COMBUSTION RESEARCH & FLOW TECHNOLOGY INC — National Aeronautics and Space Administration SBIR Phase I: Z10

Description

The process of chilling propellant transfer lines, before ignition of liquid rocket engines is initiated is a critical step before launch.nbsp; Similarly, establishing fuel depots in low earth orbit to replenish propellant supply of long-range exploration missions also places a greater reliance on the chilldown process in ensuring safe and efficient protocols for cryogenic propellant transfer.nbsp; Over the past few decades, several experiments related to the quenching of heated tubes in a cryogenic environment have been carried out to understand the phase change process and the resulting complex two-phase regimes.nbsp; These studies have established that the phase change process evolves through different stages of film, transition and nucleate boiling before the walls are quenched and single-phase convective heat transfer between the wall and the cryogenic liquid is restored.nbsp; Efforts at developing empirical correlations of the heat transfer coefficient and porting it to thermal-fluid codes has resulted in large deviations between predictions and experimental observations of quenching time.nbsp; The innovation in this proposal involves the development of a comprehensive high-fidelity multiscale simulation framework that accounts for all the boiling regimes related to the chilldown process by utilizing a sub-grid scale nucleate boiling model embedded within a multiphase CFD solver.