Scaling two-phase flows to Mars and Moon gravity conditions

Hydrodynamic measurements are presented for two-phase flows in Mars and Moon gravity conditions. High accuracy pressure drop and flow rate data were obtained using dichlorodifluoromethane (i.e., R-12) as the working fluid flowing in a nominally 11.1 mm inner diameter tube. Measurements were made at Mars gravity, approximately 0.38-g, and Moon gravity, approximately 0.17-g, using NASAʹs KC-135 aircraft. A simplified scaling approach was developed using dimensional analysis and can be used to design an Earth-based test bed to simulate a Mars or Moon gravity prototype. For a specific geometry, a selected working fluid at a fixed temperature and pressure, and a particular flow regime condition, the pressure drop functional scaling equation is a simple, power-law relationship for the Euler number as a function of only the Froude number. The research completed supports the use of Earth-g tests to predict the behavior of two-phase systems for Moon-g and Mars-g applications.