Low Emissions Combustion for the Regenerative Gas Turbine: Part 1—Theoretical and Design Considerations

This first part, of a two part paper, reviews the NO_x emission problem of the regenerative gas turbine engine for automotive application. It discusses the problem of fuel droplet burning, which causes heterogenous combustion with resulting high flame temperatures and high levels of oxides of nitrogen. The paper proposes means to achieve homogeneous combustion and shows that, even with this approach, flame temperatures need to be closely controlled to effect a compromise between NO_x, CO, and HC emissions in order to meet the stringent numerical levels of emissions specified by the Federal standards for 1976 and subsequent model year automobiles. The paper shows that combustor inlet temperature of a homogeneous system has little effect, theoretically, on computed NO_x emissions expressed as grams per mile, thereby strengthening the case for the regenerative turbine engine. A design concept for homogeneous combustion with controlled flame temperature is discussed.