DETERMINATION OF ADEQUACY OF MATHEMATICAL MODELS FOR HEAT TRANSFER DURING FIRE INCIDENTS IN VERTICAL CABLE TUNNELS OF NUCLEAR POWER PLANTS

Abstract

The aim of this research is to identify the characteristics of heat transfer processes during real fires in vertical cable tunnels of nuclear power plants. Studying the adequacy of constructed mathematical models will enable the assessment of the effectiveness of thermal process modeling for use in researching the fire resistance of vertical cable tunnel enclosures in nuclear power plants. To achieve this goal, natural experiments were conducted and data on the temperature dynamics in a vertical cable tunnel with known geometric parameters and fire loads were obtained at the training and sports complex of the 1st State Fire and Rescue Unit of the Main Directorate of the State Emergency Service of Ukraine in Zaporizhzhia Region. A mathematical model of the vertical cable tunnel, similar to the physical one, was created in the Fire Dynamics Simulator software, followed by a computational experiment. Modeling, as a method of scientific research, allows for conducting all necessary experiments regarding the determination of temperature regimes during fires in vertical cable tunnels without the need for expensive and labor-intensive physical experiments on models. Based on the results of the computational experiment and natural tests, adequacy criteria were calculated. Fisher, Student, and Cochran criteria are used to validate the constructed mathematical model. An analysis of the adequacy of the mathematical models used was conducted. By comparing the dispersion of the results of mathematical modeling of the heat and mass transfer process during a fire, it can be observed that none of the adequacy criteria values exceeded permissible limits, and the relative deviation was 7.85%, indicating the effectiveness of modeling thermal processes for further research into temperature regimes during fires in vertical cable tunnels of nuclear power plants. This work contributes to the further application of computational experiments for studying heat and mass transfer processes during fires in vertical cable tunnels of nuclear power plants.