Liquid Ring Research Articles

Analysis of ABS Plastic and Concentric Cylindrical Shells’ Chemical Detonation Scatter Process

In this paper, basing on the FAE theory, simulating the process of scatter from chemical detonation about ABS plastic and concentric cylindrical shell according to experiment, on the basis of the assumption that the initial moment of the explosion being at the source ,we analyzed the gaseous phase motion equation and liquid ring controlling equation, and build the liquid ring movement mathematical model, then analyze the scatter process according to the chemical detonation scatter experiment, and classify the chemical detonation scatter into acceleration phase and deceleration phase, form the initial fog group, then we can reveal the mechanism of changing the chemical detonation into the fog. After the initial fog being formed, the effect of the chemical detonation disappeared, and the water molecules are uniformly dispersed into the air.

Hydrophobic ionic liquids as novel extractants for gold(I) recovery from alkaline cyanide solutions

AbstractBACKGROUNDAlthough ionic liquids (ILs) as green solvents have become a focus of research in the field of metal ions separation, little attention has been paid to gold(I) recovery from alkaline cyanide solutions using ILs as extractants. Therefore, this work explores gold(I) extraction using hydrophobic imidazolium‐based ionic liquids.RESULTSIt was found that an increase in the alkyl group chain substituted on the cation ring of the ionic liquid corresponded with an increase in gold(I) extraction. Almost all of the gold(I) (>98%) was extracted from the aqueous phase into the organic phase using pure [C8mim][PF6] as an extractant. With increased reaction temperature, the gold extraction efficiency also increased. The transfer mechanism of Au(CN)2− into the ionic liquid was proved to be an anion exchange reaction. Most of the gold(I) (>90%) in the [C8mim][PF6] phase could be directly deposited on a copper cathode through electrowinning. Energy dispersive spectrometry analysis and X‐ray diffraction patterns suggested that the yellow deposits on the copper cathode were pure gold. Results of three recycling experiments indicated the excellent stability of the [C8mim][PF6].CONCLUSIONIonic liquid extraction followed by direct electrodeposition from the organic phase is a feasible method for gold recovery from alkaline aurocyanide solutions. © 2014 Society of Chemical Industry

The KALPUREX-process – A new vacuum pumping process for exhaust gases in fusion power plants

The Karlsruhe Institute of Technology (KIT) is developing a continuously working and non-cryogenic pumping solution for torus exhaust pumping of a demonstration power plant (DEMO) including Direct Internal Recycling (DIR).This full pumping system consists of three pumps, namely a metal foil pump for gas separation, a linear diffusion pump as primary pump and a liquid ring pump as backing pump. The latter two pumps apply mercury as working fluid due to its perfect tritium compatibility. This asks for a baffle system on both sides of the pumping train to control working fluid vapour and to avoid any mercury propagation in the machine.In this paper, the arrangement of all torus pumps required for a power plant reactor as well as the corresponding infrastructure and its effect on the DEMO machine design is presented and discussed. The full pumping process is called ‘Karlsruhe liquid metal based pumping process for fusion reactor exhaust gases’ (KALPUREX process, patent pending).

Development of Advanced Exhaust Pumping Technology for a DT Fusion Power Plant

The main functions of the exhaust pumping system of a Deuterium-Tritium (DT) fusion device are to pump out the helium ash and control the divertor neutral gas density. This requires the handling of large gas throughputs at high pumping speeds (but at relatively moderate vacua). The pumped exhaust gas is then usually transported to the tritium plant for cleaning, which involves impurity removal and separation of the pure hydrogenic species for reinjection as fuel. In view of a fusion power plant, a systematic technical review of primary and roughing pump technologies is conducted in order to identify potential exhaust pumping concepts, which eliminate some of the disadvantages that eventually result from simple scale-up of the ITER solutions that are based on batchwise operating cryogenic pumps. This paper also illustrates the methodology applied to come to unbiased results and describes the final configuration, which is based on a vapor diffusion pump as primary pump together with a metal foil pump for hydrogen separation, and a liquid metal ring pump as roughing pump. All pumps are working continuously and do not require cryogenic temperatures. The new concept will reduce the tritium inventories of a power plant: 1) because of the continuous pumping characteristics of the pumps involved and 2) because the metal foil pump allows for internal recycling of the unburnt fuel species directly from the divertor to the fuelling systems, bypassing the tritium plant. A research and development program was initiated in EU to demonstrate the feasibility of this novel approach and, thus, to make it the reference solution for a fusion power plant. The current status in this effort is summarized, and the test facility to be employed is described in full detail.

