Liquid Cylinder Research Articles

Insulation excellence and storage dynamics in a 500-litre self-developed vehicular liquid hydrogen cylinder: thermal leakage and status analysis

Abstract Liquid hydrogen storage represents an efficient and highly promising method for hydrogen encapsulation, particularly relevant for hydrogen-powered vehicles. This paper describes a novel self-developed 500-litre vehicular liquid hydrogen cylinder featuring high vacuum multi-layer insulation (HVMLI) and eight-point support structures. The study quantitatively analyzes the heat leakage from the thermal insulation layer, support structures, and accessory pipelines of this cylinder, with a total thermal leakage rate of 11.759 W, mainly stemming from the support structure. Moreover, using the BoilFAST software, simulations were conducted to investigate variations in the pressure of the ullage space, the temperature of the stored liquid hydrogen, and the temperature of the vapor within the ullage space across different liquid filling rates and stationary periods. This paper provides valuable insights into the development of vehicular liquid hydrogen cylinders, and the simulation results improved comprehension of the internal storage status and variations of associated physical parameters.

3D Modelling of Electro Vortex Flow Inside Liquid Metal and Effect of External Magnetic Fields

Electrovortex flow emerges when the current inside conducting liquids interacts with its self-induced magnetic field. The flow structure and strength of the flow are dictated by the current value and the presence of an external magnetic field. We present here 3D simulations for the electrovortex flow inside a liquid metal cylinder. The results presented reveal a typical electrovortex structure for low currents. Higher currents induce turbulence inside the electrovortex flow without any presence of an external magnetic field. In presence of Earth’s magnetic field, the flow structure is affected significantly. Cyclone, tornado, and rope tornado are observed inside the domain due to the earth’s magnetic field depending on the ratio of current applied and the earth’s magnetic field.

Numerical Modeling of Foam Carrying Sand Transport in Multifactor Horizontal Wells.

The solution of wellbore multiphase flow models has an important position in oil-gas field development. However, the solution of multiphase flow models often involves a series of complicated situations such as interphase mass and energy transfer, surface problems, and so on. Foam carrying sand particles in the wellbore is a solid, liquid, and gas three-phase cylinder flow problem. To solve this problem, we developed a computational fluid dynamics-discrete element method model based on the traditional N-S equations to track the streamline of the foam fluid and sand particles in the wellbore. On this basis, we investigated the influence of three factors, i.e., foam and sand properties and wellbore parameters, on the sand carrying rate of foam. The results show that whether the sand mound at the bottom of wells that can be dispersed is mainly affected by the properties of foam. The location of sand deposition in the wellbore and the effectiveness of foam in sand transportation are mainly influenced by the wellbore parameters and sand properties.

Longitudinal wave propagation in an elastic cylinder embedded in a viscoelastic fluid

Abstract A novel analytical investigation of longitudinal wave propagation in an elastic cylinder embedded in a viscoelastic fluid is proposed. The Maxwell model is used to describe the viscoelastic fluid behavior. With appropriate boundary conditions, a complex dispersion equation of longitudinal wave has been established. The aim of this paper is to study the effect of the fluid rheological properties on the longitudinal wave characteristics (attenuation and velocity). It is shown that the attenuation is the sum of a viscous and non viscous component. The viscosity induced attenuation is predominant at low frequencies. On the other hand, the effect of the liquid amount and elastic cylinder radius on the attenuation and velocity are studied. A critical normalized liquid thickness is highlighted. Beyond this critical value, the influence of the outer boundary condition can be neglected. At last, among other interesting phenomena, it is highlighted that if the Deborah number increases, the attenuation decreases. This variation characterize a stiffening of the viscoelastic medium. In addition, the obtained results show that the viscosity measurement should be performed at low frequencies using small elastic cylinder radius. Accordingly, these investigations are novel and can be applied in geophysics, food industry, medicine, non-destructive testing of materials, design and development of fluid sensors.

Pinching Dynamics and Multiple Droplet Generation in Partial Coalescence.

When a drop merges with its homophase, a liquid cylinder appears in certain conditions, which is pinched off leading to partial coalescence. We investigate the process experimentally and numerically, and find that the Rayleigth-Plateau instability is able to pinch off the cylinder when its height-to-neck ratio exceeds one. Surfactants are found to attenuate the cylinder and produce multiple droplets at moderate concentrations. For both the pinch-off of the mother drop and the subsequent breakup of the liquid threads in partial coalescence, the neck thinning is initially in the inertial (I) regime and then shifts to the inertial-viscous (IV) regime. An intermediate regime is seen at larger surfactant concentrations, which accelerates the thinning and favours the generation of multiple droplets.

