Simulation Analysis of Electromagnetic-Fluid-Temperature Field in Cable Shafts of High-Rise Buildings

High-rise building fires can be characterized by a rapid spreading and are challenging to extinguish. The chimney effect of cable shafts in high-rise buildings will greatly increase the spread speed of fire and smoke, and will also make it harder to put out fires. Therefore, fire-blocking materials or fire protection measures are usually used in cable shafts to slow down or even block the spread of fire. Currently, most of the research focuses on the fire performance of fire protection materials, and there are relatively few studies on the impact of fire-blocking materials on the operation state of cables. Based on the theories of electromagnetism, fluid mechanics, and thermodynamics, the paper establishes a multiphysics simulation model of a double-layer cable shaft. Then, the electromagnetic-fluid-temperature distribution in the cable shaft under rated operating conditions is analyzed, and the influence of the fire-blocking material is discussed. The simulation results show that the firestop material will affect the heat dissipation of the cable, which causes the hot-spot temperature of the cable to slightly increase by 1 to 2°C, and the relative growth rate of its hot-spot temperature rise is close to 6.83%.