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Japan Aerospace Exploration Agency

CFD technology for supporting the design of realistically-shaped aircraft engine combustors

Until now, when developing combustors for aero-engines, JAXA has used CFD (computational fluid dynamics) in conjunction with engine combustion testing under actual temperature and pressure conditions. By developing a computational grid generation method in units of engine components and an assembly grid method in which the combustor is embedded in a multi-block structure grid solver, JAXA has conducted flow analysis for numerous non-combustion interiors while changing the size, shape, and position of air apertures and other elements of combustors with complex shapes.

In order to improve the environmental performance of jet engines, it is necessary to further increase the temperature and pressure under which combustors can operate, to further reduce hazardous substances such as NOx (nitrogen oxide) and PM (particulate matter), and to suppress combustion instability. In order to achieve such goals, it is essential to assess the internal flow for the entire combustor, as well as the distribution, evaporation and combustion of fuel droplets. In recent years, advancements have been made in technology which uses lasers, etc., to measure the status of such factors. The enhancement of CFD (computational fluid dynamics) technology is an urgent theme for further supplementing such measurement technology.

In response, in order to facilitate the development of aircraft engine combustors, JAXA is working to realize design tools which predict the dispersion, evaporation, mixing and combustion of liquid fuel particles inside the realistically-shaped combustors. Specifically, based on the solver which has been used at JAXA, we are creating practical design tools which will ultimately model the dispersion, evaporation, mixing and combustion of liquid fuel particles by converting the dispersion phase and gas phase of fuel droplet behavior into a mixture gas and incorporating real gas effects.

By using these tools, JAXA aims to dramatically improve the efficiency of R & D for realistically-shaped combustors. Furthermore, in the future, we seek to realize a tool which conducts analysis by connecting the entire aero-engine.