Design And Experimental Study Of A Forced Draught And Partially-aerated Chinese Cooking Appliances

A large number of coal consumption in China makes haze and other environmental problems increasingly serious.With the emphasis on environmental protection work and the vigorous promotion of "coal to gas" project,the natural gas industry has been developing vigorously.Under the general application prospect of natural gas,gas cookers will also usher in new development.As the main cooking equipment in the logistic kitchen such as canteen,guesthouse and so on,the number of Chinese cooking appliances is increasing.At present,most of the Chinese cooking gas appliances stoves in the market are mainly atmospheric or air blast burner,with low thermal efficiency,only about 20% and incomplete combustion,causing environmental pollution in the kitchen.Energy saving,high efficiency,low carbon and environmental protection gas burner has become a new requirement for the development of gas cookers in the future.This paper first introduces the basic theory of gas combustion and the mixing of gas and air jets,and designs a new type of forced draught and partially aerated burner.The air pipe of the primary air and secondary air of the new type of forecd draught and partially aerated burner adopts the concentric circle arrangement,so that the air volume is all supplied by the fan,avoiding the interference from the external air flow to the combustion condition and making the combustion more complete.Secondly,based on the conservation of heat,this paper makes a theoretical study on the heat transfer process of all parts of the Chinese cooking gas applianecs,and establishes a steady heat transfer model of the Chinese cooking gas applianecs,which is of great guiding significance for the design of Chinese cooking gas applianecs.Then,through the experimental study,this paper examines whether the heat load and thermal efficiency of the forced draught and partially aerated burner are in conformity with the design requirements and whether the pollutant discharge reaches the standard,and the applicability of the steady heat transfer model of the Chinese cooking gas applianecs is verified.The experimental results show that: Because of the different gas properties and the influence of the burner structure,the heat load of the new type of forecd draught and partially aerated burner is less than that of the theoretical calculation under the pressure before the brner which is within the range of 1500 Pa ~ 2800 Pa.And Its deviation coefficient is between 1.08 and 1.10.Under rated pressure,the burner’s thermal efficiency reaches 40.08%,reaching the state level two energy efficiency standard,and CO and NOx emissions meet discharge standards;For the steady heat transfer model of the Chinese cooking gas appliancs,the temperature measurement value of the furnace wall surface and the flue gas is greater than the theoretical value,but the relative error of the two temperature values is less than 10%,which shows that the steady heat transfer model has high accuracy.Finally,by analyzing the heat of each part of the Chinese cooking gas appliances,we can see that the heat loss from the flue gas discharge is the largest,reaching 81.86% of the total heat loss.The heat transfer model is applied to optimize the calculation of the thermal efficiency of Chinese cooking gas appliances and it is found that: When the air temperature rises 100 ℃,the heat efficiency can be increased by 2.4%,which is equivalent to 5% of the gas saving.The air is preheated to 300 ℃ by the waste heat of the flue gas,and the theoretical thermal efficiency can reach 46.02%;Reducing the excess air coefficient of the burner from 1.9 to 1.5,the thermal efficiency can be increased by 18.81%;When the bottom diameter of the furnace is set at 50 mm~90 mm,the high efficiency of the Chinese cooking gas stove can reach 39.37% ~ 40.31%.