Experimental Investigation of Fluidic Diodes

摘要

Fluid diodes are used to protect pressure pipelines from hydraulic shocks, they can be applied as rectification elements of high operational reliability fluid machinery in pump manufacturing and in microfluidics. The quality of fluid diodes is determined by diodicity - the ratio of diode hydraulic resistance to the flow in forward and reverse directions. Vortex diodes are the most efficient ones in terms of diodicity. It is commonly known that diodicity from resistance depends on the geometrical arrangement of the fluid diode flow part and the fluid flow pattern. However, the latter dependence has not been investigated properly. The goal of this research is to study the dependence of hydraulic resistance coefficient of the Reynolds number. To achieve this aim, a vortex diode was designed and experimentally tested. Air was used as the working fluid. Test results showed that for the Reynolds numbers of less than 500, the hydraulic resistance coefficient has almost linear dependence of the Reynolds number and declines sharply with the Reynolds number increase. In the range of Reynolds numbers from 500 to 1300, the intermittent transition from laminar to turbulent flow patterns and the scattering of experimental points are observed. In the area of flow initial turbulent conditions, within the range of Reynolds numbers from 1300 up to 3000, hydraulic resistance coefficient is stabilized and with Reynolds numbers more than 3000, the area of resistance self-similarity is observed. Thus, the application of vortex diodes is appropriate only for Reynolds numbers over 3000.