Design and Analysis of a High Pressure Apparatus

In the determination of equilibrium phase diagrams, i.e., pressure volume-temperature relations for lubricants at pressures up to 2800 MPa and temperatures of 378K, one must carry out a highly sophisticated design of a high pressure apparatus. In 1935 Bridgman designed a piston-displacement device and measured the compressibility of numerous materials at high pressures. However, in order to obtain accurate equilibrium phase diagrams for lubricants, Bridgman’s relatively crude analysis must be considerably refined. The authors have extended this original design using finite element techniques to accurately correct pertinent measurements which are in turn incorporated into the expressions used in determining the pressure-volume temperature relations of lubricants.