Transient Computer Code for Two-Phase Systems in Microgravity

Current two-phase computer codes for modelling of spacecraft thermal management systems or experiments are inadequate in many respects. Their multiphase models are inaccurate, outmoded, or poorly implemented. They are difficult to use without extensive training, and computation times are measured in days. We propose to develop an innovative computer code incorporating both modern, userfriendly interfaces and fundamental mechanistic models for two- phase flow and heat transfer in microgravity. Using state-of-the- art concepts in multiphase modelling and in software design, our objective is to provide a design tool (computer code) that is compact, fast, and portable, easily used by experimentalists and designers for transient or steady-state calculations. In Phase I, a subset of the complete code will be developed and tested for a condensing radiator model and will also be used to compare with NASA LeRC flight test data. The final design tool will be the only existing transient code for spacecraft thermal management systems which can, by its basic structure, correctly include the twofluid models for two-phase flow in microgravity from ongoing research at NASA LeRC. Expected NASA applications include design of two-phase systems and supporting experiments, and the benefits are greatly reduced training and computational time for the users.