| Abstract: | Rankine cycle engines have a high potential for meeting the emission levels established by the 1970 amendment to the Federal Clean Air Act for the 1975-76 automobile. This paper discusses a Solar research and development program sponsored by EPA/APCO which demonstrates a full scale 2 million Btu per hour working model of a Rankine cycle engine combustor and controls which can surpass the emission goals established. Special features of the combustor are the unique methods of precisely controlling both the fuel and air to provide optimum flame performance at any engine power level. This paper discusses the special requirements of the Rankine cycle engine and shows why the very wide range of fuel flow required necessitates use. of special techniques in fuel atomization, fuel and air control, and aerodynamics. Sufficient discussion is included to show the design methods that are necessary, in general, to achieve low emissions in continuous flow combustion systems. Emphasis is placed on the importance of interfacing a combustion system with other engine parts if a successful low emission, wide turndown ratio combustor working model is to be achieved. Sufficient discussion on combustion kinetics is included to advise on approaches necessary to minimize NO formation in external combustion systems while maintaining high efficiency and low CO and unburned hydrocarbons. |
