Optimizing Study About Exhaust Hood For The Air Supplement System Of The Kitchen

Due to the progress and development of social,pursuit about people of the quality of indoor air quality is also growing.In the modern society,people spend about more than 80%of the time on the indoor activities,especially children.The older spend longer periods of time.So that the indoor air quality is closely linked to the healthy and quality of life.Kitchen,as an integral part of the house,is the main source of indoor pollution.When people cooking in the kitchen,temperature of the environment is high.In the condition of high temperature oil and food will happen thermal oxidation decomposition reaction,and generate mixed gas,smoke and fuel exhaust gas.Because of the air tightness and thermal insulation of modern residential wall have been improved,it prevents harmful gas such as lampblack escaping from kitchen in a way.According to the investigations and researches,they point out that if we purpose to relieve the harmful gas,we must adopt effective methods to control the spread of harmful gases such as lampblack and reduce the concentration of the pollutants in the kitchen.In present residential kitchen exhaust hoods are usually selected in kinds of ways to control the process of cooking oil fume,but this method does not completely eliminate lampblack pollution effectively.Because the modern basic residential kitchen doors and windows are always closed,in this case,the natural ventilation rate is limited by the larger,and the filling volume which is mainly rely on the crack of door and window.Due to the small air volume,it cannot satisfy the balance of air volume.Bad air quality caused by lampblack will not only affect the comfort of people but also harm to people's health.The author grasps the knowledge of the civil residence kitchen layout,and uses commercial CFD-AIRPAK3.0.16 software on the study of air distribution of kitchen.Simulation is mainly conducted from two aspects:on the one hand,analyze temperature field,velocity field,pressure field and concentration field of the kitchen and calculates the power of lampblack machine exhaust hood in the condition of passive air supplement.On the other hand establish four slots to supply air around the stove to simulate the temperature field inside the kitchen,velocity field,pressure field and concentration field of air distribution form under different working conditions.By adjusting the exhausting air,the wind slot width,jet velocity from slots learned that exhaust air,the wind slit width don't make an important role to control the concentration of pollutants in kitchen but the different pressure between inside and outside of the working area of the unfavorable point which is caused by the change of velocity flow from slot plays an decisive role in controlling the concentration of the pollutants.Calculate the power of exhaust hood in the best working conditions including passive air supplement and slot air supplement separately and infer the energy saving rate of the optimized exhaust system to improve the indoor air quality.The air supplement of this study reduces the pressure effectively which is caused by the inside and outside when the exhaust hood running and reduces the negative pressure of the room.It avoids the indoor drain water seal which will be damaged and prevents the poison gas being pumped into the room by the drainage system.