Turbomachinery Active Subspace Performance Maps

2017 ◽  
Author(s):  
Pranay Seshadri ◽  
Shahrokh Shahpar ◽  
Paul Constantine ◽  
Geoffrey Parks ◽  
Mike Adams
Keyword(s):  
Performance Metrics ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Flow Capacity ◽  
Trade Offs ◽  
Design Variables ◽  
Contour Plots ◽  
Active Subspaces ◽  
The Impact ◽  
Active Subspace

Turbomachinery active subspace performance maps are 2D contour plots that illustrate the variation of key flow performance metrics with different blade designs. While such maps are easy to construct for design parameterizations with two variables, in this paper maps will be generated for a fan blade with twenty-five design variables. Turbomachinery active subspace performance maps combine active subspaces — a new set of ideas for dimension reduction — with fundamental turbomachinery aerodynamics and design spaces. In this paper, contours of (i) cruise efficiency, (ii) cruise pressure ratio, (iii) maximum climb flow capacity and (iv) sensitivity to manufacturing variations, are plotted as objectives for the fan. These maps are then used to infer pedigree design rules: how best to increase fan efficiency; how best to desensitize blade aerodynamics to the impact of manufacturing variations? In the present study, the former required both a reduction in pressure ratio and flow capacity — leading to a reduction of the strength of the leading edge bow wave — while the latter required strictly a reduction in flow capacity. While such pedigree rules can be obtained from first principles, in this paper these rules are derived from the active subspaces. This facilitates a more detailed quantification of the aerodynamic trade-offs. Thus, instead of simply stating that a particular design is more sensitive to manufacturing variations; or that it lies on a hypothetical ‘efficiency cliff’, this paper seeks to visualize, quantify and make precise such notions of turbomachinery design.

Turbomachinery Active Subspace Performance Maps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Pranay Seshadri ◽  
Shahrokh Shahpar ◽  
Paul Constantine ◽  
Geoffrey Parks ◽  
Mike Adams
Keyword(s):  
Performance Metrics ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Flow Capacity ◽  
Trade Offs ◽  
Design Variables ◽  
Contour Plots ◽  
Active Subspaces ◽  
The Impact ◽  
Active Subspace

Turbomachinery active subspace performance maps are two-dimensional (2D) contour plots that illustrate the variation of key flow performance metrics with different blade designs. While such maps are easy to construct for design parameterizations with two variables, in this paper, maps will be generated for a fan blade with twenty-five design variables. Turbomachinery active subspace performance maps combine active subspaces—a new set of ideas for dimension reduction—with fundamental turbomachinery aerodynamics and design spaces. In this paper, contours of (i) cruise efficiency, (ii) cruise pressure ratio (PR), (iii) maximum climb flow capacity, and (iv) sensitivity to manufacturing variations are plotted as objectives for the fan. These maps are then used to infer pedigree design rules: how best to increase fan efficiency; how best to desensitize blade aerodynamics to the impact of manufacturing variations? In the present study, the former required both a reduction in PR and flow capacity—leading to a reduction of the strength of the leading edge bow wave—while the latter required strictly a reduction in flow capacity. While such pedigree rules can be obtained from first principles, in this paper, these rules are derived from the active subspaces. This facilitates a more detailed quantification of the aerodynamic trade-offs. Thus, instead of simply stating that a particular design is more sensitive to manufacturing variations; or that it lies on a hypothetical “efficiency cliff,” this paper seeks to visualize, quantify, and make precise such notions of turbomachinery design.

Effects of Flow Injection From Outer Casing Upon Turbine Nozzle Vane Flow Field

2002 ◽  
Author(s):  
K. Funazaki ◽  
C. F. F. Favaretto ◽  
T. Tanuma
Keyword(s):  
Flow Field ◽  
Flow Injection ◽  
Three Dimensional ◽  
Leading Edge ◽  
Main Stream ◽  
Flow Angle ◽  
Aerodynamic Loss ◽  
Nozzle Vane ◽  
Design Variables ◽  
The Impact

In the present paper steady three-dimensional numerical calculations were performed in order to investigate the effects of flow injection from the outer casing upon turbine nozzle vane flow field. Several test cases were analyzed by applying different nozzle vane configurations such as the blade lean, injection slot width and distance from the leading edge. Numerical simulations were conducted considering the no injection case, 5% and 10% main stream flow injection from the outer casing. The impact of the flow injection design variables and the blade lean angle on the aerodynamic loss in terms of the energy loss coefficient and the outlet flow angle were analyzed through a parametric study.

