Cylindrical Container Research Articles

Development of novel correlations towards the freezing time estimation of phase change material inside a cylindrical capsule involving thickness and its thermal conductivity for thermal storage applications – An experimental and parametric studies

The freezing of phase change materials (PCM) is a widespread phenomenon with numerous potential applications in fields such as refrigeration, thermal storage, chemical industries, etc. Thermal energy storage (TES) is one such application where the inward freezing concept is utilised during the solidification of a PCM in cylindrical container. Literature shows various correlations to predict the inward and outward freezing duration of PCM inside a cylindrical container. However, no correlation describes the effect of container material properties on the PCM freezing time. Therefore, two new correlations are developed - one for the inward freezing time of PCM inside a cylindrical container and the other for the outward freezing time around it, taking into account the effect of container material thermal conductivity and its thickness. Subsequently, experimental research is conducted to validate the proposed correlation, which agrees with the experimental freezing time, with a maximum inaccuracy of around 7.8 %. Finally, a parametric study analysing the effect of container thermal conductivity and thickness on the inward freezing time of PCM reveals that the thickness of the container plays no role in freezing when container thermal conductivity exceeds 5 W m−1 K−1.

Experimental and numerical investigation of thermally induced convection along a high-temperature borehole heat exchanger

Thermally induced convection in the vicinity of borehole heat exchangers (BHE) in porous media affects the heat transfer behaviour between the BHE and the surrounding ground and thereby their performance for building climatization, heat extraction and heat storage. This study presents a combined experimental–numerical analysis of the qualitative and quantitative impacts of convection on heat transfer for a laboratory-scale BHE analogue over a wide temperature range. For this purpose, a grouted coaxial high-temperature BHE was installed within a fully saturated porous sand medium in a cylindrical container of 1.4 m3 volume under spatially extensive temperature monitoring. Four transient heat charging/discharging experiments were performed at different charging temperatures of 30, 50, 70, and 90 °C and analysed for the onset and magnitude of convection. After minimal calibration, a numerical model accurately reproduced the experimental data of all experiments and helped quantify the contribution of convection to the total heat transfer at each temperature level. For heat charging at 30 °C, the heat transfer was dominated by conduction. At higher temperatures, convection increased the total heat-transfer rate by up to 35% in the experimental setup. In contrast, for heat discharge, due to thermal stratification in the sand medium, convection reduced the heat transfer rate and heat recovery by up to −30% and −35%, respectively. Rayleigh numbers, buoyant flow velocities, and the centre of heat were derived from the monitoring and simulation data and consistently indicated the onset of convection for the experimental setup at a BHE operating temperature of 50 °C. The Rayleigh number was found to be closely correlated with the magnitude of the convective flow. Overall, the results suggest that the performance of BHEs in cooling applications may benefit from thermal convection, while the performance of BHEs for thermal energy storage may deteriorate markedly at high operating temperatures.

Vibration Analysis of Thin Circular Disc Interacting With A Fluid in Cylindrical Container

In this paper, vibration analysis of a thin circular disc interacting with a fluid in cylindrical container is carried out. It has been done systematically by carrying our mathematical modeling and subsequently validated by ANSYS software. The author has first determined natural frequencies and mode shapes for a thin circular disc alone and then for fluid contained by a cylindrical vessel alone. The author had then found natural frequencies and mode shapes for coupled case of thin circular disc interacting with a fluid contained by the cylindrical container. The same had been validated by ANSYS software. It is found that natural frequencies of coupled vibrations are different than that of the frequency of disc or fluid taken separately. In order to study the correct failure pattern of the coupled vibration system, it, thus, becomes a necessity to study coupled vibration analysis

Battery thermal management of a novel helical channeled cylindrical Li-ion battery with nanofluid and hybrid nanoparticle-enhanced phase change material

Electric vehicles (EVs) have emerged as a viable alternative to Internal Combustion (IC) engine-powered vehicles, and efforts have been directed toward developing EVs that are more reliable and safer to operate. The safe working of EVs necessitates the use of an efficient battery cooling system. In this paper, cooling of cylindrical type Li-ion battery embedded with helical coolant channels is proposed. The effects of nanoparticles on removing heat from the battery cooling system have been investigated for four different nanoparticle concentrations: 0, 2, 5, and 10% of Al2O3 in the base fluid. Two cases of base fluids are considered: phase change material kept in a concentric container surrounding battery volume and coolant water circulated through liquid channels attached to the outer walls of the PCM (phase change material) cylindrical container. This study presented the three configurations (i) base case PCM-WLC: battery cooling system with a cylindrical enclosure filled with RT-42 phase change material. (ii) base case nePCM-WLC: battery cooling system filled with nano-enhanced phase change material. (iii) nePCM-LC: battery cooling system with helical liquid channels and filled with nano-enhanced PCM. The nanofluid was circulated through the liquid passages connected to the PCM container. Results showed using the helical channels, the nePCM-LC arrangement efficiently removes accumulated heat from the phase change material and provides better battery cooling than straight rectangular channel-based BTMS (battery thermal management system).

