A Software for Forecasting the Flow Patterns in Microgravity

Abstract

Abstract The problem of two-phase flow regime diagnostics and prediction remains one of the most complicated problems in modern thermodynamics and hydrodynamics. Despite the great importance of the flowing regime proper choice, it is still based on empirical or semi-empirical approaches, and analytical studies are mainly rather superficial. At the present, due to joint efforts of Russia and the USA, a new two-phase Thermal Control System (TCS) has been developing for the International Space Station «Alpha» (ISSA). Anhydrous ammonia is chosen as a TCS’ working fluid. TCS includes Evaporative Heat Exchangers (EHE) that are assigned to collecting heat escaped during functioning of different equipment in different ISSA modules. To the inlet of EHE, a subcooled ammonia is supplied. Ammonia is then heated and boils in internal EHE channels, and at vapor quality x ≫ 0.6 ... 0.8, it enters the Adiabatic Transportation Tube (ATT). Vapor quality in ATT may vary in a wide range in respect to the level of heat load in EHEs. That is why the forecasting of the two-phase flow pattern is an important problem in a pressure drop prediction.