Electrostatic Side-Drive Rotary Stage on Liquid-Ring Bearing

We present an electrostatically actuated rotary stage featuring liquid rings, which serve as both mechanical bearings and electric connections between the rotor and the substrate. The liquid rings are formed by confining a liquid inside hydrophilic grooves and repelling it from the superhydrophobic surfaces outside the grooves. Made of a fluid, the liquid-ring bearing avoids the dry friction of the solid bearings, significantly improving the reliability. Formed as rings, it avoids the resistance of contact-angle hysteresis sliding over droplets, and hence dramatically reducing the static friction. Furthermore, surface tension facilitates the self-alignment of the rotor to the substrate and stator during the assembly and provides the stability against drift and shock during operation. Electrically, each liquid ring passes an independent electric signal, allowing a direct electrical path between the substrate and potential components on the rotor. A three-phase electrostatic rotary stage has been design, fabricated, and tested. The minimum torque to initiate the rotation is ~ 2.5 nN·m-hundreds of times smaller than droplet-based counterparts. The device has operated successfully by applying sequential voltages of 50 VDC between the rotor and the stators. The electric transmission has been verified by powering an LED on a rotating rotor. This is the first report of an electrostatically actuated rotating microdevice with a liquid bearing and a direct power transmission.

Comparison of Navier-Stokes simulations with long-wave theory: Study of wetting and dewetting

The classical long-wave theory (also known as lubrication approximation) applied to fluid spreading or retracting on a solid substrate is derived under a set of assumptions, typically including small slopes and negligible inertial effects. In this work, we compare the results obtained by using the long-wave model and by simulating directly the full two-phase Navier-Stokes equations employing a volume-of-fluid method. In order to isolate the influence of the small slope assumption inherent in the long-wave theory, we present a quantitative comparison between the two methods in the regime where inertial effects and the influence of gas phase are negligible. The flow geometries that we consider include wetting and dewetting drops within a broad range of equilibrium contact angles in planar and axisymmetric geometries, as well as liquid rings. For perfectly wetting spreading drops we find good quantitative agreement between the models, with both of them following rather closely Tanner's law. For partially wetting drops, while in general we find good agreement between the two models for small equilibrium contact angles, we also uncover differences which are particularly evident in the initial stages of evolution, for retracting drops, and when additional azimuthal curvature is considered. The contracting rings are also found to evolve differently for the two models, with the main difference being that the evolution occurs on the faster time scale when the long-wave model is considered, although the ring shapes are very similar between the two models.

Instability of a rotating liquid ring

It is shown numerically that a rotating inviscid liquid ring has a temporally oscillating state, where the radius of the ring varies periodically because of the competition between the centrifugal force and the centripetal force caused by the surface tension. Stability analysis reveals that an enlarging or shrinking ring is unstable to a varicose-type mode, which is affected by both the radial velocity and the radius ratio between the cross section and the ring. Furthermore, uniform rotation of a ring leads to a traveling unstable mode, whose frequency is determined by a simple sinuous mode, while the surface shape is modulated by the varicose mode and twisted by the rotation-induced Coriolis force.

Destabilization of a liquid ring in the binormal direction

The instability of a circular inviscid ring in its binormal direction is investigated theoretically by linear analysis. The analytical solutions of growth rates are obtained for both the simple sinuous mode and the varicose mode, namely, the classical Rayleigh mode. Different from the varicose mode, the unstable sinuous mode is caused not by the surface tension but by the aerodynamic lift force. The superimposition of these two modes provides a surface shape, which is qualitatively consistent with experimental observations on drop splash.

Proposal for water reuse in the Kraft pulp and paper industry

The reuse of wastewater by the pulp and paper industry reduces environmental impacts by contributing to raw water conservation, thereby making a greater volume of fresh water available for nobler purposes, and reducing wastewater treatment. This study evaluated a proposed system of water reuse at a Kraft pulp and paper plant in Brazil, based on a survey of water quality required by its consumption points, supplied by its water treatment plant. Results after ultrafiltration included: turbidity of 0,3 NTU and pH 7,5, average values of BOD 66,4 mg/L, COD 9,6 mg/L and the colour of 280,5 ppm Pt were measured after ultrafiltration. The ultrafiltered wastewater was considered available for reuse, and its quality was compared with that of the water supplied by the water treatment plant, which provided for the classification of potential reuse points. Water colour was identified as the limiting factor for reuse; thus the reuse points were two Kraft paper machines, and the water flow to the liquid ring formations that generate the vacuums inside nineteen pumps for these two machines. The advantages of this proposal for water reuse include: ultrafiltered water quality sufficient for the vacuum pumps, the small distance between the point of reused water generation and the paper machines section, and the reused water has no contact with the final product. The calculated cost and return time for the water reuse system was US$ 607.020,00 in 15 years.

