粒径对庚烷液雾爆炸场影响的数值模拟

Numerical Simulation of the Influence of Partical Size on Explosion Parameters of n-Heptane/Air Mixtures

为了研究液雾索特直径(D_(32))对爆炸参数的影响,以庚烷为对象,控制液雾总浓度不变(80 g·m^(-3)),改变液雾粒径,数值模拟了爆炸容器内庚烷(C_7H_(16))液雾粒径对爆炸参数的影响。结果表明:庚烷液雾场索特直径D_(32)为0~18.1μm时,最大爆炸压力p_(max)随D_(32)增加逐渐减小,最大值为1.01 MPa,最小值为0.9015 MPa。最大爆炸压力上升速率随D_(32)增大整体呈下降趋势,在0处达到最大值0.37571 MPa·ms^(-1),在18.1μm处达到最小值0.18439 MPa·ms^(-1),但在6.81~12μm发生反向突变,在10.1μm处达到极大值0.34217 MPa·ms^(-1),随后恢复下降趋势。液雾的径向火焰传播速度在径向距离15 cm附近突然增加,在16 cm之后剧烈下降。最大火焰速度随液雾场D_(32)不同而变化,D_(32)=10.1,12.9,18.1,6.81,0μm条件下液雾场的最大火焰速度依次降低,最大值为5.714 m·s^(-1),其后依次为1.737,1.36,1.34,1.27 m·s^(-1)。

To study the effect of Sauter diameter( D_(32)) of droplets on the explosion parameters,the effect of the droplets size of n-heptane( C_7 H_(16)) on the explosion parameters in explosion vessel was numerically simulated,while controlling the total concentration of droplets of 80 g·m^(-3),when changing the droplet size. Results show that when D_(32) of n-heptane droplets is between 0-18.1 μm,the maximum explosion pressure p_(max) decreases gradually with the increase of D_(32),the maximum value is 1.01 MPa and the minimum value is 0.9015 MPa. The maximum explosion pressure rise rate reveals an overall downward trend with the increase of D_(32),which reaches the maximum value of 0.37571 MPa·ms^(-1) at 0 μm,and the minimum value of 0.18439 MPa·ms^(-1) at 18.1 μm. But in the range of 6.81-12 μm,the reverse mutation occurs,reaching the maximum value of 0.34217 MPa·ms^(-1) at 10.1 μm,and then restoring the downward trend. The radial flame propagation velocity of droplets suddenly increases near the radial distance of 15 cm,and then decreases sharply after 16 cm. The maximum flame velocity varies with D_(32) of droplets. Under the conditions of D_(32) = 10.1,12.9,18.1,6.81 μm and 0 μm,the maximum flame velocity of droplets field decreases successively. The maximum value is 5.714 m·s^(-1),followed by 1.737,1.36,1.34 m·s^(-1) and 1.27 m·s^(-1).