Helical screw rheometer: a new concept in rotational rheometry

The helical screw rheometer represents a new concept in viscometry: a rotational instrument that generates a pressure difference and therefore does not require torque measurement. The device is basically a metering screw that operates with no discharge. The results that are necessary to obtain the power-law constitutive parameters from pressure drop and rotation rate data are presented along with comparisons between theory and experiment for a prototype instrument operated at ambient conditions. The helical screw rheometer may offer advantages over conventional instruments for: 1) high-pressure measurements, 2) chemically-reacting fluids, 3) heterogeneous fluids and 4) on-line measurements.