Aerodynamic Optimization of Turbine Based Combined Cycle Nozzle

2018 ◽  
Vol 35 (4) ◽  
pp. 385-394
Author(s):  
Shangze Li ◽  
Yufei Zhang ◽  
Haixin Chen ◽  
Kaiwen Deng
Keyword(s):  
Differential Evolution Algorithm ◽  
Aerodynamic Performance ◽  
Combined Cycle ◽  
Two Dimensional ◽  
Objective Functions ◽  
Dimensional Model ◽  
Aerodynamic Optimization ◽  
Evolution Algorithm ◽  
Mach Numbers ◽  
Turbine Flow Path

Abstract This paper aims at optimizing a Turbine Based Combined Cycle (TBCC) nozzle for upgrading its aerodynamic performance in multiple flight conditions. An in-house RANS solver called NSAWET is employed for aerodynamic evaluation. The optimizer is a differential evolution algorithm combined with a response surface. Firstly, a two-dimensional model of the initial TBCC nozzle system is investigated. The flow field of the nozzle contains complicated shockwave interactions that cause thrust loss. Then multi-point aerodynamic optimization of a two-dimensional ramjet nozzle is carried out, which objectives are to maximize the thrust coefficients at Mach numbers 2.5, 3.0 and 4.0. The objective functions are increased substantially at the first two Mach numbers after optimization, while slightly decreased at the last Mach number. The turbine flow path is built up based on the optimized profile and the performances in typical flight conditions are validated. Results demonstrate that both the ramjet and turbine nozzles are improved in most flight conditions.

Transient Source Two-Dimensional Source Item Inverse Problem Research and Accuracy Impact Analysis Based on the Differential Evolution Algorithm in the Wide/Shallow Watercourse

2013 ◽  
Vol 380-384 ◽  
pp. 1156-1160
Author(s):  
Rui Huang ◽  
Long Xi Han
Keyword(s):  
Inverse Problem ◽  
Differential Evolution ◽  
Distribution System ◽  
Impact Analysis ◽  
Differential Evolution Algorithm ◽  
Two Dimensional ◽  
Sources Identification ◽  
Transient Source ◽  
Result Show ◽  
Evolution Algorithm

Through the differential evolution algorithm, the transient source two-dimensional source item inverse problem in the wide/shallow watercourse is converted into the optimal control problem of the distribution system. Concrete steps that utilize differential evolution algorithm are given to carry out example analysis. The result show that the method could be used for the study of pollution sources identification .

Design and validation of a two-dimensional variable geometry inlet

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Huacheng Yuan ◽  
Yunfei Wang ◽  
Jun Liu ◽  
Zhengxu Hua
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Back Pressure ◽  
Variable Geometry ◽  
Two Dimensional ◽  
Validation Experiment ◽  
Mach Numbers ◽  
Dimensional Variable

Abstract The design of a two-dimensional variable geometry inlet which applied to a tandem type turbine-based combined cycle (TBCC) propulsion system was investigated in the present paper through three-dimensional simulations and wind tunnel tests. The operation Mach number range was between 0 and 3. A multi-ramp geometry scheme was adopted to achieve acceptable performance at different inflow Mach number. The first ramp angle was fixed whilst the angles of the second and the third ramps were variable at different inflow Mach numbers. The Mach numbers at throat region were maintained between 1.3 and 1.5 at different inflow Mach numbers according to this variable geometry scheme. A fixed geometry rectangular-to-circular shape diffuser was adopted to improve aerodynamic performance of the inlet. Three-dimensional numerical simulations were carried out between Ma1.5 and Ma3.0. The results indicated that good aerodynamic performance can be achieved at different inflow speed. At the design point, total pressure recovery of the inlet was 0.66 at critical condition. Wind tunnel validation experiment tests were conducted at Ma2.0, showing the movement of terminal shock wave from downstream to upstream as the back pressure increased. The inlet operated at supercritical, critical and subsonic conditions at different back pressure.

Solving Problems in Chaos Control though an Differential Evolution Algorithm with Region Zooming

2011 ◽  
Vol 110-116 ◽  
pp. 5048-5056 ◽  
Author(s):  
Fei Gao ◽  
Yi Bo Qi ◽  
Qiang Yin ◽  
Jia Qing Xiao
Keyword(s):  
Differential Evolution ◽  
Chaos Control ◽  
Uniform Design ◽  
Differential Evolution Algorithm ◽  
Initial Population ◽  
The Novel ◽  
Objective Functions ◽  
Unstable Periodic Orbits ◽  
Evolution Algorithm ◽  
Best Parameters

In this paper, a novel scheme is propose to solve the problems in chaos control via a nonnegative multi–modal nonlinear optimization, which finds the unstable periodic orbits and best parameters of chaos system such that the objective function is minimized. The novel scheme embeds with a differential evolution algorithm consisting of techniques in three aspects: uniform design to the initial population, deflection and stretching to the objective functions, and the region zooming self–adaptively, which result in a much more effective searching mechanism with fine equilibrium between exploitation and exploration. To exhibit the new scheme’s performance, the experiments done to Hénon, Chen and Lü system are given, and the simulations done show that the method has better adaptability, dependability and robustness.

scholarly journals Clustering Analysis of the Population in Db_SHADE Algorithm

MENDEL ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 9-16
Author(s):  
Adam Viktorin ◽  
Roman Senkerik ◽  
Michal Pluhacek ◽  
Tomas Kadavy
Keyword(s):  
Clustering Analysis ◽  
Differential Evolution Algorithm ◽  
Future Research ◽  
Two Dimensional ◽  
Exploration And Exploitation ◽  
Research Directions ◽  
Adaptive Differential Evolution ◽  
Future Research Directions ◽  
Evolution Algorithm ◽  
Exploration Phase

This paper provides an analysis of the population clustering in a novel Success-History based Adaptive Differential Evolution algorithm with Distance based adaptation (Db_SHADE) in order to analyze the exploration and exploitation abilities of the algorithm. The comparison with the original SHADE algorithm is performed on the CEC2015 benchmark set in two dimensional settings (10D and 30D). The clustering analysis helps to answer the question about prolonged exploration phase of the Db_SHADE algorithm. Possible future research directions are drawn in the discussion and conclusion.

Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

2002 ◽  
Vol 61 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Eric Tafani ◽  
Lionel Souchet
Keyword(s):  
Higher Education ◽  
Social Representations ◽  
Cognitive Restructuring ◽  
Social Representation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Social Actions ◽  
The Social ◽  
Two Dimensional Model ◽  
Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

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