Abstract
Influence of wall effect for measurement of planar elongational viscosity by 4-roll mill flow cell was investigated. Elongation rate distribution along laser beam for measuring flow-birefringence was become clear by flow visualization. It was shown that the degree of two-dimensionality was decreased by the bottom wall effect and the non-uniformity of elongational distribution makes an error on the result of planar elongational viscosity. The conduit for light was attached on the bottom wall to reduce the wall effect and it was shown that using the conduit can reduce the error of measurement of planar elongational viscosity.
