Purpose -The paper aims to present a way of engine model integration, an aircraft (multitask) and the mission into the single model that allows to study, from the level of selection of the engine cycle parameters, the feasibility of a specific mission with the assumed aerodynamic characteristics exemplified by a multitask airplane. Design/methodology/approach -There were introduced dimensionless geometric and energetic criteria, binding parameters of the engine and the airplane. The following models were built: of the turbofan engine and the aircraft movements with the application of these criteria, creating a dimensionless model allowing for measuring the impact of engine design parameters on the efficiency of the mission undertaken. Findings -The results were limited to the presentation of the impact of circuit parameters, such as engine TIT, OPR, BR on the defined criteria. The application of dimensionless criteria reduced the dimension of the task. Practical implications -The presented method can be useful for engineers involved in the task of engine integration and the airplane at the preliminary design stage. Originality/value -The originality of the presented solutions is reduced to provide a different, unconventional approach to the design process and not (so far) the engine itself but the entire aviation system.
The problem of design parameters selection of the turbine engine is the most important task at the preliminary design stage of the multipurpose aircraft. A special feature of the multipurpose aircraft mission is a sudden (even pulse) weight change, especially its decrease as a result of discharge of cargo bombing or rockets due to the ammunition consumption during air combat manoeuvring. In this article the attempt to use economic and mass criteria to assess the impact of the type of air missions on the choice of the design parameters of the engine was done. As the design, parameters there were selected the following measures: compression ratio, the turbine temperature and the bypass ratio. A mathematical model of the engine-aircraft-air task system was built (taking into account the flight conditions, the mission elements-the subsonic and supersonic flight, flight time, thermo-gas-dynamic and mass model of the engine). The model enables to conduct the simulation research of the complex flight missions and their assessment on the basis of the constructed criteria. The model includes a parametric description of physical processes in the turbofan engine, thereby allowing a direct assessment of the impact of the selection of engine parameters on the effectiveness of the mission. The paper presents the results of calculations according to the classical criteria (e.g. kilometre fuel consumption, specific fuel consumption of the engine). New criteria for evaluation were presented; they are the energy efficiency of complex mission of an aircraft and the relative total and specific fuel consumption. The values of circuit parameters that need to be taken as design constraints for the engine to allow the implementation of the aviation missions were determined. The results are shown in an illustrative way on the number of graphs.
Abstract:The paper presents an analysis of influence of selected fault states on properties of brushless DC motor with permanent magnets. The subject of study was a BLDC motor designed by the authors for unmanned aerial vehicle hybrid drive. Four parallel branches per each phase were provided in the discussed 3-phase motor. After openwinding fault in single or few parallel branches, a further operation of the motor can be continued. Waveforms of currents, voltages and electromagnetic torque were determined in discussed fault states based on the developed mathematical and simulation models. Laboratory test results concerning an influence of open-windings faults in parallel branches on properties of BLDC motor were presented.
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