The Experimental And Simulation Research On Flexibility Of Atmospheric Gas Buner

As China's natural gas industry development, China has increased demand for natural gas. In order to make up for the domestic shortfall, China needs to import foreign natural gas through multiple channels, resulting in the change of pattern of city gas supply. Meanwhile, the city gas load fluctuates over time. To ensure the supply of gas, the city gas gate station puts the other gas into the transmission and distribution system. Both of the cases can lead to the change of gas composition, so it's necessary to study the flexibility of atmospheric gas burner. With the methodology combining experimental and numerical simulation methods, the research of flexibility of atmospheric gas burner are done as following,from which relevant conclusions can be drawn:Some characteristics index related to gas combustion are discussed firstly in the paper, simultaneously, the laminar premixed flame characteristics of atmospheric gas burner is analyzed, and the method of structure about atmospheric gas burner is sorted out, which provide theoretical support for experimental and numerical simulation analysis. Based on the gas distribution experimental platform, the volumetric composition about four types of pure single-component gas, including methane, hydrogen, nitrogen, and isobutene, is obtained, when the natural gas appliances occur the flame-out, flashback and CO overrunning phenomenon, then the flexibility domain of natural gas appliances are obtained by using the MATLAB software. Through the flexibility domain, the reasons emerging above three abnormal combustion conditions are analyzed, the static pressure and primary air coefficient in the atmospheric gas burner, which are the two main factors affecting the combustion condition are obtained.Based on computational fluid dynamics theory, the simulation model of the injector in the atmospheric gas burner is built, and then the steady-state process of gas mixing with air in the injector is simulated by using the Fluent software, the simulation results are proven correct by comparing with the theoretical results. Based on the simulation results, the pressure field, concentration field and velocity field are analyzed under five different ejector inlet pressure and outlet pressure conditions, the degree of mixing of two gases in the injector is verified to achieve practical requirement, meanwhile, the self adjusting dynamic characteristics of injector is obtained, the impact of supply pressure change on flame stability is analyzed through the self adjusting dynamic characteristics. Based on the structure of atmospheric gas burner, with associated fluid mechanics theory, the impact of gas composition change on flame stability is analyzed, to draw a conclusion that the variation of primary air coefficient because of gas composition change leads to the alteration of the flame combustion condition.Through the study about flame combustion condition of atmospheric gas burner and ejector operation condition in the paper, it can analyze the impact of the flame combustion condition factors, providing technical support for gas stove adjusting and flame stability controlling in the city gas application field.