Research On The Influence Of Pilot Stage On The Ignition Performance Of Coaxial Staged Combustor

As people pay more and more attention to the impact of environmental changes on the quality of life,governments of various countries have introduced relatively strict emission standards.The level of gas turbine technology,as an important part of a country’s industrial strength,is one of the long-term goals of researchers to ensure efficient combustion of gas turbines while reducing emissions.In order to reduce emissions from the combustion chamber,lean premixed combustion technology has emerged,but the use of this technology will reduce the equivalence ratio in the combustion chamber and have a significant impact on the ignition performance and combustion stability of the combustion chamber.In summary,although lean premixed coaxial staged combustion chambers can effectively reduce pollutant emissions from the combustion chamber,there are problems such as difficulty in ignition.Therefore,this article conducts numerical simulation calculations on a certain type of coaxial staged combustion chamber,optimizes the design of the swirler pilot stage structure of the combustion chamber,and studies the ignition start-up process of the combustion chamber.The main contents are as follows:(1)Design and optimize the two types of head shift structures of the model combustor.The first type of pilot stage outlet fuel aperture,axial position,jet angle and fuel grading ratio were studied to determine the best structure of the first type of pilot stage;four structures designed for the second type of pilot stage were numerically simulated and calculated to study different air channel structures and different pilot stage outlet structures.The impact on the flow field characteristics of the combustor and calculated and analyzed the flow field characteristics of the combustor using the second type of pilot stage structure under different fuel grading ratios.(2)Simulate and calculate the cold and hot state flow fields of the combustors using two types of pilot stage structures under different working conditions.Summarize and analyze the changes in the internal flow field of the combustor with changes in working conditions,compare the impact of two types of pilot stage on performance parameters such as pressure loss,combustion efficiency,pollutant emissions,etc.under various working conditions,and select a better performing pilot stage structure.(3)Perform transient simulation calculations on the hot jet ignition process of a combustor using a second type(premixed)pilot stage structure.Study four factors such as different ignition positions,hot jet velocity,hot jet duration,and ignition fuel flow rate on the ignition performance of the combustor,and couple the above four ignition factors to select the best ignition method combination and simulate the ignition process of the combustor.(4)Monitor and analyze the changes in parameters such as heat release rate,product generation rate,OH component content,etc.during the ignition process of the combustor,study the changes in these parameters with the development of the ignition fireball,and simulate the process of the combustor from the ignition working condition to the slow car working condition.Calculate and study the changing trends of parameters such as flame shape,shear layer position,heat release rate,etc.in the combustor during this variable working condition process.