Design Of The Dome Of A Co-axial Staged Combustor And The Numerical Simulation For The Combustion Field

Nowadays the environmental problem is getting more and more serious,which imposes stricter regulations on amount of emissions of gas turbine.To make gas turbines have both low emission and high-performance has become the hot spot of resent research.Comparing to other low emissions technologies,the co-axial staged combustion technology has many advantages like compact structure,versatility and wide working range,but researchers from home and abroad havn’t done any effective study for design of the dome of co-axial staged combustor,fuel-air rapid mixing technology in small region and prediction of combustion flow field.The main target is to give a dome scheme which can satisfy the design objective.This thesis uses 0-D design method basing on empirical equations,1-D air distribution method basing on chemical reaction network and 3-D numerical simulation to solve the problems above.On the basis of a short annual combustor,this thesis gives the design method for co-axial staged dome and improves the performance of the dome.A prediction method is also given.These works have important value on research of domestic low emission gas turbine.The main research contents are as follows.(1)For the co-axial staged swirl-mixing dome,this thesis puts forward a design procedure which uses 0-D empirical method,and gives out the original dome structure.Then,this thesis uses 1-D chemical reaction network to determine the air distribution plan.(2)For the improvement for the combustion performance,this thesis does the numerical simulation for the designed dome under full-operation mode and tests the performance.Then,this thesis optimizes the fuel orifices and swirling direction of blades,which can help improve the combustion performance.(3)For the improvement for the mixing quality,this thesis does the numerical simulation for the single blade passage of the swirler to do orthongonal analysis and single variable analysis to study the momentum ratio,positions and number of fuel orifices.Such parameters have great influence on the mixing uniformity.Finally,the thesis puts forward the best shceme for the mixing structure.After optimizing the geometry of the dome,total pressure loss and emission are decreased obviously.(4)This thesis raises a simple and useful idea by comparing the cold and hot parameters distribution,which uses cold flowfield to predict hot flowfield,and gives the correlations between swirl numbers and flow factors including parameters of flame and recirculation zone.Finally,the scheme of dome is given and the combustion performance can meet the demand.