Experimental and numerical investigation of an efficient oxygen supply device for improving the sleep environment at high altitudes

Hypoxic environments at high altitudes can cause severe sleep disorders in nonlocal personnel. However, existing oxygen supply methods are plagued by discomfort, restricted movement and inefficiency. To alleviate the above disadvantages, this study presents an efficient wall attachment oxygen supply device (WAOS-D) to improve the oxygen environment during sleep. The flow characteristics of jet, including the jet trajectory of the WAOS-D, were revealed by experimental and numerical methods. Furthermore, semi-empirical formulas for centerline velocity and concentration decay were obtained, which provides clear guidance on WAOS-D design under different operating condition, such as different altitudes. The WAOS-D was compared with the full-space diffuse oxygen supply (FDOS) method and traditional local diffuse oxygen supply (LDOS) method in terms of the oxygen enrichment effects. The results showed that after 1 hour of oxygen supply, the oxygen concentrations at the optimal breathing point of WAOS-D, FDOS, and LDOS were 25.6 %vol, 22.7 %vol, and 22.0%vol. The oxygen rise rates of the WAOS-D were 2.7 and 4.6 times higher than those of the FDOS and LDOS, respectively. The LDOS method showed the highest inhomogeneity coefficient within the breathing zone, followed by FDOS and WAOS-D, indicating that WAOS-D provides the best oxygen enrichment uniformity. The study indicated that the WAOS-D could efficiently create a comfortable and uniform oxygen-enriched environment during sleep. The current study motivates further research on the efficient oxygen supply method at high altitudes.