Short flow and green process for the production of V2O3 powder via ammonia reduction method

BackgroundThe NH3, a clean reductant, generated by the thermolysis of NH4VO3, is not effectively utilized in the conventional process of vanadium metallurgy. Additionally, the preparation process of V2O3 is both long and costly. Ammonia recovery is essential to prevent environmental issues resulting from ammonia release. By direct thermolysis of NH4VO3 and effectively utilizing of active NH3, it is possible to achieve the short flow and green process for the production of V2O3. MethodIn an open NH3 atmosphere, one end of the flange was connected to the liquid ammonia gas cylinder, while the other end was connected to the tail gas absorber. Furthermore, in a closed NH3 atmosphere, both ends of the tube furnace were sealed with flanges, and the initial atmosphere in the tube was pre-injection NH3. The products of NH4VO3 thermolysis were characterized using various techniques, including XRD, FT-IR, ICP-OES, SEM, XPS, and TG. Significant findingThe thermolysis process of NH4VO3 with pre-injection of NH3 under the sealed condition was a simulation of the continuous production process of V2O3 using a rotary kiln in industrial production. The rational utilization of ammonia resulted in the reduce of energy consumption, extra reductant consumption, and significant NH3 emissions compared to the traditional V2O3 production process. It was observed that V2O3 was easily obtained through the thermolysis of NH4VO3 with pre-injection of NH3 under the sealed condition at 600 °C for 3 h, using a dosage of NH4VO3 ranging from 2 g to 10 g. During this process, the NH4VO3 went through the phase transition as follows: NH4VO3→NH4V3O8→(NH4)0.38V2O5→V6O13→VO2→V4O7→V3O5→V2O3, and the relevant characterization of products showed that the V2O3 obtained was qualified. These experimental results were of great significance to the industrial practice of vanadium metallurgy. Based on these results, short flow and green process of V2O3 could be achieved in industry by partially improving the calcination process of NH4VO3 in large-scale rotary kilns.

The Causes of Explosion Failure of Liquid Ammonia Cylinder

Gas cylinders are widely used in industrial production and daily life. Due to the complexity of the medium contained in the cylinder and the unsafe factors in the use and management, cylinder accidents occur more frequently. This paper analyzes the cause of a burst accident in the liquid ammonia cylinder. The results show that the chemical composition and mechanical properties of cylinder materials basically meet the requirements of relevant standards. No obvious defects were found on the weld and fracture surface during NDT. The outer surface of the gas cylinder is severely corroded, especially in the weld area, where there is a lot of pitting corrosion.

Vehicle-mounted Dual Liquid Hydrogen Cylinders Parallel Balanced Transport Experimental and Simulation Research

For heavy vehicle liquid hydrogen storage and supply system, the use of double liquid hydrogen cylinders to increase the supply of liquid hydrogen. When two liquid hydrogen cylinders supply liquid hydrogen in parallel, the flow resistance of the gas and liquid channels of the liquid hydrogen cylinders is difficult to achieve complete consistency, which makes the flow of the two liquid hydrogen cylinders in the process of hydrogen supply different, resulting in inconsistent liquid levels in the two liquid hydrogen cylinders. For this reason, a parallel balanced transport technology scheme of two liquid hydrogen cylinders was proposed. Two liquid hydrogen cylinders with identical size were used to supply liquid hydrogen, and a gas-line connecting pipe was used in the gas path of the liquid hydrogen cylinder to achieve the same pressurization pressure of the two liquid hydrogen cylinders. A regulating valve was used to realize the consistent flow of liquid route at the outlet of liquid hydrogen cylinders. Then, the experimental system modified with real liquid hydrogen cylinder was tested with water medium, and the correctness of the simulation results was verified by the test results. Finally, the simulation results show that the proposed method can ensure that the level difference of liquid hydrogen cylinders meets the requirements in the process of parallel supply of liquid hydrogen.

