Research On Central Exhaust System For Residential Kitchen In High-rise Buildings By Cfd

With in-depth understanding of the dangers of indoor pollutants and the requirements for indoor air quality on continuous improvement, related research on kitchen cooking oil fume and kitchen ventilation system were more and more. The shared-vertical exhaust system which was used to high-rise residential buildings commonly, played a vital role for ensuring good indoor air quality. Such systems included vertical exhaust main pipe, horizontal exhaust branch pipe, range hoods, the roof hood, fire-protection device and check valve. However, through the relevant data and response of the households, found that this exhaust system existed phenomena of flue gases flowing back to the no-cooking kitchen and poor effect in the bottom households.In this paper, several recommended styling products in national standard atlas-residential exhaust passage (一) (Atlas No.07J916-1), were computed by the method of CFD. Through the 12-storey residential kitchen exhaust system simulation, no increase in cross-sectional area and increase the range hood performance,serveral results were obtained as follows:(1) High-rise residential kitchen exhaust system of the flow resistance was too large, the bottom households of exhaust volume could not reach the design exhaust volume (370m3/h), general was below 300m3/h. (2) The problem of uneven exhaust was serious, the value of Qmax-Qmin was between 170 and 270 m3/h, but the average value about 350 m3/h.(3)The low and middle parts of system were in a high static pressure, about 200Pa, it could not fundamentally solve the phenomenon of flue gases backflow through setting variable-pressure board in the local and optimization of diversion device, etc.(4)Equal-section exhaust passage in which added diversion device, was better than not added. However, added diversion device and variable-pressure board all together, the using effects were changed bad on the contrary. Advised designers and developers to select the exhaust passage that only diversion device were set up.In this paper, about the method, which get through households choosing different performance of range hoods by zone, was reserched in order to inhancing system's exhaust uniformity. Based on the example of the calculation of 12-storey residential, results indicated that households'exhaust uniformity had greatly improved, when households choosing different performance of range hoods by zone. After households choosing different performance of range hoods by zone (0.66 of simultaneous coefficient), the average exhaust volume for all households of this system had risen 9.2%,the difference between the maximum and minimum exhaust volume was reduced 86.9%. Therefore, this method could be researched for further and applied it in the future.For the current exhaust system of high-rise residential kitchen exist ills that the flue gases flowed back to the no-cooking kitchen, a new idea was presented and new type of exhaust passage construction was given in this paper. Through adding a negative pressure exhaust duct between the original exhaust passage and the kitchen, could effectively prevent flue gases flowing back to the no-cooking kitchen, but also to ensure that the no-cooking kitchen maintain a certain amount of exhaust, bring about ventilation of residential buildings.