Development of fully superconducting 5 MW aviation generator with liquid hydrogen cooling

The use of liquid hydrogen as a fuel will be inevitable in the aviation of the future. This statement means that manufacturers will also implement liquid hydrogen for cooling all superconducting aviation equipment of an electric propulsion system. The development of fully electric aircraft is the most promising solution in this case. Scientists from the Department of electrical machines and power electronics of Moscow aviation institute have conducted calculations and theoretical researches of critical specific mass-dimensional parameters (MW/ton and MW/m3 at 21 K) of fully superconducting aviation synchronous generator of the electric propulsion system. The results are in this article. The article discusses the results 3D finite element modeling (FEM) simulation of a 5 MW fully superconducting synchronous generator with combined excitation. Superconducting armature and axial excitation windings based on second generation high temperature superconductors (HTS-2G) are located on the stator, which makes it possible to contactlessness and the absence of sliding seals. A dry gap will reduce gas-dynamic losses and increase the nominal peripheral speed of the rotor. The use of liquid hydrogen as a coolant makes it possible to significantly increase the linear load of the generator, and high current densities to reduce the cross-sectional area of the coils, which will make it possible to place them in individual cryostats in the future. Individual cryostats will allow to remove the heat release of magnetic losses from the cryogenic zone and reduce the consumption of refrigerant. For the purpose of internal redundancy of the HTS coils, the machine has a complete set of reserve winding made of ultrapure aluminum, also cooled by liquid hydrogen. If the superconducting coils get out of the stand, the generator will provide 15 % power on standby

Conceptual Design, Sizing and Performance Analysis of a Cryo-Electric Propulsion System for a Next-Generation Hydrogen-Powered Aircraft

In this paper, we present a comprehensive sizing and performance analysis framework for a disruptive cryo-electric propulsion system intended for a hydrogen-powered regional aircraft. The main innovation lies in the systematic treatment of all the electrical and thermal components to model the overall system performance. One of the main objectives is to study the feasibility of using the liquid hydrogen (LH\textsubscript{2}) fuel to provide cryogenic cooling to the electric propulsion system, and thereby enable ultra-compact designs. Another aim has been to identify the optimal working point of the fuel cell to minimize the overall propulsion system's mass. The full mission profile is evaluated to make the analysis as realistic as possible. Analyses are done for three different 2035 scenarios, where available data from the literature are projected to a baseline, conservative, and optimistic scenario. The analysis shows that the total propulsion system's power density can be as high as 1.63 kW/kg in the optimistic scenario and 0.79 kW/kg in the baseline scenario. In the optimistic scenario, there is also sufficient cryogenic cooling capacity in the hydrogen to secure proper conditions for all components, whereas the DC/DC converter falls outside the defined limit of 110 K in the baseline scenario.

Conceptual Design, Sizing and Performance Analysis of a Cryo-Electric Propulsion System for a Next-Generation Hydrogen-Powered Aircraft

In this paper, we present a comprehensive sizing and performance analysis framework for a disruptive cryo-electric propulsion system intended for a hydrogen-powered regional aircraft. The main innovation lies in the systematic treatment of all the electrical and thermal components to model the overall system performance. One of the main objectives is to study the feasibility of using the liquid hydrogen (LH\textsubscript{2}) fuel to provide cryogenic cooling to the electric propulsion system, and thereby enable ultra-compact designs. Another aim has been to identify the optimal working point of the fuel cell to minimize the overall propulsion system's mass. The full mission profile is evaluated to make the analysis as realistic as possible. Analyses are done for three different 2035 scenarios, where available data from the literature are projected to a baseline, conservative, and optimistic scenario. The analysis shows that the total propulsion system's power density can be as high as 1.63 kW/kg in the optimistic scenario and 0.79 kW/kg in the baseline scenario. In the optimistic scenario, there is also sufficient cryogenic cooling capacity in the hydrogen to secure proper conditions for all components, whereas the DC/DC converter falls outside the defined limit of 110 K in the baseline scenario.

Low-orbit spacecraft for highly detailed observation with a long lifetime in working orbits with an altitude below four hundred kilometers

The paper analyzes mass-dimensional design parameters of the optical-electronic equipment for Earth’s remote sensing from heights in the range of 300...400 km. Within the research, we carried out the synthesis of a mirror-lens telescopic complex with an additional rotary mirror tilted to the optical axis of the main mirror and selected the design parameters from the conditions for ultra-high spatial resolution satellite images. Furthermore, we analyzed the mass-dimensional parameters of the spacecraft as a whole, the parameters allowing for the smaller effect of the Earth’s upper atmosphere on the evolution of the parameters of the working orbit. To maintain the radius of the low working orbit of the spacecraft for seven years, an electric propulsion system is proposed. To compensate for the aerodynamic drag force in the investigated range of heights and in any conditions of the upper atmosphere, a thrust force of no more than 18 milliNewtons is sufficient. The reserves of the mass of the working body for the operation of the electric propulsion system depend on the design-ballistic parameters of the spacecraft and the required lifetime in a given working orbit.