In this article, determination of protective panel limits of fluidic anti-icing system on leading edge of the high aspect ratio wing of a piston powered aircraft is studied numerically. Define surfaces of wing to be protected against ice accretion is the most important part of fluidic anti-icing system design. The first step of numerical code is devoted to flow field computation using control volume method. The second step is calculation of droplet’s trajectory and impingement characteristics using the Euler approach and, finally, ice shape and ice accretion rate are obtained using the messenger model. The code was used to obtain ice shape and droplets impingement limit in different sections of the wing and, as a result, protection panel geometry limits were determined, on the wing’s upper and lower surfaces. Also, by the introduced method in this work, ice formation is predicted on NACA0012 airfoil, and a good agreement was shown between predicted ice shape and experimental data. Finally, environmental and airflow parameters effect on the limitation of protective panel are obtained. The results indicated that only two parameters, liquid water content and exposure time have no effect on the panel limits.
In this paper, the optimum parameters of a row of cylindrical film cooling holes have been investigated using a multiobjective evolutionary approach so as to achieve a compromise between film cooling effectiveness and coolant mass flow rate which are in opposite directions and compete with each other. For this purpose, chord-wise position of film holes as well as diameter and injection angles and holes spacing were chosen as design parameters. Forty samples were generated as database through CFD runs; artificial neural network (ANN) method was used to construct the surrogate model to approximate the optimization targets as functions of design parameters and genetic algorithm (GA) was used as optimizer. Design iterations were repeated seven times through the mentioned CFD-ANN-AG loop and optimum configuration, including film holes spacing, diameter, injection position and angle, based on objective function values was found. However, added row imposed an excess amount of coolant mass flow rate through the vane cavity which had a negative impact on the engine performance. Therefore, at last part of this work a thermal barrier coating layer was applied on external surfaces of the vane in order to assess the possibility of decreasing coolant mass flow rate with no additional increase on its exerted thermal loads. Keywords Artificial neural network (ANN) Á Computational fluid dynamics (CFD) Á Conjugate heat transfer (CHT) Á Film cooling Á Turbine blade Á Genetic algorithm (GA) Á Multi-objective optimization Á Thermal barrier coating (TBC)
In this research, an experimental investigation was conducted to predict the Laminar-turbulent transition over the wing surface. Furthermore, the effects of a tractor propeller slipstream on both wing aerodynamics and transition front were studied. For tests, a rectangular wing was used with a NACA 6-series airfoil section and with a total of 22 pressure orifices. Unsteady pressure measurements were performed over the upper and lower surfaces of the wing in different spanwise locations at different incidence angles. Existence of propeller slipstream changed pressure distribution over the wing surfaces, in both chordwise and spanwise directions and hence affected the wing loading distribution. Statistical analysis of pressure signals was used to predict the boundary layer transition over the wing by computing the root mean square and skewness of the pressure data. The results showed that the transition location moves toward the leading edge due to propeller slipstream. Increase in propeller rotational speed causes that the turbulent flow covers whole portion of the wing surface.
This study deals with the application of optimization in Finocyl grain design with ballistic objective functions using a genetic algorithm. The classical sampling method is used for space filling; a level-set method is used for simulating the evaluation of a burning surface of the propellant grain. An algorithm is developed beside the level-set code that prepares the initial grain configuration using a computer-aided design (CAD) to export generated models to the level-set code. The lumped method is used to perform internal ballistic analysis. A meta-model is used to surrogate the level-set method in an optimization design loop. Finally, a case study is done to verify the proposed algorithm. Observed results show that the grain design method reduced the design time significantly, and this algorithm can be used in designing any grain type.
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