| Increasing the intake pressure and flame temperature of combustion chamber to improve the thermal efficiency has become the mainly development trend of international heavy gas turbine combustor technology.As the intake pressure and flame temperature are further increased,how to ensure the stability of combustion conditions and low NO_x emissions remain to be key issues in the design of gas turbine combustor.Intake pressure affects the chemical reactions of C/H atoms in hydrocarbon fuel and oxygen molecules,and thus affects the temperature distribution,combustion instability and the formation of pollutants such as NO_x and CO in the combustion chamber.Therefore,it is imperative to carry out lean-premixed combustion test under high pressure.Based on the major research projects supported by “the Fundamental Research Funds for the Central Universities(2014ZZD04)” and “The natural foundation of Beijing(3162030)”,this dissertation designs and builds the high pressure combustion test platform for the study “burner suitable for turbine with ultrahigh expansion ratio and high-pressure combustion chamber of compressed air energy storage system”,which can be used for experimental research of lean premixed combustion of gaseous fuel with intake pressure at the range of 0.1 MPa~ 4.0 MPa.The design of high pressure combustion chamber,the composition of high pressure combustion test system,the design and inspection of main parts,the principle of test system and the selection of main parts are also discussed in this dissertation.Base on this high pressure combustion test platform,experimental study and large eddy simulation are used to further study the rules of effects of the structure and intake parameters of combustion chamber such as swirl number,Reynolds number,equivalent ratio,fuel distribution and pressure on the thermal state flow,combustion,the formation process of pollution,PVC structure and large-scale instability in different types of combustion chambers under high pressure conditions,as well as the similarities and differences between the rules of different combustion chambers are compared and summarized.These works could provide a theoretical basis for the design and reforming of gas turbine dry low-emission combustor.The specific work of this paper are as follows:Firstly,in view of the general technical experience at home and abroad,the high pressure combustion test system for the study of burner suitable for turbine with ultrahigh expansion ratio and high-pressure combustion chamber of compressed air energy storage system is designed and calculated.The structure and design principle of each subsystem,as well as the inspection of the main parts and the basic design criteria of the controlling software are introduced in detail in this dissertation.Secondly,based on this high pressure combustion test platform,the influence of the structure and operating parameters such as intake pressure,swirl number,Reynolds number and equivalent ratio on the flame morphology,temperature distribution and pollutant emission in the combustion chamber under high pressure conditions are studied.The applicability of the sub-grid combustion model under high pressure condition is also verified.Thirdly,based on the combustion experiments,large eddy simulation is used to solve and get the dynamic information of the flow field that can't be obtained by experiments.The effects of different constructure and intake parameters on turbulent flow,combustion,vortex shedding,precessing vortex and low frequency oscillations in the high pressure combustion chamber are studied.Finally,based on the verification of sub-grid combustion mechanism,effects of the structure and intake parameters on the performance of different type of combustion chamber are studied using large eddy simulation.Furthermore,their effects on compressing the NO_x emission and combustion instability are further makes clear which could provides a theoretical basis for the design and reform of dry low-emission combustor for micro and heavy duty gas turbine. |
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