Design and optimization of three-dimensional supersonic asymmetric truncated nozzle

2017 ◽  
Vol 232 (15) ◽  
pp. 2923-2935 ◽  
Author(s):  
Meijun Zhu ◽  
Lei Fu ◽  
Shuai Zhang ◽  
Yao Zheng
Keyword(s):  
Lift Force ◽  
Pareto Front ◽  
Pressure Ratio ◽  
Supersonic Nozzle ◽  
Three Dimensional ◽  
Expansion Ratio ◽  
Minimum Length ◽  
Hypersonic Vehicles ◽  
Air Breathing ◽  
Design And Optimization

Three-dimensional supersonic nozzle is an important component of air-breathing hypersonic vehicles to produce thrust and lift force. Since the length of nozzle with ideal design is too long to meet the trim requirements of integrated air-breathing hypersonic vehicles, it is necessary to design a truncated nozzle to provide excellent aerodynamic performance. In the present study, an axisymmetric minimum length nozzle was firstly designed using method of characteristics. Then, streamlines trace technique with an offset circular entrance was adopted to extract the three-dimensional asymmetric nozzle. Nonlinear compression method was applied to compress the nozzle to a suitable length. Afterward, a surrogate-based optimization of three design variables, namely pressure ratio of nozzle’s exhaust to ambient, reserved initial expansion ratio, and average compression ratio was performed with the objectives of thrust and lift force, and a Pareto optimal front was therefore obtained. Numerical simulations were also made at six selected Pareto front cases to offer an insight into the flow fields. An infection point was observed in the Pareto front due to the maximum constrained length. The pressure ratio was found to be the most influential parameter, and the middle parts of Pareto front revealed better uniformity of exit flow.

scholarly journals Design and Optimization of Multiple Circumferential Casing Grooves Distribution Considering Sweep and Lean Variations on the Blade Tip

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2401
Author(s):  
Weimin Song ◽  
Yufei Zhang ◽  
Haixin Chen
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Distribution ◽  
Stall Margin ◽  
Design Point ◽  
Casing Treatment ◽  
Design And Optimization ◽  
Practical Engineering ◽  
Engineering Strategy ◽  
Blade Tip

This paper focuses on the design and optimization of the axial distribution of the circumferential groove casing treatment (CGCT). Effects of the axial location of multiple casing grooves on the flow structures are numerically studied. Sweep and lean variations are then introduced to the blade tip, and their influences on the grooves are discussed. The results show that the ability of the CGCT to relieve the blockage varies with the distribution of grooves, and the three-dimensional blading affects the performance of both the blade and the CGCT. Accordingly, a multi-objective optimization combining the CGCT design with the sweep and lean design is conducted. Objectives, including the total pressure ratio and the adiabatic efficiency, are set at the design point; meanwhile, the choking mass flow and the near-stall performance are constrained. The coupling between the CGCT and the blade is improved, which contributes to an optimal design point performance and a sufficient stall margin. The sweep and lean in the tip redistribute the spanwise and chordwise loading, which enhances the ability of the CGCT to improve the blade’s performance. This work shows that the present CGCT-blade integrated optimization is a practical engineering strategy to develop the working capacity and efficiency of a compressor blade while achieving the stall margin extension.

Meanline Modeling of a Radial-Inflow Turbine Nozzle With Supersonic Expansion

2016 ◽  
Author(s):  
Shuo Li ◽  
Eric M. Krivitzky ◽  
Xuwen Qiu
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Expansion Ratio ◽  
Accurate Estimation ◽  
Nozzle Outlet ◽  
Supersonic Expansion ◽  
High Pressure Ratio ◽  
Flow Deviation

High pressure ratio, radial-inflow turbines typically experience supersonic expansion in the nozzle section. Accurate estimation of the flow conditions and velocity triangle at the nozzle outlet is of critical importance in correctly predicting the overall turbine performance. The meanline modeling of such a nozzle requires special attention, due to the significantly altered flow field downstream of the throat. In this study, the flow field of a supersonic expansion nozzle is investigated, using a three-dimensional (3D) computational fluid dynamics (CFD) simulation calibrated with test data. Three different CFD configurations are explored: the nozzle alone, the nozzle plus rotor coupled with a mixing plane, and the nozzle plus rotor coupled with the nonlinear harmonic (NLH) method. These configurations are compared to each other to gauge the effect of the rotor and stator interaction and the potential for error in establishing the velocity triangles. The exit vane angle, number of vanes, and expansion ratio across the nozzle are systematically varied to provide the data as the base for nozzle modeling. Finally, a meanline method is proposed to calculate the pressure loss and flow deviation at the nozzle outlet and is compared with CFD results.

