Determination of the pressure dependent viscosity of non-Newtonian fluid using a new rheometrical device

A new type of rheometer has been designed based on hydrodynamic principle. The pressure chamber (rheometer) consists of a rotating inner cylinder (shaft) in a fixed hollow outer cylinder. The complex geometry gap between the two cylinders is filled with a viscous non-Newtonian fluid. When the solid cylinder moves inside the hollow cylinder shearing takes place and hydrodynamic pressure develops. The magnitude of the pressure depends upon the shear rate, i.e. the speed with which the inner solid cylinder is rotated and the viscosity of the fluid. The rheometer has been developed to measure the rheological properties of viscous fluid at pressures up to 4 MPa. The rheometer has a shear rate range 1000–3000 s−1. A number of experiments have been carried out to determine the effects of shear rate and pressure on the viscosity of glycerine. This paper outlines the method for establishing the pressure dependent viscosity–shear rate relationship based on experimental results and theoretical analysis.