Study On Temperature Distribution And Cooling Technology Near The Wall Of Low Emission Combustor

In recent years,gas turbines have made remarkable progress in aviation,power generation and industry.To meet the high temperature,high efficiency and high power requirements of these applications,gas turbine technology has been optimized in many ways.However,with the high temperature,high efficiency and high power operation of the gas turbine,the gas temperature in the combustion chamber rises,which exceeds the heat resistance that the materials in the combustion chamber can withstand,so the research of wall cooling technology becomes particularly important.In this paper,the flow and heat transfer characteristics of different geometric parameters under the impact film cooling and multi-inclined hole cooling unit structure are analyzed.The influence of different geometric parameters on the boundary temperature characteristics and combustion performance of the combustion chamber is analyzed by taking the impact film cooling and multi-inclined hole cooling model combustor as the research object,which provides the basis for the design and parameter selection of the combustor wall cooling structure.The work of this paper is as follows:(1)In the impact/air film cooling structure geometric parameters(such as aperture,length of the guide ring,the distance between the guide ring and the location of the impact hole)on the flow and heat transfer research,it is found that small aperture leads to high wall temperature of the guide ring;Increasing the length of the guide ring can increase the length of the impact gas film protection.When the impact interval is moderate,the gas film effectiveness is the best.The farther the impact hole is from the root of the diversion ring,the better the cooling effect is.(2)According to the geometric parameters of multi-oblique hole cooling structure(such as pore diameter,guide ring length,hole axial inclination angle,mass flow rate per unit area of inlet and hole arrangement),it is found that the cooling effect is negatively correlated with the inclination angle of the hole,and the effectiveness of the cooling air film fluctuates and increases with the increase of the inclination angle of the hole and the cooling air flow.Increasing the flow rate and blowing ratio of the cooling air can make the cooling air film form wider and complete,but too large the blowing ratio may cause the cooling air flow to mix more seriously with the mainstream air flow,weakening the protective effect of the air film.The resistance loss is negatively correlated with the aperture and hole inclination angle,positively correlated with the cooling air flow,and is insensitive to the hole arrangement.(3)Taking the model combustion chamber with impact film cooling and multi-inclined hole cooling as the research object,the influence of different geometrical parameters of cooling structure on the boundary temperature and combustion characteristics of the combustion chamber was analyzed.It was found that the cooling scheme could form a symmetrical kidney shaped reflux zone under different guide ring spacing.When the length of the diversion ring is12 mm,the effect of gas film superposition is the best.The best impact film cooling structure is the pore size of 1.4mm,the diversion ring spacing of 1.0mm and 14 rows.The multi-inclined hole cooling scheme can effectively reduce the hot spot area at high temperature,but the combustion efficiency decreases with the increase of cooling aperture.The hole arrangement has little influence on the temperature field in the combustion chamber.The staggered cooling scheme has more advantages in the uniformity of the temperature field at the outlet,and the sequential cooling scheme has more complete combustion.In terms of axial dip Angle,the combustion effect is best at 30°.