reactor technologies. In the past, knowledge of hydrodynamics and transport characteristics of multiphase reactors has been interpreted in the form of empirical correlations, which have numerous restrictions in terms of their validity for different operating conditions. Computational fluid dynamics (CFD) simulation, on the other hand, deals with the solution of fluid dynamic equations on digital computers, requiring relatively few restrictive assumptions and thus giving a complete description of the hydrodynamics of these reactors. This detailed predicted flow field gives an accurate insight to the fluid behaviour and can sometimes give information, which cannot be obtained from experiments. These days, due to cheaper computational resources, CFD simulations are becoming economically reliable for modeling of multiphase processes including GTL (Gas-to-liquid) processes. In this paper, a comprehensive review of different multiphase flow simulation approaches has been presented. The recent progress made in hydrodynamic modeling of multiphase reactors, their capabilities and limitations (with special focus on GTL processes) are discussed in detail. Finally, case studies with different simulation approaches (Eulerian-Eulerian and VOF (Volume of fluid) simulations of bubble column reactors operating in different flow regimes) are discussed to demonstrate the power of this emerging research tool.

Unsteady Flow Analysis of the Stator-Rotor Interaction in an Axial Flow Fan

2003 ◽  
Author(s):  
J. Ferna´ndez Oro ◽  
K. Argu¨elles Di´az ◽  
C. Santolaria Morros ◽  
R. Ballesteros Tajadura
Keyword(s):  
Unsteady Flow ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Axial Flow ◽  
3D Models ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Axial Flow Fan ◽  
Rotating Blade ◽  
Flow Phenomena

In the usual operation of turbomachinery, some unsteady flow phenomena appear due to the non uniformity of the flow inside the rotor, when observed in the fixed reference frame. These phenomena are often related to the unsteady character of the pressure and velocity fields, which produce oscillating forces on the blades, superimposed to the steady force. These oscillating forces are the main mechanism of noise generation, which appear even at a constant rotational speed and at flow rates where the performance curves are stable. In axial turbomachines, the interaction is due to relative motion between the static and rotating blade rows. Considering the case of a fixed blade row (stator) placed upstream of the rotor, the non uniform flow leaving those blades (usually referred as IGV blades) is observed as an unsteady flow by the rotor blades. The effect of this interaction is the generation of unsteady forces on the rotor blades, which generate vibrations (risk of fatigue failure) and noise, and non-uniformity and unsteadiness of the pressure field, that propagates as an acoustic wave. The first part of this work is a brief description of a URANS numerical modeling of the unsteady flow characteristics of a one-stage subsonic axial flow fan with a reaction degree greater than 1. The focus is placed on the statorrotor interaction performance. Both 2D and 3D models of the fan, with 13 IGV’s and 9 rotor blades, were developed and an unsteady simulation was achieved to carry out the main characteristics of the flow inside the turbomachine. Once the actuating forces are determined, the influence of the radial position, the operating conditions and the distance of the fixed and the rotating blade rows is also analyzed. The final part of the paper is focused over the identification, through the definition of deterministic stresses — related to the characteristic blade-passage frequency of every row — that provoke the interaction between fixed and rotating blade rows and its evolution through time. The object is to obtain, in a stress tensor form, the contribution of the velocity field, that is changing because of the sucessive relative positions between blade rows, to the pressure distribution over the blade surfaces in the interior of the stage. Finally, a map of deterministic stresses and even, deterministic kinetic energy, can be obtained to show the influence of the blade rows in the interaction, unsteady phenomena.

scholarly journals CFD Study of Nozzle Configurations for Ultra High Bypass Engines

1993 ◽  
Author(s):  
H. Zimmermann ◽  
R. Gumucio ◽  
K. Katheder ◽  
A. Jula
Keyword(s):  
Engine Performance ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Thrust Coefficient ◽  
Optimum Range ◽  
Installation Effects ◽  
Wide Range ◽  
And Performance ◽  
Aircraft Aerodynamics ◽  
Bypass Ratio

