Field test and CFD modeling for flow characteristics in central cooking exhaust shaft of a high-rise residential building

Abstract

With the increasement of worldwide population, high-rise buildings of multi-dwelling units have been widely used as a residential building, especially in China, United States and India etc. At present, most of cooking exhaust shafts in high-rise residential building takes the form of central exhaust system. However, the mal-distribution of exhaust flow in central exhaust system often leads to oil fumes reflux and odor migration, which decreasing the performance of kitchen hoods. This study is conducted in a 32-storey residential building which employed central exhaust system. Static pressure and velocity distribution were investigated in central exhaust shaft with uniform cross section. In addition, Computational Fluid Dynamics was adopted to analyze flow characteristics and validated by comparing the simulation results with experimental data. The emphasis of this study lies in the effects of temperature differences and equally spaced operating rates of kitchen hoods on flow characteristics in central exhaust shaft. The results showed that when the temperature difference varies from −12°C to 30°C, the locations of maximum static pressure gradually moved downwards and presented a low-high-low distribution. The maximum occurred in the middle-low storeys under different operating rates. This paper is valuable for HVAC engineers to improve the design of central cooking exhaust shafts in high-rise residential buildings, and solve the mal-distribution problems of exhaust flow in central exhaust systems.