Study of the heat and mass transfer characteristics of the main cable dehumidification process under internal and external environments

<p indent="0mm">Main cable dehumidification is one of the most important tasks in the maintenance of suspension bridges. The accurate prediction of the characteristics of the main cable dehumidification process is a prerequisite for developing an efficient dehumidification system. However, the internal structure of the main cable is complicated, and the main cable dehumidification process is significantly affected by the natural environment and operating conditions. Therefore, a more comprehensive heat and mass transfer model for main cable dehumidification is constructed in this paper. This model integrates the coupling effects of internal air supply parameters (i.e., inlet speed, inlet relative humidity, inlet temperature, and inlet pressure) and external environmental factors (i.e., solar radiation intensity, environmental temperature, and environmental wind velocity) on the main cable dehumidification process of suspension bridges. The sensitivity of each parameter is analyzed via the response surface methodology. The results show that relative humidity and velocity of inlet air, environmental temperature, and solar radiation intensity are the main factors affecting the evaporation rate of water in the main cable. The discussion of the interaction of the aforementioned factors on the evaporation rate reveals that increasing the inlet velocity can enhance the evaporation rate. However, the upward trend of the evaporation rate plateaus as the inlet velocity continues to increase. The enhancement of the evaporation rate by increasing the inlet velocity becomes more significant with the increase in environmental and inlet temperatures. Moreover, increasing the environmental wind velocity decreases the evaporation rate. However, the downward trend of the evaporation rate with the increase in environmental wind velocity gradually plateaus, and the velocity at the flattening point is approximately <sc>6 m/s.</sc> The decrease in evaporation rate due to the increase in environmental wind velocity becomes more pronounced with the increase in environmental temperature and radiation intensity. Furthermore, the increase in solar radiation intensity can effectively improve the evaporation rate, and the effect is more prominent at higher environmental temperatures. The solar radiation intensity increases from <sc>0 W/m²</sc> to <sc>615 W/m²,</sc> and the evaporation rate increases by 26.3% at an ambient temperature of <sc>313.15 K.</sc> This increase in evaporation rate is 9.7 times that of the increased evaporation rate at an ambient temperature of <sc>273.15 K.</sc> The increase in the surface absorption rate of the main cable can further improve the dehumidification efficiency of the main cable using solar energy. Taking Runyang Bridge as an example, when the absorption rate increases from 0.2 to 0.9, the evaporation rate increases by 11%–18% in different seasons. This paper provides a more comprehensive theoretical basis and engineering guidance for the development and improvement of the main cable dehumidification system.