An Impact of Various Shroud Bleed Slot Configurations and Cavity Vanes on Compressor Map Width and the Inducer Flow Field

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early ◽  
Bahram Nikpour
Keyword(s):  
Flow Field ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Operating Conditions ◽  
Choked Flow ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
Compressor Map ◽  
The Impact

This paper describes an investigation of map width enhancement and a detailed analysis of the inducer flow field due to various bleed slot configurations and vanes in the annular cavity of a turbocharger centrifugal compressor. The compressor under investigation is used in a turbocharger application for a heavy duty diesel engine of approximately 400 hp. This investigation has been undertaken using a computational fluid dynamics (CFD) model of the full compressor stage, which includes a manual multiblock-structured grid generation method. The influence of the bleed slot flow on the inducer flow field at a range of operating conditions has been analyzed, highlighting the improvement in surge and choked flow capability. The impact of the bleed slot geometry variations and the inclusion of cavity vanes on the inlet incidence angle have been studied in detail by considering the swirl component introduced at the leading edge by the recirculating flow through the slot. Further, the overall stage efficiency and the nonuniform flow field at the inducer inlet have been also analyzed. The analysis revealed that increasing the slot width has increased the map width by about 17%. However, it has a small impact on the efficiency, due to the frictional and mixing losses. Moreover, adding vanes in the cavity improved the pressure ratio and compressor performance noticeably. A detail analysis of the compressor with cavity vanes has also been presented.

A Comparison of Two Fan Stage Designs With Different Rotor Leading Edge Sweep

2014 ◽  
Author(s):  
John Gunaraj ◽  
David Hanson ◽  
Jeffrey Hayes ◽  
Heath Lorzel ◽  
Nick Nolcheff ◽  
...  
Keyword(s):  
Pressure Ratio ◽  
Stability Margin ◽  
Leading Edge ◽  
Flow Capacity ◽  
Numerical Predictions ◽  
Performance Trends ◽  
Ansys Cfx ◽  
Significant Difference ◽  
Total Temperature ◽  
The Individual

Two modern single-stage fans have been designed to meet the same set of performance objectives. The most significant difference between the two designs is the fan rotor leading edge sweep. The baseline rotor has a moderately aft swept leading edge while the redesigned rotor has a more complex sweep distribution, including moderate forward sweep in the tip region. Each stage consists of the fan rotor, full span stator, and split mid-frame, and is designed for a medium bypass ratio turbofan application. The stator and the mid-frame are identical for the two configurations. The primary purpose of this study is to validate the CFD methodology, in this case a steady ANSYS-CFX approach, to predict the fan stage performance at the operating point at two tested speeds and also to predict the stalling throttle condition. Numerical predictions and engine test results are presented and show good agreement. These predicted results are compared with high quality test data including thorough measurements of total pressure and total temperature at both the rotor and stator exits allowing for a detailed understanding and comparison of the individual blade row performance. The analytical model identifies the key performance trends, including an increase in flow capacity and stability margin with equivalent stage pressure ratio and efficiency for the redesigned fan relative to the baseline.

