underexpanded supersonic plume surface interactions ......-transient & steady-state rans eqns...

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Underexpanded supersonic plume surface interactions: applications for spacecraft landings on planetary bodies

Manish Mehta, Ph.D.Aerosciences Branch, EV33

NASA Marshall Space Flight CenterAnita Sengupta, Ph.D.

NASA Jet Propulsion LaboratoryNilton O. Renno, Ph.D.

University of MichiganJohn W. Van Norman

Analytical Mechanical Associates, Inc.Peter G. Huseman and Douglas S. Gulick

Lockheed Martin Space Systems

April 18,2011“Approved for public release; distribution is unlimited.”

Outline

♦ Introduction• Motivation• Near-field and far-field plume flow fields• Scaling Theory

♦Phoenix Mars spacecraft• Experimental• Numerical• Data comparison/Flow Physics

♦Mars Science Lab (MSL) Descent Stage spacecraft • Experimental• Numerical • Data comparison/Flow Physics

♦Conclusion

2

Motivation

♦ Plume-surface interactions due to spacecraft landings• Spacecraft stability and survival

− Moments/Torques− Updraft plumes− Plume induced heating

• Cratering & dust lifting • Implications for manned and large payload landings to Mars,

moon, asteroids and other planetary bodies

♦ Theory, test data and numerical simulations were used to characterize the complex plume impingement physics and identify the environments observed due to spacecraft landings

3

1998 Mars Polar Lander Failure Report (Whetsel et al, 2000)

- MPL Project failed to conduct studies on plume-surface interactions - Recommended these investigations for future powered descent landing missions to Mars

These NASA spaceflight projects deemed it necessary to conduct these investigations thru University research partnership.

Phoenix: Pulsed-modulated descent system (Rocket Engine Module – REM)

Mars Science Lab: Sky-crane throttled landing system (Mars Landing Engine – MLE)

2007 2011

Last detailed study was completed in 1973 for Viking 1 and 2.

Motivation

4

Near-field flow –TEST DATA

Underexpanded Supersonic Jet

Overexpanded Supersonic Jet

Planar Laser Induced Fluorescence Imaging

Inmann et al., 2009

Important flow structures with implications to cratering, acoustics and spacecraft dynamics during descent

Far-field flow/Impingement zone – TEST DATA

Lamont and Hunt, 1976 5

( )

( ) 1MaMa

Re

PrRe1

][Re1

Fr1

22

22

22

2

−==

′+′′

′′+′∇′′⋅∇′=′′

′′

′⋅∇′+′∇′−′=′′

′

′⋅∇′′−=′′

γ

φβλρ

τρρ

ρρ

epe

e

epe

epeepep

Tcc

TcU

TcU

tDpDT

TcUT

tDTDc

pgtDvD

vtD

D

( ) ( ) ( ) Re

1Ma 1MaPrRe

1 22 φγβγλρ ′−

+′′

′′−+′∇′′⋅∇′=′′

′′tDpDTT

tDTDcp

Scaling theory for plume-surface interactions

6

( )

][

φβλρ

τρ

ρρ

++∇⋅∇=

⋅∇+∇−=

⋅∇−=

DtDpTT

DtDTc

pfDtUD

UDtD

p

( )