Drop impact on super-wettability-contrast annular patterns

AbstractExtreme wetting properties of solids, either superhydrophobic or superhydrophilic, provide versatile methods to achieve unusual liquid deposit morphologies, such as liquid pearls or polygonal films. Here we report the dynamics of liquid drops that impact on solid surfaces where the extreme wetting properties are coupled in such a way that a superhydrophilic annulus is patterned on a superhydrophobic background. The drop that initially spreads on the inner superhydrophobic region is arrested by the hydrophilic annulus. The liquid deposit gets destabilized because of the strong water repellence of the inner region, exhibiting the burst and disengagement of the liquid film. This process leads to the formation of a liquid ring defined by the annulus pattern, which has practical implications in rapid printing of functional liquids. We visualize such drop dynamics with a high-speed camera and characterize their salient features by combining experimental measurements and theoretical considerations.

The Direct Internal Recycling concept to simplify the fuel cycle of a fusion power plant

A new concept, the Direct Internal Recycling (DIR) concept, is proposed, which minimizes fuel cycle inventory by adding an additional short-cut between the pumped torus exhaust gas and the fuelling systems. The paper highlights quantitative modelling results derived from a simple fuel cycle spreadsheet which underline the potential benefits that can be achieved by implementation of the DIR concept into a fusion power plant.DIR requires a novel set-up of the torus exhaust pumping system, which replaces the batch-wise and cyclic operated cryogenic pumps by a continuous pumping solution and which offers at the same time an additional integral gas separation function. By that, hydrogen can be removed close to the divertor from all other gases and the main load to the fuel clean-up systems is a smaller, helium-rich gas stream. Candidate DIR relevant pump technology based on liquid metals (vapour diffusion and liquid ring pumps) and metal foils is discussed.

Conceptuation of a continuously working vacuum pump train for fusion power plants

The Karlsruhe Institute of Technology (KIT) is developing a continuously working and non-cryogenic pumping solution for a demonstration power plant (DEMO). This pumping train shall cover the full operational pressure regime of a fusion reactor and is based on two pump types, namely diffusion pumps and liquid ring pumps. The whole pumping train must fulfill high safety and reliability requirements and it has to be made fully tritium compatible. In this paper, the design of a prototype pumping train and the special requirements for a DEMO machine are presented and discussed. A central feature of this pumping train is the use of a liquid metal as tritium compatible working fluid in both pump types, that leads to a pumping train which is able to cover a pressure range of 12 decades, namely from 10−9 to 103mbar. Finally, a test facility for pump testing over a wide pressure regime is described. In this facility (THESEUS), experiments with a diffusion pump have been performed and first results are presented.

Stability of a liquid ring on a substrate

AbstractWe study the stability of a viscous incompressible fluid ring on a partially wetting substrate within the framework of long-wave theory. We discuss the conditions under which a static equilibrium of the ring is possible in the presence of contact angle hysteresis. A linear stability analysis (LSA) of this equilibrium solution is carried out by using a slip model to account for the contact line divergence. The LSA provides specific predictions regarding the evolution of unstable modes. In order to describe the evolution of the ring for longer times, a quasi-static approximation is implemented. This approach assumes a quasi-static evolution and takes into account the concomitant variation of the instantaneous growth rates of the modes responsible for either collapse of the ring into a single central drop or breakup into a number of droplets along the ring periphery. We compare the results of the LSA and the quasi-static model approach with those obtained from nonlinear numerical simulations using a complementary disjoining pressure model. We find remarkably good agreement between the predictions of the two models regarding the expected number of drops forming during the breakup process.

Inertial collapse of liquid rings

AbstractLiquid rings can be generated in the Leidenfrost state using liquid oxygen of low boiling point ($- 183~\textdegree \mathrm{C} $) and high magnetic susceptibility, allowing one to ‘sculpt’ the liquid into a ring shape using an annular magnet. When the magnetic field is turned off, the ring shrinks back into a puddle with a constant acceleration. A potential flow approach accurately describes the dynamics of closure with an equation reminiscent of the Rayleigh–Plesset equation for the collapse of transient cavities.

