Presentation on theme: "High Viscous Flow in Silk Spinneret 2004.May.4 th Tetso Asakura* Ayano Ino* Toshiyuki Suzuki** * Tokyo University of Agriculture and Technology ** CHAM."— Presentation transcript:
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 For create silk artificially, it is important to application of process of silk spinning. Silk worm
Silkworm spinneret Spinneret 530μm from Spigot
3D structure silkworm spinneret Silk chitin plate Silk Press part 530 m 10 m 100 m 1mm spigot Silk tube
Process of Silk spinning Silk spinning α to β transition by shear Stress β Shear Stress FiberLiquid Protein α
Shear rate of Silk fibroin Experiment of critical shear rate Kataoka at.al transition shear rate is 1E+02 1E-3 sec-1 concentration Critical shear rate
High Viscosity Flows Transport Equations u=0 uu= p/ρ μ u 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=ΣA nb Φ nb +b Matrix A included convection and diffusion fluxes
Convergent test Use cut model near chitin plate No. of cells =94x114x63
Flow rate balance=(inlet+outlet)/inlet
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)
Slip Velocities of cross section [1/sec]
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.