乙烯对煤粉-氧气爆轰波起爆特性影响机制的实验研究

doi:10.12382/bgxb.2022.0600

摘要/Abstract

摘要：

为实现煤粉连续旋转爆轰发动机的可靠点火,开展乙烯对煤粉-氧气起爆特性的影响机制研究。在初始压力p₀=100kPa下,采用高能电点火对有无0.5当量比乙烯氛围下的煤粉-氧气混合物开展直接起爆实验研究。点火能量通过测定在空气中高能电火花产生的爆炸波压强进行计算。计算后发现:采用6.3J的有效点火能量,煤粉-氧气在不含乙烯的氛围下无法起爆;在此能量下,煤粉-氧气在0.5当量比的乙烯氛围条件下可实现直接起爆;将能量降低为3.6J,使其低于乙烯-氧气(0.5当量比)混合物的临界起爆能量,虽然乙烯-氧气无法直接起爆,但是在加入煤粉后却可以形成稳定的自持爆轰波。研究结果表明:若要实现煤粉-氧气的直接起爆,则需要添加一定量的助爆气体(如乙烯);煤粉的加入还可以拓宽乙烯-氧气混合物的起爆极限。所得结果可以为煤粉连续旋转爆轰发动机的点火起爆提供理论依据并提供技术支撑。

关键词: 粉末连续旋转爆轰发动机, 爆轰, 煤粉, 直接起爆, 临界起爆能量, 气-固两相爆轰

Abstract:

The influence mechanism of ethylene on the detonation initiation characteristics of coal powder/oxygen mixture is studied to realize the reliable ignition of the coal powder continuous rotating detonation engine. At the initial pressure of 100kPa, an electric ignition with high energy is used to carry out the direct detonation initiation experiments on the coal powder/oxygen mixture with and without the ethylene. The ignition energy is calculated by measuring the pressure of explosive wave produced via a high-energy electric spark in air. The coal powder/oxygen mixture cannot detonate without ethylene under the action of effective ignition energy of 6.3J. In this energy, if the ethylene with the equivalence ratio of 0.5 is added, the coal powder/oxygen mixture can be successfully initiated. If the effective ignition energy is reduced to 3.6J to made it be lower thanthe critical initiation energy of ethylene/oxygen mixture with an equivalent ratio of 0.5. the detonationcould be onset after adding coal powder. The above studies show that a certain amount of detonable gas (such as ethylene) needs to be added for the dirct detonation initiation of coal powder/oxygen mixture. On the other hand, the addition of coal powder can also broaden the detonation limit of ethylene/oxygen mixture. The results of this study can provide theoretical basis and technical support for the ignition of coal continuous rotating detonation engine.

Key words: powder continuous rotating detonation engine, detonation, coal powder, direct initiation, critical initiation energy, gas-solid two-phase detonation

中图分类号:

O381

罗永晨, 续晗, 张锋, 郑权, 翁春生. 乙烯对煤粉-氧气爆轰波起爆特性影响机制的实验研究[J]. 兵工学报, 2024, 45(3): 754-762.

LUO Yongchen, XU Han, ZHANG Feng, ZHENG Quan, WENG Chunsheng. Experimental Study on the Effect of Ethylene on the Detonation Wave Initiation of Coal Powder/oxygen Mixture[J]. Acta Armamentarii, 2024, 45(3): 754-762.

图/表 18

图1 装置结构图

Fig.1 Schematic diagram of experimental setup

图2 喷嘴结构

Fig.2 Nozzle structure

图3 同步时序控制

Fig.3 Operation time sequences for ignition experiment

图4 理想点源球面爆炸波的马赫数Mash与rsh/r0的关系[21]

Fig.4 Mash as a function of rsh/r0 for a spherical explosive wave from ideal point energy source[21]

表1 不同点火能量下的相关参数(C=20μF,p01=101.35kPa)

Table 1 Related parameters related under different ignition energies (C=20μF,p01=101.35kPa)

参数	高点火能量	低点火能量
电压U/kV	14	12
超压p_sh/kPa	1.75	1.15
爆炸波马赫数Ma_sh	1.575	1.405
归一化传播距离r_sh/r₀	1.26	1.52
激波能量E_sh/J	6.3	3.6

