PurposeSeeks to examine the performance of conventional turbulence models modelling strongly swirling flows within a Symmetrical Turn up Vortex Amplifier, with adjustment of the turbulence model constants to improve agreement with experimental data.Design/methodology/approachFirst, the standard k‐ε model and the Reynolds Stress Model (RSM) were used with standard values of model constants, using both the first order upwind and the quadratic upstream interpolation for convective kinetics (QUICK) schemes. Then, the swirling effect was corrected by adjusting the model coefficients.FindingsThe standard RSM with the QUICK did produce better predictions but still significantly overestimated the experimental data. Much improved simulation was obtained with the systematic adjustment of the model constants in the standard k‐ε model using the QUICK. The physical significance of the model constants accounted for changes of the eddy viscosity, and the production and destruction of k and ε.Research limitations/implicationsMore industrial cases could benefit from this simple and useful approach.Originality/valueThe constant adjustment is regular and directed, based on the eddy viscosity and the production and destruction of k and ε. The regularity of the effect of the model constants on the solutions makes it easier to quickly adjust them for other industrial applications.

Fluidic systems have been developed for handling toxic and corrosive fluids in U.K. nuclear plant. Recent work carried out in the CEFT department in collaboration with UKAEA, Risley, which has led to the installation of plant hardware is described. The systems include: single and double-acting pumps with no-moving-part driving units, experiments on multistage pumps and the effect of temperature on pumping rate, fluidic control of mixer-settlers, and pulse-columns. Also described are applications in ventilation plant control and the effect of argon controlling air in a vortex amplifier.

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. A microfluidic sample-sequencing unit was developed as a part of a high-throughput catalyst screening facility. It may find applications wherever a fluid is to be selected for analysis from any one of several sources, such as microreactors operating in parallel. The novel feature is that the key components are fluidic valves having no moving parts and operating at very low sample flow Reynolds numbers, typically below 100. The inertial effects utilized in conventional no-moving-part fluidics are nearly absent; instead, the flows are pressure-driven. Switching between input channels is by high-Reynolds-number control flows, the jet pumping effect of which simultaneously cleans the downstream cavities to prevent crosscontamination between the samples. In the configuration discussed here, the integrated circuit containing an array of 16 valves is etched into an 84 mm diameter stainless steel foil. This is clamped into a massive assembly containing 16 mini-reactors operated at up to 400 C and 4 MPa. This paper describes the design basis and experience with prototypes. Results of CFD analysis, with scrutiny of some discrepancies when compared with flow visualization, is included. 0263-8762/04/$30.00+0.00 # 2004 Institution of Chemical Engineers www.ingentaselect.com=titles=02638762.htm Trans IChemE, Part A, June 2004 Chemical Engineering

No abstract

The design and operation of a novel type of fluidic vortex amplifier have been investigated experimentally using model tests with ambient air, and using computationally time-dependent computational fluid dynamics (CFD) simulation. The ultimate objective is to develop a no-moving-part variable air distribution device for implementation within gas turbine combustors using the fuel flow as the controlling agent. Although both liquid and gaseous fuels are ultimate goals of this device, this paper describes the first stage of the work involving operation with nominally uniform density fluid (air). There is some discrepancy between the simulation and test data, but design and performance trends were usefully simulated. An important feature of the CFD was the occurrence of a weak time dependent flow structure, particularly with the Reynolds stress model (RSM). Flow modulation within the desired range (4.5 compared with 2.6) was demonstrated, and these are shown, along with some general points concerning computational modelling convergence and turbulence models.