A New Structure of Cooling Wall Tube for Supercritical CO2 Coal-Fired Power Plants

In terms of developing supercritical CO2(sCO2) coal-fired power plants,enhancing cooling wall performance is one of significant factors to improve system performance.In this paper,a new cooling wall tube structure is proposed to match the non-uniform heat flux(NUH) with the thermal resistance by changing the cooling wall tube eccentricity.A three-dimensional multi-physical coupling model of cooling wall is constructed to compare the novel structure to the conventional structures.The properties of fluid dynamics,thermal stress,coupled heat transfer and cooling wall deformation are analyzed.In contrast to the traditional structure,the maximum temperature and circumferential temperature difference(CTD) of the proposed structure can be reduced by 2% and 27.4%,respectively.The essential working parameters related to the performances of the cooling wall tube are discussed.The maximum temperature of the new structure is reduced by 8-13 K and the maximum thermal stress is reduced by about 10%-15% under all the simulated working conditions when the eccentricity changes from 0 to 0.2.The proposed structure can effectively reduce the maximum temperature and circumferential temperature gradient under NUH.Consequently,a novel insight is put out for the design and optimization of the cooling wall tube in coal-fired power plants.