Performance and aerodynamic aspects of ultra-high bypass ratio ducted engines have been investigated with an emphasis on nozzle aerodynamics. The interference with aircraft aerodynamics could not be covered. Numerical methods were used for aerodynamic investigations of geometrically different aft end configurations for bypass ratios between 12 and 18, this is the optimum range for long missions which will be important for future civil engine applications. Results are presented for a wide range of operating conditions and effects on engine performance are discussed. The limitations for higher bypass ratios than 12 to 18 do not come from nozzle aerodynamics but from installation effects. It is shown that using CFD and performance calculations an improved aerodynamic design can be achieved. Based on existing correlations, for thrust and mass-flow, or using aerodynamic tailoring by CFD and including performance investigations, it is possible to increase the thrust coefficient up to 1%.

Flow Features Analysis of Throttle Notches of Proportional Direct Valve

2011 ◽  
Vol 189-193 ◽  
pp. 2285-2288
Author(s):  
Wen Hua Jia ◽  
Chen Bo Yin ◽  
Guo Jin Jiang
Keyword(s):  
Fluid Flow ◽  
Dynamic Behavior ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
3D Models ◽  
Operating Conditions ◽  
Flow Models ◽  
Flow Features ◽  
Rate Discharge ◽  
Spool Valve

Flow features, specially, flow rate, discharge coefficient and efflux angle under different operating conditions are numerically simulated, and the effects of shapes and the number of notches on them are analyzed. To simulate flow features, 3D models are developed as commercially available fluid flow models. Most construction machineries in different conditions require different actions. Thus, in order to be capable of different actions and exhibit good dynamic behavior, flow features should be achieved in designing an optimized proportional directional spool valve.

A Fully Coupled Approach for the Integration of 3D-CFD Component Simulation in Overall Engine Performance Analysis

2017 ◽  
Author(s):  
C. Klein ◽  
S. Reitenbach ◽  
D. Schoenweitz ◽  
F. Wolters
Keyword(s):  
Performance Analysis ◽  
Boundary Conditions ◽  
Progress Monitoring ◽  
Cfd Simulation ◽  
System Simulation ◽  
Pressure Ratio ◽  
Performance Model ◽  
Operating Conditions ◽  
Operating Characteristics ◽  
Design Environment

Due to a high degree of complexity and computational effort, overall system simulations of jet engines are typically performed as 0-dimensional thermodynamic performance analysis. Within these simulations and especially in the early cycle design phase, the usage of generic component characteristics is common practice. Of course these characteristics often cannot account for true engine component geometries and operating characteristics which may cause serious deviations between simulated and actual component and overall system performance. This leads to the approach of multi-fidelity simulation, often referred to as zooming, where single components of the thermodynamic cycle model are replaced by higher-order procedures. Hereby the consideration of actual component geometries and performance in an overall system context is enabled and global optimization goals may be considered in the engine design process. The purpose of this study is to present a fully automated approach for the integration of a 3D-CFD component simulation into a thermodynamic overall system simulation. As a use case, a 0D-performance model of the IAE-V2527 engine is combined with a CFD model of the appropriate fan component. The methodology is based on the DLR in-house performance synthesis and preliminary design environment GTlab combined with the DLR in-house CFD solver TRACE. Both, the performance calculation as well as the CFD simulation are part of a fully automated process chain within the GTlab environment. The exchange of boundary conditions between the different fidelity levels is accomplished by operating both simulation procedures on a central data model which is one of the essential parts of GTlab. Furthermore iteration management, progress monitoring as well as error handling are part of the GTlab process control environment. Based on the CFD results comprising fan efficiency, pressure ratio and mass flow, a map scaling methodology as it is commonly used for engine condition monitoring purposes is applied within the performance simulation. Hereby the operating behavior of the CFD fan model can be easily transferred into the overall system simulation which consequently leads to a divergent operating characteristic of the fan module. For this reason, all other engine components will see a shift in their operating conditions even in case of otherwise constant boundary conditions. The described simulation procedure is carried out for characteristic operating conditions of the engine.