e22

e2

e

/ ,/ , ,/ ,/ ,/

, / ,/ , / , / ,/ ,/

µµµµφφβββλλλ

ρρρρ

=′=′∇=∇′=′=′=′=′=′−=′=′=′=′

eeeepepp

eeeee

UDDccc

TTTUpppUuvDtUtDxx

Schlichting and Gersten, 2001

Normalized parameters

Continuity

Conservationof Momentum

Conservationof Energy

Nondimensional Navier-Stokes Equations

Scaling theory for plume-surface interactions

7

( ) ratioexpansion jet 1 1

222 =−

=

−

=−

=′ ∞∞∞

∞ eU

ePU

PPP

UPPp

eeee

e

ee

efb ρρρ

eve

pe

e

pee

e

ee

e

ee

UfD

ccc

aU

gDUDU St , ,Pr ,Ma ,Fr ,Re ====== γ

λµ

µρ max

∞

−=P

PCα ∞

=PPe e 2)1( Mk −= γγ

Free surface boundary condition

Nondimensional numbers that satisfy dynamic similarity

Phoenix Mars Spacecraft

Courtesy of NASA/JPL/Lockheed Martin

8

Experimental and Numerical Methodology

9

-½ scale Phoenix nozzle (MR-107)-N2 test gas-10 Hz pulsing-Mars atmosphereUniversity of Michigan Thermal Vacuum Chamber

Numerical Methodology

-Two Navier-Stokes computational solvers were used for modeling and analyses

-ANSYS FLUENT-3-D & axisymmetric density based solver-Transient RANS-Time step – 1 us – explicit marching-Turbulent (RNG) model-Adaptive meshing for resolving shocks-Grid independence-2nd order upwind discretization scheme-2 million unstructured grid cells

-Aerosoft GASP-3-D density based solver-Transient & steady-state RANS eqns solved-Van Leer flux splitting-Laminar-Dual implicit time stepping-Single species – frozen flow-Grid independence-4 million unstructured grid cells

Experimental Methodology

Plemmons, Mehta et al, 2008

Ground pressure profiles – TEST DATA


Overpressure

Temporal Profile Spatial Profile

Pc ~1200 kPa0 deg canth/de = 8.410 Hz pulsingN2 test gas

10

Ground pressureat centerline

Chamber stagnation pressure

Back pressure

Observed large transient overpressures during engine start-up and shut down

Observe a monotonic rise in ground pressurefollowed by a drop in centerline pressure

t = 0.112 sec

t = 0.136 sec

MARS ATMOSPHERE ~ 700 Pa

Plate shock dynamics - CFD

Mechanism deduced from experimental measurements, transient numerical simulations and theory.

Gulick et al., 2006

N2 test gasAxisymmetric transient simulation

Pc ~ 1200 kPa0 deg canth/de = 8.4

GASP

11

Plate (recovery) shock formation



Plate shock formation and collapse

Ground pressure spatial profiles


Wall jet

Plate shockcollapse

- N2 test gas-Axisymmetric- Transient-10 Hz pulsing

Pc ~1200 kPa0 deg canth/de = 25

FLUENT12




FLUENT

- N2 test gas-Axisymmetric- Transient

Pc ~1200 kPa0 deg canth/de = 25

13

Plate shock formation and collapse

3-D full-scale flow field and ground pressure profiles -CFD

14

3-D transient simulations of full-scale Phoenix plumes interacting at surface

Pc ~ 1200 kPa0 deg canth/de = 2510 Hz pulsingEquivalent plume gas

GASP

Gulick et al, 2006

Modeled as a 60 degree wedge to reduce computational resources

3-D numerical simulations show that ground pressure loads are asymmetric and develop overpressures during rapid engine startup and shutdown

1E4

1E3

1E2

(Pa)


Experimental and numerical data

Good agreement between experimental results and numerical simulations (CFD)

Gulick et al, 2006

GASP

FLUENTShadowgraphPc ~ 1200 kPa0 deg canth/de = 8.410 Hz pulsingN2 test gas 15

Dashed lines – surface pressureSolid lines – thruster inlet stagnation pressure

(chamber pressure)

Comparing spatial and temporal ground pressure profiles

Comparing plume shock structureTEMPORAL

SPATIAL

Red line – CFDDots – Test Data


MSL Descent Stage Spacecraft & Testbed

16

- ¼ scale MSL MLE nozzle-N2 test gas-steady operation-Mars atmosphere-NASA Ames Research Center Planetary Aeolian Laboratory

