Simulation And Dehumidification Of The Utility Tunnel Ventilation System In Humid Area Based On CFD

Based on the imbalance and incoordination between the urbanization process and the underground pipeline construction in China,the state has proposed to strengthen the transformation of the urban pipe network and the construction of utility tunnel network.In view of the problems existing in the construction and management of utility tunnel network,a new research upsurge has gradually formed.Ventilation is an important way to solve the internal temperature,humidity and air quality problems of the utility tunnel and guarantee the safe operation.However,for the utility tunnel project in the humid area,there are often situations such as excessive humidity load in the corridor,or the air humidity load in the corridor will be aggravated due to the excessive humidity of the external fresh air,and so on.Therefore,it is necessary to adopt reasonable and effective methods to dehumidify the ventilation process.In this paper,the dehumidification requirements are discussed from the perspective of the high humidity environment adverse impacts on the utility tunnel.Then,based on Pingtan utility tunnel project,Computational Fluid Dynamics(CFD)was used for numerical simulation to compare and analyze the dehumidification effect of the comprehensive cabin in different mechanical ventilation forms,and the result shows that the form of "one end for air inlet and one end for air exhaust"has better dehumidification performance.Based on this,this paper takes the mechanical ventilation model of the comprehensive cabin with "one end for air inlet and one end for air exhaust"as the research object,and focuses on its ventilation and dehumidification control problems,mainly including:(1)Aiming at the condition of the high moisture load in the corridor,the dehumidification effect of the comprehensive cabin under the action of the different factors are numerically simulated.The results show that increasing ventilation partition length or ventilation frequency can both effectively reduce the actual ventilation time,but the effect slows down after reaching a certain value,and the influence of inlet air temperature on the dehumidifying effect is related to the initial value of the temperature in the corridor,the smaller the difference between the two,the better the dehumidification effect.(2)Based on multivariate regression analysis,an effective duration prediction model is established.The comparison with the simulated data of the reference group shows that the error is 0.43%and the prediction model has a good fitting effect(3)For the problem of excessive humidity of external fresh air,the multi-objective optimization of ventilation and dehumidification control process are carried out based on BB-MOPSO algorithm,and the air inlet state parameter controller is proposed.The results shows that the controller could make decisions on the adjustment level of the air inlet according to the air state in the corridor and the external fresh air state,so as to realize real-time control of the air inlet state parameters(4)Combined with the IOT,GIS and other technologies,the realization path of the intelligent control of ventilation and dehumidification in the comprehensive cabin is designed,and a feedback correction mechanism for the control process of ventilation and dehumidification is constructed.The results show that the feedback correction mechanism is feasible,and it can help to facilitate the intelligent and automatic implementation of ventilation and dehumidification control.The research shows that the effective duration prediction model of ventilation and dehumidification and the air inlet state parameter controller established in this paper have engineering application value and can be applied to the ventilation and dehumidification control of comprehensive cabin.At the same time,this paper has a strong reference value for the research and development of the intelligent and integrated ventilation and dehumidification control system of utility tunnel.