Liquid Fluidization of Short Hollow Cylinders

We perform numerical simulations on fluidized dense suspensions of solid spheres, solid cylinders, and hollow cylinders in a Newtonian liquid. The simulations are three-dimensional and time-dependent and aim to resolve the flow around and─for the hollow particles─inside individual particles. We use a lattice-Boltzmann scheme that includes an immersed boundary approach for imposing no-slip at solid surfaces. The overall solids volume fraction is 0.5 for the solid particles and 0.375 for hollow cylinders. The latter have a length over outer diameter aspect ratio in the range of 0.56–1.58, while the ratio of outer to inner diameter is 2. Archimedes numbers of the order 103–104 are such that we expect inhomogeneous fluidization with wave-type voidage instabilities. We have a particular interest in the flow through the inner diameter of the hollow cylinders and the extent to which it could contribute to liquid–solid mass transfer.

Development of Portable Oxygen Concentrator - A Review

The Covid-19 Pandemic, with its first ever reported case in the Wuhan province of China in the year 2019, has led to a newfound global demand for Medical Oxygen supply at a sudden and unprecedented rate. In India, people battled to breathe as oxygen demand shot up with a sudden surge in COVID-19 cases the year 2020. The additional requirement of oxygen was tried to be fulfilled by various means such as oxygen generators installed at hospitals, transported medical as well as Industrial liquid oxygen, oxygen cylinder and oxygen concentrator. During the Covid-19 outbreak, large crowds gathered outside hospitals, and many patients were treated at home, breathing with the assistance of an oxygen concentrator and cylinders. However, cylinders must be refilled, whereas unlimited supply of medical grade oxygen can be obtained by oxygen concentrator if a power backup is maintained. In addition to this, safety, cost and size are the additional features of oxygen concentrator. It is a boon for the sufferer at the initial stage or even after treatment of covid-19, which is made available anywhere. In this paper, an attempt has been made to study an oxygen concentrator in which the principle of Pressure Swing Adsorption (PSA) method is used for oxygen separation. In addition to this, some trends of recently evolved developments in oxygen concentration methods are also reviewed for the readers’ reference. This effort will help to develop the oxygen concentrator to fulfill the demand of oxygen at local level during the waves of Covid or similar incidences in future.

Instability and Atomization of Liquid Cylinders after Shock Wave’s Impacting

This paper describes an experimental study on the instability and atomization of liquid cylinders after the impact of shock waves. Single row water column, in-line double rows water columns and alongside triple rows water columns were evaluated in a horizontal shock tube. The diameter of water column and the Mach number in the experiments were 2.0–4.14 mm and 1.10–1.25, respectively. The global instability along the axial direction of water cylinders was focused. Using a high-speed camera, the developments of spike height, bubble depth and turbulent mixing zone, width were measured. Some comparison was also made between the present experimental results and the existing theoretical model.

A Correct Benchmark Problem of a Two-Dimensional Droplet Deformation in Simple Shear Flow

In this article, we numerically investigate a two-dimensional (2D) droplet deformation and breakup in simple shear flow using a phase-field model for two-phase fluid flows. The dominant driving force for a droplet breakup in simple shear flow is the three-dimensional (3D) phenomenon via surface tension force and Rayleigh instability, where a liquid cylinder of certain wavelengths is unstable against surface perturbation and breaks up into individual droplets to reduce the total surface energy. A 2D droplet breakup does not occur except in special cases because there is only one curvature direction of the droplet interface, which resists breakup. However, there have been many numerical simulation research works on the 2D droplet breakups in simple shear flow. This study demonstrates that the 2D droplet breakup phenomenon in simple shear flow is due to the lack of space resolution of the numerical grid.

Dynamic stabilisation of Rayleigh–Plateau modes on a liquid cylinder

We demonstrate dynamic stabilisation of axisymmetric Fourier modes susceptible to the classical Rayleigh–Plateau (RP) instability on a liquid cylinder by subjecting it to a radial oscillatory body force. Viscosity is found to play a crucial role in this stabilisation. Linear stability predictions are obtained via Floquet analysis demonstrating that RP unstable modes can be stabilised using radial forcing. We also solve the linearised, viscous initial-value problem for free-surface deformation obtaining an equation governing the amplitude of a three-dimensional Fourier mode. This equation generalizes the Mathieu equation governing Faraday waves on a cylinder derived earlier in Patankaret al.(J. Fluid Mech., vol. 857, 2018, pp. 80–110), is non-local in time and represents the cylindrical analogue of its Cartesian counterpart (Beyer & Friedrich,Phys. Rev.E, vol. 51, issue 2, 1995, p. 1162). The memory term in this equation is physically interpreted and it is shown that, for highly viscous fluids, its contribution can be sizeable. Predictions from the numerical solution to this equation demonstrate the predicted RP mode stabilisation and are in excellent agreement with simulations of the incompressible Navier–Stokes equations (up to the simulation time of several hundred forcing cycles).