Mechanical Equilibrium of a Nonmagnetic Body Immersed in a Cylindrical Container with a Magnetic Fluid Magnetized by an External Homogeneous Magnetic Field

Purpose. Analytical and numerical description of the magnetohydrodynamic forces acting on a small nonmagnetic spherical body in a cylindrical container with magnetic fluid (magnetofluid dispenser and separator approximation) that determine the hydrostatic mechanical equilibrium in the system.Methods. The numerical study solves the magnetostatic problem by the finite element method in the FEMM program package using the Lua script language. The system of Maxwell’s equations is solved by the standard method in the vector potential formulation. The analytical solution of the magnetostatic problem is obtained by the mirror image method using a simplifying model representation of the linear law of magnetization of a magnetic fluid. The ponderomotive force acting on a body immersed in a magnetic fluid is calculated using the Rosensweig formula and the energy approach.Results. A refined expression for the magnetic ponderomotive force acting on a nonmagnetic sphere immersed in a cylindrical container with magnetized magnetic fluid is obtained. Direct numerical simulation of the laboratory experiment is performed, which allows us to compare the accuracy of the numerical and analytical solutions with the experimental data. Despite violating the limits of applicability of the analytical theory, the new expression correctly describes the nonmonotone coordinate dependence of the force, and the error in determining the coordinate extremums does not exceed 6 % and 26 % in absolute value. The physical justification for the condition of mechanical equilibrium in the model system under study is given.Conclusion. The competition of two oppositely directed magnetic forces leads to the fact that a nonmagnetic sphere in a cylindrical container with magnetized magnetic fluid has one unstable mechanical equilibrium position in the center of the container, so that the body is pressed against the wall, or (additionally) two stable equilibrium positions that allow the body to levitate near the container wall without touching it.

Simulation of Heat Storage and Heat Regeneration in Phase Change Material

The present study explores numerically the energy storage and energy regeneration during Melting and Solidification processes in Phase Change Materials (PCM) used in Latent Heat Thermal Energy Storage (LHTES) systems. Transient two-dimensional (2-D) conduction heat transfer equations with phase change have been solved utilizing the Explicit Finite Difference Method (FDM) and Grid Generation technique. A Fortran computer program was built to solve the problem. The study included four different Paraffin's. The effects of container geometrical shape, which included cylindrical and square sections of the same volume and heat transfer area, the container volume or mass of PCM, variation of mass flow rate of heat transfer fluid (HTF), and temperatures difference between PCM and HTF were all investigated. Results showed that the PCMs in a cylindrical container melt and solidify quicker than the square container. The increase in mass flow rate and/or temperature difference decreases the time required for complete phase change. Paraffin's solidify quicker than they melt and store more energy than they release

Flow past a sphere translating along the axis of a rotating fluid: revisiting numerically Maxworthy's experiments

We compute the flow induced by the steady translation of a rigid sphere along the axis of a large cylindrical container filled with a low-viscosity fluid set in rigid-body rotation, the sphere being constrained to spin at the same rate as the undisturbed fluid. The parameter range covered by the simulations is similar to that explored experimentally by Maxworthy (J. Fluid Mech., vol. 40, 1970, pp. 453–479). We describe the salient features of the flow, especially the internal characteristics of the Taylor columns that form ahead of and behind the body and the inertial wave pattern, and determine the drag and torque acting on the sphere. Torque variations are found to obey two markedly different laws under rapid- and slow-rotation conditions. The corresponding scaling laws are predicted by examining the dominant balances governing the axial vorticity distribution in the body vicinity. Results for the drag agree well with the semi-empirical law proposed for inertialess regimes by Tanzosh & Stone (J. Fluid Mech., vol. 275, 1994, pp. 225–256). This law is found to apply even in regimes where inertial effects are large, provided that rotation effects are also large enough. Influence of axial confinement is shown to increase dramatically the drag in rapidly rotating configurations, and the container length has to be approximately a thousand times larger than the sphere for this influence to become negligibly small. The reported simulations establish that this confinement effect is at the origin of the long-standing discrepancy existing between Maxworthy's results and theoretical predictions.

Numerical study on melting and heat transfer characteristics of vertical cylindrical PCM with a focus on the solid-liquid interface heat transfer rate

In this paper, a two-dimensional symmetric transient numerical heat transfer model for the melting of PCM was established based on a vertical cylindrical energy storage device filled with lauric acid. Based on the enthalpy method, the phase transition process of a vertically placed cylindrical PCM container was numerically solved, with constant side/all surface wall temperature. A new evaluation index, namely the solid-liquid interface heat transfer rate, was established to further clarify the melting and heat transfer characteristics of cylindrical containers under different structural parameters and boundary conditions. The results showed that when the aspect ratio changed from 1 to 2, the melting and heat transfer effects of side surface heating changed most obviously, the average solid-liquid interface heat transfer rate qave increased by 8.04 %, and the total melting time was shorten by 8.52 %; the melting and heat transfer effects of all surfaces heating had the weakest change, with only a 5.20 % decrease in qave and a 5.48 % increase in total melting time. This study reveals the essence of characteristic structure optimization of cylindrical energy storage devices under different thermal boundary conditions, which improves energy storage efficiency.

