<p> </p> <p>Over the last few years, there has been a concerted effort to develop and validate models<br> aiding the development of cryogenic refueling technologies. This effort is focused on the goal<br> of one day being able to refuel and store cryogenic propellants in the low gravity environ-<br> ment of space. The purpose of this research is to leverage the capabilities of some of these<br> recently developed models to create new ones and model more phenomena related to the<br> space applications of cryogenics.<br> The modelling work presented here is focused in the areas of cryogenic tank chilldown<br> and tank pressure control during storage/transfer. These tools are meant to help inform<br> future experiments being performed at the Glenn Research Center and elsewhere.<br> The model focusing on cryogenic tank chilldown provides a transient approach using<br> the charge-hold-vent (CHV) methodology to calculate the mass and time required to chill<br> a tank down to a desired temperature. Building on the 1-g Universal No-Vent Fill model<br> developed by NASA, the model captures the flashing of pooling liquid during the rapid<br> de-pressurization caused during the vent stage of the chilldown process. The model is com-<br> pared against two different datasets and successfully predicts pressure response throughout<br> the process to within 22%.<br> The thermodynamic vent system (TVS) model has been designed to be seamlessly inte-<br> grated into the 1-g Universal No-Vent Fill model to predict condensation and heat transfer<br> provided by the TVS during a no-vent fill. The TVS coil is spatially discretized and the<br> axial temperature distribution solved for. The model is capable of adapting to a rapidly<br> lowering or rising fill level that can lower the overall heat removal provided by the TVS.<br> While the heat removal is of primary importance, by capturing secondary phenomena such<br> as two-phase pressure drop, the TVS model is also capable of informing design decisions for<br> future systems. The model is compared against three test cases and predicts heat removal<br> to within 2%.<br> <br> </p> <p> </p>