Effect of Fuel Staged Proportion on NO_X Emission Performance of Centrally Staged Combustor

The low NO_X emission technology has become an important feature of advanced aviation engine. A wide range of applications attempt to take advantage of the fact that staged combustion operating under lean-premixed-prevaporized (LPP) conditions can significantly decrease pollution emissions and improve combustion efficiency. In this paper a scheme with fuel centrally staged and multi-point injection is proposed. The mixing of fuel and air is improved, and the flame temperature is typically low in combustion zone, minimizing the formation of nitrogen oxides (NO_X), especially thermal NO_X. In terms of the field distribution of equivalence ratio and temperature obtained from Computational Fluid Dynamics (CFD), a chemical reactor network (CRN), including several different ideal reactor, namely perfectly stirred reactor (PSR) and plug flow reactor (PFR), is constructed to simulate the combustion process. The influences of the pilot equivalence ratio and percentage of pilot/main fuel on NO_X and carbon monoxide (CO) emissions were studied by Chemical CRN model. Then the NO_X emission in the staged combustor was researched experimentally. The effects of the amount of pilot fuel and primary fuel on pollution emissions were obtained by using gas analyzer. Finally, the effects of pilot fuel proportion on NO_X emission were discussed in detail by comparing predicts of CRN and experimental results.