LES-DQMOM based Studies on Reacting and Non-reacting Jets in Supersonic Crossflow

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LES-DQMOM based Studies on Reacting and Non-reacting Jets in Supersonic Crossflow

  1. 1. 50th AIAA Aerospace Science Meeting Nashville, Tennessee January 10th, 2012 Acknowledgements Texas Advanced Computing Center Large Eddy Simulation based Studies of Reacting and Non-reacting Transverse Jets in Supersonic Crossflow Shaun Kim a,b Pratik Donde a Venkat Raman a Kuo-Cheng Lin c Campbell Carter d Department of Aerospace Engineering and Engineering Mechanics The University of Texas at Austin a b c d
  2. 2. data have shown that this is not a reali free-stream, plume overexpansion do Motivation 354 Subsequently, Champigny and Lacau supersonic cross-flow. TheirS. K. stru S. Kawai and flow LelCrossflow Jet • Combustion inside hypersonic engine requiresetmixing of an und Figure 1. Schematics of the transverse injection crossflow (Ben-Yakar al. 2006; Gruber, Nejad, optimization due to short residence time Figure 1 turing flows with complex shocks and contact surfaces a eddying motions present in high Reynolds number flowf The Champigny–Lacau model has • Jet in supersonic crossflow exhibits complex flow upstream separation zone created fro In the present study, an under-expanded sonic jet inj is numerically simulated by using layer interaction also g shock/boundary a high-order low dis features; shock-turbulence interactions, 3D vortical difference scheme (Lele the crossflow, but turns downstre into 1992) and spatial filtering (Gait structures capture the physicsreferred to as the barrel shock. The ba of the supersonic turbulent mixing. R capturing schemes the high-wavenumber biased artificia of plume moves downstream. A se vortices moving downstream along th 2005) and diffusivity (Fiorina & Lele 2007) are simpli and stretched grid originating from the& Lele 2007) to se framework (Kawai boundary layer p • Supersonic combustion modeling is crucial to predict examines this near field mean flow stru objective of this paper is to develop further insights into chemical reaction characteristics the supersonic jet mixing. Comparisons between the L data (Santiago & Dutton 1997) are also performed for v
  3. 3. Outline• Jet in supersonic crossflow (JISC)• Numerical methodology - Compressible flow solver - Direct quadrature method of moments (DQMOM)• Result and discussions - Non-reacting jet in supersonic crossflow - Reacting jet in supersonic crossflow
  4. 4. flowfield that makes it difficult to quantify its effect on forces and moments. In the past, some res suggested that the jet can be properly represented by a solid cylinder of given transverse length in in Jet in Supersonic Crossflow data have shown that this is not a realistic representation. Such a model does not include plume exp free-stream, plume overexpansion downstream or the horseshoe vortex surrounding the jet arou Subsequently, Champigny and Lacau5 gave a detailed explanation of the flow phenomena pres354 supersonic cross-flow. TheirS. K. structure model is shown in Fig. 1. S. Kawai and flow Lele crossflow (Ben-Yakar et al. 2006; Gruber, Nejad, ChenChampigny-Lacau Figure 1. Schematics of the transverse injection of an under-expanded jet into a supersonic & Dutton 1995). Figure 1. Champigny and Lacau flow structure model.5 • Jet/crossflow interaction creates complex 3D vorticalturing flows with complex shocks and contact surfaces and the 3-D broadband turbulent The Champigny–Lacau model has found widespread acceptance currently. Amongst the flow feaeddying motions present in high Reynolds number flows. structures In the present study, an under-expanded sonic jet injected bow a supersonic crossflow the approaching bounda upstream separation zone created from a into shock interaction withis numerically simulated by using layer interaction also generatesand dissipative compactshock. As the jet exits, it i shock/boundary a high-order low dispersive a shock, or separationdifference scheme (Lele the crossflow, but turns downstream because of 2000) to properly a shock forms around th into 1992) and spatial filtering (Gaitonde & Visbal this interaction and • Shock-turbulence interactioncapture the physicsreferred to as the barrel shock. The barrel shock is terminated with a Mach disk and wake vortices a of the supersonic turbulent mixing. Recently developed discontinuity-capturing schemes the high-wavenumber biased artificial viscosity (Cook formed aft2004, jet plume with the so-c of plume moves downstream. A secondary shock is & Cabot of the2005) and diffusivity (Fiorina & Lele 2007) are simplified and extended to curvilinear model describes the hors vortices moving downstream along the surface. The Champigny–Lacauand stretched grid originating from the& Lele 2007) to separation upstream of the jet main framework (Kawai boundary layer perform the simulation. The between the -shock region. Th • Highly unsteady flow fieldobjective of this paper is to develop further insights into the 3-D complex flow physics and moments. examines this near field mean flow structure and their effects on forces ofthe supersonic jet mixing. Comparisons between the LES results and the experimental
