Fast Optimisation of a Three-Dimensional Bypass System Using a New Aerodynamic Design Method

2017 ◽  
Author(s):  
F. Barbarossa ◽  
M. E. Rife ◽  
M. Carnevale ◽  
A. B. Parry ◽  
J. S. Green ◽  
...  
Keyword(s):  
Power Plants ◽  
Static Pressure ◽  
Design Method ◽  
Three Dimensional ◽  
Civil Aviation ◽  
Propulsive Efficiency ◽  
Singularity Method ◽  
Design Variables ◽  
Computational Fluid Dynamics Cfd ◽  
Bypass Ratio

The propulsive efficiency of civil aviation power plants can be effectively improved by increasing the bypass ratio. Higher bypass ratios, however, exacerbate issues of performance, stability and integrity due to the interaction between the engine pylon, the outlet guide vanes (OGV) and the fan. These issues are due to the distortion of the static pressure field at fan exit due to the presence of the pylon and its transmission through the OGV bladerow and are more pronounced the closer the components of the low pressure compression (LPC) system are. These issues make a rational and effective design of the LPC system of paramount importance for the success of very high-bypass ratio engines. At the preliminary design phase, methods that utilise computational fluid dynamics (CFD) are prohibitively expensive, particularly if they are used as part of optimisation processes involving highly three dimensional, non-axisymmetric OGV designs. An alternative method is being developed exploiting the simplicity and the accuracy of surface singularity element methods to investigate the sensitivity of the bypass system to changes in the design variables. Although the singularity method is based on simplified assumptions of inviscid, incompressible flow, it still performs remarkably well when combined with a tailored optimisation technique. This paper discusses the optimisation framework in detail, including the underlying mathematical models that describe the three-dimensional aerodynamic flowfield as well as the optimisation tools, variables and cost functions used within the optimisation process. The results show that the proposed approach can be used to explore quickly and efficiently a far wider design space than attempted so far in literature. Furthermore, the proposed method leads to non-axysymmetric cascade designs whereby every vane has the same load as the nominal vane whilst greatly reducing the static pressure distortion at fan exit.

Inverse Design of 3D Multi-Stage Transonic Fans at Dual Operating Points

2013 ◽  
Author(s):  
James H. Page ◽  
Paul Hield ◽  
Paul G. Tucker
Keyword(s):  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Inverse Design ◽  
Flow Angle ◽  
Trade Offs ◽  
Multi Stage ◽  
Full Speed ◽  
Computational Fluid Dynamics Cfd ◽  
Operating Points

Semi-inverse design is the automatic re-cambering of an aerofoil, during a computational fluid dynamics (CFD) calculation, in order to achieve a target lift distribution while maintaining thickness, hence “semi-inverse”. In this design method, the streamwise distribution of curvature is replaced by a stream-wise distribution of lift. The authors have developed an inverse design code based on the method of Hield (2008) which can rapidly design three-dimensional fan blades in a multi-stage environment. The algorithm uses an inner loop to design to radially varying target lift distributions, an outer loop to achieve radial distributions of stage pressure ratio and exit flow angle, and a choked nozzle to set design mass flow. The code is easily wrapped around any CFD solver. In this paper, we describe a novel algorithm for designing simultaneously for specified performance at full speed and peak efficiency at part speed, without trade-offs between the targets at each of the two operating points. We also introduce a novel adaptive target lift distribution which automatically develops discontinuous changes of calculated magnitude, based on the passage shock, eliminating erroneous lift demands in the shock vicinity and maintaining a smooth aerofoil.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

scholarly journals Feasible Concept of an Air-Driven Fan with a Tip Turbine for a High-Bypass Propulsion System

