| The secondary system is an important system for energy transfer,conversion,and production in nuclear power systems.The widespread application of computer simulation technology in the field of nuclear power plant simulation has led to increasing attention to the refined modeling and simulation of secondary circuit heat exchange equipment.A refined simulation model for equipment can provide detailed parameter distribution information of secondary circuit equipment,providing simulation research and decision support for efficient operation of nuclear power systems.The fine simulation modeling of secondary heat exchange equipment requires modeling verification at the equipment level and joint debugging at the system level.In the modeling work at the equipment level,combined with the basic ideas in the modeling research of the secondary heat exchanger,the refined model of the heat exchanger is established;In the system level debugging work,the established refined model of heat exchange equipment is used to couple with the flow network system for debugging and calculation verification.For the research on refined modeling of feedwater heaters,this article adopts refined simulation models of feedwater heaters with different pipe pass divisions.On the basis of the modeling method for water supply heater zoning and node division,the subdivision is refined based on the shell side water level and the pipe side separation line.The model can provide parameter distribution information for multiple partitions and nodes,and verify and analyze it under multiple calculation conditions.For the research on refined modeling of condensers,this article adopts a segmented and segmented condenser refined simulation model.Establish a hot well deoxygenation model and a bypass discharge expansion vessel model to expand the parameter solution range of the condenser simulation model;The calculation method of "uniform segmentation equivalent calculation" is adopted to dynamically calculate the shell side water level,heat transfer area,and tube side flow rate of the condenser under water level fluctuation conditions.Simulate and verify the refined model of the condenser under multiple calculation conditions.For the research on fine modeling of deaerator,this article adopts a fine simulation model of deaerator with water droplet grouping.Combining the partition modeling method and introducing the distribution relationship of feedwater droplets,the atomized droplets are divided into droplet groups based on their diameter,and a feedwater droplet grouping model is established;Establish a mass transfer and deoxygenation calculation model using the mass transfer dual membrane theory.The model can provide parameter information for heat and mass transfer processes,and verify them through calculations under multiple operating conditions.Finally,this article adopts a data coupling method to complete the joint calculation of the refined simulation model of the secondary heat exchange equipment and the flow network system for the built feedwater heater,condenser,and deaerator,and verifies the effectiveness of the equipment refined model established in this article. |
