Analyzing temperature distribution in cable cabins within utility tunnels: Developing effective ventilation strategies for local thermal environment enhancement

Abstract

Convection heat transfer between the cables and the air in the cable cabin of the utility tunnel can lead to high temperatures in the cable cabin. High-temperature environments may cause the performance of cable systems to degrade, threatening the stability of the city's power supply. Increasing ACH (air changes per hour) alone could not effectively improve the high temperature at the end of the cable cabin. This paper employed numerical simulations and rigorous experimental validation to study the summer temperature field of cable cabins in Xi'an. An innovative disturbance ventilation method was proposed to alleviate the high-temperature phenomenon. The results indicated that as the wind flow length increases, the temperatures rise rapidly with the distance increased, resulting in a stable high-temperature area at the end of the cable cabin and the high-temperature air accumulated at the top by thermal buoyancy. When the ACH (air changes per hour) increased from 2 to 6, the temperature field range decreased by 3.25–6.39 %, and the variance decreased by 6.03–14.42 %. After installing a disturbance fan at the beginning of the stable zone, the temperature field in the cable cabin was fully mixed. Compared to directly increasing the ACH, the temperature field range decreased by 20.65–44.76 %, and the variance decreased by 40.28–64.47%. The introduction of a disturbance fan could thoroughly mix the air and effectively improve the local thermal environment in the cable cabin. This study contributed to the optimization of cable cabin ventilation strategies.