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3350 ◽  
Author(s):  
Guoping Huang ◽  
Xin Xiang ◽  
Chen Xia ◽  
Weiyu Lu ◽  
Lei Li
Keyword(s):  
Fluid Dynamics ◽  
Carbon Dioxide Emissions ◽  
Three Dimensional ◽  
Propulsion System ◽  
Navier Stokes ◽  
Three Dimensional Flow ◽  
Low Pressure Turbine ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Bypass Ratio

The reduction in specific fuel consumption (SFC) is crucial for small/mid-size cost-controllable aircraft, which is very conducive to reducing cost and carbon dioxide emissions. To decrease the SFC, increasing the bypass ratio (BPR) is an important way. Conventional high-BPR engines have several limitations, especially the conflicting spool-speed requirements of a fan and a low-pressure turbine. This research proposes an air-driven fan with a tip turbine (ADFTT) as a potential device for a high-bypass propulsion system. Moreover, a possible application of this ADFTT is introduced. Thermodynamic analysis results show that an ADFTT can improve thrust from a prototype turbofan. As a demonstration, we selected a typical small-thrust turbofan as the prototype and applied the ADFTT concept to improve this model. Three-dimensional flow fields were numerically simulated through a Reynolds averaged Navier-Stokes (RANS)-based computational fluid dynamics (CFD) method. The performance of this ADFTT has the possibility of amplifying the BPR more than four times and increasing the thrust by approximately 84% in comparison with the prototype turbofan.

scholarly journals Application of a three-dimensional viscous transonic inverse method to NASA rotor 67

2002 ◽  
Vol 216 (3) ◽  
pp. 243-255 ◽  
Author(s):  
W. T. Tiow ◽  
M Zangeneh
Keyword(s):  
High Speed ◽  
Inverse Method ◽  
Static Pressure ◽  
Three Dimensional ◽  
Test Case ◽  
Shock Formation ◽  
Pressure Loading ◽  
Design Computation ◽  
Computational Fluid Dynamics Cfd ◽  
Blade Geometry

The development and application of a three-dimensional inverse methodology in which the blade geometry is computed on the basis of the specification of static pressure loading distribution is presented. The methodology is based on the intensive use of computational fluid dynamics (CFD) to account for three-dimensional subsonic and transonic viscous flows. In the design computation, the necessary blade changes are determined directly by the discrepancies between the target and initial values, and the calculation converges to give the final blade geometry and the corresponding steady state flow solution. The application of the method is explored using a transonic test case, NASA rotor 67. Based on observations, it is conclusive that the shock formation and its intensity in such a high-speed turbomachinery flow are well defined on the loading distributions. Pressure loading is therefore as effective a design parameter as conventional inverse design quantities such as static pressure. Hence, from an understanding of the dynamics of the flow in the fan in relation to its pressure loading distributions, simple guidelines can be developed for the inverse method in order to weaken the shock formation. A qualitative improvement in performance is achieved in the redesigned fan. The final flowfield result is confirmed by a well-established commercial CFD package.

scholarly journals Development of a Method for Enhanced Fan Representation in Gas Turbine Modeling

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Georgios Doulgeris ◽  
Hossein Khaleghi ◽  
Anestis Kalfas ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Prediction Models ◽  
Three Dimensional ◽  
Civil Aviation ◽  
Noise Mitigation ◽  
Streamline Curvature ◽  
Surge Margin ◽  
Three Dimensional Representation ◽  
Compressor Performance ◽  
Bypass Ratio

A challenge in civil aviation future propulsion systems is expected to be the integration with the airframe, coming as a result of increasing bypass ratio or above wing installations for noise mitigation. The resulting highly distorted inlet flows to the engine make a clear demand for advanced gas turbine performance prediction models. Since the dawn of jet engine, several models have been proposed, and the present work comes to add a model that combines two well-established compressor performance methods in order to create a quasi-three-dimensional representation of the fan of a modern turbofan. A streamline curvature model is coupled to a parallel compressor method, covering radial and circumferential directions, respectively. Model testing has shown a close agreement to experimental data, making it a good candidate for assessing the loss of surge margin on a high bypass ratio turbofan, semiembedded on the upper surface of a broad wing airframe.

