Parametric study of the performance of two-dimensional scramjet intake
V. Jagadish BabuPratik Raje, Rachit Singh, Subhajit Roy, Krishnendu Sinha
Department of Aerospace Engineering, IIT Bombay
18th Annual CFD Symposium, August 10-11, 2016, Bangalore
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Schematic of scramjet engine
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Schematic of scramjet engine
Schematic of scramjet engine
Inlet Combustor Nozzle
Schematic of scramjet engine
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Schematic of scramjet engine
Primary objectives in designing efficient inlet
isolator
Ramp1Ramp2
Ramp3
Airintake system
1 Near to isentropic and high pressure recovery.2 High capture area (high mass flow).3 Uniform flow.4 Wide range of operation.
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Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
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Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
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Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
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Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
Vemula (IIT-B) Scramjet design 5 / 31
Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
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Schematic of scramjet engine
Performance parameters
Static temperature ratio
ψ = TexitTinlet
Static pressure ratio
r = PexitPinlet
Total pressure ratio
πc =Po,exit
Po,inlet
Kinetic energy efficiency
ηKE = 1 − 0.2(
1 − MexitMinlet
)5
Captured mass flow ratemc = ρAcVinlet
Ac
A0
Aexit
Inlet Outlet
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Objective
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Objective
Objective
1 Design a scramjet inlet (at a cruising flight Mach number-6.5).2 Effect of angle of attack, α.3 Effect of cowl deflection angle, θc.
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Inlet design
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Inlet design
Inlet Design
Design criteria:1 Shock-on-lip condition2 Uniform flow
A B
C
D
C’M
E
F
β2
β1
β3
A’
Input parameters1 Mach number (M)2 First ramp length (AA’).3 Distance of the cowl tip from the first ramp leading edge (AB).4 Total intake height (DB).
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Inlet design
Physical and Computational domain
Details of scramjet intake geometry (All dimensions are in meters)
0.40.5
0.9
0.0367
0.3
11.52o
15.28o
0.5906
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Inlet design
Physical and Computational domain
Grid structure and boundary conditions.
x
y
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
0
0.2
0.4
0.6
Supersonic exit
Inviscid WallFree Stream
Inviscid Wall
Supersonic exit
Cowltip
Ramp2 Isolator
Ramp1
550 x 250 grid points, with x-stretching factor of 1.28
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Inlet design
Numerical methodology
1 In-house code2 Finite volume formulation3 Modified Steger-Warming flux splitting (Computers and Fluids, 1989)
4 Implicit Data Parallel Line Relaxation method (AIAA, 1998)
J. Propul. Power (2012) AeSI CFD Sym. (2009)
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Inlet design
Numerical methodology
1 In-house code2 Finite volume formulation3 Modified Steger-Warming flux splitting (Computers and Fluids, 1989)
4 Implicit Data Parallel Line Relaxation method (AIAA, 1998)
J. Propul. Power (2012) AeSI CFD Sym. (2009)
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On-design condition
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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On-design condition
On-design condition (M = 6.5)
x
y
0 0.5 10
0.1
0.2
0.3P/P∞: 2 5 8 11 14 17 20 23 26 35
Ramp1 shock
Ramp2 shock
cowl tip
Expansion corner
M = 6.5, T = 219.3K, ρ = 0.0343 kg/m3
Cowl shock
Pressure contour of inlet for on-design Mach number at α = 0◦ and θc = 0◦.
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Mach effect
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Mach effect
Mach effect
Table : Comparison of the analytical and numerical simulation results with respect to various parameters forscramjet inlet.
Mach Tiso/Tinlet Po,iso/Po,inlet Piso/Pinlet MisoTheo. CFD Theo. CFD Theo. CFD Theo. CFD
4.5 2.298 2.295 0.742 0.745 13.660 13.652 2.446 2.4505.5 2.716 2.707 0.630 0.637 20.804 20.797 2.824 2.8306.5 3.197 3.197 0.521 0.523 30.422 30.533 3.127 3.1207.5 3.743 3.76 0.422 0.414 42.827 42.769 3.370 3.370
The difference is within the ±2 % error range for all parameters.
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Effect of angle of attack
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Effect of angle of attack
Flow structure for varying α at M = 6.5
x
y
0 0.5 10
0.1
0.2
0.3P/P∞: 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Ramp1 shock
Ramp2 shock
cowl tip
Expansion corner
M = 6.5, T = 219.3K, ρ = 0.0343 kg/m3, α = 3
0
Cowl shock
Expansion fan
(a) α = −3◦
x
y
0 0.5 10
0.1
0.2
0.3P/P∞: 5 20 35 50 65 80 95 110 125 140 155 170
Ramp1 shock
Ramp2 shock
cowl tip
Expansion corner
M = 6.5, T = 219.3K, ρ = 0.0343 kg/m3, α = 6
0
Cowl shock
Expansion fan
Reflected shock
(b) α = 6◦
Pressure contour for varying α at Mach 6.5 and θc = 0◦.Vemula (IIT-B) Scramjet design 17 / 31
Effect of angle of attack
Performance parameters (varying α and M)
M
Texit
/T
inle
t
4 4.5 5 5.5 6 6.5 7 7.5 82
2.5
3
3.5
4
4.5
5
5.5
6
α = 3
α = 0
α = 3
α = 6
M
Pexit
/P
inle
t
4 4.5 5 5.5 6 6.5 7 7.5 810
20
30
40
50
60
70α = 3
α = 0
α = 3
α = 6
∴
At the fixed angle of attack, the strength of the shocks increases with increasing Mach number
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Effect of angle of attack
Continue...
