Investigation of regular and anomalous behavior of liquid media under high pressure using ultrasonic methods

摘要

In many industrial technological processes, liquids are subjected to high pressures, e.g., in the high pressure food preservation. Similarly, in modern fuel injection systems for diesel engines, biofuel is subjected to a pressure up to 300 MPa. In such conditions, in liquids, high-pressure phase transitions (solidification) can occur that substantially increase the density and liquid viscosity. This solidification can result in significant problems with engine failure under cold-start conditions. This is an evident recipe for disaster, since the engine and its accessories would be very likely quickly destroyed. Thus, it is important to determine at what pressures and temperatures phase transitions occur. Conventional mechanical methods for measuring physicochemical properties of liquids at these extreme conditions do not operate. By contrast, ultrasonic techniques are very suitable for measurements of physicochemical properties of liquids at high pressure, since they are non-destructive, can be fully automated and are characterized by the absence of moving parts. The aim of this work is to study the high-pressure physicochemical properties of liquids (exemplified by a Camelina sativa - false flax oil) using novel ultrasonic methods.