Numerical Simulation Of Pollution Control In Commercial Kitchen

Modern commercial kitchen is often exposed to the indoor environment with high energy consumption,high heat load and high pollution due to the amount of food cooked and special cooking methods,which poses a great threat to chefs.The catering industry is becoming an important part of China’s service economy.With the increasing demand for indoor air quality,more attention has been paid to the research on the efficient collection technology of oil fume,which is of great significance to guarantee the health of chefs and improve the comfort of the kitchen environment.In this paper,Computational Fluid Dynamics(CFD)software Fluent is used to simulate and analyze the basic situation of typical commercial kitchen.On this basis,an efficient exhaust hood structure and make-up air system is proposed.The primary collection efficiency of fume particles,mean PMV and PMV uneven coefficient are taken as the standard for evaluating the performance of commercial exhaust hoods and the thermal comfort of the human body,respectively.It indicates that the hood with convex butterfly-shape guide plates is recommended under the reference exhaust airflow rate of cooking zone,which has an average primary collection efficiency of18.15% higher than that of the canteen hood and alleviates the local thermal discomfort of the chefs in the cooking zone.Based on the optimal design of the exhaust hood structure,the make-up air system of the canteen is optimized.We put forward the downward air curtain combined vent supply and upward air curtain combined vent supply modes and calculate the best air curtain supply volumes in different modes.The collection effect is better when the air curtain supply volume accounts for 8% ～ 10% of the exhaust airflow rate.The three supply modes are further compared on the basis of the optimal air curtain supply volume.It is concluded that the average primary collection efficiency of the cooking zone in the upward air curtain mode is slightly higher than the downward air curtain mode by 1.58%.In the former mode,the PMV distribution is more uniform than the latter,and a better thermal comfort experience can be obtained.Comparing the improvement effect of the exhaust hood structure and the make-up air system on primary collection efficiency,it is found that the structure optimization contributes up to 80% to the primary collection efficiency improvement of the cooking zone,which means the hood structure of the commercial kitchen should be regarded as the primary design factor.The simulation work is conducted by adding momentum source item to simulate the arm movement of chef cooking operation.When the stirring velocity changed from 0 to 1.5 rps,the reductions of the primary collection efficiency caused by the simplified vertical and horizontal disturbance modes are both within 5%.The anti-interference of the above design is verified.Among them,the horizontal disturbance mode interferes with the oil fume collection by less than 3%,so it is suggested as a preferential cooking way for reducing kitchen fume pollution.