Premixed flame propagation

Vaporization (no flame spread) Mode 1

Expanding diffusion flame

Droplet

Active vaporization

Flammable mixture layer

Ignition

Flammable mixture

Mode 2

図 3-2 燃え広がりモードの定義

58

0 0.1 0.2 0.3 0.4

4 5 6 7

Gas equivalence ratio, 

_g

D

f

/ d

n-decane, normal gravity d0 = 1.0 mm

○d = 0.6 mm

△d = 0.8 mm

□ d = 0.9 mm

図 3-3 単一液滴燃焼における気体当量比と無次元火炎直径の関係（デカン）

59

S = 1.6 mm, d0 = 0.8 mm,_g= 0.4

t= 0 ms n-decane

1st 2nd 10th

Closed

Igniter end

5 mm

t= 35 ms

t= 70 ms

t= 105 ms

図 3-4 液滴列の燃え広がり挙動

（デカン，S= 1.6 mm, d⁰= 0.8 mm, g= 0.4）

60 n-decane

1st 2nd Igniter

8th

S = 2.0 mm, d0 = 0.8 mm,_g= 0.4

5 mm t= 0 ms

t= 35 ms

t= 70 ms

t= 105 ms

図 3-5 液滴列の燃え広がり挙動

（デカン，S= 2.0 mm, d⁰= 0.8 mm, g= 0.4）

61

S = 5.0 mm, d0 = 0.8 mm,_g= 0.4

n-decane 5 mm

1st 2nd 3rd 4th

t= 0.68 s

t= 0.72 s

t= 0.75 s

t= 0.78 s

図 3-6 液滴列の燃え広がり挙動

（デカン，S= 5.0 mm, d⁰= 0.8 mm, g= 0.4）

62

0.05 0.1 0.15 0.2

5 10 15 20

0

F lam e fr ont pos ition, m m

Time, s

n-decane, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _g = 0.4 Vs = 81.6 mm/s