  5. 5. UTCOMP : Compressible Flow Solver• Large-eddy simulation (LES) captures unsteady flow motion in turbulence with large length scale• Flow in subfilter scale needs closure - Dynamic Smagorinsky model is used for closing convective terms• High numerical scheme : 5th order WENO• MPI based parallelization
  6. 6. ied. The rate of mixing depends on the coefficient Direct quadrature method of momentsC / that appears in the definition of the mixing timescale (Eq. (5)). Figure 5 shows the time-averaged (DQMOM)absolute difference between the abscissas normal-ized by the mean scalar values. When the mixingcoefficient is doubled in value, the peaks are pulled • Joint PDF of thermochemical composition variables istowards the mean, which is reflected in the lowernormalized value. This plot also shows that thereis significant evolved using DQMOM method variation in the abscissas with themaximum OH variation being around four timesthe mean value. Since these fluctuations occur inthe shear• Developed forany given time, combustion by Koo et al. layer, it is likely that at supersonicthe weight associated with the Combustion Institutes, 2011) (Proceedings ofpeaks. of the peaks is onemuch higher than the other This will reduce Fig. 7. Instantaneous snapshots of OH mass fraction forthe impact of the temperature difference between (top) high inlet temperature and (bottom) low inlet temperature cases. Supersonic reacting jet Supersonic cavity-stabilized flame
  7. 7. Results and Discussion• Non-reacting Jet in Supersonic Crossflow• Reacting Jet in Supersonic Crossflow
  8. 8. Non-reacting Jet in Supersonic Crossflow• Sonic jet in Mach 2 crossflow• Momentum ratio = 1.52• Compared with the experiment from Air Force Research Laboratory (AFRL) by Lin et al. (Journal of Propulsion and Power, 2010) Crossflow Jet Air C2H4 M = 2.0 M = 1.0 ρ = 0.65 kg/m3 ρ = 2.504 kg/m3 T = 167 K T = 287.5 K p = 31 kPa p = 213.8 kPa δ = 6.4 mm d = 4.8 mm
  9. 9. Computational details 24d• 17 million grid cells over 31d x 8d x 24d 8d computational domain - 15y+ x 1.5y+ x 15y+ near wall 31d• Spatial discretization - Flow : 5th order WENO | Scalar : 3rd order QUICK• Crossflow simulated separated as boundary layer• Periodic boundary condition in spanwise direction• Computed with 480 processors for 36 hours
  10. 10. Flow Evolution of Non-reacting JISC C2H4Density gradient magnitude Ma
  11. 11. Flow Evolution of Non-reacting JISC C2H4Density gradient magnitude Ma
  12. 12. Comparison with the Experiment LES ExperimentC2H4 on symmetric plane x/d x/d x/d=5 x/d=25 x/d=5 x/d=25 y/d y/d y/d y/dC2H4 at x/d=5 and x/d=25 z/d z/d z/d z/d Wall PSPWall pressure distribution x/d x/d
  13. 13. Comparison with the Experiment LES Experiment y/d y/dC2H4 on symmetric plane x/d=5 x/d x/d=5 x/d z/d z/d y/d y/dC2H4 at x/d=5 and x/d=25 Wall PSP Wall PSP x/d=25 x/d=25Wall pressure distribution x/d x/d z/d x/d z/d x/d
  14. 14. Comparison with the Experiment LES ExperimentC2H4 on symmetric plane x/d x/d x/d=5 x/d=25 x/d=5 x/d=25 y/d y/d y/d y/dC2H4 at x/d=5 and x/d=25 z/d z/d z/d z/d Wall PSPWall pressure distribution x/d x/d
  15. 15. Shock Structures in JISC Bow shock Reflected shock λ-shock Barrel shockRecirculation zones Expansion fan Mach disk • Most of jet fluid passes through windward side of barrel shock and Mach disk
  16. 16. suggested that the jet can be properly represented by a solid cylinder of given tra Shock Structures in JISC data have shown that this is not a realistic representation. Such a model does no free-stream, plume overexpansion downstream or the horseshoe vortex surrou Subsequently, Champigny and Lacau5 gave a detailed explanation of the flo354 supersonic cross-flow. TheirS. K. structure model is shown in Fig. 1. S. Kawai and flow Lele Bow shock Reflected shock λ-shock Barrel shock crossflow (Ben-Yakar et al. 2006; Gruber, Nejad, ChenChampigny-Lacau Figure 1. Schematics of the transverse injection of an under-expanded jet intoMach disk Expansion fan a supersonic & Dutton 1995). Figure 1. Champigny and Lacau flow structure moturing flowsUnderexpandedand contact surfaces and the 3-D barrel shock • with complex shocks jet in crossflow creates broadband turbulent The Champigny–Lacau model has found widespread acceptance currently. Aeddying motions present in high Reynolds number flows. and Mach disk In the present study, an under-expanded sonic jet injected bow a supersonic crossflow the a upstream separation zone created from a into shock interaction withis numerically simulated by using layer interaction also generatesand dissipative compactshock. shock/boundary a high-order low dispersive a shock, or separationdifference scheme (Lele the crossflow, but turns downstream becausethethis interaction and a sho • Common1992) and structures are visible Visbal 2000) to properly into shock spatial filtering (Gaitonde & in of resultcapture the physicsreferred to as the barrel shock. The barrel shock is terminated with a Mach disk of the supersonic turbulent mixing. Recently developed discontinuity-
  17. 17. Vortical Structures in JISC
  18. 18. Vortical Structures in JISC agn itude m ient gradDensity
  19. 19. Vortical Structures in JISC
  20. 20. Vortical Structures in JISC C2H4 = 0.8 Q-criterion vorticity with contour of C2H4
  21. 21. Vortical Structures in JISC
  22. 22. Vortical Structures in JISC C2H4 = 0.8 Vortical structure• Boundary layer thickening is seen in the shock-boundary layer interaction• Jet/crossflow interaction creates vortical structures• Interaction of vortical structures is closely related to efficient mixing in the near field
  23. 23. Vortical Structures in JISC
  24. 24. Vortical Structures in JISC
  25. 25. Vortical Structures in JISC Long streak of streamwise vorticity
  26. 26. Vortical Structures in JISC x/d = 5 x/d = 0 Long streak of streamwise vorticity x/d = 3 x/d = 5 0 LES Experiment
  27. 27. Results and Discussion• Non-reacting Jet in Supersonic Crossflow• Reacting Jet in Supersonic Crossflow
  28. 28. Reacting Jet in Supersonic Crossflow• Sonic jet in Mach 3.38 crossflow• Momentum ratio = 1.4• Compared with the experiment by Ben-Yakar et al. (Physics of Fluids, 2006) Crossflow Jet Air C2H4 M = 3.38 M = 1.0 ρ = 0.0846 kg/m3 ρ = 7.02 kg/m3 T = 1290 K T = 263 K p = 32.4 kPa p = 550 kPa δ = 0.75 mm d = 2 mm
  29. 29. Computational details 24d• 15 million grid cells over 21d x 10d x 24d 10d computational domain - 60y+ x 2y+ x 60y+ near wall 21d• Periodic boundary in spanwise direction• LES-DQMOM methodology for combustion modeling - Reduced 13 species C2H4-air mechanism• Computed with 820 processors for 72 hours
  30. 30. 026101-9 Transverse jets in supersonic crossflows Shock Structures Comparison LES Experiment 026101-6 Ben-Yakar, Mungal, and HansonInstantaneousTime-averaged • Shock structure is highly unsteady dueschlieren imagefeatures coherent structures FIG. 5. An example to flapping s exposure time for injection case. While the unsteady with 3 motion at the windward sideaged tothe some of the weak shocks such as upstream separat of zero, barrel shock wave and downstream recompression wave are emphasized.
  31. 31. Flow Evolution of Reacting JISC Mixture Fraction Temperature (K)
  32. 32. Flow Evolution of Reacting JISC Mixture Fraction Temperature (K)
  33. 33. Flow Evolution of Reacting JISC t1 0.5 flow t2 residence timeMixture FractionTemperature (K) OH
  34. 34. Flow Evolution of Reacting JISC 0.5 flow residence time
  35. 35. Flow Evolution of Reacting JISC 0.5 flow residence time• Mixing depends on much larger coherent motions• Low Reynolds number in crossflow cause the mixing process to be “tearing up” rather than effective turbulent mixing
  36. 36. Flow Configuration• Difference in flow configuration between non-reacting and reacting jet• Reacting case had thinner boundary layer thickness (shock tunnel) Non-reacting Reacting J 1.52 1.4 ± 0.1 Rejet ~420,000 ~480,000 Reδ ~190,000 ~3,000 δ 1.33 D 0.375 D Ujet 325 m/s 315 m/s
  37. 37. Time-averaged Mixing Properties• Entrainment heavily depends on large coherent motion• Inefficient mixing quality in the near field (mixture fraction RMS ~ 0.5)• Flow residence time much smaller than ignition time delay
  38. 38. Conclusions• LES captures unsteady motion of jet in supersonic crossflow accurately• Flow structures in JISC were studied• LES-DQMOM methodology was used to study supersonic combustion with multivariate ethylene-air reaction mechanism• Reacting case did not have enough near field mixing• No flame stabilization was found in the reacting case
  39. 39. Questions Large Eddy Simulation based Studies of Reacting and Non-reacting Transverse Jets in Supersonic Crossflow Shaun Kim a,b Pratik Donde a Venkat Raman a Kuo-Cheng Lin c Campbell Carter da b c d

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