Phase Separation of Liquid Mixtures

  • A. G. Lamorgese
  • R. Mauri


We simulate the phase segregation of a deeply quenched binary mixture using a pseudo-spectral method. Our theoretical approach follows the standard model H, where convection and diffusion are coupled via a body force, expressing the tendency of the demixing system to minimize its free energy. This driving force induces a material flux which, for liquid mixtures, is much larger than that due to pure molecular diffusion, as in a typical case the Peclet number N Pe , expressing here the ratio of thermal to viscous forces, is of order 104. Using a pseudo-spectral method, we integrate the equations of motion in 2D, showing that the behavior of the system as it phase segregates depends on the values of the Peclet number. When N Pe < 102, the formation of sharp interfaces and the growth of the single- phase domains are two successive stages of the phase segregation process, while for N Pe > 103 the two events occur simultaneously, showing that the system is never at quasi-equilibrium during the segregation process. In addition, we show that, when N Pe > 103, the microscale Reynolds number increases dramatically.


Phase Separation Liquid Mixture Peclet Number Spinodal Decomposition Sharp Interface 
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Copyright information

© Springer-Verlag Italia, Milan 2002

Authors and Affiliations

  • A. G. Lamorgese
    • 1
  • R. Mauri
    • 1
  1. 1.Dipartimento di Ingegneria Chimica, Chimica Industriale e Scienza dei MaterialiUniversità di PisaPisaItaly

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