Application Of Multi-grade Parking Vortex Technology To Annular Combustion Chamber

With the awareness of environmental protection is increasing day by day, the requirements of aircraft engine emissions performance have been become increasingly prominent, the domestic and international setting increasingly stringent emissions standards.To this end, a lot of research for low-emission combustion have been done in the countries around the world, some different cleaner combustion chambers were developed and designed.In this paper, taking a short annular combustor aero gas turbine as based model,discusses a new way to organize combustion, designed a multi-pointed star blunt head structure in the combustion chamber to organize the flow of chamber, the multi-grade parking vortex will be formed with the joint role of head blunt body structure and the primary holes,seeking an high efficient and low-emissions combustion's design ideas by organizational staged combustion.Firstly, combustion chemical reaction networks is established by Chemkin software,calculated the gas distribution of chamber roughly, using micro-element method to obtain the minimum effective response volume of each reaction zone of the combustion chamber, ensure that sufficient reaction volumn could be provided. In order to save the time and effort, one single flame tube, namely 1/20 of the entire combustion chamber, is selected as the primary subject. Designed multi-pointed star blunt body intake structure at the head of chamber.ICEM software is used to mesh the computational domain. When carrying out numerical simulation in FLUENT software, Realizable k-? turbulence model and ED combustion model are employed; CONE injection model is used to simulate the atomization process of the fuel. To include the description of variation process of liquid oil droplets, the Particle trajectory model is activated. For equation discretions, the upwind scheme is utilized.Standard wall functionand the SIMPLE algorithm method are used to solve the wall problem and the equations, respectively. The combustion flow field is simulated to investigate the influence of various multi-pointed star blunt modification on the combustion chamber's performance.The results show that: the intake structure' change of the head playing a major role on formation and size of the vortex. when the external angle's cross profile of hexagonal blunt body is perpendicular to the direction of primary holes jet, the most optimal effect in the parking vortex grading could be obtained; the size of first-level vertex will get the maximum when head intake proportion about 40%. Total pressure recovery coefficient of the combustion chamber and the maximum temperature unevenness of the outlet are showed a tendency increased with head intake ratio increscent. The highest temperature position of combustion chamber wall appears in the vicinity of both outer flanks of the primary holes,and its temperature decreased with head intake ratio increscent. It is difficult to obtain the effect of low NO_x emissions when only increase the flow area of head structure; the outlet NO_x content was significantly reduced after mutual adjust the head structure and primary holes' intake area,however, not conducive to the total pressure recovery.