Stduy Of Fuel Mixing Organization And Switching Strategy For Dual Fuel Gas Turbine Combustor

In today’s society,the problems of energy shortage and environmental pollution are becoming increasingly serious.Countries around the world are committed to the research and development of new energy and alternative fuels,and expanding fuel adaptability has become one of the future development directions of gas turbines.With the continuous advancement of China’s marine strategy,the number of offshore oil and gas exploitation platforms has rapidly increased,and the demand for dual-fuel gas turbine generator sets equipped with them has increased day by day,but the sources all rely on imports.This directly threatens the production safety of China’s offshore oil and gas platforms.Therefore,it is of great significance to fully master the dual-fuel combustion technology of gas turbines,promote the localization of dualfuel engines,and break through foreign technical blockades to solve national energy production safety issues and achieve China’s energy structure transformation.During the fuel switching process in the dual-fuel combustion chamber,problems such as changes in flame shape and unstable combustion are prone to occur when gas/liquid fuel is mixed and burned.Therefore,this article uses numerical simulation methods to study the combustion organization and combustion stability of gas/liquid mixed combustion and fuel switching in the dual-fuel gas turbine combustion chamber used on offshore oil and gas platforms:1)Based on the structure of the prototype combustion chamber,a dual-fuel nozzle capable of burning gas/liquid fuel at the same time was designed.The design method of gas/liquid dualfuel nozzle was obtained.The two-phase interaction law inside the fuel nozzle and the liquid film primary and secondary crushing behavior were studied through VOF simulation.The rationality of the design was proved;The air path optimization comprehensively considers factors such as outlet temperature uniformity,combustion efficiency,and processing technology.2)The influence laws of state parameters and operating conditions on liquid fuel evaporation,mixing,fuel spatial distribution and flame surface position in gas/liquid dual-fuel mixed combustion were studied.The mixed stable combustion boundary of gas/liquid fuel was mastered.The law of dual-fuel combustion on combustor performance was obtained: under rated conditions,the combustor performance experienced three stages of improvement,deterioration and recovery during the mixed combustion process.There is a critical point for combustor performance changes.There is no improvement stage under non-rated conditions.At the same time,the critical point for performance deterioration advances.The combustion efficiency and outlet average temperature drop more.3)The effects of gas/liquid fuel ratio on flow field structure,combustion stability and conventional performance of combustor during fuel switching process were analyzed;The difference in performance fluctuation during fuel switching process under different fuel supply strategies was compared.A control strategy for stable switching was obtained.The rationality of the strategy was verified by full-process switching simulation.A database of combustion characteristics during fuel stable switching process was established.