CFD Analysis of Compressible Flow Across a Complex Geometry Venturi

2007 ◽  
Vol 129 (9) ◽  
pp. 1193-1202 ◽  
Author(s):  
Diego A. Arias ◽  
Timothy A. Shedd
Keyword(s):  
Compressible Flow ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Turbulent Model ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Computational Fluid Dynamics Cfd ◽  
Fuel Tube

A commercial computational fluid dynamics (CFD) package was used to develop a three-dimensional, fully turbulent model of the compressible flow across a complex-geometry venturi, such as those typically found in small engine carburetors. The results of the CFD simulations were used to understand the effect of the different obstacles in the flow on the overall discharge coefficient and the static pressure at the tip of the fuel tube. It was found that the obstacles located at the converging nozzle of the venturi do not cause significant pressure losses, while those obstacles that create wakes in the flow, such as the fuel tube and throttle plate, are responsible for most of the pressure losses. This result indicated that an overall discharge coefficient can be used to correct the mass flow rate, while a localized correction factor can be determined from three-dimensional CFD simulations in order to estimate the static pressure at locations of interest within complex venturis.

Numerical Study of the Effects of Confined Airfoils Usage in High Bypass Ratio Turbofan Engines

2020 ◽  
Author(s):  
Rene Aguilar ◽  
Cesar Celis ◽  
Marcio Pontes
Keyword(s):  
Airline Industry ◽  
Power Plants ◽  
Numerical Study ◽  
Flow Behavior ◽  
Flow Region ◽  
Bypass Flow ◽  
Numerical Work ◽  
Propulsive Efficiency ◽  
Turbofan Engines ◽  
Bypass Ratio

Abstract Turbofan engines are the main power plants used in the commercial airline industry. Increasing the bypass ratio (BPR) in turbofan engines enhances their propulsive efficiency and reduces both noise and harmful gas emissions. Over the years the aero engine industry has devoted huge efforts and enormous amounts of money to improve turbofans’ propulsive efficiency through the increase of their BPR. Based on the current technology however, there is a practical limit to how much BPR can be increased before significant penalties associated with increased both engine weight and nacelle drag erode the benefits. This work numerically studies thus the benefits of using confined airfoils in the engine bypass flow region to counteract the turbofan engine weight and alleviate the efforts over the aircraft wing structure. Accordingly, a description of the proposed engine-airfoils arrangement, relative dimensions and airfoils adequate placement inside the engine bypass duct is initially presented. Two different flight conditions, take-off and cruise, are numerically assessed next using computational fluid dynamics (CFD) based approaches to characterize the particular bypass flow behavior. The numerical work includes the study of engine configurations similar to those used in long-range aircraft. A structured multi-domain mesh, in conjunction with both Reynolds-average Navier Stokes (RANS) and steady-state mixing planes approaches, are used in the numerical model utilized. The main results indicate that using confined airfoils produces substantial lift respect to the engine weight. Engine weight reductions of up to 23% are observed because of the use of confined airfoils in the engines bypass ducts.

Multi-Objective Combinatorial Optimization Design Method for the Compressor Splitter

2015 ◽  
Author(s):  
Limin Gao ◽  
Xiaoming Deng ◽  
Lei Gao ◽  
Ruiyu Li ◽  
Ruihui Zeng ◽  
...  
Keyword(s):  
Combinatorial Optimization ◽  
Design Of Experiment ◽  
Optimization Design ◽  
Static Pressure ◽  
Complex Geometry ◽  
Design Method ◽  
Multi Objective ◽  
Geometry Modeling ◽  
Design Variables ◽  
Core Components

