Study On Wall Temperature Characteristics Of Coupled Heat Transfer Of Combustion And Hydrodynamics In 700? USC Technology

High parameter 700?ultra-supercritical power generation technology has been the future option for China with its high generating efficiency and low pollutant emission,on the basis of mature grasp of 600?ultra-supercritical thermal power units.However with the parameter increasing,due to lacking study of coupling heat transfer of combustion and hydrodynamics,the problems of tube failure have not been solved yet.This paper establishes the coupling heat transfer model of combustion and hydrodynamics via two variables,wall flux and working medium heat absorption,obtaining wall temperature distribution under no deviation The maximum wall temperature in 700?USC reaches 626?and can go as high as 652?when the deviation of flame center is 3meter.In the main combustion area high temperature flue gas enhances convective heat transfer,and heat transfer in combustion model has the leading effect in the coupling mechanism.While in the upper and lowerparts of big furnace,hydrodynamics has more influence on the coupling model.This paper sets up experimental bench,choosing CO₂ and nickel base alloy Inconel617 tubes to carry out the heat transfer research.By comparing experimental results with heat transfer correlations,heat transfer characteristics in Inconel617 tubes is 4%higher than regular stainless steel tubes.With pressure and mass flux increasing,heat transfer coefficient increases as well,and reaches its maximum value at 8 MPa,which is in accordance with the variation characteristics of physical properties in critical region.Physical property variation have great influence on heat transfer correlations.This paper sets up the first coupling experimental bench of combustion and hydrodynamics in China with parameter of 700?,35MPa,and carries out simulative experiments of boiler furnace heat transfer.In order to make sure the full combustion of coal,temperature of the experimental bench furnace should be above1100?.Wall temperature distribution and operating experience have been obtained,which providing a good foundation for theory and practice study in the future on 700?ultra-supercritical technology.