| Yang Chan tomb in Honghuagang District,Zunyi City,Guizhou Province,is a national key protected cultural relic unit,known as the "treasure house of ancient stone carving art in southwest China",with great historical,cultural and artistic value.However,due to the long-term semi-enclosed environment,Yang Chan tomb has been subjected to various water hazards.Among them,condensation on the wall surface of cultural relics is one of the main diseases.The condensation of water vapor not only directly causes the expansion of the internal components of sandstone artifacts,making cracks in the artifacts;it also reacts with the components in the air to produce acidic substances,causing damage to the artifacts,so the treatment of water vapor condensation in the burial chamber is a matter of urgency.If accurate prediction and assessment of heat and humidity distribution characteristics of the environment inside the burial chamber can be carried out,it will provide important theoretical and data support for environmental regulation and preventive protection of the chamber.The environment of the tomb is more special,a concrete waterproof structure is built around the tomb,which is covered with soil,so the distribution of heat and humidity inside the tomb is more complex.The building envelope heat and moisture transfer model and computational fluid dynamics(CFD)airflow model are commonly used in current research,but the building envelope heat and moisture transfer model does not consider the effect of air exchange inside and outside the building on heat and moisture transfer;and the CFD airflow model does not consider the heat and moisture migration inside the wall.Therefore,this paper integrates these two aspects and investigates the heat and humidity transfer in the chamber under the action of airflow,which is used to respond to the more complex characteristics of heat and humidity environment in the tomb chamber.The specific study is divided into the following parts:(1)Monitoring of environmental meteorological data inside and outside the tomb chamber and analysis of the spatial and temporal characteristics of air temperature and relative humidity inside and outside the chamber and at different depths of the chamber;(2)Establishment of a heat and moisture transfer-CFD airflow model,given the assumptions,initial conditions and boundary conditions of the model,and determination of the unknown parameters of the material by experiment;(3)Using multi-physics field simulation software to simulate the heat and moisture distribution characteristics of the chamber,and extract the temperature of the chamber walls to analyze the change pattern of its condensation generation,which can be used to guide the subsequent water vapor condensation control;(4)According to the mechanism of vapor condensation and the simulated law of condensation generation and change,the prevention and management of condensation damage of Yang Chan tomb is discussed,providing a reference basis for the subsequent work of heritage conservation. |
