Novel Compressor Blade Shaping Through a Free-Form Method

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Alistair John ◽  
Shahrokh Shahpar ◽  
Ning Qin
Keyword(s):  
Axial Compressor ◽  
Optimization Method ◽  
Aerodynamic Performance ◽  
Compressor Blade ◽  
Free Form ◽  
The Novel ◽  
Surface Sensitivity ◽  
Free Form Deformation ◽  
Blade Shape ◽  
Novel Design

This paper describes the use of the free-form-deformation (FFD) parameterization method to create a novel blade shape for a highly loaded, transonic axial compressor. The novel geometry makes use of precompression (via an S-shaping of the blade around midspan) to weaken the shock and improve the aerodynamic performance. It is shown how free-form-deformation offers superior flexibility over traditionally used parameterization methods. The novel design (produced via an efficient optimization method) is presented and the resulting flow is analyzed in detail. The efficiency benefit is over 2%, surpassing other results in the literature for the same geometry. The precompression effect of the S-shape is analyzed and explained, and the entropy increase across the shock (along the midblade line) is shown to be reduced by almost 80%. Adjoint surface sensitivity analysis of the datum and optimized designs is presented, showing that the S-shape is located in the region predicted to be most significant for changes in efficiency. Finally, the off-design performance of the blade is analyzed across the rotor characteristics at various speeds.

Alleviation of Shock-Wave Effects on a Highly Loaded Axial Compressor Through Novel Blade Shaping

2016 ◽  
Author(s):  
Alistair John ◽  
Shahrokh Shahpar ◽  
Ning Qin
Keyword(s):  
Axial Compressor ◽  
Free Form ◽  
Stable Operation ◽  
The Novel ◽  
Negative Effects ◽  
3D Design ◽  
Free Form Deformation ◽  
Wave Effects ◽  
Simulation Optimisation ◽  
Highly Loaded

This paper describes the use of the Free-Form-Deformation [1] parameterisation method to create a novel blade shape for a highly loaded, transonic axial compressor. The novel geometry makes use of pre-compression (via an S-shaping of the blade around mid-span) to weaken the shock and improve the aerodynamic performance. It has been known for some time that reducing the pre-shock Mach number of transonic compressors (via pre-compression) can improve their efficiency [2]. However, early attempts at this in the 60s [3] showed undesirable results (such as bi-stable operation), leading the design community to shy away from using pre-compression [4]. This issue is re-addressed here. It is shown that using modern simulation, optimisation and a 3D design, large amounts of pre-compression may be employed without the negative effects that plagued early attempts. This paper shows how Free-Form-Deformation offers superior flexibility over traditionally used parameterisation methods. The novel design (produced via an efficient optimisation method) is presented and the resulting flow analysed in detail. The efficiency benefit is over 2%, surpassing other results in the literature for the same geometry. The pre-compression effect of the S-shape is analysed and explained, and the entropy increase across the shock (along the mid-blade line) is shown to be reduced by almost 80%. Adjoint surface sensitivity analysis of the datum and optimised designs is presented, showing that the S-shape is located in the region predicted to be most significant for changes in efficiency. Finally the off-design performance of the blade is analysed across the rotor characteristics at various speeds.

Sweep in a Transonic Fan Rotor: Part 1 — 3D Geometry Package

1998 ◽  
Author(s):  
Hazem F. Abdelhamid ◽  
Raymond P. Shreeve
Keyword(s):  
Axial Compressor ◽  
Compressor Blade ◽  
Design Parameters ◽  
Control Points ◽  
Manufacturing Optimization ◽  
3D Geometry ◽  
Blade Shape ◽  
Two Parameters ◽  
Transonic Fan ◽  
Blade Element

A geometry package was developed which uses six Bezier surfaces to describe an axial compressor blade. The blade is defined by 32 control points and two parameters, which determine the leading and trailing edge extensions. The package was used to represent a reference transonic fan rotor to within machining tolerances, and then to introduce forward and backward sweep holding blade-element design parameters fixed. Blade lean and point geometry manipulations were also demonstrated. All geometries produced by the package are machinable without approximation. The Bezier-surface representation was chosen in order to minimize the number of control points required to specify the blade shape and eventually enable aero-structural-manufacturing optimization.

Multiple Surrogate Modeling for Axial Compressor Blade Shape Optimization

2008 ◽  
Vol 24 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Abdus Samad ◽  
Kwang-Yong Kim ◽  
Tushar Goel ◽  
Raphael T. Haftka ◽  
Wei Shyy
Keyword(s):  
Shape Optimization ◽  
Axial Compressor ◽  
Surrogate Modeling ◽  
Compressor Blade ◽  
Blade Shape

Aerodynamic design optimization of a hypersonic rocket sled deflector using the free-form deformation technique

2021 ◽  
pp. 095441002199498
Author(s):  
Tianjiao Dang ◽  
Bingfei Li ◽  
Dike Hu ◽  
Yachuan Sun ◽  
Zhen Liu
Keyword(s):  
Design Optimization ◽  
Optimization Method ◽  
Free Form ◽  
Aerodynamic Design ◽  
Aerodynamic Shape ◽  
Aerodynamic Design Optimization ◽  
Continuous Adjoint Method ◽  
Free Form Deformation ◽  
Shape Parameterization ◽  
Continuous Adjoint

An aerodynamic design optimization of a hypersonic rocket sled deflector is presented using the free-form deformation (FFD) technique. The objective is to optimize the aerodynamic shape of the hypersonic rocket sled deflector to increase its negative lift and enhance the motion stability of the rocket sled. The FFD technique is selected as the aerodynamic shape parameterization method, and the continuous adjoint method based on the gradient method is used to search the optimization in the geometric shape parameter space; the computational fluid dynamics method for a hypersonic rocket sled is employed. An automatic design optimization method for the deflector is carried out based on the aerodynamic requirements of the rocket sled. The optimization results show that the optimized deflector meets the design requirement of increasing the negative lift under the constraint of drag. By improving the pressure distribution on the surface of the deflector, the negative lift is increased by 7.39%, which confirms the effectiveness of the proposed method.

