| Summary: | 碩士 === 國防大學理工學院 === 機械工程碩士班 === 98 === The solid blast walls were settled in proper locations of most of the ammunition storage facilities or major command centers to protect the buildings from bomb attack. The main function of blast walls is to sustain the impact from high temperature and pressure explosive waves, fragments and flames from inside or outside of buildings. The military affair understands that undergrounding of important facility or command station is the trend. Especially the accuracy of upgrading weapons on target is enhanced with advanced technologies. To ensure the buildings away from the damage from the bomb threat at close range, a systemically design on the geometry of blast wall is necessary due to there is a limited distance and size considerations. Present thesis aims to change the wall configuration, height and thickness of the blast walls and tests their performance on reduction in detonation pressure over walls.
The computational fluid dynamics approach based on the control volume method is employed in present work. The detailed flow field is obtained by solving the transient, two-dimensional and compressible Navier-Stokes equation with laminar flow assumption. The ANSYS Gambit 2.4.6 software is used to generate the solid models and the grid systems in computational domain. The high temperature and pressure gradient generated by the explosive of TNT bomb, propagation process of blast wave, and interaction of blast wave with blast walls are simulated with the commercial software of Fluent 12.0.7. The post-processing process was achieved with the Tecplot 360 software. A validation run with published data (TM5-1300) was finished and results showed that a reasonable agreement can be achieved with present numerical code. Among tested parameters, the effect of blast wall’s height on the reduction of denotation pressure is most significant. A increasing of blast wall with 1 mm caused the drop in overpressure ratio of 40% can be observed.
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