Study And Control Of Condensation Water In Yungang Grottoes

The process the water vapor becomes the liquid state by the gaseous state is to be called congeals. In atmosphere, so long as vapor pressure achieved or surpasses saturation water vapor pressure, the water vapor can congeal. In the summer of Yungang Grottoes, the temperature of rock surface and interior is 1-5 ℃ lower than the air temperature in the caves, if further lower than the dew-point temperature, it can cause the water vapor supersaturation and congeals in the air, and the water vapor congeals on the surface of the cave's wall of low temperature. The existence of condensation accelerates physical and chemical weathering of the statue in the hole.The first part of paper designs and optimizes a set of testing method about the volume of the weakly seeping and condensation water in Yungang Grottoes for doing preparative works on avoiding suffering from coagulate water. First, we simulate devices indoor, and check them, then operate the autopsy tests. The laboratory's simulation is in a loop system, but actually the experiment in the scene is in a half loop system, therefore we come forth some new problems, we should answer them one by one.We use the principle of torrefaction in an airproof condition to design the equipment that can measure the water-volume of weakly seeping and condensation water. First, we calculate the volume of the seeping water, and then by subtracting it from gross to gain the volume of the condensation water.We calculate dew-point temperature by the Goff-Grattch's saturated water barometric formula, and then through the comparison between the dew-point temperature and the temperature of rock surface and interior, we can determine whether the condensation water does form or not. We. can analyze the result via comparison and anterior experiments data and conclude something as follow:1. During the greater humidity time in summer, the rock surface can appear the condensation water.