2332 Measurement of First Normal Stress Difference Using by Concentric Cylinder Flow Cell
Details
New measurement technique for the first normal stress difference using by a conventional rheometer with concentric cylinder flow cell is developed. The conventional rheometer which can control the up and down speed of the cylindrical bob and can also measure the thrust force is used in this technique. The other additional instruments or the optional parts are not required. The cylindrical bob is pushed down at a constant velocity into the sample filled in the cap. The resistant force acting on the bob is measured during this motion. The resistant force is caused by the buoyancy, the shear stress acting on the side surface of the bob and the pressure acting on the top and bottom of the bob. The buoyancy and the shear stress can be calculated from the shape of the bob and the moving velocity. If the entry and exit loss can be ignored, the pressure caused by the first normal stress difference can be evaluated from the thrust force and the information of the shear viscosity.