A Turbomachinery Blade Design and Optimization Procedure

2002 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Design Process ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Compressor Blade ◽  
Advanced Technology ◽  
Test Case ◽  
Blade Design ◽  
Design And Optimization

With the development of the advanced technology, the combustion temperature is raised for increased efficiencies. At the same time, the turbine and compressor pressure ratio and the mass flow rate rise; thus causing turbine and compressor blades turning and blade lengths increase. Moreover, the high efficiency requirements had made the turbine and compressor blade design difficult. A turbine airfoil has been custom designed for many years, but an optimization for the section design in a three-dimensional consideration is still a challenge. For a compressor blade design, standard section cannot meet the modern compressor requirements. Modern compressor design has not only needs a custom designed section according to flow situation, but also needs three-dimensional optimizations. Therefore, a good blade design process is critical to the turbines and compressors. A blade design of the turbomachines is one of the important steps for a good turbomachine design. A blade design process not only directly influences the overall machine efficiency but also dramatically impact the design time and cost. In this study, a blade design and optimization procedure was proposed for both turbine and compressor blade design. A compressor blade design was used as a test case. It was shown that the current design process had more advantages than conventional design methodology.

Design and optimization of bump (compression surface) for diverterless supersonic inlet

2021 ◽  
pp. 095441002110029
Author(s):  
Irsalan Arif ◽  
Hassan Iftikhar ◽  
Ali Javed
Keyword(s):  
Fitness Function ◽  
Supersonic Jet ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Least Square ◽  
Pressure Recovery ◽  
Design Parameters ◽  
Inlet System ◽  
Design And Optimization ◽  
Supersonic Inlet

In this article design and optimization scheme of a three-dimensional bump surface for a supersonic aircraft is presented. A baseline bump and inlet duct with forward cowl lip is initially modeled in accordance with an existing bump configuration on a supersonic jet aircraft. Various design parameters for bump surface of diverterless supersonic inlet systems are identified, and design space is established using sensitivity analysis to identify the uncertainty associated with each design parameter by the one-factor-at-a-time approach. Subsequently, the designed configurations are selected by performing a three-level design of experiments using the Box–Behnken method and the numerical simulations. Surrogate modeling is carried out by the least square regression method to identify the fitness function, and optimization is performed using genetic algorithm based on pressure recovery as the objective function. The resultant optimized bump configuration demonstrates significant improvement in pressure recovery and flow characteristics as compared to baseline configuration at both supersonic and subsonic flow conditions and at design and off-design conditions. The proposed design and optimization methodology can be applied for optimizing the bump surface design of any diverterless supersonic inlet system for maximizing the intake performance.

scholarly journals Evasion guidance for air-breathing hypersonic vehicles against unknown pursuer dynamics

2021 ◽  
Author(s):  
Tian Yan ◽  
Yuanli Cai ◽  
Bin Xu
Keyword(s):  
Parameter Estimation ◽  
Gradient Descent ◽  
Rapid Development ◽  
Energy Optimization ◽  
Hypersonic Vehicles ◽  
Air Breathing ◽  
Related Research ◽  
Practical Guidance ◽  
Simulation Results ◽  
Guidance Algorithm

AbstractThe rapid development of hypersonic vehicles has motivated the related research dramatically while the evasion of the hypersonic vehicles becomes one of the challenging issues. Different from the work based on the premise that the pursuers’ information is fully known, in this paper the evasion guidance for air-breathing hypersonic vehicles (AHVs) against unknown pursuer dynamics is studied. The gradient descent is employed for parameter estimation of the unknown dynamics of the pursuer. The energy-optimized evasion guidance algorithm is further developed by taking the acceleration constraint and energy optimization into consideration. Under the proposed algorithm, the system can deal with the unknown pursuer dynamics effectively and provide more practical guidance for the evasion process. The simulation results show that the proposed method can enable the AHV to achieve successful evasion.

