Research On The Heads Projects Of LPP Low Emission Combustor

The heads of Lean Premixing Prevaporizing(LPP) low emission combustor are studied by usingnumerical simulation and experiment, the basic designing idea is to decrease combustion temperatureand reduce the area of high temperature through applying staged supply fuel and zoning combustion,so as to reduce NOXemission. The head of LPP low emission combustor is made up of primaryswirler and pilot swirler, combustion of pilot swirling is diffusion combustion, it can be used to asstable ignition source.But comparing with the whole fuel mass, the fuel rate of pilot atomizer is verylow, therefore the area of high temperature is small. The major fuel is injected from many multipointfuel direct injection holes located between primary swirler vanes of primary swirler,the combustion ofprimary swirling is basically lean premixing prevaporizing or both diffusion and premixingcombustion, because of lean uniform combustion of primary swirling, combustion temperature iscomparatively low.This paper includes three contents:Firstly,in order to investigate the influence of different vane angles of primary swirler oncombustion flow field and combustion performance, two phase spray combustion and combustionperformance of six heads are studied by applying numerical simulation.Numerical results showthat:(1)With the increase of vane angle, the area that combustion temperature over1950K shrinksfirstly and then augments;(2)The change rule of NOXmass fraction at LPP combustor outlet is thesame as the change rule of the area that combustion temperature over1950K;(3)The combustionperformance and emission of the C head is best among the six heads.Secondly, in order to study the influence of different inlet conditions and different locatedposition of pilot nozzle on cold flow field and fuel spray field of LPP combustor with G head,PIVmeasuring technique is used, experimental results show that:(1)The inlet air mass of LPP combustorhas no effect on the shape of velocity distribution,variation trend and the shape of primaryrecirculation zone;(2)When the pilot nozzle operates only,with the increase of fuel mass, fuelatomization becomes badly, and the influence of different pilot nozzle position on the fuel atomizationbecomes small gradually;(3)When the primary fuel nozzles operate only, with the increase of fuelmass, the fuel atomization become well;(4)When the primary nozzles and pilot nozzle operate at thesame time, keeping the fuel mass, with the increase of primary fuel mass and the decrease of pilot fuelmass corresponding,the quality of fuel atomization improves and the influence of different pilotnozzle positions on the quality of fuel atomization becomes small gradually. Finally, in order to get combustion performance of LPP combustor with H head,combustionexperimentsare carried, temperature distribution and pressure loss coefficient of LPP combustor outletare gained respectively, experimental results show that:(1) At the direction of radius, the temperaturedistribution of combustor outlet is relatively poor, further research are needed;(2)The color ofcombustion flame is light blue, it shows that combustion process in LPP combustor is good andbasically obtains the designing requirement of LPP combustor.The achievements of this paper getting can be used to design and optimize the head of LPP lowemission combustor,and provide technical reserve for low emission combustion technology of civilaviation in our county.