Research On Key Technical Parameters Of Mechanical Ventilation System In Dunhuang Mogao Grottoes

Mogao Grottoes,as a result of many Buddhist caves,also known as the thousand Buddha cave,is located in Gansu,Northwest China’s Dunhuang Province,adjacent to the Xinjiang Uygur Autonomous Region.Construction began in the former Qin Dynasty era,and improvement over the southern and Northern Dynasties to the Yuan Dynasty about one thousand years of construction,formed in the cave murals,statues featuring huge cave groups,but also so far the largest and best preserved Buddhist treasures.Dunhuang grottos arts is integrated arts that are composed of buildings,murals and statues,the mural is undoubtedly the most difficult to protect and repair.But,the weather has extreme changed recently in Dunhuang,short-term heavy rain for several years,high humidity air infiltration to the cave through the vents of windows or doors,making the relative humidity increase.The increase of humidity can lead to the dissolution and migration of salt,and increase the potential risk of salt damage.In addition because the shape characteristics of individual caves,a large number of visitors to exceed the standard concentration of carbon dioxide in the cave,which is a potential hazard for the mural protection,while reducing the air quality in the cave.So the protection of the cave paintings is imminent.In this paper,we first analyze the climatic environment in Dunhuang and Mogao Grottoes,the characteristics of rainfall,temperature and humidity and wind environment in the area were obtained;Then,the article on the Dunhuang Mogao Grottoes 138 caves and 131 cave natural ventilation research test and analysis,found the same size cave depth direction and height direction of the gas flow rule,according to the above rules and existing test,simulation analysis and calculation,the main factors that affect the flow distribution in Mogao Grottoes;Finally,The typical Mogao Grottoes cave 328 as the research object,from the perspective of cultural relics of caves,natural ventilation and mechanical ventilation under the micro environment,in order to obtain the ideal mechanical ventilation is conducive to the protection of cultural relics of air flow and wind speed,and provide the basis for the stability of temperature and humidity inside the cave.According to the carbon dioxide as the tracer gas,this gas calibration of original air inside the cave,analyzing the air inside and outside the exchange rate in cave,and simulating the temperature and humidity and ventilation frequency of corresponding scale cave,a comprehensive analysis of all the results,finally obtained the airflow delivery is beneficial to the protection of cultural relics is stable at the temperature and humidity.