Ventilation performance of a novel multi-mode fume hood with supply air on contaminant with different densities

A multi-mode air-supply fume hood was designed to effectively remove contaminants of varying densities within the cabinet by altering the position and angle of the air supply. Numerical simulation methods were employed to analyse the performance of heavy-density and light-density modes in handling contaminants of different densities and to evaluate the impact of the airflow distribution on contaminant removal efficiency. The study demonstrates that optimised designs can reduce the leakage rate of the fume hood, enhancing its performance and efficiency. In heavy-density mode, increasing air supply effectively reduces room air conditioning load and building energy consumption, with a downward vertical air supply angle and a 70% air supply-exhaust ratio providing higher safety. In light-density mode, a vertically downward air supply angle offers better safety, and a downward air curtain at the lower end of the operating door is more effective in controlling contaminant leakage compared to a bottom slit air supply. The average concentration of contaminants in the fume hood was reduced by 35.98% at a 60% supply-to-exhaust ratio.