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Experimentation and computation show that the tilted orifice common in some Diesel fuel injectors sometimes functions similar to a swirl atomizer. In this paper the internal fluid dynamics, including different instances of cavitation, are examined. The authors and others around the world have shown that cavitation at the inlet to the orifice aids in the creation of desired sprays. Because of the complexity of this unsteady, two-phase flow with non-equilibrium bubble dynamics, true scale and true pressure are used for flow visualization. Thus, the cavitation inside tilted 200 micron spray holes at pressures up to 210 MPa (2,000 atmospheres) is imaged.

This paper describes modeling results for the on-orbit thermal response of spacecraft propellant used for orbit stationkeeping. The specific objectives of the work are to improve analytical models of a transient thermal Propellant Gauging System (PGS) in use on communications satellites. This simple method uses tank wall heaters and temperature sensors and a transient energy balance to obtain periodic measurements of remaining propellant fill. The fill levels must be related to the on-orbit sensor measurements through a thermal model of the system. In the past, relatively simplified representations have been used due to the complex liquid/gas geometry when in a weightless state. In the current work, advanced modeling tools are utilized to allow a more detailed representation of the actual liquid/gas geometry. Model results are presented for a range of fill levels later in life to assess PGS measurement resolution.