The Investigation On The Lean Blowout Performance Of Central-staged Combustor

Lean blowout performance as a measure of an important indicator of combustion chamber stability,accurate prediction of lean blowout limit is a very important work in the gas turbine combustor design.The two means of lean blowout limit research include numerical prediction and experimental research,the numerical prediction method has advantages of low cost,convenient engineering application,is widely used in the analysis of the combustion performance of the combustor.The central-staged combustor as an advanced combustor with high temperature rise,predicting the lean blowout limit has important guiding significance for engineering practice.The research object of this paper is a new type of central-staged combustor.According to the different structure of swirler at different levels,a variety of combinatorial schemes are divided.The results of numerical simulation of cold flow field were compared with PIV test.Two kinds of prediction methods are used to predict numerically lean blowout limit of the central-staged combustor,and compared with the experimental values of extinction.It is concluded that the prediction accuracy is better by the method of fuel steady state successive approximation.Using fuel steady-state method of successive approximation,analysis effects of all levels of the structure of swirler on lean blowout performance of central-staged combustor.The research results show that: In the process of lean blowout in the main combustion zone,temperature field gradually are depressed until the moment of extinction.After flameout occurred the high temperature zone still exists;the lean blowout flame was “M” pattern;axial and radial size of the recirculation zone enlarged gradually.In terms of first grade of pilot stage,with the increase of the blade mounting angle,fuel air ratio of lean blowout decreases;In terms of second grade of pilot stage,with the increase of the blade mounting angle,the fuel air ratio of lean blowout decreased.But the magnitude of the reduction is greater than that of the first stage;In terms of the main combustion stage,with the increase of the blade mounting angle,fuel air ratio of lean blowout increases slowly;In terms of pilot stage,reverse scheme compared with the same scheme,lean blowout limit is lower;In terms of the main combustion stage and second grade of pilot stage,same scheme compared with the reverse scheme,lean blowout performance is better;Compared with direction of rotation of the main combustion stage,direction of rotation of pilot stage has more influence on ean blowout performance.