Twenty-Fourth Symposium on Naval Hydrodynamics (2003) / Chapter Skim
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Experimental and CFD Analysis for Rotor-Stator Interaction of a Waterjet Pump
Experimental and CFD Analysis for Rotor-Stator Interaction of a Waterjet Pump
Pages 774-788
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From page 774... ...
To handle interface boundary between the rotor and the stator, the sliding multiblock technique using cubic spline and bilinear interpolation method were applied. The numerical pressure distribution on the intake duct surface was compared with experiment and a good agreement was obtained.
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From page 775... ...
+ ~`En+l + ~O~Fn+l +'~`Gn+l = &:,EVn+~ + 611 FVn+i + &`GVn+i (2) The barred quantities denote the column vector matrices consisted of momentum equations only.
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From page 776... ...
Again, when /\p goes to zero, the continuity equation is exactly satisfied at each time step. The spatial derivatives of convective flux terms are differenced by using third order accurate upwind QUICK scheme(Leonard, 1979)
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From page 777... ...
,::: - ' ~ =,Nf 0.5 1 XIC (c) Cx/U= 0.96 Figure 3: Time averaged Cp of a rotor at three different rotational speeds.
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From page 778... ...
The discharge nozzle has the grid points of 20x61x29. Figure 5: Configuration of waterjet propulsor Figure 4: Tip vortex formation After the code validation, the present iterative time marching procedure has been applied to the flow within the waterjet propulsion system which consists of four rotors and nine stators as shown in Figure 5, which was previously experimented with a 1/5 scale model (shun, 2001)
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From page 779... ...
Figure 9 shows the cross-sectional pressure contours at designated downstream locations of Figure 8. The streamlines given by Figure 9 show the secondary flow of vortex that is formed by the change of cross-section shape from rectangle to circle and, consequently, the variation of cross-sectional pressure distribution along the streamwise direction.
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From page 780... ...
A fairly good agreement between the present calculation and experiment is obtained. To illustrate the smoothness of flow properties across the block interface boundary of sliding multiblock technique, the velocity vectors in the body-fixed frame, streamlines in the inertial frame, and pressure contours across the block interface boundary are drawn in Figure 12.
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Locations of pressure tabs Figure 11: Surface pressure, compared with experiment (shun, 2001 3 (a) Velocity vectors in the body-fixed frame Figure 12: Velocity vectors, streamlines, and pressure contours across the block interface boundary.
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Limiting streamlines (b) Pressure contours Figure 13: On the suction side of the rotor (b)
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From page 783... ...
Of the stator Figure 17: Time averaged surface pressure distribution of the rotor and the stato23 0 10 20 30 40 50 60 70 80 90 Azimuthal angle(deg.)
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From page 784... ...
~ (c) at r/R=0.96 Figure 19: Velocity components after the trailing edge of rotor impeller 4 o 3 :0 2 .o o E -1 ._ z -2 u, 3 :0 2 tts 1 o u' o E -1 .
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From page 785... ...
Pressure contours Figure 22: Velocity and pressure in the symmetry plane of discharge nozzle Figure 21: Surface pressure distribution on the rotor, stator, and hub surface Figure 23: Pressure contours of stator and nozzle along r/R=0.5 plane
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Rear oblique view Figure 25: Streamlines past the stator
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From page 787... ...
CONCLUSION The numerical analysis of a waterjet propulsion system was performed to provide a detail understanding of complicated three-dimensional viscous flow phenomena including rotor and stator interaction and contracted discharge nozzle. The incompressible RAN S equations were solved on a moving, non-orthogonal body-f~tted multiblocked grid system.
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From page 788... ...
The pressure was obtained by the Neumann boundary condition. We also have tried another simulation which had large reservoir region, outside of nozzle exit and, then, imposing free stream velocity profile and hydrostatic pressure.
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