The Numerical Simulation Of Combustion Flow Field For Radial Grade Annular Combustor

Due to its excellent properties,Gas turbine are widely used all over the world,the standards of gas turbine pollution getting more and more strict,how to reduce the pollutant emissions without reducing the gas turbine performance has become an important research direction.Combustion chamber is the core component of gas turbine,its performance directly affects the quality of engine,combustor is also the main research object to reduce NOx emissions.With development of these years,the low emission technology of combustion chamber getting more mature,because of its ultra low emissions and stability performance,technology of lean direct injection(LDI)has a quite important position among all the low emissions technology,it has drawn the scholars’ attention from all over the world and has a very good prospect.Radial stage combustion chamber of low emissions is the research object in this paper,the process from zero dimensional design of single LDI head to multi-injection combustion field analysis is completed,the relationship between the structural parameters and combustion field and the influence of different array form are the most important attention in this paper.The main research content as follows:(1)The process of zero dimensional structure design of the study object according to the empirical formula is completed,including the calculation and analysis of the overall size,single head structure and multi-point injection arrangement.(2)The parts for combustion field according to the form of combustor flow field and temperature distribution are built,the chemical reactor network model(CRN)of the whole combustion field is created,infinitesimal method is used to calculate effective volume and the characteristic length of each part,the combustor flow distribution is analysed,the structure of combustion chamber is optimized.The final air flow rate for swirler is confirmed to be 75%and the air flow rate for cooling is confirmed to be 25%.(3)The swirl number impact on combustion field of single head LDI combustor is analysed,read the volume of backflow zone with the method of sealing isolation,build the relation between the volume and swirl number and the relation between the resistance loss and the swirl number,finally the conclusion of back flow and resistance are increased with the increase of swirl number is found out.(4)The LDI single head is arranged on annular combustion chamber,the simplified model of multi-injection combustion chamber is built in this paper,how different rotate direction and venture distance affect the performance of combustion field are analysed.The results show that the rotate direction and venture distance don’t have a very large effect on the average temperature and maximum temperature of the combustor outlet,the plan C which the outside adjacent swirlers have opposite rotate direction has lower NOx emissions compare with the other two plans;with the increase od venture distance,the NOx emissions show the trend of increase first and then decrease because of the influence by the swirlers compaction and wall resistance.