中文摘要：

为了研究障碍物条件下纳米SiO2粉体对瓦斯爆炸的抑制特性,采用自行搭建的150 mm×150 mm×500 mm可视化瓦斯爆炸试验系统,分别对不同质量浓度和粒径的纳米SiO2粉体抑爆特性进行了试验研究。结果表明：在障碍物条件下,纳米SiO2粉体对瓦斯爆炸具有良好的抑制效果,0.10 g/L的30 nm SiO2粉体可使9.5%瓦斯气体的最大火焰传播速度降低35%,爆炸超压降低34%;然而,纳米SiO2粉体并非质量浓度越大抑爆效果越好,而是存在最佳抑爆质量浓度,即随纳米SiO2粉体质量浓度上升,其抑爆性能先增大后减小,最佳抑爆质量浓度约为0.10 g/L;此外,纳米SiO2粉体的抑爆性能与其粒径相关,且存在最佳抑爆粒径,相同质量浓度下30 nm SiO2粉体比15nm和50 nm SiO2粉体的抑爆效果好。

英文摘要：

The present paper intends to make an exploration of the mitigation function of SiO2 nanoparticles against the gas explosion in the presence of obstacles through a self-built visualized experimental system of gas explosion with the internal volume of 150 mm × 150 mm × 500 mm. In our experiment,we have adopted a high-speed digital camera and a pressure transducer to measure both the entire process of the methane/air mixture explosion and its mitigation,as well as the different mass concentrations and different diameters of SiO2 nanoparticles. The experimental results have shown that,if 0. 1 g/L of SiO2 nanoparticles in a diameter of30 nm were added to the methane/air mixture（ with 9. 5% methane volume fraction） in the explosion chamber,it would be possible for the maximum flame front propagating velocity and the maximum explosion overpressure of the said mixture to decrease dramatically by about 35% and 34%,respectively,as against with no SiO2 nanoparticles. Thus,it can be seen that the SiO2 nanoparticles enjoy excellent suppression power for the gas explosion in the presence of obstacles. Nevertheless,the SiO2 nanoparticles at high or great mass concentration rate do not seem always in favor of the suppression effects for the gas explosion,however,there should be existing an optimum mass concentration rate for the gas explosion suppression. In other words,the explosion suppression effects that are developed by the SiO2 nanoparticles tend to increase at first and then decrease with the increase of the mass concentration rate of SiO2 nanoparticles,with the optimal mass concentration rate turning to be at about 0. 1 g/L of SiO2 nanoparticles. Moreover,the gas explosion suppression effects should also be related with the particle size of SiO2 nanoparticles. That is to say,there should exist an optimized particle size for the gas explosion suppression. It has also been found that,under the same mass concentration,the explosion inhibitive effect of SiO2 nanoparticles in a diameter of 30 nm prove to be more advanta