Courtesy of NASA/JPL/Caltech

Descent stage Testbed

Thruster

ImpingementPlate

Testbed

Numerical methodology

- NASA OVERFLOW 2.1- 3-D time-marching implicit code- structured overset grid- Navier-Stokes eqns solved over full domain and internal nozzle- SST turbulence model- compressibility correction- steady-state - frozen flow used for modeling rocket plume gases- 12 million cells

17

Temporal ground pressure profiles – TEST DATA

18

Earth AtmosphereSteady Supersonic Jet

Mars atmosphereSteady Supersonic Jet

Pc ~1700 kPa22.5 deg canth/de = 35

Repetitive overpressures not observed

N2 test gassteady operation

Spatial ground pressure profiles – TEST DATA

19

Pc ~1700 kPa22.5 deg canth/de = 35N2 test gassteady operation

Pg/Pc

Pg/Pc Ps = Pg

Shows that the plume is collimated and leads to large pressure gradients at Mars atmospheric pressure

Ground pressure and rise rate vs. jet expansion ratio –TEST DATA

20

−

−=

∆

∆=

minmax

minmax 11 rate riseggc

gg

c

g

ttPPP

tPP

ratioexpansion jet amb

e

eamb

ee

PP

APAPe ===

Overshoot = Max ground pressure – quasi-steady ground pressure

Plume flowfield and spatial pressure profiles - CFD

Pc ~ 1.7e3 kPa22.5 deg canth/de ~35

e =3.5

OVERFLOW

N2 test gassteady-state

Pc ~ 1.7e3 kPa22.5 deg canth/de ~35EquivalentPlume gassteady-state

21

Plume is collimated and does not dissipate at large axial distances – in agreement with test data


Experimental and numerical data

22

OVERFLOW

Pc ~ 1.7e3 kPa22.5 deg canth/de ~35N2 test gas


Jet expansion ratio

EARTH MARS MOON

Stitt, L.E. , 1963

23

TEST DATA

CFD – Mach Contours

e = 4.50 e = 0.02

All tests were done at steady engine operation

Max normalized ground pressure

Mars – moderately underexpandedplumes lead to max ground pressure loads due to collimated plume structure and development of a small areal plate shock

Earth – highly overexpanded plumes dissipate/no plate shock formation

Moon – highly underexpanded plumes leads to a large areal plate shock – decreases ground pressure

Other shock interaction effects during spacecraft landings

Altitude Effects Spatial Asymmetry

Pc ~ 1200 kPa0 deg canth/de = 25Steady-state

FLUENTGASP Gulick et al, 2006

N2 test gas

24

SURFACESHEAR STRESS SURFACE PRESSURE

MACH CONTOUR

Ground pressure vs normalized altitude

MARS ATMOSPHERE ~ 700 PaMARS ATMOSPHERE ~ 700 Pa

Conclusions♦ Moderately underexpanded jets demonstrate:

• collimated shock structures• large supersonic core lengths• plate shock dynamics • max pressure loads

♦ Plate shock dynamics leads to:• large pressure gradients• asymmetry • overpressure

♦ Ground pressure loads are highly sensitive to • jet expansion ratio • strouhal number• spacecraft altitude

♦ Scaling laws show that cold plume gases can simulate ground pressure loads and interaction physics due to rocket plumes provided dynamic similarity is satisfied

♦ How does this effect spacecraft landing? • Transient ground pressure loads translate to load perturbations at the spacecraft base which may lead to

destabilizing moments (observed to a minor degree on the Phoenix spacecraft, Gulick et al, 2006)• Pressure loads can lead to extensive cratering and dust lifting which can destabilize the spacecraft upon

touching down on the surface (observed at the Phoenix Landing Site, Mehta et al, 2011)• Dust lifting can erode important spacecraft sensors and science instrumentation (a concern for the MSL

mission, Mehta et al, 2011)• Propulsion systems of small scale landers show maximum ground pressure loads at Mars atmosphere at

relatively high altitudes (h/de ~35) (a concern for the MSL mission)

♦ Provided JPL with landing environments which they incorporated into their risk analysis models 25

MISSION SUGGESTION: Due to highly complex plume impingement physics, accurate landing environments are needed for future planetary manned and robotic spaceflight missions

Acknowledgement

♦ I would like to thank my supervisor Mark G. D’Agostino and my colleagues within the home organization – Aerosciences Branch (EV33) at NASA Marshall Space Flight Center for their support.

