Modelling Micro-Rheological Effects in Micro Injection Moulding with Dissipative Particle Dynamics
D. Kauzlaric, A. Greiner and J.G. Korvink
University of Freiburg, Germany, DE
Keywords: injection moulding, Poiseuille flow, Newtonian flow limit, dissipative particle dynamics
It will be demonstrated how Dissipative Particle Dynamics (DPD), a particle based simulation method, can contribute to the rheological study of fluids in micro-cavities, e.g. in Micro Injection Moulding. It is already known that DPD is able to reproduce the rheological results obtained from the continuous Navier-Stokes equations in the continuum limit. We will show that it also gives insight into the micro-rheological behaviour of the fluid delivering microscopic information, which is not accessible with the continuum approach, e.g., density fluctuations. By measuring the density distribution over the channel cross-section for the DPD-fluid under pressure driven Poiseuille flow, we will show that the assumption of a constant density becomes inaccurate when the channel width, or more precisely the average number of particles per channel width at a constant average density decreases. Above a certain threshold for the driving force, we observe non-linear behaviour of the DPD-fluid, without having introduced any specific model of non-linearity. Results for flow passing a forward and backward micro-step allow the conclusion that the viscosity of our model has to be increased in order to model real feedstocks appropriately.
Nanotech 2004 Conference Technical Program Abstract