parametric study of the performance of two-dimensional...

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

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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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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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