Liquid subcooling bubble point pressure model

The seven known parameters that affect the bubble point pressure include the surface tension (liquid type), contact angle, effective pore diameter (which takes into account screen style, mesh, and metal type), liquid temperature, degree of subcooling (pressure), and pressurant gas type and temperature. The model will be validated through data collected over the past half-decade, as well as with data from the current work, which spans the space of these seven parameters. Ultimately, to be of topmost relevance for all future cryogenic propulsion missions, the model will be formulated in such a way that typical mission parameters like screen mesh, liquid properties, and pressurant gas properties can be input into the equation to obtain bubble point pressure easily and quickly at any desired condition. 

To model this gain, the bubble point formula for saturated cryogenic liquid states can be modified to incorporate subcooled liquid states. Examination of subcooled data indicates that the gain in bubble point pressure is approximately linearly proportional to the degree of subcooling, or distance away from the saturation curve, on a temperature/pressure plot. Therefore, the proposed subcooled bubble point model takes the following form ... 

The heated gas coefficients were determined in the same manner as the subcooled liquid coefficients. For each heated gas data point, a corresponding model generated saturated bubble point was calculated at each liquid temperature. For a given screen, pressurant gas, and cryogenic liquid, the heated gas loss, defined as the ratio of bubble point pressures ... 

If reseal diameter is known, the reseal pressure equation can theoretically be used to determine the reseal point of any fluid with a known surface tension. However, the same problem arises with cryogenic reseal data as with the cryogenic bubble point data. The room temperature prediction value matches neither the non-condensable or autogenous pressurant gas case. In addition, the room temperature model cannot be used to predict reseal pressures of subcooled cryogenic liquid states or elevated pressurant gases. Therefore, the new model must therefore address the following three discrepancies that exist between cryogenic reseal pressure data and simplified room temperature model. These are ... 

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