Comprehensive Application of a First Principles Based Methodology for Design of Axial Compressor Configurations

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Vishwas Iyengar ◽  
Lakshmi N. Sankar
Keyword(s):  
First Principles ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Design Parameters ◽  
Axial Compressors ◽  
Design Variables ◽  
Improved Accuracy ◽  
Total Pressure Ratio

Axial compressors are widely used in many aerodynamic applications. The design of an axial compressor configuration presents many challenges. It is necessary to retool the design methodologies to take advantage of the improved accuracy and physical fidelity of these advanced methods. Here, a first-principles based multiobjective technique for designing single stage compressors is described. The study accounts for stage aerodynamic characteristics and rotor-stator interactions. The proposed methodology provides a way to systematically screen through the plethora of design variables. This method has been applied to a rotor-stator stage similar to NASA Stage 35. By selecting the most influential design parameters and by optimizing the blade leading edge and trailing edge mean camber line angles, phenomena such as tip blockages, blade-to-blade shock structures and other loss mechanisms can be weakened or alleviated. It is found that these changes to the configuration can have a beneficial effect on total pressure ratio and stage adiabatic efficiency, thereby improving the performance of the axial compression system.

An Impact of Various Shroud Bleed Slot Configurations and Cavity Vanes on Compressor Map Width and the Inducer Flow Field

2011 ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early ◽  
Bahram Nikpour
Keyword(s):  
Flow Field ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Operating Conditions ◽  
Choked Flow ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
Compressor Map ◽  
The Impact

This paper describes an investigation of map width enhancement and a detailed analysis of the inducer flow field due to various bleed slot configurations and vanes in the annular cavity of a turbocharger centrifugal compressor. The compressor under investigation is used in a turbocharger application for a heavy duty diesel engine of approximately 400hp. This investigation has been undertaken using a CFD model of the full compressor stage which includes a manual multi-block structured grid generation method. The influence of the bleed slot flow on the inducer flow field at a range of operating conditions has been analysed, highlighting the improvement in surge and choked flow capability. The impact of the bleed slot geometry variations and the inclusion of cavity vanes on the inlet incidence angle have been studied in detail by considering the swirl component introduced at the leading edge by the recirculating flow through the slot. Further, the overall stage efficiency and the non-uniform flow field at the inducer inlet have been also analysed. The analysis revealed that increasing the slot width has increased the map width by about 17%. However, it has a small impact on the efficiency due to the frictional and mixing losses. Moreover, adding vanes in the cavity improved the pressure ratio and compressor performance noticeably. A detail analysis of the compressor with cavity vanes has also been presented.

Optimum Design of Control System Compensators

1978 ◽  
Vol 100 (2) ◽  
pp. 140-151
Author(s):  
K. A. Afimiwala ◽  
R. W. Mayne
Keyword(s):  
Control System ◽  
System Performance ◽  
Design Criterion ◽  
Speed Of Response ◽  
Trade Offs ◽  
Design Variables ◽  
Sensitivity Curves ◽  
Contour Plots ◽  
System Requirements ◽  
Reference Input

Compensators are designed for a plant to optimize its transient response during load disturbances and changes in reference input, and subject to constraints on plant input, peak displacements during the transients, and speed of response. Optimum controller parameters are determined here by making a sequence of 2D minimizations, approximating the design criterion and constraints with polynomials, and using contour plots for estimating the 2D minimums. Contour plots generated help identify the feasible design region and show the influence of the design variables and constraints on the system performance. Finally, sensitivity curves are generated at the optimum to aid the designer in making trade-offs between competing objectives and to select a new design when system requirements are modified.

Constrained multi-objective aerofoil design using a multi-level optimisation strategy

2015 ◽  
Vol 119 (1217) ◽  
pp. 833-854
Author(s):  
L. Cameron ◽  
J. Early ◽  
R. McRoberts ◽  
M. Price
Keyword(s):  
Leading Edge ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Multi Objective ◽  
Trade Offs ◽  
Novel Approach ◽  
Design Variables ◽  
Business Jet ◽  
Global And Local ◽  
Local Optimisation

AbstractA novel approach for the multi-objective design optimisation of aerofoil profiles is presented. The proposed method aims to exploit the relative strengths of global and local optimisation algorithms, whilst using surrogate models to limit the number of computationally expensive CFD simulations required. The local search stage utilises a re-parameterisation scheme that increases the flexibility of the geometry description by iteratively increasing the number of design variables, enabling superior designs to be generated with minimal user intervention. Capability of the algorithm is demonstrated via the conceptual design of aerofoil sections for use on a lightweight laminar flow business jet. The design case is formulated to account for take-off performance while reducing sensitivity to leading edge contamination. The algorithm successfully manipulates boundary layer transition location to provide a potential set of aerofoils that represent the trade-offs between drag at cruise and climb conditions in the presence of a challenging constraint set. Variations in the underlying flow physics between Pareto-optimal aerofoils are examined to aid understanding of the mechanisms that drive the trade-offs in objective functions.

