(202a) Development of a Custom High-Temperature, High-Pressure Phase Behavior Apparatus

This presentation is an update on the development a custom apparatus to measure the phase behavior and density of highly asymmetric mixtures to pressures of 240 MPa and temperatures of 673 K is presented. The instrument consists of a variable-volume view-cell and camera to monitor the phase behavior and an LVDT coupled with a metal bellows to track the internal volume of the view-cell. Both the view cell and thermostat were designed using finite element analysis to ensure the operability of the instrument to high pressures and stable temperature control could be achieved at high temperatures. Additionally, image analysis tools were used to accomplish automated data acquisition of bubble points, liquid-liquid phase separation, and solidification phase behavior. Presented in this work are the pressure and temperature measurement schemes and validation measurement with pure fluids and select asymmetric fuel-nitrogen mixtures. These data are used to rigorously quantify the uncertainties temperature, pressure, composition, and density uncertainties associated with the instrument.