Study on Tunnel Air Curtain Insulation System for Cold Areas

With the growing number of tunnels in high-latitude and high-altitude areas, freezing damage is all the more obvious. In traditional insulation layer method, insulation layer is laid in the tunnel to prevent invasion of cold air by taking advantage of its low thermal conductivity. However, due to its narrow temperature adaptation range and high construction and maintenance costs, this method cannot completely solve the problem of tunnel freezing damage. To solve this problem, this paper proposes tunnel air curtain insulation system which can generate electricity using solar energy. Based on parameters such as indoor air temperature and wind velocity in the thermal insulation room, on the one hand, it intelligently controls running sets of air curtain, jet flow angle, and velocity, prevents invasion of the external cold temperature into the tunnel, so that the tunnel maintains an interior temperature above 0°C. On the other hand, it intelligently diagnoses air curtain machine to provide system fault warning, so that the system keeps safe and reliable operation. The results show that air curtain technology can effectively solve the problem of tunnel freezing damage in cold areas; multiple air curtains in series connection provide better barrier efficiency. From the measured data and calculation results of Lafashan tunnel, it can be seen that an air curtain is installed at the tunnel portal with jet speed of 22.7 m/s and temperature of 35.24°C, which can meet the tunnel without freezing damage when the external temperature is −10°C, and the external wind speed is 2 m/s, providing a new method for tunnel insulation technology in cold area.

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