Study On Boundary Temperature Characteristics Of Cooling Structure Of Coaxial Staged Combustion Chamber

At present,gas turbines are widely used.As the performance of gas turbines continues to increase and the temperature of the combustion chamber continues to increase,the temperature of the gas produced by the combustion chamber can easily exceed the heat-resistant temperature to which the materials of the combustion chamber are subjected.In addition,because the combustion chamber outlet temperature distribution determines the working reliability and life of the turbine blades,the high temperature rise and low pollution combustion chamber has no mixing holes for outlet temperature regulation,and the combustion chamber outlet temperature distribution regulation is completely controlled by the imported controllable boundary.Without affecting the combustion structure,the selection and variation range of the controllable boundary of the inlet is very limited,so it is of great significance to study the reasonable control technology of the boundary temperature distribution.In this paper,a coaxial staged model combustion chamber is used as the research object.The numerical simulation method is used to study the control of the boundary temperature distribution.The cooling characteristics of the combustion chamber wall and the outlet temperature distribution rule are analyzed.The boundary temperature optimization method and wall cooling structure provide guidance for the regulation of the combustion chamber boundary temperature.The main contents of this article are as follows:(1)Aiming at a variety of commonly used wall cooling technologies at present,numerical simulation methods are used to compare and analyze the cooling characteristics of the three cooling methods of multiple oblique hole cooling,compound angle cooling and impact / air film cooling under the flat model structure.: Under the condition that the total cooling air flow rate is determined,the cooling performance of multi-inclined holes and compound angles decreases with the increase of the hole diameter,and the impact of the impact film cooling is reversed.The more oblique holes and compound angles are better as the hole diameter decreases,the larger the diameter of the impinging gas film becomes,and the better the effect of gas film adherence is.And the impact / air film cooling structure has better performance of the multiinclined hole and compound angle cooling structure under the same incoming flow conditions.(2)Aiming at the combustion performance and boundary temperature characteristics of the model combustion chamber,the numerical simulation method was used to study the combustion performance and boundary temperature characteristics of the model combustion chamber.The results show that during the combustion process,the recirculation zone will shrink inwardly as the aperture becomes larger;part of the third-stage cyclone’s airflow adhering to the wall will protect the wall to a certain extent.The maximum non-uniformity at the outlet increases with the pore size,and the total pressure loss decreases with the pore size.(3)A numerical simulation method was used to compare and analyze the characteristics of the combustion chamber performance and the boundary temperature distribution under different improved optimization schemes.The results show that the exit can be effectively achieved under the conditions of reasonable wall cooling structure,cyclone structure and fuel distribution.Expected temperature rise of 1100 K and flame tube wall temperature below 950℃.