Acceleration Method for Evolutionary Optimization of Variable Cycle Engine

2020 ◽  
Author(s):  
Wang Hao ◽  
Li Zhou ◽  
Xiaobo Zhang ◽  
Zhanxue Wang
Keyword(s):  
Evolutionary Optimization ◽  
Dramatic Reduction ◽  
System Variable ◽  
Design Point ◽  
Engine Model ◽  
De Algorithm ◽  
Acceleration Method ◽  
Newton Raphson ◽  
Call Number ◽  
Convergent Solution

Abstract Variable cycle engine (VCE) is considered as one of the best options for advanced military or commercial supersonic propulsion system. Variable geometries enable the engine to adjust performance over the entire the flight envelope but add complexity to the engine. Evolutionary algorithms (EAs) have been widely used in the design of VCE. The initial guesses of the engine model are generally set using design point information during evolutionary optimization. However, the design point information is not suitable for all situations. Without suitable initial guesses, the Newton-Raphson solver will not be able to reach the solution quickly, or even get a convergent solution. In this paper, a new method is proposed to obtain suitable initial guesses of VCE model during evolutionary optimization. Differential evolution (DE) algorithm is used to verify our method through a series of optimization cases of a double bypass VCE. The result indicates that the method can significantly reduce the VCE model call number during evolutionary optimization, which means a dramatic reduction in terms of evolution time. And the robustness of the optimization is not affected by the method. The method can also be used in the evolutionary optimization of other engines.

Research on Genetic Algorithm-Based Solution Method for Variable Cycle Engine Model

2014 ◽  
Vol 668-669 ◽  
pp. 633-636
Author(s):  
Zheng Jia Wu ◽  
Rong Hua Meng ◽  
Ji Li
Keyword(s):  
Complex System ◽  
Genetic Algorithm ◽  
Solution Method ◽  
Initial Value ◽  
Engine Model ◽  
Computation Efficiency ◽  
Implicit Equations ◽  
Newton Raphson ◽  
The Mathematical Model ◽  
Raphson Method

Variable cycle engine is a complex system, which is usually mathematically modeled as a series of multi-dimensional nonlinear implicit equations. Processes for solution of these equations are often complicated; therefore, a genetic algorithm-based method was presented in this paper for the solution of the mathematical model. The method was also evaluated by such parameters as initial value sensitivity, computation efficiency, convergence and stability; and compared with Newton-Raphson method. It shows that genetic algorithm-based method is less sensitive to initial values, more capable in convergent and computing stability than Newton-Raphson method, however more time consuming.

Acceleration Method for Evolutionary Optimization of Variable Cycle Engine

2021 ◽  
Author(s):  
Wang Hao ◽  
Li Zhou ◽  
Xiaobo Zhang ◽  
Zhanxue Wang
Keyword(s):  
Evolutionary Optimization ◽  
Acceleration Method

Turboelectric Distributed Propulsion Modelling Accounting for Fan Boundary Layer Ingestion and Inlet Distortion

2020 ◽  
Author(s):  
Georgios Athanasakos ◽  
Nikolaos Aretakis ◽  
Alexios Alexiou ◽  
Konstantinos Mathioudakis
Keyword(s):  
Boundary Layer ◽  
Parametric Design ◽  
Pressure Ratio ◽  
System Level ◽  
Design Point ◽  
Engine Model ◽  
Inlet Distortion ◽  
Distributed Propulsion ◽  
Inlet Conditions ◽  
The Impact

Abstract A modelling approach of Boundary Layer Ingesting (BLI) propulsion systems is presented. Initially, a distorted compressor model is created utilizing the parallel compressor theory to estimate the impact of inlet distortion on fan performance. Next, a BLI propulsor model is developed considering both distortion effects and reduced inlet momentum drag caused from boundary layer ingestion. Finally, a Turbo-electric Distributed Propulsion (TeDP) model is set up, consisting of the BLI propulsor model, the associated turboshaft engine model and a representation of the relevant electrical system. Each model is validated through comparison with numerical and/or experimental data. A design point calculation is carried out initially to establish propulsor key dimensions for a specified number of propulsors and assuming common inlet conditions. Parametric design point analyses are then carried out to study the influence of propulsors number and location under different inlet conditions, by varying fan design pressure ratio between 1.15 and 1.5. BLI and non BLI configurations are compared at propulsion system level to assess the BLI benefits. The results show that maximum BLI gains of 9.3% in TSFC and 4.7% in propulsive efficiency can be achieved with 16 propulsors and FPR = 1.5, compared to podded propulsors, while further benefits can be achieved by moving the propulsor array backwards in the airframe.

WebEngine: A Web-Based Gas Turbine Performance Simulation Tool

2013 ◽  
Author(s):  
Asteris Apostolidis ◽  
Suresh Sampath ◽  
Panagiotis Laskaridis ◽  
Riti Singh
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Parametric Analysis ◽  
Model Development ◽  
Simulation Tool ◽  
Web Based ◽  
Performance Simulation ◽  
Design Point ◽  
Engine Model ◽  
Turbine Performance

The WebEngine is a web-based gas turbine performance simulation tool. The main advantage from this approach is the ease-of-use as no local installation is required. A number of different user categories such as students, researchers, gas turbine operators etc. can immensely benefit from this tool. The WebEngine has been under development for two years and is strongly supported by various associated research work in the department. It offers a large number of simulation capabilities such as design point and off-design single runs/parametric analysis, engine library, engine model design, virtual engine sensors and power plant operating plan. The WebEngine core is a high quality and robust gas turbine performance simulation code, developed by the Department of Power and Propulsion of Cranfield University, called Turbomatch. This approach offers modular component structure and high flexibility in the model development, as any engine configuration modelling is possible. In addition, the ergonomic graphical user interface offers a suitable and relaxing environment for the user. Related case studies are provided wherein a turbojet engine model development procedure, a turbofan design point fan pressure ratio optimization and an off-design parametric analysis are enumerated. Finally, a monthly power plant operating schedule is calculated for June 2013. A number of future additions is planned for the tool, with the diagnostics capability having the principal role.

Who Is Ivan? A Lesson in Eyewitness System-Variable Violations

1990 ◽  
Vol 35 (9) ◽  
pp. 876-877
Author(s):  
Gary L. Wells
Keyword(s):  
System Variable

Comparison of Progressive Antithrombin Activity and the Concentration of Three Thrombin Inhibitors in Nephrotic Syndrome

1981 ◽  
Vol 46 (03) ◽  
pp. 623-625 ◽  
Author(s):  
B Boneu ◽  
F Bouissou ◽  
M Abbal ◽  
P Sie ◽  
C Caranobe ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Antithrombin Iii ◽  
Heparin Therapy ◽  
Thrombin Inhibitors ◽  
Compensatory Mechanism ◽  
Dramatic Reduction ◽  
Antithrombin Activity ◽  
Α2 Macroglobulin ◽  
At Iii ◽  
A Prospective Study

SummaryIn order to compare the plasmatic progressive antithrombin activity to the concentration of three thrombin inhibitors, antithrombin III (AT III), α2 macroglobulin (α2, M), α1 anti-trypsin (α1 AT) in nephrotic syndrome, a prospective study was carried out on a group of 28 children affected with the disease. A dramatic reduction of the level of AT III and of α1 AT, two inhibitors of molecular weight close to that of albumin, was observed. The decreased level of AT III was counterbalanced by an increase in α2 M. This phenomenon accounts for the increased progressive antithrombin activity observed in all the affected children. It is suggested that the above compensatory mechanism explains the absence of thrombotic accidents in this series and that the benefit of heparin therapy is doubtful in these conditions.

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