Prediction of flow pattern of gas–liquid flow through circular microchannel using probabilistic neural network

The present study attempts to develop a flow pattern indicator for gas–liquid flow in microchannel with the help of artificial neural network (ANN). Out of many neural networks present in literature, probabilistic neural network (PNN) has been chosen for the present study due to its speed in operation and accuracy in pattern recognition. The inbuilt code in MATLAB R2008a has been used to develop the PNN. During training, superficial velocity of gas and liquid phase, channel diameter, angle of inclination and fluid properties such as density, viscosity and surface tension have been considered as the governing parameters of the flow pattern. Data has been collected from the literature for air–water and nitrogen–water flow through different circular microchannel diameters (0.53, 0.25, 0.100 and 0.050mm for nitrogen–water and 0.53, 0.22mm for air–water). For the convenience of the study, the flow patterns available in literature have been classified into six categories namely; bubbly, slug, annular, churn, liquid ring and liquid lump flow. Single PNN model is unable to predict the flow pattern for the whole range (0.53mm–0.050mm) of microchannel diameter. That is why two separate PNN models has been developed to predict the flow patterns of gas–liquid flow through different channel diameter, one for diameter ranging from 0.53mm to 0.22mm and another for 0.100mm–0.05mm. The predicted map and their transition boundaries have been compared with the corresponding experimental data and have been found to be in good agreement. Whereas accuracy in prediction of transition boundary obtained from available analytical models used for conventional channel is less for all diameter of channel as compared to the present work. The percentage accuracy of PNN (∼94% for 0.53mm ID and ∼73% for 0.100mm ID channel) has also been found to be higher than the model based on Weber number (∼86% for 0.53mm ID and ∼36% for 0.05mm ID channel).

Pumping through a Luttinger liquid ring threaded by a time-varying magnetic field

We consider a quantum ring laterally connected to open one-dimensional leads described within the Luttinger liquid (LL) model and subject to a time-dependent driving magnetic field o(t ). The closed loop is obtained by connecting two points of the LL by a weak link, which is treated exactly to lowest order in perturbation theory. Analytical results for the current across the weak link, as well as in the external circuit and inside the loop, are obtained. We pay special attention to the case of smooth magnetic pulses such that the response of the system is approximately adiabatic. We find that the response to the flux o is linear only if o is a small fraction of a flux quantum o0. By inserting whole quanta, a current goes in the external wires as two bunches, separated by a time proportional to the length of the loop, and a net pumped current in the external wires is produced. This kind of pumping is consistent with the predictions of the corresponding tight-binding model in the uncorrelated limit, but is not destroyed by electron-electron interactions.

Integrated Optofluidic Iris

An optofluidic iris, which uses the absorption of an opaque liquid in combination with a second transparent liquid for defining optical apertures of variable diameters, tuned by directly deforming a ring-shaped liquid-liquid interface using electrowetting on dielectrics, is presented. The novelty lies not only in the absence of any moving parts or membranes but also in the design of the liquid ring, which allows planar microfabrication processes to be used exclusively for defining all functional parts of the iris. When compared to other optofluidic approaches, this concept combines ultracompactness, full integration, moderate drive voltage (75 V), low power consumption (<; 5 mW), highly robust and repeatable tunability, adequate tuning speed (<; 1 s), high uniform transmission (>; 86%), and an optical quality suitable for imaging applications, with a fabrication process which will allow mass fabrication.

Ionic liquid assisted synthesis of nano-porous TiO2 and studies on confined ionic liquid

Nanoporous anatase form of TiO2 powder was synthesized by non-hydrolytic sol–gel method with and without ionic liquid (1-ethyl-3-methylimidazolium ethyl sulphate) [EMIM] [EtSO4]. The prepared nanoporous TiO2 powders were characterized by Thermogravimetric Analysis, Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, Brunauer–Emmet–Teller N2 gas adsorption–desorption isotherms, X-ray diffraction and transmission electron microscopy. Confinement of ionic liquid (IL) in porous TiO2 resulted in change in the glass transition temperature (Tg), shift in the C–H vibrations wave number of alkyl chain and ring of the ionic liquid and increase in surface area of the TiO2 particles prepared with IL. TiO2 particles obtained without ionic liquid were amorphous in nature whereas TiO2 particles obtained after the incorporation of ionic liquid were of poly-crystalline (anatase) form.

46.1: Invited Paper: A Novel Optical Switch and Display Based on Variable Aperture

AbstractWe report a novel optical switch and display using fringing field‐induced aperture change of a bracelet‐like liquid ring. To prove concept, we demonstrated a 4times4 color pixel array and a black‐and‐white single pixel for an optical switch. Without an electric field, the pixel has the largest clear aperture. The applied fringing field stretches the liquid surface, leading to a decreased aperture size. For a 230‐μm‐diameter pixel, the switchable aperture ratio is over 80% and the response time is ∼10 ms. This device has following advantages: polarization independence, fast response time, and easy fabrication.

Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15)K. Excess molar volume VE, deviation in isentropic compressibility ΔKS, partial molar excess volume ViE, deviation in partial molar isentropic compressibility ΔKS,i, deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1H and 13C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.