SUBJECT: Ph.D. Dissertation Defense
   
BY: Michael Baldwin
   
TIME: Thursday, January 14, 2021, 10:30 a.m.
   
PLACE: https://bluejeans.com/885535781, Online
   
TITLE: Flow and Phase Change Phenomena of Cryogens and Cryogenic Fuels
   
COMMITTEE: Dr. S. Mostafa Ghiaasiaan, Chair (ME)
Dr. Lucas Graber (ECE)
Dr. Sangkwon Jeong (KAIST)
Dr. Yogendra Joshi (ME)
Dr. Alok Majumdar (NASA/MSFC)
Dr. Zhuomin Zhang (ME)
 

SUMMARY

The hydrodynamics of cryogenic fluid flow through microporous media based on first principles. The systems of interest are the fillers of regenerators in pulse tube and Stirling cryocoolers which will be modeled using 3D computational fluid dynamics. Hydrodynamic parameters, including the Darcy permeability and Forchheimer coefficient, for periodic flow in the microporous media of interest are determined and compared with relevant models and data. Both steady state unidirectional flow and 3D periodic flow are investigated. The second part of the research includes a critical review of existing literature dealing with pool and flow boiling of cryogens relevant to spacecraft fuel systems involving liquid oxygen (LO2), liquid hydrogen (LH2), and liquid methane (LCH4), and the development of stand-alone computational routines for accurately modeling two-phase flow and boiling of such cryogens. These computational routines are developed to be compatible with NASA's flow system simulation tool Generalized Fluid System Simulation Program (GFSSP). A critical assessment of all accessible experimental data pertinent to two-phase flow and boiling of the aforementioned cryogens are performed, a reliable set of boiling data are selected, and the most accurate boiling correlations are determined. The applicability or otherwise of well-established two-phase flow and boiling closure relations for the aforementioned key cryogens of interest for space fuel systems are determined. A road map for experiments addressing potential gaps in the available experimental data dealing with LO2 and LCH4 are proposed.