Avşar, Gökhan
This study aims to optimize the impeller geometry of a backward-curved blade centrifugal fan in a helicopter oil cooler to improve the aerodynamic performance of the impeller. The study consists of three main parts: aerodynamic design and parametrization of the impeller, numerical analysis of impeller performance, and multi-objective design optimization to maximize fan static pressure and total to static isentropic efficiency. In the first part, a one-dimensional impeller design is performed using quasi-experimental methods and a direct optimization method with the multi-objective genetic algorithm, and the impeller geometry is parameterized through a commercial tool. The three-dimensional flow through the impeller is solved in the second part with a commercial computational fluid dynamics tool. The Reynolds-Averaged Navier-Stokes equations are solved on a multi-block grid, and a second-order accurate finite volume method is employed. The most appropriate turbulence model and grid size are selected considering time, cost, and fidelity. In the third part, a sensitivity analysis is performed with the design-of-experiment method, and the parameters that affect the objective function most significantly are determined. A multi-objective design optimization based on a non-dominated sorting genetic algorithm is performed with the Kriging Response Surface Method, and pareto optimal solutions are obtained. Results show that, at the design point, there is a 9.6% and 0.96% increase in the fan static pressure and total to static isentropic efficiency, respectively. The trained Kriging response surface model predicts the fan static pressure and total to static isentropic efficiency with an error of 0.12% and 0.33%, respectively.


Aerodynamic shape optimization of wind turbine blades for minimizing power production losses due to icing
Yirtici, Ozcan; Tuncer, İsmail Hakkı (2021-05-01)
Ice formation on a wind turbine alters the airfoil profiles of the blades and causes degradation in the aerodynamic performance of the wind turbine and the resulting power production losses. Since the blade profile plays a significant role in the icing of a blade, power production losses due to icing can be minimized by optimizing the blade profile against icing. In this study, blade profiles are optimized in order to minimize power production losses. A Gradient based aerodynamic shape optimization method i...
Genetic Algorithm based aerodynamic shape optimization tool for wind turbine blades and its implementation to helicopter blades
Polat, Özge; Sezer-uzol, Nilay; Tuncer, İsmail Hakkı (2014-01-01)
This study presents a methodology first built up for the aerodynamic shape optimization for wind turbine rotors and its modified version for a helicopter rotor in hover. The Genetic Algorithm (GA) coupled with an in-house Blade Element Momentum (BEM) tool is used in the design optimization process. The wind turbine blade optimization studies are performed for maximizing the power production at a given wind speed, rotor speed and rotor diameter, while for the helicopter blade optimization in hover, figure of...
Active Control of Smart Fin Model for Aircraft Buffeting Load Alleviation Applications
Chen, Yong; Ulker, Fatma Demet; Nalbantoglu, Volkan; Wickramasinghe, Viresh; Zimcik, David; Yaman, Yavuz (2009-11-01)
Following the program to lest a hybrid actuation system for high-agility aircraft buffeting load alleviation oil the full-scale F/A-18 vertical fin structure, an investigation has been performed to understand the aerodynamic effects of high-speed vortical flows on the dynamic characteristics of vertical fin structures. Extensive wind-tunnel tests have been conducted on a scaled model fill integrated with piezoelectric actuators and accelerometers to measure file aft-tip vibration responses under various fre...
Design and Experimental Investigation of a Wind Tunnel Gust Generator
Yığılı, İmge; Andırın, Mert Ali; Kurban, Erk; Başkan Perçin, Özge; Perçin, Mustafa (2021-09-10)
This work aims at developing a two-vane gust generator for a small size open-loop wind tunnel to study the unsteady aerodynamic response of lift producing test models. The focus of the study is two-fold: (1) the design of a gust generator which produces the desired gust profiles by varying the parameters such as flow speed, pitching frequency of the vanes, maximum angle of deflection of the vanes and spacing between the vanes and (2) the experimental investigation of the gust velocity profiles via particle ...
Development of a design method for subsonic intakes with improved aerodynamic performance and reduced radar signature
Ünlü, Tezcan; Eyi, Sinan; Department of Aerospace Engineering (2021-9-2)
In this thesis, a design method for a subsonic intake with high aerodynamic performance and reduced radar signature is developed. Intakes are key components of aircrafts’ propulsion systems that create open ended cavities resulting in increased radar signature. To achieve reduced radar signature characteristics, a parameterized double curved intake is proposed. Due to the nature of this multi-objective and multi-disciplinary engineering problem, surrogate based analysis and optimization approach is taken to...
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