Study on the Diffusion Law of Heavy Gas Leakage in Complex Scenarios Based on Scaled-Down Experiments

In order to study the effects of temperature, wind speed, and leakage volume on the diffusion of heavy gas leakage, this paper establishes a scaling model for the experimental study of gas leakage and diffusion by using the similarity theory with a certain factory as the target. And carbon dioxide gas is selected to replace the toxic and harmful heavy gas to carry out experiments under different temperatures (0-40 °C), wind speeds (0-2 m/s), and leakage velocities (2.5-12.5 L/min), respectively. The results showed that the diffusion rate of heavy gas expanded with increasing temperature under the conditions of wind speed of 0.25 m/s and leakage velocity of 1.5 L/min. When the temperature was increased from 0 to 40 °C, the concentration increase at each location was 125-290% at 600 s. Under the condition of temperature of 20 °C and leakage velocity of 5 L/min, the concentration at each location increased linearly with diffusion time when there was wind, while the linear relationship was not obvious when there was no wind. The effect on the concentration was larger when the wind speed was less than 1 m/s and smaller when the wind speed was greater than 1 m/s. At 20 °C and a wind speed of 0.5 m/s, the concentration of carbon dioxide at each location was increasing as the leakage increased. As the leakage velocity increases from 2.5 to 12.5 L/min, the carbon dioxide concentration at 600 s spreads 2-14 times. The research in this paper provides some decision support for the rescue work, which is important for improving the emergency rescue capability of the leakage accident.