Reseal point pressure model

The Reseal Point Pressure Model for Cryogenic Propellants... 

Figure 11.9 plots the comparison of experimental and model generated reseal point pressures for the consolidated database of 4815 data points. Table 11.6 shows the model performance against the data, organized by screen and liquid where 6,

Analogous to the bubble point pressure, the reseal pressure can be defined from a simplification of the general 3D YT.E for the pressure drop across a curved L/V interface embedded within the 3D space of the mesh. Consider the L/V interface formed within the LAD mesh screen as shown in Eigures 3.16 and 3.17. Retaining assumptions 1-4 from the bubble point model in Section 3.2.2, the following additional assumptions are required to solve the reseal pressure ... 

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 ... 

FIGURE 11.7 (a) Data and (b) Model Generated Bubble Point as a Function of the Liquid Temperature and Pressure at the LAD Screen for a 325 x 2300 Mesh in Liquid Nitrogen using Gaseous Helium as a Pressurant. The black line is the nitrogen saturation curve. Color indicates magnitude of the reseal point. 

FIGURE 11.10 Model Generated 450 x 2750 Liquid Hydrogen (a) Bubble Point Pressure and (b) Reseal Pressure using Gaseous Helium as a Pressurant. Color indicates magnitude of bubble point and reseal pressure, respectively. 

The set of primary and secondary factors which influence LAD design were formulated, and a suite of physics-based models for the influential factors were developed and validated both in storable and cryogenic propellants. While the models agreed well with historical room temperature data, all LAD models validated by cryogenic data, including bubble point pressure, reseal pressure, FTS pressure drop, TVS cooling efficiency, and full-scale LAD channel pressure drop show strong temperature dependence and deviation from the room temperature behavior. The models derived here and validated both by the... 

Chapter 10 presents the revised empirical static bubble point model for cryogenic liquids. Model dependencies are systematically presented to explain the trends in the data. Chapter 11 echoes Chapter 10 by presenting a refined reseal pressure drop model, using cryogenic data to build the model. Chapter 12 presents a new steady state quasi-3D... 

As mentioned in Section 3.9.2, there are only three previous studies where reseal data was reported. Reseal pressure data was collected alongside all bubble point test data from both room temperature as well as cryogenic bubble point tests for a 200 x 1400, 325 x 2300, 450x2750, and 510x3600 Dutch Twill LAD screen in IPA, methanol, acetone, water, LH2, LN2, LQX, and LCH4. A total of 4836 reseal pressure data points, of which 4815 were new points, were collected, processed, and analyzed to develop this model. 

FIGURE 11.9 Comparison of Experimental and Model Generated Reseal Pressures for the Consolidated Database of 4815 Points. 

The full reseal pressure point model takes the following final form ... 

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