Validation of MISES Two-Dimensional Boundary Layer Code for High-Pressure Turbine Aerodynamic Design

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Philip L. Andrew ◽  
Harika S. Kahveci
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Operating Cost ◽  
Design Tool ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
High Pressure Turbine ◽  
Reduce Operating Cost ◽  
Wide Range ◽  
Dimensional Boundary

Avoiding aerodynamic separation and excessive shock losses in gas turbine turbomachinery components can reduce fuel usage and thus reduce operating cost. In order to achieve this, blading designs should be made robust to a wide range of operating conditions. Consequently, a design tool is needed—one that can be executed quickly for each of many operating conditions and on each of several design sections, which will accurately capture loss, turning, and loading. This paper presents the validation of a boundary layer code, MISES, versus experimental data from a 2D linear cascade approximating the performance of a moderately loaded mid-pitch section from a modern aircraft high-pressure turbine. The validation versus measured loading, turning, and total pressure loss is presented for a range of exit Mach numbers from ≈0.5 to 1.2 and across a range of incidence from −10 deg to +14.5 deg relative to design incidence.

scholarly journals Development of the PGT 25 High Efficiency Gas Turbine: Part 2 — Aerodynamic Design and Performance

1984 ◽  
Author(s):  
E. Benvenuti ◽  
B. Innocenti ◽  
R. Modi
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Performance Testing ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Direct Drive ◽  
Gas Generator ◽  
Full Load ◽  
Wide Range ◽  
Overall Performance

This paper outlines parameter selection criteria and major procedures used in the PGT 25 gas turbine power spool aerodynamic design; significant results of the shop full-load tests are also illustrated with reference to both overall performance and internal flow-field measurements. A major aero-design objective was established as that of achieving the highest overall performance levels possible with the matching to latest generation aero-derivative gas generators; therefore, high efficiencies were set as a target both for the design point and for a wide range of operating conditions, to optimize the turbine’s uses in mechanical drive applications. Furthermore, the design was developed to reach the performance targets in conjunction with the availability of a nominal shaft speed optimized for the direct drive of pipeline booster centrifugal compressors. The results of the full-load performance testing of the first unit, equipped with a General Electric LM 2500/30 gas generator, showed full attainment of the design objectives; a maximum overall thermal efficiency exceeding 37% at nominal rating and a wide operating flexibility with regard to both efficiency and power were demonstrated.

CAD in the CIM Environment: Where Do We Go From Here?

1986 ◽  
Vol 39 (9) ◽  
pp. 1345-1349 ◽  
Author(s):  
Dell K. Allen ◽  
W. Van Twelves
Keyword(s):  
Computer Aided Design ◽  
Material Selection ◽  
Operating Conditions ◽  
Computer Integrated Manufacturing ◽  
Accurate Information ◽  
Functional Requirements ◽  
Essential Information ◽  
Design Systems ◽  
Aided Design ◽  
Product Definition

The importance of computer-aided design (CAD) has not been fully appreciated as it relates to computer integrated manufacturing (CIM). The CAD product definition model can provide essential information for many down-stream production, estimating, tooling, and quality assurance functions in the CIM environment. However, the product definition model may be inaccurate or incomplete, thus causing incomplete communication with possible scrap, re-work, and missed production deadlines. Other problems are related to the fact that many of our expert designers are retiring and taking their expertise with them. Merely being able to make 2D or 3D drawings on a CAD workstation does not make its operator a designer. A knowledge of production processes, tolerances, surface finish, and material selection is needed to supplement a designers knowledge of user needs, product functional requirements, operating conditions, cost, quality, and reliability targets. One of the most promising methods for providing timely and accurate information to the designer on an “as-needed” basis is through the use of expert design systems. Such systems promise to bridge the knowledge gap between CAD and CAM and help to incorporate these functions into the overall CIM environment.

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