Shear-thinning property of liquid system in many-body dissipative particle dynamics model

Many scientific research papers report that jet-like flow during speech is a potent route for viral transmission in the COVID-19 pandemic. Droplet emission occurs during breaking, speaking, singing, coughing and sneezing, which could be affected by the shear-thinning rheology of the liquid. Here we test the viscosity of simple liquid system in many-body dissipative particle dynamics model under different driven forces, which illustrates that the simple liquid system interestingly has shear-thinning property. Based on this, we simulate the process of jet-like flow and capture the rupture of liquid cylinder and the process of drop generation, which implies the jet-induced liquid pinchoff and drop generation can be regulated by initial driven force and its temperature. The results show that larger pressure pulse could generate longer liquid cylinder and larger drops, as well as at lower force frequency. This work can provide an insight in liquid jet-like flow with shear-thining property and yield a better understanding of virus spreading via salivary droplets.

Interactions Between Shock Waves and Liquid Droplet Clusters: Interfacial Physics

Abstract This study quantitatively investigates the behaviors of single and multiple liquid cylinders placed in the path of a traveling normal shock wave using high-fidelity numerical simulations. The research is motivated by next-generation liquid-fueled scramjet and rotating detonation engines (RDE) where the liquid fuel interacts with shock waves and undergoes deformation, fragmentation, atomization, and vaporization before it mixes with the air and subsequently burns—the focus of this study is on the deformation and interfacial physics. The mathematical formulation to investigate this multiphase problem is based on a modified five-equation Kapila model that incorporates pressure-relaxation, viscous, and surface tension effects. A diffuse interface method is used to capture the liquid–gas interface. Two configurations are studied in this effort: (1) a single column of diameter 22 mm exposed to a shock wave traveling at Mach 2.4 and (2) a two identical cylinder system with diameters of 4.8 mm and 30 mm apart, and exposed to a shock wave moving a Mach number of 1.47. The computational results show excellent agreement with high-speed images and droplet deformation measured in the experiments. For both cases, it is found that the shock and the flow field in its wake leads to the flattening of the cylinder, followed by the formation of instability waves that are amplified by the baroclinic torque and the continuous reflections of the waves transmitted inside the liquid interior, eventually leading to ligament stripping. Based on the spatiotemporal evolution of the liquid and gaseous flowfields, time evolution of shock strength and parent droplet's mass and translation distance are also discussed.

Application of finite volume particle method for axisymmetric modeling of droplet formation in dripping and Rayleigh regimes

An axisymmetric model has been developed in the finite volume particle method (FVPM). FVPM is a conservative, consistent, meshless particle method that incorporates properties of both smoothed particle hydrodynamics (SPH) and the mesh-based finite volume method (FVM). The surface tension effect amplifies capillary instability which is the main mechanism in dripping and jet disintegration. The simulations are performed in 2D cylindrical coordinates by only considering the liquid flow (one phase). The model is validated for free liquid droplet evolved from cylindrical state, dripping from a capillary tube, Rayleigh instability of capillary liquid cylinder columns, and Rayleigh breakup of viscous jets. The FVPM-predicted pressure and oscillating period are in good agreement with theoretical solution for a free droplet. The FVPM-computed dripping length shows good consistency with provided experimental data in literature. The predicted growth rate of capillary instability is in good agreement with analytical solutions for flows with different orders of Ohnesorge numbers. The numerical breakup length of jet with Weber numbers between 2.5 and 40 has been determined with good accuracy based on analytical experimental solution.

