Supercritical fluid properties are implemented in a one-dimensional counterflow flame simulation code using the Soave-Redlich-Kwong equation of state and modifying the transport properties for high-pressure, low-temperature conditions. Examination of a GH 2 /LOX diffusion flame at supercritical pressure reveals an extremely fine structure at the edge of the oxygen diffusion layer, indicating that a DNS-like approach to simulation of such flames is not practical in the near term, and flame modeling must be used. To investigate flamelet table construction, we compare simulations that use supercritical fluid and standard temperature and pressure (STP) gas properties. Both types of simulations are shown to produce almost identical flame structures when we parameterize the flame with the scalar dissipation rate at its stoichiometric position. The results show that the use of STP gas property simulation is expected to be an effective means of greatly reducing the computational cost of constructing flamelet tables at supercritical pressures.

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To enhance worldwide environmental conditions, the air transport industry must drastically reduce carbon dioxide emissions. Electrification of aircraft propulsion systems is one way to meet this demand. In particular, the focus is on obtaining single-aisle aircraft with partial turboelectric propulsion and approximately 150 passenger seats by the 2030s. To develop a single-aisle aircraft with partial turboelectric propulsion, an aircooled interior permanent magnet (IPM) motor with an output of 2 MW is desired. One of the most difficult problems in air cooling is that air-cooling performance decreases with increasing altitude because the air density decreases. To investigate the effect of altitude on air-cooling performance in the IPM motor, the authors formulated mathematical system equations to describe heat transfer inside the target air-cooled IPM motor, and mathematical analytical solutions were obtained. The most severe condition is the top-of-climb condition. For this condition, a designer should choose cooling air mass flow rates that keep the temperature of the permanent magnets below the maximum temperature limit of 100 °C and the temperature of the coils below the maximum temperature limit of 250 °C. Here, the sizes of the air-cooling channels strongly affect air cooling with the IPM motor. In this paper, the authors briefly review the mathematical formulations and their solutions, investigate the effect of channel size on air-cooling performance in an IPM motor, and explore the optimum configuration and settings for the air cooling channels.