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Lookup NU author(s): Dr Jonathan McDonough, Dr Richard Law, Professor Adam Harvey
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Fluidic oscillators of the bistable amplifier type are one example of fluidics that has found new interest in a wide range of applications. Fluidic oscillators use internal feedback to induce periodic oscillations. By operating these devices with two outlet channels, periodic flow switching between the channels leading to dual stream pulsations can be achieved. In a previous study, the switching frequencies obtained in single feedback loop oscillators containing two outlet channels were investigated. Here, a parametric study bolstered by the use of 3D printing investigated the effects of seven geometrical parameters on the flow switching response for a variety of glycerol-water mixtures. Frequencies of 2–22 Hz were produced for kinematic viscosities of 1.00–4.37 mm2/s, in the range of Re = 600–12,000 [1]. A potential new application of liquid-based fluidic oscillators is their use in reactors. The oscillatory baffled reactor for example operates through a vortex production and dissipation cycle by oscillating the fluid in the presence of baffles. When this mechanism is superimposed onto a net flow rate, plug flow can be realised due to the analogous behaviour of well mixed tanks-in-series. The use of moving parts for the generation of oscillatory flow has been non-problematic in laboratory settings. However, the use of moving parts may have hindered the uptake of this technology to industrial applications. Our current focus is testing the use of these oscillators in applications relevant to process intensification. The primary goal is achieving a no-moving-parts mixer. Secondary objectives are: achieving lower-flow rate pulsations, plug flow generation, enhanced heat transfer, enhanced mass transfer, improved mixing and automated flow distribution. Preliminary experiments have been performed to assess the plug flow generating capability of these devices. A KCl tracer was injected at the inlet of various 3D printed reactor geometries (straight channel, straight channel + helical coil, and helix channel) and the conductivity measured at the outlet. The results suggest that the pulsatile flows generated by these oscillators can indeed improve the plug flow response of the three reactor geometries (producing narrower RTDs). It is intended in due course to perform a more robust analysis of the plug flow response by using a visual dye tracer to improve the time resolution of the measurements. Experiments are also being designed to assess the potential heat transfer and mixing improvements. Additionally, continued characterisation work is being undertaken to further understand the design rules of fluidic oscillators and to develop multi-channel oscillatory devices for distribution applications. [1] McDonough JR, Law R, Kraemer J, Harvey A. Effect of geometrical parameters on flow-switching frequencies in 3D printed fluidic oscillators containing different liquids. Chem Eng Res and Des 117 (2017) 228-239
Author(s): McDonough JR, Law R, Harvey AP
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 10th World Congress of Chemical Engineering
Year of Conference: 2017
Pages: 2009
Online publication date: 22/12/2017
Acceptance date: 31/05/2017
URL: http://wcce10.org/images/site/boa.pdf
Library holdings: Search Newcastle University Library for this item
ISBN: 9788469786291
