Spatial Heat Flow Field Of Coupled Combustion Of Columnar Sodium And Concrete And The Thermal Conductivity Of Concrete

Nuclear power is gaining importance as energy resources become more scarce.The favored reactor type for fourth-generation nuclear energy systems,sodium-cooled fast reactors,also have a number of safety concerns.When liquid sodium spills,it reacts aggressively with water,air,and other materials right away.The liquid sodium will leak onto the floor and walls when the leaked ones reach a particular range and will react with the bound water in the concrete as well as with the chemical elements in the concrete.Therefore,it is crucial to investigate both the internal temperature distribution of concrete and the spatial temperature distribution of the combined combustion of columnar sodium with concrete.This study uses models and experiments to analyze the internal temperature field of concrete as well as the spatial temperature field of coupled combustion of columnar sodium with concrete.Investigations are conducted into the laws of temperature variation above concrete,both vertically and laterally.Because of the mutual interaction of the linked burning of sodium and concrete,the combustion is split into two portions.In order to get the reaction mass ratio,the energy equation in this study that is based on the coupled combustion of sodium and concrete is decoupled.Additionally,the simulation technique based on FLUENT is being further developed in order to write UDF.Both the sodium-concrete reaction simulation model and the column sodium combustion simulation model have been finished.In order to complete the sodium-concrete reaction simulation model,the thermal conductivity model that was already in use was chosen based on how water flows during the reaction in order to construct the relationship between concrete temperature and water content.When the outcomes of the aforementioned two models were contrasted with the experimental data,it was discovered that the central temperature measurement point performed better.The simulation results of multiple linear regression analysis of various factors indicate that the oxygen concentration as well as the ambient temperature has a significant impact on the space stability temperature,and the fitted relationship equation of multiple factors on the stability temperature is fitted,according to the simulation results of column sodium combustion.After identifying the important variables,such as oxygen concentration and ambient temperature,a dimensionless fitted relationship between these variables and stable temperature at various initial temperatures was determined.This relationship was consistent with linear variation for oxygen concentration and logarithmic function for ambient temperature.The simulation results of sodium and concrete revealed that the central temperature of the concrete increased by about 30% for concrete with a thickness of 150 mm when the initial temperature increased from 300°C to 500°C and by about 9% when the flow rate increased from 0.04 kg/s to 0.3 kg/s.The reaction of sodium with oxygen enhanced the reaction of sodium with concrete with sidewall confinement,which led to higher concrete slab temperature and more water precipitation because more heat was released.This in turn led to a more intense reaction of sodium with concrete,and the concrete slab temperature was about 26% higher under the condition of sodium reaction with oxygen compared to before the sidewall confinement.These investigations offer a technical reference and protection evaluation for the potential coupling of columnar sodium combustion with concrete.