The Research About The Characteristics And Optimization Of High-Rise Residential Kitchens Centralized Exhaust System

With the rapid development of the city and the scarcity of land resources, high-rise buildings gradually become a mainstream trend, high-rise residential buildings as a typical high-rise buildings form has also been rapid development. In residential buildings, the kitchen as the "three meals a day" prepared place of each family, it is the most serious air pollution in residential areas. Currently, the kitchen of high-rise residential buildings mainly use concentrated exhaust system to exclude the fumes generated by cooking.The paper mainly on the basis of domestic and foreign relevant research, in CFD simulation-based analysis, and verified by the experimental model, made a series of studies of high-rise residential kitchen central exhaust system. Respectively, with 10 floors, 20 floors, 30 floors model as an example, analyzed the influence of floor height, flue-sectional dimensions, fan models, opening rate, and segments matching forms to exhaust efficiency, and put forward corresponding optimization programs to address the uneven exhaust, smoke intrusion and other issues.Firstly, analyzed the variation of pressure and velocity of the flue under the conditions of designing air flow 300m~3/ h, when even and uneven open. Studies have shown that static pressure of main pipe is gradually reduced from the bottom to the top, the static pressure on the bottom is large so that exhaust resistance is also large and the static pressure on the top is small so that exhaust resistance is also small, which given the basis of different segments matching forms after behind; the total pressure of main pipe is also gradually reduced from the bottom to the top, only has sudden increase on the place fan opened; the dynamic of main pipe is also gradually increased from the bottom to the top, only has sudden increase on the place fan opened; and the larger the open ratio, the greater the overall pressure inside the flue and smoke more unfavorable.Secondly, carried out the analysis of exhaust effect when power matching, studies have shown that the different performance of fans have a great influence on exhaust system, the performance curve steeper and the wider range of air flow and pressure of fan, the better of exhaust effect. When under different segments matching forms, the uniformity and overall amount of smoke of exhaust system has greatly improved, and more refined partition, the better exhaust effect; there are also illustrated that the increased flue-sectional dimensions can effectively improve the exhaust effect, a reasonable crosssectional dimensions of 10 floors model is 320X250 mm, a reasonable cross-sectional dimensions of 20 floors model is 500X320 mm, a reasonable cross-sectional dimensions of 30 floors model is 600X450 mm.Finally, analyzed the variation of the bus links local resistance coefficient under distributed multi-power source system, and pointed out the main factors, explained the main difference about the variation of the bus links local resistance coefficient between the distributed multi-power source system and unpowered free outflow system; also proposed a new flue form, by changing the angle between main pipe and branch pipe to improve the exhaust situation, analysis and demonstration of its exhaust effect can effectively improve and has a great performance and optimize of the central exhaust system.