| With the advancement of urbanization,the national electricity consumption has surged,and the amount of coal burned has gradually increased,which has caused huge environmental problems.Light gas turbines are widely used in the field of power generation due to their high efficiency and low pollution emissions.The combustor as an important component of the gas turbine directly determines the service life and performance of the entire gas turbine.Therefore,the numerical simulation of the combustor is of great practical significance for the design of the combustor and the optimization of the gas turbine.In this paper,a type of gas turbine can annular combustor is taken as the research object to study the interior of the combustor in the cold and hot state flow field under rated operating conditions and the variable state hot state flow field under different excess air coefficients and inlet temperature.For the purpose of field distribution and performance parameters,a three-dimensional simulation of turbulent flow is performed using numerical simulation methods.In the simulation,the SST k-? turbulence model and the EDM combustion model are used.The combustion mechanism adopts the methane-air two-step reaction mechanism.After analysis,the following conclusions are obtained:(1)In the cold flow field,an obvious rotating jet can be seen at the outlet section;however,the recirculation zone cannot be seen in the longitudinal section flow diagram.At this time,the main role of the swirler is to promote the velocity of the rotating jet axis Of attenuation.(2)In the hot flow field,there are eight near-circular low-velocity zones at the outlet section of the can annular combustor.The low velocity in this zone is almost 0.The pressure field corresponds to the velocity field.,the distribution of the components of the can annular combustor corresponds to the temperature distribution.The fuel and the incoming air can be effectively mixed and burned,and the combustion efficiency is high.There is a local high temperature area near the wall of the combustor,but it is not enough to cause ablation failure,and the cooling effect is general.The depth of the mixing hole of the flame tube in the combustor is insufficient,and the geometric parameters of the mixing hole need to be modified to improve the distribution of the outlet temperature field.The total pressure loss of the combustor meets the design requirements.(3)Keep the other conditions unchanged,and change the excess air coefficient of the incoming air.When the excess air coefficient gradually increases,the pressure in the combustor decreases as a whole,the area of the high-speed area increases,and the peak velocity becomes larger;The average content of carbon dioxide decreases,the average content of nitric oxide decreases,and the average content of carbon monoxide gradually increases.The increase of the excess air coefficient will also reduce the combustion efficiency,increase the total pressure loss and deteriorate the uniformity of the outlet temperature.(4)Keep other conditions unchanged,change the incoming air inlet temperature.When the incoming air temperature changes in the range of 616K-716K,it will have little effect on the pressure and velocity distribution in the combustion chamber.When the intake air temperature gradually increases,the area of the high temperature area in the liner of the combustor increases,the average content of carbon dioxide dose not change a lot,the average content of nitric oxide increases,and the average content of carbon.monoxide decreases.The increase of the inlet temperature will also increase the combustion efficiency,which will improve the uniformity of the outlet temperature distribution within a certain temperature range,and the increase of the intake air temperature will have little effect on the total pressure loss. |
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