Study of mechanical choked Venturi nozzles used for liquid flow controlling

Motivated by the principles of the cavitating Venturi nozzle (CVN) used for controlling fluid flow and addressing limitations of CVN, this paper proposes a mechanical choked Venturi nozzle (MCVN) which achieves choking flow via a mechanical action. The MCVN is constructed by inserting a floating springed blockage into a Venturi nozzle to imitate the bubble dynamics of CVN. First, an initial MCVN design was derived theoretically. Then, using numerical simulation and an iterative procedure, this original design was corrected to build an optimized design. Finally, the optimized design was investigated and tested both numerically and experimentally. The experimental results show that the MCVN can maintain constant flow with a flow control error of 3.8% and a maximum back pressure ratio of 0.97. Since MCVN can achieve constant flow without fluid vaporization, the pressure ratio range for applying a choking flow device is expanded and some limitations of CVN are overcome. The principles and experimental results obtained in this research can be used as a framework for the design of improved constant flow control devices for liquid flow.