气体泄爆压力分步计算模型及其湍流修正

通过将密闭空间内爆燃泄放过程进行微分,假设各微分时段内爆燃泄放过程均按照先燃烧、再泄放、最后压力平衡的过程独立分步进行,最终得到泄爆压力分步计算模型。同时,在尺寸为2 m×1.2 m×0.6 m的爆炸腔体一端安装击穿压力相同、泄放面积不同的泄爆构件进行泄爆实验,对分步压力计算模型进行验证。对比发现:大面积泄放条件下,2个传感器测得的压力曲线基本重合,均为单峰值曲线,此时模型计算值与实验结果吻合较好;小面积泄放条件下,腔体内压力曲线均为双峰值曲线,由于泄放截面改变加剧口部湍流扰动,使得腔体内部产生压力梯度,近泄爆口处传感器测得的第2个压力峰值要大于腔体内部传感器相应的测量值,经湍流速度修正后的压力计算模型可以较好地描述近泄爆口处的压力变化情况。

A sub-step calculation model of gas explosion venting pressure and its turbulent correction

By differentiating the explosion venting process in a confined space, the process in each step was assumed to develop in three independent sub-steps: combustion, venting and equilibrium, and a sub-step calculation model was obtained for gas explosion venting pressure. In order to verify the calculation model, the vented explosion experiments were carried out in a 2 m×1.2 m×0.6 m chamber, in which was mounted on two kinds of venting components with the same burst pressure and different venting areas. The results show that: in the case of large-size venting, only one peak overpressure was measured and the pressure curves recorded by the pressure transducers T1 and T2 were nearly overlapping. In this condition, the pressure values by the model agree well with the test data. In the case of small-size venting, double-peak pressure curves were recorded. The second peak measured by the pressure transducer T1 near the vent is larger than that measured by the pressure transducer T2 in the chamber as a result of pressure gradient, which is caused by the turbulent distortion due to the change of the flow cross section. The calculation model under turbulent velocity correction can well describe the pressure change near the vent.