Hiroshige Uchiyama

Anomalous Decrease in Flow Rates of Micro-Orifice Flows of Water With Increasing the Elapsed Time After Inception of the Flow

Flow rates under some pressure differentials were measured for the flow of water through micro-orifices. It was found that the flow rate decreases as the time has elapsed after inception of the flow under a constant pressure differential and that the decrease in flow rates is larger for city water than for pure water, and the gold orifice provides a less decrease with time in flow rates than the nickel orifice, although the flow rate at the incipient stage of the experimental run is lower in the gold orifice than in the nickel orifice.© 2011 ASME

Flow Properties for Several Kinds of Liquid Flows Through Micro-Orifices

In this paper, the flow properties of several types of liquid passing through various sizes of micro-orifices were investigated. The jet thrust and pressure drops were measured for two polyethylene glycol solutions and four surfactant solutions. Different flow properties were found for the various surfactant solutions depending on the charge of the solute. For an anionic surfactant, the results were similar to those for water, whereas in the case of a cationic surfactant, both the jet thrust and pressure decreased greatly in comparison with the other test liquids. Finally, a nonionic surfactant exhibited a steep rise in the pressure drop at a particular value of the Reynolds number. In explaining this behavior, the liquid-solid interface and alignment of the surfactant molecules are considered, and consequently, it is strongly suggested that the elastic stress on elongational flows is a contributing factor. In addition, the decreases in pressure and thrust for polyethylene glycols are attributed to viscoelastic properties, regardless of the molecular weight of PEG.© 2011 ASME