摘要
以无水乙醇为燃料,运用荷电雾化技术,实验研究了锥-射流喷雾模式下双网格燃烧器的燃烧与热损失特性。结果表明,在当量比Φ为0.85~1.40区间内燃烧稳定,圆形片状火焰附着于燃烧网格附近,火焰直径与燃烧器内径相当。火焰温度、燃烧效率均随当量比的增大先上升后下降,在当量比Φ=1时分别达到最大值1 197.38 K、93.26%。尾气温度随当量比的增大而降低,壁面热损失随当量比增大而增加。壁面热损失与燃料完全燃烧释放热量比例为27.25%~33.08%,其中辐射热损失略高于对流热损失。燃烧器热效率在当量比Φ≤1下可达69%。双网格燃烧器可实现小尺度条件下液体乙醇的良好喷雾、蒸发与燃烧。
Electrospray technique is one of the reliable approaches to disperse liquid fuels at low flow rate. Heat loss has an important influence on the performance of micro/small scale combustors. Pure ethanol was chosen as liquid fuel,and electrospray technique was applied for fuel dispersion. The combustion and heat loss characteristics were experimentally studied in a small scale combustor with double meshes under the condition of cone-jet mode. The results showed that a round slice flame was anchored near the combustion mesh. Stable combustion was established in the equivalence ratio Φ range of 0. 85 ~ 1. 40. The diameter of the flame was near to the inner diameter of the combustor. The distance between combustion mesh and flame changed with equivalence ratios,which can be seen from the temperature distribution. The larger the equivalence ratio was,the shorter the distance was. Flame temperature and combustion efficiency were all increased firstly,and then decreased as the increase of equivalence ratios. When Φ = 1,the highest flame temperature was up to 1 197. 38 K,and the highest combustion efficiency was up to 93. 26%. The exhausted gas temperature was decreased and wall heat losses were increased with the increase of equivalence ratio Φ. The exhausted gas temperature was influenced by the distance between combustion mesh and flame. Wall heat losses accounted for27. 25% ~ 33. 08% of total heat based on complete combustion of input fuel. Radiation heat loss accounted for about 56% of wall heat losses. Under the condition of Φ≤1,the thermal efficiency of the combustor was near to 69% and then decreased as the increase of Φ. The present combustor with double meshes can realize effective atomization,evaporation and combustion of liquid ethanol at small scale.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2018年第1期375-380,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51776077
51376066)
广州市科技计划项目(201707010071)
内燃机燃烧学国家重点实验室开放基金项目(K2016-01)
关键词
小尺度
乙醇
荷电喷雾
热损失
燃烧效率
热效率
small scale
ethanol
electrospray
heat loss
combustion efficiency
thermal efficiency
