Browsing by Author "Hatzikiriakos, Savvas George"

Now showing items 1-6 of 6

    • Article  

      Mechanism for extrusion instabilities in polymer melts 

      Fyrillas, Marios M.; Georgiou, Georgios C.; Vlassopoulos, Dimitris; Hatzikiriakos, Savvas George (1999)
      A mechanism for explaining some of the instabilities observed during the extrusion of polymer melts is further explored. This is based on the combination of non-monotonic slip and elasticity, which permits the existence ...
    • Article  

      On numerical simulations of polymer extrusion instabilities 

      Achilleos, Evdokia C.; Georgiou, Georgios C.; Hatzikiriakos, Savvas George (2002)
      The objective of this study is mainly to review recent work concerning the numerical modeling of the stick-slip and gross melt fracture polymer extrusion instabilities. Three different mechanisms of instability are discussed: ...
    • Article  

      Role of processing aids in the extrusion of molten polymers 

      Achilleos, Evdokia C.; Georgiou, Georgios C.; Hatzikiriakos, Savvas George (2002)
      Product quality and, in general, processing windows and rates of production in the extrusion of molten polymers are limited by various flow instabilities (mainly melt fracture) that are observed at high production rates. ...
    • Article  

      Sharkskin and oscillating melt fracture: Why in slit and capillary dies and not in annular dies? 

      Delgadillo-Velázquez, O.; Georgiou, Georgios C.; Sentmanat, M.; Hatzikiriakos, Savvas George (2008)
      The sharkskin and stick-slip polymer extrusion instabilities are studied primarily as functions of the type of die geometry. Experimental observations concerning the flow curves, the critical wall shear stress for the onset ...
    • Conference Object  

      Stability of the annular Poiseuille flow of a Newtonian liquid with slip along the walls 

      Chatzimina, Maria Evangelia; Georgiou, Georgios C.; Housiadas, Kostas D.; Hatzikiriakos, Savvas George (2008)
      The annular Poiseuille flow of a compressible Newtonian fluid is studied assuming that slip occurs along the wall. Different slip models relating the wall shear stress to the slip velocity are employed. In the case of ...
    • Article  

      Stability of the annular Poiseuille flow of a Newtonian liquid with slip along the walls 

      Chatzimina, Maria Evangelia; Georgiou, Georgios C.; Housiadas, Kostas D.; Hatzikiriakos, Savvas George (2009)
      The annular Poiseuille flow a Newtonian fluid is studied assuming that slip occurs along the walls. Different slip models relating the wall shear stress to the slip velocity are employed. In the case of non-monotonic slip ...