Study On Temperature Field And Structure Optimization Of Pellet Fuel Oven

The oven,as a kitchen appliance,has been gradually popularized in China.While the pellet fuel oven,as a new type of oven in recent years,has the advantages of low use cost and good food baking taste.However,due to the lack of structural design experience,the plane of grill will have problems of uneven temperature distribution and low thermal efficiency.How to solve this problem has troubled most domestic production enterprises.This paper focuses on this problem,conducts research on a certain type of pellet fuel oven,combines numerical simulation and experimental verification methods,analyzes its internal flue gas flow and temperature distribution law,explores the causes of uneven temperature distribution and low thermal efficiency on the plane of grill,and carries out structural optimization design for the pellet fuel oven with this goal.First of all,this paper introduces the structure and the flow heat transfer principle of pellet fuel oven.The high-temperature flue gas generated by the combustion of pellet fuel,then flows through the plate for guiding oil,plate for blocking fire,grill and finally flows out of the chimney and oil guide port.This process is accompanied by convection heat transfer and radiation heat transfer,thus baking food.Secondly,according to the actual structure of the pellet fuel oven,a reasonable simulation model is established and numerical simulation research is carried out.Compared with the experimental data,the simulation results are consistent with the experimental results.The results show that because the fan is located at the lower left of the oven body,the wind speed and direction of each vent on the combustion chamber are different,resulting in the bias of the hot air at the combustion chamber outlet.At the same time,due to the obstruction of the plate for guiding oil,plate for blocking fire,the hot air enters the plane of grill from the front and rear sides.The front hot air does not flow through the main baking area,reducing the convection heat transfer effect,resulting in uneven temperature distribution and low thermal efficiency on the plane of grill.Thirdly,in order to improve the temperature distribution uniformity and thermal efficiency on the plane of grill,different structural improvement schemes are proposed.The bias of the hot air at the combustion chamber outlet is solved by placing the fan under the combustion chamber and uniformly distributing the vent.The problem that the hot air does not flow through the main baking area is solved through the oil collecting pan and the cylindrical fixed structure.By increasing the height of the combustion chamber and reducing the volume of heating space,the total heat energy flowing to the plane of grill is increased.Based on the above improvements,a new type of pellet fuel oven is designed,and its numerical simulation research is carried out.The results show that the standard deviation of temperature of the new type of pellet fuel oven is 69.2% lower than that of the original pellet fuel oven,and the average temperature is 11.8% higher than that of the original pellet fuel oven,which has been significantly improved in both aspects.Fourth,in order to increase the baking area,a new type of multi-layer pellet fuel oven structure is designed,in which a hot air channel is set at the bottom of the oven and the inner side of the two walls,through which the hot air flows into each layer of the grill.The original mode of single heat source at the bottom of the oven is changed to the mode of multiple heat sources on both sides of the grill,which reduces the influence of food on the flow rate and direction of hot air,makes the temperature difference between different layers of grills relatively small,and the temperature distribution of the same layer of grills relatively uniform,so it is feasible.Finally,a comparative experiment was carried out on the pellet fuel oven before and after the improvement,which verified the validity of the simulation model and the feasibility of the optimization scheme and also reflected that the research results can effectively improve the baking effect of food,which has good reference value for the research and development of pellet fuel oven equipment and the baking preparation process.