LAUSR

Abstract A new tunnel with closed portal has been constructed in the real project, most of current research on fire smoke movement are focus on traditional tunnel with two opening portals. In this paper, 44 numerical simulation tests were conducted in a 1:10 small scale model tunnel with different sealed situations, blockages and cross-sections. More specifically, two blockage ratios, width-blockage ratio β 1 and height-blockage ratio β 2 were introduced. Moreover, the maximum temperature under tunnel ceiling, as well as temperature distribution in downstream direction along the tunnel centerline were especially investigated. The results indicated that: 1) The smoke accumulated and temperature increased in the tunnel caused by the closed portal. 2) The stability of smoke layer in the tunnel destroyed and the height of smoke layer interface reduced by the blockage of metro train. 3) As the width-blockage ratio β 1 decreased, the vertical temperature and temperature in downstream direction decreased. Meanwhile, as the height-blockage ratio β 2 decreased, the vertical temperature decreased but temperature in downstream direction increased. 4) The maximum temperature beneath tunnel ceiling was positively related to the height-blockage ratio β 2 , but negatively related to the width-blockage ratio β 1 . Based on theoretical analysis and simulation results, a revised prediction model for the maximum temperature beneath tunnel ceiling was proposed, which taking into account the blockage, tunnel cross-section and heat release rate.