Considering the present backward situation of the compressor splitter designing level, a multi-objective Combinatorial Optimization Design method is put forward for the splitter design consisting of three core components: the CST parameterized method, the Design of Experiment and the ASA optimization algorithm. In the whole optimization design process, the CST parameterized method is developed for the complex geometry modeling and geometric samples generating of splitter. The Design of Experiment is taken used to qualitatively analyze the multiple design variables and adjust their number and scopes. The ASA algorithm takes charge of the global optimization of splitter geometry samples, and selects the best geometry conform to the design target. All the relevant optimization components and modules are integrated by the Isight software and be interacted and automatically called by the edited scripts. The effectiveness of the proposed design method is verified through a practical splitter example. Results show that: 1) the CST parameterized method of fourth order or above is of great accurately to fit the splitter geometry, in order to generate variable geometric samples. 2) The Design of Experiment is able to identify the different influence of multiple design variables on the design objectives and lead to the optimization process more targeted. 3) The performance of optimization result is improved significantly, in which the core duct behaves more sensitive to splitter geometry changing and the low-static pressure and high-radial velocity areas reduced to half of the initial design.

Optimization of 6.2:1 Pressure Ratio Centrifugal Compressor Impeller by 3D Inverse Design

2011 ◽  
Author(s):  
M. Zangeneh ◽  
N. Amarel ◽  
K. Daneshkhah ◽  
H. Krain
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Mechanical Performance ◽  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Inverse Design ◽  
Transonic Compressor ◽  
Design Variables ◽  
Compressor Impeller

In this work, the redesign of a centrifugal transonic compressor impeller with splitter blades by means of the three-dimensional inverse design code TURBOdesign-1 is presented. The basic design methodology for impellers with splitter blades is outlined and is applied in a systematic way to improve the aero/mechanical performance of a transonic 6.2:1 pressure ratio centrifugal compressor impeller. The primary design variables are the main and splitter blades loading and their thickness distributions, the splitter to main blade work ratio, as well as the span-wise swirl distribution. The flow in the original and redesigned impellers are then analyzed by means of a commercial CFD code (ANSYS CFX). The predicted flow field for the original impeller is compared with detailed L2F measurements inside and outside the impeller. The validated CFD results are used to compare the flow field in the optimized and original impeller. It is shown that the inverse design method could be effectively used to control the position and strength of the shock waves, eliminate flow separation and hence obtain a more uniform impeller exit flow in order to improve the aerodynamic performance. In addition, some results are presented on the comparison of stress and vibration in both impellers.

Aerodynamic Design of a Highly Loaded Axial Flow Fan Rotor Using a Novel One-Dimensional Design Method With its Numerical Simulation

2016 ◽  
Author(s):  
Ali Shahsavari ◽  
Mahdi Nili-Ahamadabadi
Keyword(s):  
Numerical Simulation ◽  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Flow ◽  
Numerical Results ◽  
Meridional Plane ◽  
Performance Curve ◽  
One Dimensional ◽  
Bypass Ratio

This paper presents a novel one-dimensional design method based on the radial equilibrium theory and constant span-wise diffusion factor to redesign of NASA rotor 67 just aerodynamically with a higher pressure ratio at the same design point. A one-dimensional design code is developed to obtain the meridional plane and blade to blade geometry of rotor to reach the three-dimensional view of rotor blades. To verify the redesigned rotor, its flow numerical simulation is carried out to compute its performance curve. The experimental performance curve of NASA rotor 67 is used for validation of the numerical results. Structured mesh with finer grids near walls is used to capture flow field and boundary layer effects. RANS equations are solved by finite volume method for rotating zones and stationary zones. The numerical results of the new rotor show about 9% increase in its pressure ratio at both design and off design mass flow rate. The new rotor has a higher outlet velocity through its upper span improving bypass ratio of a turbofan engine. To prove the new fan ability of producing more bypass ratio, a thermodynamic analysis is conducted. The results of this analysis show 13% increase in bypass ratio and 5.7% decline in specific fuel consumption in comparison to NASA rotor 67.

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