Flame characteristics of alcohol electro-spraying in counter-flow combustor

doi:10.11949/0438-1157.20190599

Abstract

Abstract:

Studying the flame characteristics of liquid fuel atomized combustion helps to understand the entire combustion process. A new counter-flow combustor based on the technology of electro-spraying was designed. Experiment studies on electro-spraying shape and flame characteristics were carried out using alcohol as fuel. The primary focus is paid on the effects of strain rate and equivalent ratio on flame characteristics at different fuel flow rate, including flame temperatures and dimensionless diameter of the flame. The results show the boundary between atomized core regions and satellite regions of the spray gradually disappears when increasing alcohol flow rate, the liquid column of spray appears when fuel flow rate arrives 13 ml/h. The flame remains stable when the equivalent ratio is less than 1 but oscillates when the equivalent ratio is more than 1, dimensionless diameter of the flame decreases with increasing equivalent ratio. As the strain rate increases, the dimensionless diameter of the flame and the temperature decrease.

Key words: gas-liquid flow, fuel, alcohol, electro-spraying, counter-flow flame, spray shape, flame characteristics

摘要：

研究液体燃料雾化燃烧的火焰特性，有助于理解整个燃烧的变化过程。基于对冲火焰结构，以无水乙醇为燃料，设计了乙醇荷电喷雾对冲燃烧装置。通过对喷雾和火焰进行拍摄，并对火焰温度进行测量，得到了不同燃料流量下的喷雾形态、火焰形态和火焰温度变化，探讨了不同当量比、应变率对火焰形态和温度的影响规律。结果表明：随着乙醇流量的增加，喷雾的雾化核心区域和卫星区域的分界逐渐消失，当乙醇流量增加到13 ml/h时，喷雾出现液柱。当量比小于1时火焰保持稳定，当量比大于1时火焰出现振荡，火焰的无量纲直径随当量比的增加呈减小趋势。随着应变率的增大，火焰的无量纲直径减小，温度降低。

关键词: 气液两相流, 燃料, 乙醇, 荷电喷雾, 对冲火焰, 喷雾形态, 火焰特性

CLC Number:

TK 16

Hongcheng YE, Yunhua GAN, Zhengwei JIANG, Yanlai LUO. Flame characteristics of alcohol electro-spraying in counter-flow combustor[J]. CIESC Journal, 2019, 70(12): 4787-4794.

叶宏程, 甘云华, 江政纬, 罗燕来. 乙醇荷电喷雾对冲燃烧的火焰特性[J]. 化工学报, 2019, 70(12): 4787-4794.

Figures/Tables 8

Fig.1 Experimental system

Table 1 Experimental uncertainties

参数	误差
q_f/(ml/h)	±2%
V/kV	±1%
q_o/(ml/h)	±1%
T/K	±3%
L/mm	±0.02 mm

Fig.2 Electro-spraying shape at cone jet mode

Fig.3 Flame shape(qf=15 ml/h; a=13 s-1; Φ=0.8)

Fig.4 Dimensionless diameter of flame varying with equivalent ratio(a=3.9 s-1)

Fig.5 Dimensionless diameter of flame varying with strain rate (Φ=0.6)

Fig.6 Flame temperatures varying with equivalent ratio(a=3.9 s-1)

Fig.7 Flame temperatures varying with strain rate(Φ=0.6)

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