Abstract:

To further study the characteristics of flame propagation and explosion wave properties of hydrogen in confined spaces under low-temperature conditions, an explosion chamber was designed, and its precooling process was undertaken. The experimental chamber was designed as a double-layer structure, and the low-temperature nitrogen gas was adopted as the precooling medium, to ensure the temperature of the premixed low-temperature hydrogen/air mixture can be maintained at the preset experimental condition. Based on the fundamental principles of thermodynamics, the steady thermal analysis approach was adopted, and a mathematical model of the chamber’s precooling process was established. The impacts of insulation layer thickness and chamber wall thickness on the precooling process were discussed, and the influences of precooling medium flow rate on precooling time and medium consumption were explored. The results revealed that, when the insulation layer thickness reached 30 mm, heat load from the environment significantly decreased. Compared with the 10 mm and 5 mm wall thickness conditions, the precooling time at 3 mm is reduced by 70.11% and 39.01% respectively, and the consumption is reduced by 70.12% and 39.00% respectively. Increasing the precooling medium flow rate can effectively shorten the precooling time, but the change in precooling medium consumption is not significant.

Key words: hydrogen, safety, explosion, low-temperature hydrogen, heat transfer, chamber precooling

摘要：

为了深入研究低温条件下受限空间内的氢气火焰传播规律及爆炸波特性，设计了爆炸腔体并对其预冷过程开展了研究。实验腔体采用双层结构，通过通入低温氮气来实现腔体预冷，以此保证低温氢气/空气预混气温度维持在设定实验温度。基于热力学基本理论，采用稳态法，建立了腔体预冷过程数学模型，分析了保温层与腔体壁厚对预冷过程的影响，探究了预冷介质流量对预冷时长、介质消耗量的影响规律。研究发现，保温层厚度达到30 mm时环境漏热显著降低；相较于10、5 mm壁厚工况，3 mm时预冷时长分别降低了70.11%、39.01%，消耗量分别降低了70.12%、39.00%；增大预冷介质流量，可以有效缩短预冷时长，但预冷介质消耗量的变化幅度不显著。

关键词: 氢, 安全, 爆炸, 低温氢气, 传热, 腔体预冷