开口率对置障管道火焰传播特性影响模拟

Simulation on effects of aperture ratio on flame propagation of barrier pipelines

为了揭示开口率对置障管道内可燃气体火焰传播特性的影响,在80 mm×80 mm×500 mm的置障管道中通过改变管道末端开口率,基于计算流体动力学(CFD)软件,采用Zimont燃烧模型,开展丙烷预混气体爆炸特性的大涡模拟研究。结果表明:置障管道的末端开口对火焰传播速度具有促进作用,火焰传播速度峰值随开口率的增大而增加;障碍物的存在导致管内产生涡团,且阻塞率越大,涡团规模越大,湍流程度增加,从而加快了火焰传播速度。管道中的峰值压力随开口率的增大而减小,开口率为6.25%时阻塞率为0、0.5、0.7置障管道内的峰值压力分别为0.0694、0.2367、0.2107 MPa,而开口率为64%时则各置障管道峰值压力分别降为0.0016、0.0052、0.0042 MPa,并且开口率越大、阻塞率越大的管道内的压力波动越明显。管道在开口状态下,障碍物阻塞率是影响火焰传播速度的主要因素,管内峰值压力随阻塞率增大呈先增大后减小的变化规律。

A 80 mm×80 mm×500 mm barrier pipeline model was created using the Zimont combustion model based on CFD software and large eddy simulation.The explosion characteristics of propane premixed gas were studied by changing the aperture ratio of pipe end.The results show that the end opening of the barrier pipe promotes flame propagation velocity,and the peak value of the flame propagation velocity increases with the increase of aperture ratio.The presence of an obstacle caused a vortex in the tube.Higher blocking ratio leads to larger vortex mass and increased turbulence,which accelerates the flame propagation velocity.The peak value of the flame propagation velocity increases with the increase of aperture ratio.The peak pressure in the pipe decreases as the aperture ratio increases.When the aperture ratio was 6.25%and the obstacle blocking ratios were 0,0.5,0.7,the peak pressures in the barrier pipes were 0.0694,0.2367,and 0.2107 MPa,respectively.When the aperture ratio was 64%,the peak pressures of the barrier pipes were reduced to 0.0016,0.0052,and 0.0042 MPa,respectively.Higher aperture and blocking ratios result in more pronounced pressure fluctuations in the pipeline.When the pipeline was in open state,the obstacle blocking ratio was the main factor affecting the flame propagation speed.The peak pressure in the pipe increased first and then decreased with the increase of the blocking ratio.