表2 煤粉成分分析

Table 2 Proximate analysis of coal sample

成分	总水分	挥发分	灰分	固定碳
质量分数/%	1.13	3.48	0.61	95.91

表3 实验工况

Table 3 Test conditions

工况	案例	燃料	氧化剂	E_sh/J	当量比
工况	案例	燃料	氧化剂	E_sh/J	煤粉	C₂H₄	全局
无乙烯氛围下煤粉-氧气点火实验	1	煤粉	氧气	3.6	0.5	0	0.5
	2	煤粉		3.6	0.7	0	0.7
	3	煤粉		6.3	0.5	0	0.5
	4	煤粉		6.3	0.7	0	0.7
在乙烯氛围下,采用高于临界起爆能量的点火能量对煤粉-氧气进行点火实验	5	C₂H₄	氧气	6.3	0	0.5	0.5
	6	煤粉+C₂H₄		6.3	0.2	0.5	0.7
	7	煤粉+C₂H₄		6.3	0.5	0.5	1.0
	8	煤粉+C₂H₄		6.3	0.8	0.5	1.3
	9	煤粉+C₂H₄		6.3	1.0	0.5	1.5
在乙烯氛围下,采用低于临界起爆能量的点火能量对煤粉-氧气进行点火实验	10	C₂H₄	氧气	3.6	0	0.5	0.5
	11	煤粉+C₂H₄		3.6	0.2	0.5	0.7
	12	煤粉+C₂H₄		3.6	0.5	0.5	1.0
	13	煤粉+C₂H₄		3.6	0.8	0.5	1.3
	14	煤粉+C₂H₄		3.6	1.0	0.5	1.5

图5 无乙烯氛围下煤粉-氧气点火实验压力-时间曲线(Esh=6.3J,案例3)

Fig.5 Pressure curve of coal powder/oxygen ignition experiment without ethylene(Esh=6.3J,Case 3)

表4 无乙烯氛围下煤粉-氧气点火实验结果

Table 4 Coal powder/oxygen ignition experiment results without ethylene

案例	E_sh/J	GER	现象
1	3.6	0.5	无反应
2	3.6	0.7	无反应
3	6.3	0.5	无反应
4	6.3	0.7	无反应

图6 当量比0.5的乙烯-氧气成功起爆时的压力-时间曲线 (Esh=6.3J,案例5)

Fig.6 Pressure-time curve of successful detonation initiation of ethylene/oxygen with the equivalence ratio of 0.5 (Esh=6.3J, Case 5)

图7 在初始气压为100kPa下不同化学当量比下的乙烯-氧气的起爆能量[23]

Fig.7 Initiation energy at different equivalence ratios of C2H4/O2 at the initial pressure of 100kPa[23]

图8 采用高点火能量,乙烯氛围下GER为1.5的煤粉-氧气成功起爆的压力-时间曲线 (Esh=6.3J,案例9)

Fig.8 Pressure-time curve of successful detonationinitiation of coal powder/oxygen with the global equivalence ratio of 1.5 under high ignition energy with ethylene (Esh=6.3J,Case 9)

图9 在乙烯氛围下,不同GER煤粉-氧气的v/vC-J和p/pC-J(Esh=6.3J)

Fig.9 v/vC-J and p/pC-J of coal powder/oxygen at different global equivalence ratios with ethylene(Esh=6.3J)

表5 采用高点火能量,在乙烯氛围下不同GER的煤粉-氧气点火实验结果(Esh=6.3J)

Table 5 Experimental results of ignition of coal powder/oxygen at different global equivalence ratios with ethylene under high ignition energy(Esh=6.3J)

案例	GER	v/v_C-J/%	p/p_C-J/%	直接点火
5	0.5	92.6	90.9	Yes
6	0.7	86.8	95.9	Yes
7	1.0	86.7	98.2	Yes
8	1.3	90.3	97.7	Yes
9	1.5	88.6	100.0	Yes

图10 当量比为0.5的乙烯-氧气未成功起爆时的压力-时间曲线(Esh=3.6J,案例10)

Fig.10 Pressure-time curve of unsuccessful detonation initiation of ethylene/oxygen with the equivalence ratio of 0.5(Esh=3.6J, Case 10)

图11 采用低点火能量,乙烯氛围下GER为1.5的煤粉-氧气成功起爆的压力-时间曲线(Esh=3.6J,案例 14)

Fig.11 Pressure-time curve of successful detonation initiation of coal powder/oxygen with the global equivalence ratio of 1.5 under low ignition energy with ethylene(Esh=3.6J,Case 14)

图12 乙烯氛围下不同GER下煤粉-氧气的v/vC-J和p/pC-J(Esh=3.6J)

Fig.12 v/vC-J and p/pC-J of coal powder/oxygen at different global equivalence ratios with ethylene (Esh=3.6J)

表6 采用低点火能量,在乙烯氛围下煤粉-氧气点火起爆的实验结果(Esh=3.6J)

Table 6 Experimental results of ignition of coal powder/oxygen at different global equivalence ratios with ethylene under low ignition energy(Esh=3.6J)

案例	GER	v/v_C-J/%	p/p_C-J/%	直接点火
10	0.5			No
11	0.7	82.9	94.4	Yes
12	1.0	86.4	98.5	Yes
13	1.3	82.7	97.0	Yes
14	1.5	87.1	98.9	Yes

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