Tomasz Seredyn, Adam Dziubiński and Piotr Jaśkowski
The article describes a computational study, using CFD models, of droplet spray dispersal in the wake of a ‘Turbo Kruk’ airplane up to 500 m downstream. The CFD Reynolds-averaged Navier-Stokes (RANS) models use a Lagrangian (droplet phase) and Eulerian (fluid phase) procedure to predict the droplet trajectories trough the turbulent aircraft wake. The methods described in the work have the potential to improve current models for aerial spraying and will help in the development of new spraying procedures. In this study, the CFD models are used to describe the phenomenon of sprays released from atomizers mounted on the plane. A parametric study of the aircraft model examines the effects of crosswind on the aircraft’s vortex structures and the resulting droplet trajectories. The study shows, that such influence is underestimated in the current models. A comparison of the present results to AGDISP predictions is provided.
The paper presents results of simulation calculations concerning an influence of stiffness of blade-hub connection on rotor loads and blades deflections in hover, level flight and pull up maneuver. The three versions of rotor are considered with articulated, elastic and stiff connections of blades and hub. The blades with the same distributions of stiffness, mass and the same aerodynamic characteristics are applied for all rotor cases. The rotor loads are calculated applying Runge-Kutta method to solve the equations of motion of deformable blades. According to the Galerkin method, the parameters of blades motion are treated as combination of considered blade bending and torsion eigen modes. The results of calculations indicate for possibility to generate the greater rotor control moments and to improve helicopter maneuverability in the case of applying the non-changed blade of articulated rotor combined with elastic rotor hub.
The purpose of this text is to demonstrate an operation of a compressed air system designed for high air flow laboratories and wind tunnels. Development of such air system is a challenge due to unusual requirements (simultaneous supply of several users having different requirements and necessity to provide extremely high flows) which have to be address by means of adequate compressed air storage capacity and sophisticated control system. Each stage of the design process is going to be described, focusing on the selection of air compressors, air receivers and air dryers, followed by an insight into a development of the control system. The air system being described in this paper was successfully implemented at the Institute of Aviation in Warsaw improving the quality of the compressed air supply and simplifying the research planning.
Gyroplanes, as ultralight aircraft, are popular transport vehicles recently. Ultralight aircraft flights take place at a low altitude – their noise is not without effect on people and nature. The localization of the sources of noise and a possibility to decrease the noise of an gyroplane are described in this paper. The rules of design and exploitation of gyroplanes do not define the limits of emitted noise.
Gyroplanes are not noisy aircraft vehicles but for their silencing the knowledge about the sources and frequency range of noise is necessary. The goal of the conducted measurement was to determine the gyro-plane noise properties and the noise measurement methods. The evaluation of the noise sources was made by acoustic beamforming and the directional emission with single microphones at various engine speeds.
The supplement of these tests should be the rotor noise measurement but that investigation should be performed on a special stand, on which the rotor propulsion noise would not disturb the measurement.
The Active Gurney Flap (AGF) is a small, flat tab cyclically deployed and retracted at lower surface of the rotor blade near its trailing edge. It is expected that the device may improve performance of modern helicopters. The main goal of presented investigations was to develop research methodology and next to use it in studies on phenomena occurring in the flow around helicopter-rotor blades equipped with AGF. Conducted CFD simulations aimed at validation of the developed methodology as well as at significant supplementing and extension of results of experimental research. Simplified sensitivity analysis has been conducted aiming at determination of geometric and motion-control parameters of the AGF, optimal from point of view of helicopter-performance improvement. Fully three-dimensional simulations of the rotor flight aimed at determination of flight conditions, in which the use of Active Gurney Flaps could significantly improve the rotorcraft performance.
This article presents selected results of I-31T propulsion tests, obtained in the framework of EU project ESPOSA (Efficient Systems and Propulsion for Small Aircraft). I-31T aircraft, as a testbed, was fitted with 180 kW turboprop engine TP100. The scope of the work include results of ground and in-flight tests of engine compartment cooling suitability. The purpose of the cooling tests was to prove that temperatures of the propulsion components are within limits set by the engine manufacturer for the engine type in the most disadvantageous conditions on the ground and in flight up to aircraft maximum altitude, maximum ambient temperature and after standard engine shutdown. Engine oil cooling is beyond the scope of this work.
The paper demonstrates the feasibility of quantitative flow visualisation methods for investigation of transonic and supersonic flows. Two methods and their application for retrieving compressible flow field properties has been described: Background Oriented Schlieren (BOS) and Particle Image Velocimetry (PIV). Recently introduced BOS technique extends the capabilities of classical Schlieren technique by use of digital image processing and allow to measure density gradients field. In the presented paper a review of applications of BOS technique has been presented. The PIV is well established technique for whole field velocity measurements. This paper presents application of PIV for determination of the shock wave position above airfoil in transonic flow regime. The study showed that application of quantitative flow visualisation techniques allows to gain new insights on the complex phenomenon of supersonic and transonic flow over airfoils like shock-boundary layer interaction and shock induced flow separation.
Paweł Magryta, Konrad Pietrykowski and Michał Gęca
The article presents assumptions of the one-dimensional model of the ASz-62IR aircraft engine. This model was developed in the AVL BOOST software. The ASz-62IR is a nine cylinder, aircraft engine in a radial configuration. It is produced by the Polish company WSK “PZL-Kalisz” S. A. The model is used for calculating parameters of the fuel stream and the air stream in intake system of the engine, as well as for the analyses of the combustion process and the exhaust flow to the external environment. The model is based on the equations describing the isentropic flow. The geometry of the channels and all parts of the model has been mapped on the basis of empirical measurements of the engine elements. The model assumes indirect injection where the gasoline was used as a fuel with the calorific value of 43.5 MJ/kg. The model assumes a mixture of a stoichiometric ratio of 14.5. This model is only part of the overall the ASz-62IR engine model. After the simulation tests on the full model the obtained results confirmed the correctness of the model used to create the mixture. It was found that the AVL BOOST software is good for the implementation of this type of work.
In the next article on synthesis of regulations, the authors presented the general legal requirements for rotorcraft, which is limited to US regulations, because the vast majority of world regulations are based on them. The Institute of Aviation in Warsaw has developed requirements concerning the construction and operation of rotorcraft in Poland. These requirements constitute an important contribution to the regulations of the Civil Aviation Authority which are in force in the air space of the Republic of Poland. This paper presents the legal situation of rotorcraft and compares the requirements for helicopters and gyroplane. The conclusions highlighted the differences that arise from regulations between helicopters and rotorcraft. The authors have suggested the necessity to separate provisions for the group of windmills, which is implemented in the regulations of the Civil Aviation Authority. The presented work is the second of a planned series of publications in which authors intend to bring some of the issues to the reader about the design aspects of aircraft in selected global aviation regulations.
Joined-wing aircraft due to its energy characteristics is a suitable configuration for electric aircraft when designed properly. However, because of the specific for this aircraft phenomenons (e.g. static indeterminacy of structure, aerodynamic interference of lifting surfaces) it demands more complicated methods to model its behavior than a traditional aircraft configurations. For these reasons the aero-structural optimization process is proposed for joined-wing aircrafts that is suitable for preliminary design. The process is a global search, modular algorithm based on automatic geometry generator, FEM solver and aerodynamic panel method. The range of aircraft was assumed as an objective function. The algorithm was successfully tested on UAV aircraft. The improvement of 19% of total aircraft range is achieved in comparison to baseline aircraft. Time of evaluation of this global search algorithm is similar to the time characteristic for local optimization methods. It allows to reduce the time and costs of preliminary design of joined-wing.