УЧЕТ ВЛИЯНИЯ ПОГРАНИЧНОГО СЛОЯ НА ВХОДЕ В ВЕНТИЛЯТОРЫ ПРИ ИНТЕГРАЦИИ РАСПРЕДЕЛЕННОЙ СИЛОВОЙ УСТАНОВКИ И ЛЕТАТЕЛЬНОГО АППАРАТА

摘要

The article presents the analysis of a distributed power plant concept for perspective long haul passenger aircraft, which is intended for ensuring more deep integration of a power plant and a flying vehicle, as well as enhancing its fuel efficiency. While employing an aircraft engine of such kind, separate modules of a power plant may be installed both in the engine nacelle and inside an airplane fuselage, made according to a "flying wing" scheme. A portion of a boundary layer, formed at the surface of an aircraft, gets into the inlet plane of fan modules, located at the top surface of the fuselage. The variant of a submerged engine inside an aircraft assumes the presence of a rather long curvilinear intake channel, in which local separations and vortexes inevitably occur. It leads to additional losses of full pressure at the engine inlet. The article considers separately the effect of two main factors on the engine thrust, namely, the drop of overall level of the total pressure at the engine inlet and its non-uniformity. To evaluate the effect of the above said components, the results of preliminary work out of the distributed power plant parameters, obtained at CIAM, named for Baranov, in the activities progress on the engines' schemes of new types, were applied. Calculations were performed employing the first level model of an aircraft gas turbine engine. Parametrical studies performed using the developed technique allowed select an optimal degree of double -flowness on specific fuel consumption at course speed, and the degree of pressure increase in the fan. The fan modules' and main engine components dimensionality was redetermined with account for various losses levels at the inlet. The effect of engine parameters changing on the its mass estimation value was performed with the developed modular technique, based on the idea of impeller machine mass proportionality to compression specific work and corrected specific air consumption. The modular technique coefficients characterizing the weight fraction of the turbojet modules were determined based on estimations obtained for detailed element-by-element mathematical model of mass, in the activities progress on the engines' schemes of new types, at CIAM, named for Baranov. The obtained results of the parametrical studies make it clear that on deterioration of the factor of total pressure preservation at the inlet by 2%, minimum specific fuel consumption at a cruising mode would be achieved in the distributed power plant with double-flowness reduced by 3%, and the total pressure increase degree in the fan reduced by 0.6%. At the same time specific fuel consumption increases on 6-7 % of percent. The specific fuel consumption herewith is increases by 6-7%. The power plant weight, without account for the weight of the remote fan modules transmission drive may increase by approximately 4-5 %. Analysis of the effects associated with the presence of non-uniform total pressure field, resulting in its averaged level reduction at the fan inlet, revealed that the effect of non-uniformity presence itself might be of 15 to 30% of the total effect on the engine thrust. It should be accounted for selection of the distributed power plant shape of the configuration under consideration.%Приведен анализ концепции распределенной силовой установки (РСУ) перспективных дальнемагистральных пассажирских самолетов, предназначенной обеспечить более глубокую интеграцию силовой установки и летательного аппарата (ЛА) и повысить его топливную эффективность. Сформирована методика расчетных исследований. Получены возможные варианты рациональных параметров РСУ, выбранные при различном уровне потерь полного давления на входе в вентиляторные модули. Проведена также оценка влияния на двигатель неравномерности полного давления на входе. По полученным результатам параметрических расчетов сделан предварительный анализ влияния падения полного давления на входе в двигатель на его экономичность и массогабаритные данные. В заключение дано сравнение основных параметров РСУ рассмотренной схемы при различном уровне потерь полного давления на входе и сделан вывод о возможности использования полученных результатов по влиянию пограничного слоя на параметры РСУ при анализе вопросов интеграции двигателя с летательным аппаратом.