320 likes | 527 Views
High Viscous Flow in Silk Spinneret. 2004. May.4 th. Tetso Asakura* Ayano Ino* Toshiyuki Suzuki**. * Tokyo University of Agriculture and Technology ** CHAM Japan. Introduction. Silk worm. For create silk artificially, it is important to application of process of silk spinning.
E N D
High Viscous Flow in Silk Spinneret 2004.May.4th Tetso Asakura* Ayano Ino* Toshiyuki Suzuki** * Tokyo University of Agriculture and Technology ** CHAMJapan
Introduction Silk worm • For create silk artificially, it is important to application of process of silk spinning.
Silkworm spinneret 530μm from Spigot Spinneret
3D structure silkworm spinneret 530m 1mm 10m 100m Silk Press part chitin plate Silk Silk tube spigot
Process of Silk spinning Shear Stress β α Liquid Protein Fiber • Silk spinning → “α to β transition” by shear Stress
Shear rate of Silk fibroin • Experiment of critical shear rate • Kataoka at.al transition shear rate is 1E+02~1E-3 sec-1 Critical shear rate concentration
Molecular Dynamics simulations Tensile stress =0.1GPa Shear stress =0.3,0.5,0.7,1.0GPa Conformational probability
Geometry from Biology Electron microscope Reconstruct 3D solid PHOENICS Object
PHOENICS OBJECTS ■PHOENICS-VR “Objects” → Don’t need BFC meshing & Easy to Use ■Complex Geometry →facet data converted from STL format ■Wall friction added automatically on Object face
STL(Stereo Lithograph) file • STL file • Solid model ⇒ triangle patches It accepts the un-closed and twist surface • Many tools can be used to make it
Graphical tools to Object(Make STL file from picture) Electron Microscope Reconstruct 1000piece Picture
Repair STL Repair STL file Cimatron Magics • What is required before importing PHOENICS ? ・ No Hole or Gap ・ Surface vector is the same direction(twist) ・ Cut small parts ・ Smoothing
Repaired by Magics Electron Microscopic
Model (meshing) 820μm (nz=205) 152μm (ny=78) 156μm (nx=78)
Properties of Silk fibroin • Density • 75%water 1.075[g/cm3] • Viscosity • Neuton Fluid 6.5E+4[P] • Ref: Water=0.01[P],Glycerin=7.982[P]
Boundary Conditions • Inlet Velocity 0.178cm/sec (spinneret velocity=1.0cm/s) • Outlet P=0 • Wall Non-Slip
High Viscosity Flows • Transport Equations ∇●u=0 ∇●uu= ー∇p/ρ + μ∇2u • Finite volume equations ΦP=(aNΦN+aSΦS+etc.)/aP
Continuity Equations • Error of continuity R*=cN-cS+etc. c: convective flux • Pressure correction equation aPpP= aNpN+aSpS+etc.+R* by default: a=dc/dp
Convergence acceleration • Pressure correction equation at ADDDIF option for High Viscosity flow aPpP=aNpN+aSpS+etc.+R* a=d(c+d)/dp Diffusion Flux
Corresponding in MIGAL • MIGAL Solver ⇒ Velocity-Pressure Coupling ApΦp=ΣAnbΦnb+b Matrix A included convection and diffusion fluxes
Convergent test • Use cut model near chitin plate No. of cells =94x114x63
Monitor value Pressure Z Velocity X Velocity
Residual Pressure Z Velocity X Velocity
Pressure and Velocity Pressure[kPa] Streamline[msec]
Slip velocities(shear rate) • In PHOENICS, the magnitude of the total rate of strain GEN1 is given as, GEN1=2*[(du/dx)2+(dv/dy)2+(dw/dz)2] +(du/dy+dv/dx)2 +(dv/dz+dw/dy)2 +(dw/dx+du/dz)2 Slip velocity is Vs=SQRT(GEN1)
Summary & Conclusion • About Simulation Result • The maximum shear velocities is 45[1/s] at silk press part. Where is provided the transition from liquid protein to fiber. • Static Pressure loss is Giga Pascal order in spinner. It is as same as the transition stress with the molecular dynamics simulation.
Summary & Conclusion 2 • About CFD technique • With some graphical tools, we can calculate easily the case with complex biology geometry by PHOENICS. • A better convergence has been gotten by adding the diffusion velocity into pressure correction equation for High Viscous Flow, If we desire much better performance, we can use MIGAL.
Summary & Conclusion 3 • Future and next step • PARSOL (Cut cell) • Pressing at chitin plate (use Moving Grid or MOFER). • Survey for the fibroin properties.