| This study is based on the phenomenon that is smoke backflow frequently in exhaust pipes in a high-rise residential kitchen,selects more powerful centralized exhaust system, uses the CFD simulation calculation as the research method. Simulates and analyzes the internal gas flow state, pressure, velocity distribution within the system and user exhaust quantity based on the designed experimental system model. Understands the system operation characteristic and determines the best suitable smoke flue section size.The research mainly includes the following respects:Analysis and calculation of the pollutants generated by kitchen lampblack and discover when the lampblack pollutants produced in cooking process mix the surrounding air flow into the common exhaust systerm, the fluid viscosity is very close to the air viscosity, the influence of the particle pollutants in kitchen lampblack to mixture gas viscosity can be ignored.Simulation the flow characteristics of the exhaust pipes afer diversion component is installed in it. And discover in the area of main and branch pipes rendezvous, velocity of main flue is the main effect to influence the tubes of ventilation.the size of the exhaust is less effect.Detailed simulated check inverse valve type centralized exhaust system, and summarize the operation characteristic of system.In the higher probability satuation, the system operation more stable;Under the same probability satuation, if the continuous boot be located in the lower position, the smoke exhaust ability of system is abate and the main flue static pressure increases, users imported flow overall decline, when it in the middle position, every few layer, a certain users imported flow is larger ascension, present certain periodic trend. The same as the main branch-type centralized exhaust system, the pressure distribution of more power check inverse valve-type exhaust system, from the lower to the upper showing low-high-low distribution trends.To the check valve-type centralized exhaust system,under the 20th-floor residents choose 400 * 400mm cross-sectional area of the pipeline,which can meet the requirment of all users exhausting simultaneously the whole operation rate. The 20th-floor residents choose 400* 400mm section size,which can meet 80% operation rate for eliminating smoke, and the proposal choose 400* 500 mm section size in whole operation rate.The 30th-floor residents choose 400* 600mm section size,which can meet the requirment of all users exhausting simultaneously the whole operation rate. |
