Using air curtains to reduce short-range infection risk in consulting ward: A numerical investigation.

Air curtains is promising in reducing the short-range infection risk in hospitals. To quantitatively evaluate its performance, this paper explores air curtains equipped on normal consulting desk to avoid doctor's direct exposure to the patient exhaled pollutants. A numerical investigation is conducted to evaluate the effects of supply air velocity and angle on cutting off performance. Simulation results show that the average mass fraction of exhaled pollutants decreases significantly (70%-90%) in the consulting ward, indicating satisfying performance of air curtains. Increasing supply air velocity is demonstrated to be conducive in forming full air curtains, whereas an excessively high supply air velocity may be of adverse effects by entraining exhaled flow. Besides, the supply air angle is also critical due to its coupling with supply air velocity. It is found that larger angle (0°-40°) is better where velocity is less than 3 m/s, otherwise a small angle (20°) is preferable where velocity is larger than 3 m/s. Exhaled flow could be well suppressed at the supply air angle 20° but moves over air curtains at 40°. This study can provide effective and intuitive guidance in applying air curtains in consulting wards. Electronic Supplementary Material ESM: Supplementary material is available in the online version of this article at 10.1007/s12273-020-0649-7. The ESM files include the animation of patient exhaled droplets from the droplet birth at 0 s to 5 s under the supply air angle 0°, 20°, 40°, at supply air velocity 3 m/s.