Numerical Study on Effect of Obstacles on Hydrogen Deflagration Characteristics
The influence of the shape,blockage ratio,and spatial position of obstacles on the deflagration characteristics of premixed hydrogen and air in a semi-confined duct was investigated using Computational Fluid Dynamics(CFD)simulation techniques.The results indicate that,when the blockage ratio is the same,the flame propagation speed is little affected by the shape of obstacles.However,the deflagration pressure is significantly influenced by obstacle shape.Triangular and circular obstacles result in the highest and minimum overpressure,respectively.The overpressures for square,rectangular and trapezoidal obstacles are close.For rectangular obstacles,the blockage ratio has a noticeable impact on both flame propagation speed and deflagration pressure.The flame propagation speed increases first and then decrease with increasing blockage ratio,while the overpressure increases with the blockage ratio.For the rectangular obstacles with the same blockage ratio and spacing,both the flame propagation speed and overpressure are the greatest when they are arranged on both the top and bottom sides of the duct,the second when they are located at the center axis of the duct,and the minimum when they are at either the top or the bottom of the duct.
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