Automatic Three-Dimensional Optimisation of a Modern Tandem Compressor Vane

2014 ◽  
Author(s):  
R. C. Schlaps ◽  
S. Shahpar ◽  
V. Gümmer
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Trust Region ◽  
Automatic Generation ◽  
Navier Stokes ◽  
Design Parameters ◽  
High Fidelity ◽  
Stall Margin ◽  
Design Choice ◽  
Multipoint Approximation

In order to increase the performance of a modern gas turbine, compressors are required to provide higher pressure ratio and avoid incurring higher losses. The tandem aerofoil has the potential to achieve a higher blade loading in combination with lower losses compared to single vanes. The main reason for this is due to the fact that a new boundary layer is generated on the second blade surface and the turning can be achieved with smaller separation occurring. The lift split between the two vanes with respect to the overall turning is an important design choice. In this paper an automated three-dimensional optimisation of a highly loaded compressor stator is presented. For optimisation a novel methodology based on the Multipoint Approximation Method (MAM) is used. MAM makes use of an automatic design of experiments, response surface modelling and a trust region to represent the design space. The CFD solutions are obtained with the high-fidelity 3D Navier-Stokes solver HYDRA. In order to increase the stage performance the 3D shape of the tandem vane is modified changing both the front and rear aerofoils. Moreover the relative location of the two aerofoils is controlled modifying the axial and tangential relative positions. It is shown that the novel optimisation methodology is able to cope with a large number of design parameters and produce designs which performs better than its single vane counterpart in terms of efficiency and numerical stall margin. One of the key challenges in producing an automatic optimisation process has been the automatic generation of high-fidelity computational meshes. The multi block-structured, high-fidelity meshing tool PADRAM is enhanced to cope with the tandem blade topologies. The wakes of each aerofoil is properly resolved and the interaction and the mixing of the front aerofoil wake and the second tandem vane are adequately resolved.

Mechanism of the Transition From In-Plane Buckling to Helical Buckling for a Stiff Nanowire on an Elastomeric Substrate

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Youlong Chen ◽  
Yong Zhu ◽  
Xi Chen ◽  
Yilun Liu
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Stretchable Electronics ◽  
Buckling Mode ◽  
Design And Optimization ◽  
Out Of Plane ◽  
Plane Direction ◽  
Plane Displacement ◽  
Helical Buckling ◽  
Selection Of

In this work, the compressive buckling of a nanowire partially bonded to an elastomeric substrate is studied via finite-element method (FEM) simulations and experiments. The buckling profile of the nanowire can be divided into three regimes, i.e., the in-plane buckling, the disordered buckling in the out-of-plane direction, and the helical buckling, depending on the constraint density between the nanowire and the substrate. The selection of the buckling mode depends on the ratio d/h, where d is the distance between adjacent constraint points and h is the helical buckling spacing of a perfectly bonded nanowire. For d/h > 0.5, buckling is in-plane with wavelength λ = 2d. For 0.27 < d/h < 0.5, buckling is disordered with irregular out-of-plane displacement. While, for d/h < 0.27, buckling is helical and the buckling spacing gradually approaches to the theoretical value of a perfectly bonded nanowire. Generally, the in-plane buckling induces smaller strain in the nanowire, but consumes the largest space. Whereas the helical mode induces moderate strain in the nanowire, but takes the smallest space. The study may shed useful insights on the design and optimization of high-performance stretchable electronics and three-dimensional complex nanostructures.

Effect of Vaned Diffuser on a Modified Turbocharger Centrifugal Compressor Performance

2014 ◽  
Vol 663 ◽  
pp. 347-353
Author(s):  
Layth H. Jawad ◽  
Shahrir Abdullah ◽  
Zulkifli R. ◽  
Wan Mohd Faizal Wan Mahmood
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Width Ratio ◽  
Outlet Section ◽  
Suction Surface ◽  
Vaned Diffuser ◽  
Minimum Width

A numerical study that was made in a three-dimensional flow, carried out in a modified centrifugal compressor, having vaned diffuser stage, used as an automotive turbo charger. In order to study the influence of vaned diffuser meridional outlet section with a different width ratio of the modified centrifugal compressor. Moreover, the performance of the centrifugal compressor was dependent on the proper matching between the compressor impeller along the vaned diffuser. The aerodynamic characteristics were compared under different meridional width ratio. In addition, the velocity vectors in diffuser flow passages, and the secondary flow in cross-section near the outlet of diffuser were analysed in detail under different meridional width ratio. Another aim of this research was to study and simulate the effect of vaned diffuser on the performance of a centrifugal compressor. The simulation was undertaken using commercial software so-called ANSYS CFX, to predict numerically the performance charachteristics. The results were generated from CFD and were analysed for better understanding of the fluid flow through centrifugal compressor stage and as a result of the minimum width ratio the flow in diffuser passage tends to be uniformity. Moreover, the backflow and vortex near the pressure surface disappear, and the vortex and detachment near the suction surface decrease. Conclusively, it was observed that the efficiency was increased and both the total pressure ratio and static pressure for minimum width ratio are increased.

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