Application of the Bleustein-Gulyaev wave method for investigation of high-pressure phase transitions in diacylglycerol oil

Phase transitions in diacylglycerol (DAG) oil were investigated by using an ultrasonic method for measuring viscosity. Viscosity of DAG oil was measured over a wide range of hydrostatic pressures up to 500 MPa, and at temperatures ranging from 10 to 40 °C. The observed discontinuities in the viscosity versus pressure curves (isotherms) indicate phase transitions. An original ultrasonic method that uses the surface acoustic Bleustein-Gulyaev (B-G) wave was employed to measure the viscosity of DAG oil at high pressure range. This method allowed for fast and reliable measurement of DAG oil viscosity along various isotherms. Moreover, the kinetics of the observed phase transformations at various temperatures was analyzed