РЕГУЛЮВАННЯ СТІЙКОСТІ РІДКИХ МІКРОСТРУМЕНІВ ПОЛІПРОПІЛЕНУ В МАТРИЦІ СПІВПОЛІАМІДУ ЗА РАХУНОК НАНОДОБАВОК

Goal. Investigation of the effect of the concentration of nanoparticles of aluminum oxide (Al2O3) and alumina modified with silver (Ag/Al2O3) on the decomposition kinetics of liquid microjets of polypropylene (PP) in a copolyamide (CPA) matrix and the possibility of controlling the microfibrillar morphology of the PP/CPA blend.Methodology. The components of the blend were mixed on a screw-disk extruder. The kinetics of the disintegration of liquid microjets was studied using a technique based on the theory of destabilization of a liquid cylinder under the action of capillary waves. The degree of dispersion of polypropylene in the matrix was evaluated by photomicrographs of cross sections of the extrudates of the blends.Results. Nanoadditives of the original and silver-modified aluminum oxide with a content of (0.1 ÷ 3.0) wt.% In the blend increase the compatibility of the components: the surface tension (γαβ) in the compositions of all compositions decreases. Ag/Al2O3 nanoparticles are more effective than aluminum oxide nanoparticles - the γαβ value decreases by 9.6 and 5.3 times, respectively, which ensures a high degree of dispersion of the dispersed phase component in the matrix. The disintegration resistance of polypropylene microjets is increasing, as evidenced by a decrease in the instability coefficient (q) and an increase in the microjet lifetime (tl). The curves of q and tl dependence on the additive content have an extreme character. The minimum values of the instability coefficient of microjets and the maximum values of their lifetime are achieved at a nanoparticle concentration corresponding to the lowest interfacial tension.Scientific novelty. The positive effect of the investigated nanoadditives on the kinetics of the decomposition of liquid microjets of polypropylene in the copolyamide matrix has been established. The highest modifying effect in the presence of Ag/Al2O3 nanoparticles is due to their amphiphilic nature, which ensures the predominant localization of nanoparticles at the interface and a synergistic increase in the degree of compatibility in the PP/CPA system.Practical significance. The regularities of increasing the stability of liquid microjets to disintegration in polymer blends filled with nanoparticles have been established, which will make it possible to determine the parameters of the processes of mixing and forming fibers and films, in which the microfibrillar structure arising during the flow of the melt will remain unchanged in the products.

Droplet condensation in the lattice gas with density functional theory.

A density functional for the lattice gas with next-neighbor attractions (Ising model) from fundamental measure theory is applied to the problem of droplet states in three-dimensional, finite systems. The density functional is constructed via an auxiliary model with hard lattice gas particles and lattice polymers to incorporate the attractions. Similar to previous simulation studies, the sequence of droplets changing to cylinders and to planar slabs is found upon increasing the average density ρ[over ¯] in the system. Owing to the discreteness of the lattice, additional effects in the state curve for the chemical potential μ(ρ[over ¯]) are seen upon lowering the temperature away from the critical temperature [oscillations in μ(ρ[over ¯]) in the slab portion and spiky undulations in μ(ρ[over ¯]) in the cylinder portion as well as an undulatory behavior of the radius of the surface of tension R_{s} in the droplet region]. This behavior in the cylinder and droplet region is related to washed-out layering transitions at the surface of liquid cylinders and droplets. The analysis of the large-radius behavior of the surface tension γ(R_{s}) gave a dominant contribution ∝1/R_{s}^{2}, although the consistency of γ(R_{s}) with the asymptotic behavior of the radius-dependent Tolman length seems to suggest a weak logarithmic contribution ∝lnR_{s}/R_{s}^{2} in γ(R_{s}). The coefficient of this logarithmic term is smaller than a universal value derived with field-theoretic methods.

Surface waves along liquid cylinders. Part 2. Varicose, sinuous, sloshing and nonlinear waves

Abstract

Quadratic cross-sections in the multiple scattering by a pair of liquid cylinders insonified by arbitrary-shaped acoustical sheets

Stemming from the law of energy conservation applied to scattering, generalized exact partial-wave series expressions are derived for the extrinsic and intrinsic acoustic scattering, extinction and absorption cross-sections for a pair of fluid/liquid-like (viscous) cylinders of arbitrary radii. The incident insonifying field is of arbitrary shape such that any structured wavefront in two-dimensions is accomodated by this formalism, in contrast with the case of plane waves. The modal expansion method in combination with the translational addition theorem for cylindrical wave functions are used to derive the exact analytical expressions for the quadratic (nonlinear) cross-sections, and numerical computations for a non-paraxial focused Gaussian acoustical sheet chosen as an example illustrate the analysis. The results clearly show the difference between the behavior of the extrinsic and intrinsic cross-sections. The formalism presented here is generalized for any acoustical sheet such that Airy, Hermite-Gaussian and other wavefronts (in 2D) can be considered provided the appropriate beam-shape coefficients are used. The analogy with the optical counterpart is also noted.