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本文在现场对比实验和相似模型实验的基础上，采用理论分析与实践相结合的方法，研究了下行通风时沼气涌出和分布的规律、降尘和降温的效果与机理、发生外因火灾时风流的逆转规律以及能够抑制采空区自然发火的原因，并全面分析了下行通风的优缺点和存在问题。提出了下行通风的合理使用条件，得出了下行通风时断面最高沼气浓度比上行通风低、沼气层长度比上行通风短、吹散沼气层所需风速也比上行通风小，而且倾角愈大它们之间的差异也愈大的重要结论。研究结果表明，采面使用下行道风后，煤尘浓度可降低２０～６０％，倾角愈大，降尘效果愈好；在相同火势的情况下下行通风本侧风路比上行通风旁侧风路风流发生逆转时所需的温度低、时间短；下行通风能有效地降低采面温度１～５℃，工作面愈长、走向长度愈长、倾角愈大、原岩温度梯度愈大、机械化程度愈高，其降温的效果也愈好。建议修改《煤矿安全规程》时，取消对下行通风的限制。
Based on the field experiments and similar model experiments, this paper combines the theoretical analysis with practice to study the law of gushing out and distribution of downhole ventilation, the effect and mechanism of dustfall and cooling, Reverse rule and the reason that can suppress spontaneous combustion in goaf, and comprehensively analyzed the advantages and disadvantages and the existing problems of down ventilation. The reasonable use conditions of downward ventilation are put forward. The maximum biogas concentration at downstream section is lower than that of upstream section, the length of biogas layer is shorter than that of upstream section, and the required wind speed of biogas layer is smaller than that of upstream section. The bigger the difference between the important conclusions. The results show that the coal dust concentration can be reduced by 20-60% after using the downwind wind on the mining face, and the greater the inclination angle is, the better the dust reduction effect is. In the same fire situation, the downwind ventilation side air duct is higher than the upside ventilation side air duct When the wind flow reverses, the required temperature is low and the time is short. Downward ventilation can effectively reduce the temperature of the mining face by 1 to 5 ℃. The longer the working face and the longer the strike length, the greater the dip angle, the greater the temperature gradient of the original rock, and the degree of mechanization The higher the cooling effect, the better. Proposed to amend the “coal mine safety regulations”, remove restrictions on the downlink ventilation.