M
ηK
E_
E
4 4.5 5 5.5 6 6.5 7 7.5 80.96
0.965
0.97
0.975
0.98
0.985
0.99
0.995
1
α = 3
α = 0
α = 3
α = 6
M
P0
,exit
/P
0,in
let
4 4.5 5 5.5 6 6.5 7 7.5 80.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
α = 3
α = 0
α = 3
α = 6
Maximum ηKE is observed at designed Mach number
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Effect of cowl deflection angle
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Effect of cowl deflection angle
Flow structure for varying θc at M = 6.5
x
y
0 0.5 1 1.50
0.1
0.2
0.3P/P∞: 2 5 8 11 14 17 20 23 26 29 32
M = 6.5, T = 219.3K, ρ = 0.0343 kg/m3, θ
c= 3
0
Ramp1 shock
Ramp2 shock
Cowl tip
Expansion corner
Cowl shock
Hinge shock
Expansion fan
(a) θc = 3◦
x
y
0 0.5 1 1.50
0.1
0.2
0.3P/P∞: 2 6 10 14 18 22 26 30 34
M = 6.5, T = 219.3K, ρ=0.0343kg/m3, θ
c= 9
0
Ramp1 shock
Ramp2 shock
Cowl tip
Expansion corner
Cowl shock Hinge shock
Expansion fan
(b) θc = 9◦
Pressure contour for varying θc at Mach 6.5 and α = 0◦.Vemula (IIT-B) Scramjet design 21 / 31
Effect of cowl deflection angle
Performance parameters (varying Mach number and θc)
M
Texit
/T
inle
t
4 4.5 5 5.5 6 6.5 7 7.5 8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
θc= 0
θc= 3
θc= 6
θc= 9
M
Pexit
/P
inle
t
4 4.5 5 5.5 6 6.5 7 7.5 85
10
15
20
25
30
35
40
θc= 0
θc= 3
θc= 6
θc= 9
Compression ratios increases with MDecreases with increasing θc
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Effect of cowl deflection angle
Continue...
M
ηK
E_
eff
4 4.5 5 5.5 6 6.5 7 7.5 8
0.986
0.988
0.99
0.992
0.994
0.996
0.998
1
θc= 0
θc= 3
θc= 6
θc= 9
M
P0
,exit
/P
0,in
let
4 4.5 5 5.5 6 6.5 7 7.5 8
0.3
0.4
0.5
0.6
0.7
θc= 0
θc= 3
θc= 6
θc= 9
↑ θc– shifts the maximum ηKE to lower Mach numbers
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Starting of intake
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Starting of intake
Flow initialization
x
u = V∞
v = 0
Earlier simulations: Free-stream velocity initialization
x
u = V∞
v = 0
u = 0
v = 0
New Simulations: Zero velocity initialization
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Starting of intake
Unstarted mode
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
3000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
5000 iterations
P/P∞: 2 8 14 20 26 32 38 44 50 56 62 68
7000 iterations
P/P∞: 2 8 14 20 26 32 38 44 50 56 62 68
8000 iterations
P/P∞: 2 22 42 62 82 102 122 142
10000 iterations
P/P∞: 2 36 70 104 138 172 206 240
12000 iterations
P/P∞: 2 30 124 152 180 208 236 264
13000 iterations
P/P∞: 2 18 34 130 152 168 184 200
14000 iterations
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Starting of intake
Starting criteria
(Ae/As) >
[γ − 1γ + 1
+2
(γ + 1)M23
] 12[
2γγ + 1
− γ − 1(γ + 1)M2
3
] 1γ−1
Ae is fixed and reducing the As by deflecting the cowl to meet Kantrowitz criteriaSelf starting is achieved , θc = 9◦
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Starting of intake
Started modeP/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
3000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
5000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
7000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
8000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
10000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
12000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
13000 iterations
P/P∞: 1.5 5.5 9.5 13.5 17.5 21.5 25.5
14000 iterations
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Summary
Outline
1 Schematic of scramjet engine
2 Objective
3 Inlet design
4 On-design condition
5 Mach effect
6 Effect of angle of attack
7 Effect of cowl deflection angle
8 Starting of intake
9 Summary
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Summary
Summary
1 Performed inviscid numerical simulations of a typical mixed-compression scramjet intake.2 Studied its performance for a range of Mach numbers, angles of attack and cowl deflection
angles.3 At off-design conditions, a set of shock and expansion fans are generated in the intake
duct, and they reflect between the duct walls.4 It is found that the maximum pressure recovery is obtained at lower Mach number with
weaker shock waves, and the capture mass flow rate is maximum at higher Mach numbers.5 As the cowl angle is increased, the maximum kinetic energy efficiency is obtained at Mach
numbers lower than the design point.6 At zero velocity initialization, intake starts with deflection of cowl.
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Summary
Thank you...
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