A Study on Multidisciplinary Optimization of an Axial Compressor Blade Based on Evolutionary Algorithms

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Chang Luo ◽  
Liming Song ◽  
Jun Li ◽  
Zhenping Feng
Keyword(s):  
Evolutionary Algorithms ◽  
Optimization Design ◽  
Maximum Stress ◽  
Mechanical Performance ◽  
Axial Compressor ◽  
Optimization Method ◽  
Compressor Blade ◽  
Multidisciplinary Optimization ◽  
Frequency Constraint ◽  
Isentropic Efficiency

An aerodynamic single disciplinary optimization and an aerodynamic/structural multidisciplinary optimization of an axial compressor blade are performed using evolutionary algorithms in this paper. The blade is optimized for maximizing its isentropic efficiency in the aerodynamic single disciplinary optimization. The isentropic efficiency of the optimum blade obtained from the aerodynamic single disciplinary optimization is 1.65% higher than that of the reference blade, however, the mechanical performance analysis indicates that it has a higher stress distribution and does not satisfy the vibration frequency constraint. In the multidisciplinary optimization, the maximum of the isentropic efficiency and the minimization of the maximum stress are selected as the design objectives. The analysis results indicate that the method of dealing with minimization of the maximum stress as a design objective is proper and that the presented multiobjective and multidisciplinary optimization method is more suitable for the optimization design of a real turbomachinery blade than the traditional heuristic aerodynamic-structural iteration.

scholarly journals Temporal Deformable Convolutional Encoder-Decoder Networks for Video Captioning

2019 ◽  
Vol 33 ◽  
pp. 8167-8174 ◽  
Author(s):  
Jingwen Chen ◽  
Yingwei Pan ◽  
Yehao Li ◽  
Ting Yao ◽  
Hongyang Chao ◽  
...  
Keyword(s):  
Fixed Number ◽  
Free Form ◽  
Sentence Generation ◽  
Video Captioning ◽  
Temporal Sampling ◽  
Free Form Deformation ◽  
Convolutional Encoder ◽  
Block Structures ◽  
Novel Design

It is well believed that video captioning is a fundamental but challenging task in both computer vision and artificial intelligence fields. The prevalent approach is to map an input video to a variable-length output sentence in a sequence to sequence manner via Recurrent Neural Network (RNN). Nevertheless, the training of RNN still suffers to some degree from vanishing/exploding gradient problem, making the optimization difficult. Moreover, the inherently recurrent dependency in RNN prevents parallelization within a sequence during training and therefore limits the computations. In this paper, we present a novel design — Temporal Deformable Convolutional Encoder-Decoder Networks (dubbed as TDConvED) that fully employ convolutions in both encoder and decoder networks for video captioning. Technically, we exploit convolutional block structures that compute intermediate states of a fixed number of inputs and stack several blocks to capture long-term relationships. The structure in encoder is further equipped with temporal deformable convolution to enable free-form deformation of temporal sampling. Our model also capitalizes on temporal attention mechanism for sentence generation. Extensive experiments are conducted on both MSVD and MSR-VTT video captioning datasets, and superior results are reported when comparing to conventional RNN-based encoder-decoder techniques. More remarkably, TDConvED increases CIDEr-D performance from 58.8% to 67.2% on MSVD.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

Airfoil Optimization Using Area-Preserving Free-Form Deformation

2015 ◽  
Author(s):  
Stavros N. Leloudas ◽  
Giorgos A. Strofylas ◽  
Ioannis K. Nikolos
Keyword(s):  
Cross Sectional Area ◽  
Equality Constraint ◽  
Optimization Process ◽  
Free Form ◽  
Sectional Area ◽  
Cross Sectional ◽  
Airfoil Optimization ◽  
Free Form Deformation ◽  
Correction Problem ◽  
Area Preserving

Given the importance of structural integrity of aerodynamic shapes, the necessity of including a cross-sectional area equality constraint among other geometrical and aerodynamic ones arises during the optimization process of an airfoil. In this work an airfoil optimization scheme is presented, based on Area-Preserving Free-Form Deformation (AP FFD), which serves as an alternative technique for the fulfillment of a cross-sectional area equality constraint. The AP FFD is based on the idea of solving an area correction problem, where a minimum possible offset is applied on all free-to-move control points of the FFD lattice, subject to the area preservation constraint. Due to the linearity of the area constraint in each axis, the extraction of an inexpensive closed-form solution to the area preservation problem is possible by using Lagrange Multipliers. A parallel Differential Evolution (DE) algorithm serves as the optimizer, assisted by two Artificial Neural Networks as surrogates. The use of multiple surrogate models, in conjunction with the inexpensive solution to the area correction problem, render the optimization process time efficient. The application of the proposed methodology for wind turbine airfoil optimization demonstrates its applicability and effectiveness.

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