Impact of Main and Splitter Blade Leading Edge Contour on the Performance of High Pressure Ratio Centrifugal Compressors

2014 ◽  
Author(s):  
Rodrigo R. Erdmenger ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Operating Range ◽  
High Pressure Ratio ◽  
The Impact ◽  
Blade Leading Edge

The impact of leading edge sweep in an attempt to reduce shock losses and extend the stall margin on axial compressors has been extensively studied, however only a few studies have looked at understanding the impact of leading edge contouring on the performance of centrifugal compressors. The present work studies the impact of forward and aft sweep on the main and splitter blade leading edge of a generic high flow coefficient and high pressure ratio centrifugal compressor design and the impact on its overall peak efficiency, pressure ratio and operating range. The usage of aft sweep on the main blade led to an increase of the pressure ratio and efficiency, however it also led to a reduction of the stable operating range of the impeller analyzed. The forward sweep cases analyzed where the tip leading edge was displaced axially forward showed a slight increase in pressure ratio, and a significant increase on operating range. The impact of leading edge sweep on the sensitivity of the impeller performance to tip clearance was also studied. The impeller efficiency was found to be less sensitive to an increase of tip clearance for both aft and forward sweep cases studied. The forward sweep cases studied also showed a reduced sensitivity from operating range to tip clearance. The studies conducted on the splitter leading edge profile indicate that aft sweep may help to increase the operating range of the impeller analyzed by up to 16% while maintaining similar pressure ratio and efficiency characteristics of the impeller. The improvement of operating range obtained with the leading edge forward sweep and splitter aft sweep was caused by a reduction of the interaction of the tip vortex of the main blade with the splitter tip, and a reduction of the blockage caused by this interaction.

scholarly journals On the Optimization of a Centrifugal Maglev Blood Pump Through Design Variations

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Wu ◽  
Jiadong Huo ◽  
Weifeng Dai ◽  
Wei-Tao Wu ◽  
Chengke Yin ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Performance Metrics ◽  
Flow Path ◽  
Secondary Flows ◽  
Blood Pump ◽  
Flow Paths ◽  
Blade Thickness ◽  
Design Variables ◽  
Blood Pumps ◽  
The Impact

Centrifugal blood pumps are usually designed with secondary flow paths to avoid flow dead zones and reduce the risk of thrombosis. Due to the secondary flow path, the intensity of secondary flows and turbulence in centrifugal blood pumps is generally very high. Conventional design theory is no longer applicable to centrifugal blood pumps with a secondary flow path. Empirical relationships between design variables and performance metrics generally do not exist for this type of blood pump. To date, little scientific study has been published concerning optimization and experimental validation of centrifugal blood pumps with secondary flow paths. Moreover, current hemolysis models are inadequate in an accurate prediction of hemolysis in turbulence. The purpose of this study is to optimize the hydraulic and hemolytic performance of an inhouse centrifugal maglev blood pump with a secondary flow path through variation of major design variables, with a focus on bringing down intensity of turbulence and secondary flows. Starting from a baseline design, through changing design variables such as blade angles, blade thickness, and position of splitter blades. Turbulent intensities have been greatly reduced, the hydraulic and hemolytic performance of the pump model was considerably improved. Computational fluid dynamics (CFD) combined with hemolysis models were mainly used for the evaluation of pump performance. A hydraulic test was conducted to validate the CFD regarding the hydraulic performance. Collectively, these results shed light on the impact of major design variables on the performance of modern centrifugal blood pumps with a secondary flow path.

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