26

References

♦ Lamont, P. J., and B. L. Hunt (1980), The impingement of underexpanded axisymetrical jets on perpendicular and inclined flat plates, J. Fluid Mechanics, 100, 471-475.

♦ Carling, J. C., and B. L. Hunt (1974), The near wall jet of a normally impinging, uniform axisymmetric, supersonic jet, J. Fluid Mechanics, 66, 11-19.

♦ Clark, L. V. (1970), Effect of retrorocket cant angle on ground erosion – a scaled Viking study, NASA Technical Memorandum. NASA TM X-2075, NASA Langley Research Center.

♦ Inman, J.A., P.M. Danehy, R.J. Nowak and D.W. Alderfer (2008) Fluorescence imaging study of impinging underexpanded jets, 46th AIAA Aerospace Sciences Meet., AIAA 2008-619.

♦ Stitt, L.E. (1963), Interaction of highly underexpanded jets with simulated lunar surfaces, NASA-TN-D-1095, NASA Glenn Research Center, Cleveland, OH.

♦ Schichting, H. and K. Gersten (2001), Boundary Layer Theory, Springer: New York♦ Van Norman, J. W. and L. Novak (2009), CFD support of MSL MLE plume simulations. NASA Contractor Report, No. NNL04AA03Z.♦ Land, N., and H. Scholl (1966), Scaled LEM jet erosion tests, NASA Langley Working Papers, LWP–252, NASA Langley Research Center.♦ Clark, L., and W. Conner (1969a), Exploratory study of scaled experiments to investigate site alteration problems for Martian soft-lander

spacecraft, NASA LWP-765, NASA Langley Research Center, Hampton, VA.♦ Sengupta, A., M. Mehta et al. (2009), Mars Landing Engine Plume Impingement Environment of the Mars Science Laboratory, IEEE/AIAA

Aerospace Conf., 1349.♦ Huseman, P. G. and J. Bomba (2000), CFD Analysis of Terminal Descent Plume Impingement for Mars Landers, AIAA Thermophysics

Conf., 2000-2501.♦ Buning, P.G., W.M. Chan, K.Z. Renze, D.L. Sondak, I.-T. Chiu, J.P. Slotnick (1993) OVERFLOW User's Manual, Version 1.6ab, NASA

Ames Research Center, Moffett Field, CA, Jan.♦ Gulick, D.S. (2006), Phoenix Mars Lander Descent Thruster Plume/Ground Interaction Assessment, WS-06-002 Lockheed Martin

Interoffice Memo, Lockheed Martin Space Systems, Denver. ♦ Mehta, M., et al. (2011), Explosive erosion during the Phoenix landing exposes subsurface water on Mars, Icarus, 211, 1. ♦ Plemmons, D. H. , M. Mehta et al (2008), Effects of the Phoenix Lander descent thruster plume on the Martian surface, J. Geophys.

Res., 113, E00A11.♦ Whetsel, C., et al. (2000), Jet Propulsion Laboratory MPL Investigation Board, Report on the Loss of the Mars Polar Lander and Deep

Space 2 Missions, JPL D-18709.

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Back-up Slide: Phoenix Entry, Descent and Landing Sequence

-200 Hz (Inertial Measureiment Unit) IMU data and 10 Hz Radar data

CurrentResearch Investigation

28

Back-up Slide: Terminal descent

Plumes interacted with the surface for less than 2 seconds (even less than predictedby landing simulations)

Lift loss occurred at ~4.5 m and ground effect started around ~3.5 m

Noticed a second bounce – could be the result of plume-surface interactions afterInitial contact.

Touchdown

29

underexpanded supersonic plume surface interactions ......-transient & steady-state rans eqns...

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