Cavitation in nozzle — Welcome to LS-DYNA Examples

This example features both a 2D input deck and a 3D input deck. In the 2D cavitation problem, we test a cavitation model implemented in the dual CESE solver (Please note,  this cavitation model has previously been implemented in the regular CESE solver). The cavitation model  used is Schmidt’s homogeneous equilibrium model^[1] (HEM), which is based on the acoustic speed of the mixture of liquid and vapor. This model is simple but contains the important characteristic information of cavitating flows. This cavitation model is very suitable for high-speed flows in small geometry, like diesel injection systems. In the 3D cavitation problem, the 2D cavitation in a non-hydro nozzle model is extended to a 3D cylinder shape non-hydro nozzle.

References:

[1] Schmidt, D.P.,Rutland, C. J., Corradini, M. L. (1999), “A Fully Compressible Two-Dimensional Model of  Small, High Speed Cavitating Nozzles,” Atomization Sprays Technology 9: 255-276.

3D Model :

*DUALCESE_MODEL

*DUALCESE_CONTROL_SOLVER

*DUALCESE_CONTROL_TIMESTEP

*DUALCESE_CONTROL_LIMITER

*DUALCESE_INCLUDE_MODEL

*DUALCESE_BOUNDARY_PRESCRIBED_SEGMENT_SET

*DUALCESE_BOUNDARY_SOLID_WALL_SEGMENT_SET

*DUALCESE_INITIAL

*DUALCESE_PART

*DUALCESE_EOS_CAV_HOMOG_EQUILIB

*DUALCESE_D3PLOT

*CONTROL_TERMINATION

*DATABASE_BINARY_D3PLOT

*DATABASE_BINARY_D3DUMP

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*KEYWORD

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

*DUALCESE_CONTROL_SOLVER

$    icese      igeom   iframe MixSelect

N-S        2D     fixed    cavi

*DUALCESE_CONTROL_TIMESTEP

$     iddt       cfl     dtint

1      0.9    0.0006

*DUALCESE_CONTROL_LIMITER

$    idlmt      alfa      beta      epsr

0      2.0       1.0       .005

$

*DUALCESE_INCLUDE_MODEL

fluid_m2h.k

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

$

$ Setup the boundary conditions for fluid

$

$ Inlet Prescribed BC (left)

$

*DUALCESE_BOUNDARY_PRESCRIBED_SEGMENT_SET

$     ssid

1

$   lcid_u    lcid_v    lcid_w    lcid_d    lcid_p    lcid_t

-1       -1                  -1        -1

$     sf_u      sf_v      sf_w      sf_d      sf_p      sf_t

-1       -1                  -1        -1

100                  0.0  9.321e-4

*DUALCESE_BOUNDARY_PRESCRIBED_SEGMENT_SET

$     ssid

4

$   lcid_u    lcid_v    lcid_w    lcid_d    lcid_p    lcid_t

-1        -1        -1        -1                  -1

$     sf_u      sf_v      sf_w      sf_d      sf_p      sf_t

1.0e+5

$

*DUALCESE_BOUNDARY_REFLECTIVE_SEGMENT_SET

$     ssid

3

$

$ Solid BC_3 (bottom)

$

*DUALCESE_BOUNDARY_SOLID_WALL_SEGMENT_SET

$     ssid

2

$

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

$

$ Setup the initial conditions for fluid

$

*DUALCESE_INITIAL

$      uic       vic       wic     rhoic       pic       tic

$       0.0       0.0       0.0    8.8e-4

0.0       0.0       0.0    .8e-6

$

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

$

$ Setup fluid properties

$

*DUALCESE_PART

$      pid       mid     eosid FSI-type MOVMSHALG

1                  3

*DUALCESE_EOS_CAV_HOMOG_EQUILIB

$    eosid   rho_gas   rho_lqd    aa_gas    aa_lqd   vis_gas   vis_lqd  psat_gas

3    0.8e-6    8.8e-4   3.34e+5  1.386e+6    1.8e-5  2.936e-3    1.2e+5

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

$

$ Handle output of flow variables

$

*DUALCESE_D3PLOT

density

pressure

velocity

void_fraction

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

*END

$================================================================================

– DUALCESE_example_2DCavity.zip

– DUALCESE_example_3DCavity.zip