High Pressure Density Properties of High Bulk Modulus Oils

摘要

Using seven kinds of test base oils, the authors carried out high pressure density test. Based on the test results, the bulk modulus at each pressure was calculated. High pressure viscosity test was also performed, and pressure viscosity coefficients were obtained. The high pressure physical properties of the high bulk modulus oil required for the oil hydraulic equipments were evaluated by the test results. All the test base oils showed the higher bulk modulus than a comparative mineral oil. Among the test oils, the aromatic ester base oils had the optimum properties for the high bulk modulus oil. Subsequently, for improving the viscosity indexes of the aromatic ester base oils, two blend oils were made by mixing each one of aromatic ester base oils and aliphatic ester base oils with the low viscosity. And each bulk modulus of these blend oils was obtained. Each of the blend oils showed the different relation between the bulk modulus and temperature. In addition, it was found that the bulk modulus is influenced by the combination of the base oils.