Mass flow rate of two-phase flows.

摘要

Experimental physics often introduces new methods in existing applications and technologies. The problem investigated here is the mass-flow rate of a liquid-gas system. The conclusions drawn from this thesis will have useful applications in the space industry where the cryogenic propellants have an unknown amount of the gaseous phase in them; a phase that the turbine flow meter used today cannot detect. Water is used as the liquid in this research due to its low cost and ease of handling. The turbine flow meter error is determined using direct optical inspection methods. The flow system containing the water and dissolved air bubbles includes a transparent plexiglas section that is illuminated with a stroboscope. The scattered light from the air bubbles is detected and imaged with a CCD camera, which in turn is connected to a computer and a frame grabber, grabbing frames at a rate of 10 Hz. The findings of this experiment confirmed that the mass flow rate of a two-phase system as measured by the turbine flow meter contains errors. The errors are due to the turbine flow meters inability to detect the gaseous phase and the error increases dramatically as the bubble content in the flow increases.