PERFORMANCE OF AMMONIA-FIRED GAS-TURBINE COMBUSTORS
CALIFORNIA UNIV BERKELEY THERMAL SYSTEMS DIV
Pagination or Media Count:
A theoretical and experimental program was undertaken to investigate scaling and combustion in gaseous ammonia-fired gas turbine combustors. Theoretical analysis of performance and scale test data previously performed strongly indicates that the final size chosen for an operating gas turbine is performance-limited almost equally by chemical reaction kinetics residence time and by turbulent diffusion or mixing processes velocity or Reynolds number. Experimental results confirmed that a small-diameter combustor is chemically rate-limited at pressures very slightly less than the minimum previously reported, and becomes limited almost equally by chemistry and mixing at higher pressures. The fundamental problem with utilizing gaseous ammonia as a turbine fuel is certainly the relatively slow compared to hydrocarbon fuels chemical reaction between ammonia and air. As air flow is reduced, to allow sufficient residence time for the reaction to progress, diminished Reynolds number effects lead to less efficient mixing. This in turn leads to decreased combustion efficiency. The only apparent solutions apart from chemical enrichment by cracking or use of additives are to use a smaller fuel nozzle orifice to create a more vigorous fuel jet in the primary zone, and to use two or more combustors in parallel rather than build a single larger combustor.
- Combustion and Ignition
- Jet and Gas Turbine Engines