Qualitative and quantitative investigation on concentration of indoor dense gas caused by leakage and diffusion

A set of experimental system was built to study the concentration field change and influencing factors for the leakage and diffusion of indoor dense gas. CO ₂ was used in the experiment. CO ₂ gas tends to settle down after leakage. CO ₂ gas concentration values are disparate at different positions in the same height. It takes longer time to get the same CO ₂ gas concentration at higher positions than low positions. The concentration distribution is relatively approximate in the horizontal plane near the ground, while an uneven distribution is shown in the vertical plane. The concentration values increase with an increase in the leakage source strength at the positions which are lower than release source. Gas concentration is relatively stable at lower positions, while the fluctuation of gas concentration appears at higher positions. When the leakage source height is higher, the concentration near the ground reduces under the same condition. However, the whole space has a higher CO ₂ concentration which can generate greater risk. Incidence angle plays a great role in CO ₂ concentration. A theoretical calculation method was presented to predict CO ₂ concentration. The validation of the computation method was made by comparison of experimental data with calculation results.