1st droplet 2nd

3rd 9th 8th 7th 6th 5th 10th

4th

図 3-7 燃え広がり火炎先端位置の時間履歴

（デカン，S= 1.6 mm, d⁰= 0.8 mm, g= 0.4）

63

0.05 0.1 0.15 0.2

5 10 15 20

0

F lam e fr ont pos ition, m m

Time, s

n-decane, normal gravity

S = 2.0 mm, d0 = 0.8 mm, _g = 0.4 Vs = 75.6 mm/s

1st droplet 2nd

3rd 9th 8th 7th 6th 5th 10th

4th

図 3-8 燃え広がり火炎先端位置の時間履歴

（デカン，S= 2.0 mm, d⁰= 0.8 mm, g= 0.4）

64

0.2 0.4 0.6 0.8 1

5 10 15 20

0

F lam e fr ont pos ition, m m

Time, s

n-decane, normal gravity

S = 5.0 mm, d0 = 0.8 mm, _g = 0.4 Vs = 18.2 mm/s

1st droplet 2nd

4th

3rd

図 3-9 燃え広がり火炎先端位置の時間履歴

（デカン，S= 5.0 mm, d⁰= 0.8 mm, g= 0.4）

65

0.2 0.4 0.6 0.8 1

50 100 150 200

0 F lam e spr ead speed, V

s

, mm/ s

Gas equivalence ratio, 

_g

n-decane, normal gravity

○ S = 1.6 mm, d0 = 0.8 mm, _l = 2.4

× S = 2.0 mm, d0 = 0.8 mm, _l = 2.0

□ S = 5.0 mm, d0 = 0.8 mm, _l = 0.8

図 3-10 気体当量比と燃え広がり速度の関係（デカン）

66

0.2 0.4 0.6 0.8 1

50 100 150 200

0 F lam e spr ead speed, V

s

d

0

, m m

2

/s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

○ S = 1.6 mm, d0 = 0.8 mm, _l = 1.6

□ S = 1.6 mm, d0 = 0.32 mm, _l = 0.1

図 3-11 気体当量比と燃え広がり速度の関係（エタノール）

67

0.4 0.8 1.2 1.6

5 10 15

0

Num ber of dr opl et s

Gas equivalence ratio, 

_g

n-decane, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _l = 2.4

□ burnt drolets

● burn-out droplets

図 3-12 燃え広がる液滴と燃え尽きる液滴個数の気体当量比依存性

（デカン，S= 1.6 mm, d⁰= 0.8 mm）

68

0.4 0.8 1.2 1.6

5 10 15

0

Num ber of dr opl et s

Gas equivalence ratio, 

_g

n-decane, normal gravity

S = 5.0 mm, d0 = 0.8 mm, _l = 0.8

□ burnt drolets

● burn-out droplets

図 3-13 燃え広がる液滴と燃え尽きる液滴個数の気体当量比依存性

（エタノール，S= 5.0 mm, d⁰= 0.8 mm）

69

10 mm 8ms

14ms

26ms

38ms

(a) Without droplet array, _g = 1.1 n-decane

図 3-14 火炎伝播挙動

（デカン，g = 1.1，液滴無し）

70

10 mm 8ms

14ms

26ms

38ms (b) n-decane

(b) With droplet array,

S = 5.0 mm, d0 = 0.8 mm, _g = 1.1

図 3-15 火炎伝播挙動

（デカン，g = 1.1，液滴有り）

71

1st droplet 2nd

3rd 9th 8th 7th 6th 5th 10th

4th

0.01 0.02 0.03 0.04

10 20 30 40 50

0

F lam e fr ont pos ition, m m

Time, s

n-decane, normal gravity

S = 5.0 mm, d0 = 0.8 mm, _g = 1.1 Vp = 878 mm/s

図 3-16 伝播火炎先端位置の時間履歴

（デカン，S= 5.0 mm, d⁰= 0.8 mm）

72

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0

500 1000 1500

F lam e pr opagat ion speed, V

p

, m m /s

Gas equivalence ratio, 

_g

n-decane, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _l = 2.4

○ without droplet array

● with droplet array

図 3-17 気体当量比と火炎伝播速度の関係

（デカン，S= 1.6 mm, d⁰= 0.8 mm）

73

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0

500 1000 1500

F lam e pr opagat ion sp eed, V

p

, m m /s

Gas equivalence ratio, 

_g

n-decane, normal gravity

S = 5.0 mm, d0 = 0.8 mm, _l = 0.8

○ without droplet array

● with droplet array

図 3-18 気体当量比と火炎伝播速度の関係

（デカン，S= 5.0 mm, d⁰= 0.8 mm）

74 8ms

10 mm 12ms

14ms

16ms

18ms Ethanol

(a) Without droplet array, _g = 0.8

図 3-19 火炎伝播挙動

（エタノール，g = 0.8，液滴無し）

75 n-decane

10 mm 12ms

14ms

16ms

18ms Ethanol

(b) With droplet array,

S = 5.0 mm, d0 = 0.8 mm, _g = 0.8

図 3-20 火炎伝播挙動

（エタノール，g = 0.8，液滴有り）

76

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0

500 1000 1500

F lam e pr opagat ion speed, V

p

, m m /s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _l = 1.6

○ without droplet array

● with droplet array

図 3-21 気体当量比と火炎伝播速度の関係

（エタノール，S= 1.6 mm, d⁰= 0.8 mm）

77

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0

500 1000 1500

F lam e pr opagat ion speed, V

p

, m m /s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

S = 5.0 mm, d0 = 0.8 mm, _l = 0.5

○ without droplet array

● with droplet array

図 3-22 気体当量比と火炎伝播速度の関係

（エタノール，S= 5.0 mm, d⁰= 0.8 mm）

78

0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0

500 1000 1500

F lam e pr opagat ion speed, V

p

, m m /s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

S = 1.6 mm, d0 = 0.32 mm, _l = 0.1

○ without droplet array

● with droplet array

図 3-23 気体当量比と火炎伝播速度の関係

（エタノール，S= 1.6 mm, d⁰= 0.32 mm）

79

0.2 0.4 0.6 0.8 1

50 100 150 200

0 F lam e spr ead speed, V

s

, m m /s

Gas equivalence ratio, 

_g

normal gravity

S = 1.6 mm, d0 = 0.8 mm

□ Ethanol

○ n-decane

図 3-24 火炎燃え広がり速度に及ぼす気体当量比および燃料揮発性の影響

80

0.4 0.8 1.2 1.6

500 1000 1500

0 F lam e speed, V

s

, V

p

, mm/ s

Gas equivalence ratio, 

_g

n-decane, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _l = 2.4

○ without droplet array

● with droplet array

図 3-25 気体当量比と火炎速度の関係

（デカン，S = 1.6 mm, d⁰ = 0.8 mm） V^p

V^s

81

0.4 0.8 1.2 1.6

500 1000 1500

0 F lam e speed, V

s

, V

p

, m m /s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

S = 1.6 mm, d0 = 0.8 mm, _l = 1.6

○ without droplet array

● with droplet array

図 3-26 気体当量比と火炎速度の関係

（エタノール，S = 1.6 mm, d⁰ = 0.8 mm） V^p

V^s

82

0.4 0.8 1.2 1.6

500 1000 1500

0 F lam e speed, V

s

, V

p

, m m /s

Gas equivalence ratio, 

_g

Ethanol, normal gravity

S = 1.6 mm, d0 = 0.32 mm, _l = 0.1

○ without droplet array

● with droplet array

図 3-27 気体当量比と火炎速度の関係

（エタノール，S = 1.6 mm, d⁰ = 0.32 mm） V^p

V^s

83

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