Method for estimating the energy and mass-dimension characteristics of an auxiliary propulsion system with fuel cells

The article is devoted to the creation of an auxiliary power plant for the implementation of the concept of an “electric aircraft”. A number of promising projects of aircraft, from a number of so-called “more electric aircraft”, presuppose the regular operation of an auxiliary power plant (APU) throughout the entire flight to generate electricity. It is assumed that the autonomous operation of the APU at the nominal mode during the whole flight is more energetically more favorable than the selection of the mechanical power from the engines with the subsequent transformation into electric power. Further realization of the concept of an “electric aircraft”, associated with the increase in energy consumption on board even with simultaneous increase in the energy efficiency of electromechanisms and other consumers, will lead to an increase in the unitary equivalent (total for electricity and air) of APU power. Another problem is related to the fact that the long-term requirements for civil and military aircraft require the search for ways to significantly increase the fuel efficiency of the aircraft as a whole. One of the main reserves to achieve these goals is a comprehensive increase in the efficiency of the propulsion system and APU as a source of secondary heterogeneous power for the aircraft users. At the present time, in the world aircraft industry, constructive solutions for the schematic redistribution of consumption and power generation are tested through the transition to electric power mechanisms and the generation of electricity in auxiliary installations. Fuel cells are considered as one of the main means of further improving the economy and improving the environmental performance of prospective aviation APUs. The basis of all circuit solutions for aviation hybrid APUs is a combination of a fuel cell (FC) battery and a turbocharger group that provides the necessary level of parameters of working bodies with respect to pressure and temperature required for the efficient operation of fuel cells. The weight of the design of the advanced aviation APU being created should not be greater than the mass of the APU structure, compared to the base one for the gas turbine aviation APU. The paper presents a methodology for estimating the main energy and mass-dimension characteristics of a power plant for conducting a comparative analysis of variants of hybrid auxiliary power plants with fuel cells for prospective civil aviation aircraft.