Evaluation of blast mitigation performance of cylindrical explosion containment vessels based on water containers

Using liquid materials with specific geometries can enhance the explosion-proof properties of confined structures. This approach is promising because bulk water has multiple blast mitigation mechanisms and adds almost no extra mass. In this study, a method of using water-filled containers to reduce both the peak and permanent deformation of cylindrical explosion containment vessels (CECVs) is investigated through experiments and numerical simulations. Several explosion experiments were performed to evaluate the blast mitigation of the empty containers and the bulk water with multiple thicknesses and heights in terms of dynamic deformation and afterburning suppression. The experimental results indicated that the bulk water with a larger thickness and a smaller height had better protective performance, which provided up to an 80.1% reduction in permanent deformation compared with no mitigant. Numerical models were established using LS-DYNA and verified by the deformation-time history curves measured in the experiments. The energy conversion process during the explosion was analyzed through the numerical simulations, and the results showed that water absorbed most of the detonation energy that should have been transferred to the steel shell, proving that momentum extraction of water was a significant mitigation mechanism for the internal blast in CECVs. Another significant mitigation mechanism was the shadowing effect of water, which changed the spatial distribution of the blast loading acting on the steel shell, especially for water containers with larger thickness and smaller height.

Effect of fin length and angle on the melting process of phase change materials in vertical latent heat storage unit

The installation of fins offers an effective solution for addressing the poor thermal conductivity of phase change materials (PCMs) in latent heat thermal energy storage (LHTES) systems. This paper aims to investigate the combined effects of unequal fin length arrangements and the inclination angle of fins on the performance of an LHTES system during the charging process. The LHTES system consists of a cylindrical container filled with paraffin (RT55) serving as the PCM. Numerical models are established and validated, followed by simulating various fin structures to analyze the complete melting time of the PCM. The characteristics of the melting process are further examined in four representative cases, including the full melting time, evolution of the melt fraction, average maximum velocity, streamline contours, temperature uniformity, and average Nusselt number. The results reveal that the optimal case, featuring unequal length and downward annular fins, achieves a significant 49.8% reduction in the complete melting time of the PCM compared to the benchmark case with ordinary annular fins. Moreover, the optimal configuration increases the largest average maximum velocity of the PCM by 35.36%, resulting in a more uniform temperature distribution and a higher Nusselt number.

Effect of heat transfer through an interface on convective melting dynamics of phase change materials

The presence of thermocapillary (Marangoni) convection in microgravity may help to enhance the heat transfer rate of phase change materials (PCMs) in space applications. We present a three-dimensional numerical investigation of the nonlinear dynamics of a melting PCM placed in a cylindrical container filled with n-octadecane and surrounded by passive air. The heat exchange between the PCM and ambient air is characterized in terms of the Biot number, when the air temperature has a linear profile. The effect of thermocapillary convection on heat transfer and the topology of the melting front is studied by varying the applied temperature difference between the circular supports and the heat transfer through the interface. The evolution of Marangoni convection during the PCM melting leads to the appearance of hydrothermal instabilities. A new mathematical approach for the nonlinear analysis of emerging hydrothermal waves (HTWs) is suggested. Being applied for the first time to the examination of PCMs, this procedure allows us to explore the nature of the coupling between HTWs and heat gain/loss through the interface, and how it changes over time. We observe a variety of dynamics, including standing and travelling waves, and determine their dominant and secondary azimuthal wavenumbers. Coexistence of multiple travelling waves with different wavenumbers, rotating in the same or opposite directions, is among the most fascinating observations.

Metal Hydride Hydrogen Storage (Compression) Units Operating at Near-Atmospheric Pressure of the Feed H2

Metal hydride (MH) hydrogen storage and compression systems with near-atmospheric H2 suction pressure are necessary for the utilization of the low-pressure H2 produced by solid oxide electrolyzers or released as a byproduct of chemical industries. Such systems should provide reasonably high productivity in the modes of both charge (H2 absorption at PL ≤ 1 atm) and discharge (H2 desorption at PH = 2–5 atm), which implies the provision of H2 equilibrium pressures Peq < PL at the available cooling temperature (TL = 15–20 °C) and, at the same time, Peq > PH when heated to TH = 90–150 °C. This work presents results of the development of such systems based on AB5-type intermetallics characterized by Peq of 0.1–0.3 atm and 3–8 atm for H2 absorption at TL = 15 °C and H2 desorption at TH = 100 °C, respectively. The MH powders mixed with 1 wt.% of Ni-doped graphene-like material or expanded natural graphite for the improvement of H2 charge dynamics were loaded in a cylindrical container equipped with internal and external heat exchangers. The developed units with a capacity of about 1 Nm3 H2 were shown to exhibit H2 flow rates above 10 NL/min during H2 charge at ≤1 atm when cooled to ≤20 °C with cold water and H2 release at a pressure above 2 and 5 atm when heated to 90 and 120 °C with hot water and steam, respectively.

High-Order Modeling, Zeroing Dynamics Control, and Perturbations Rejection for Non-Linear Double-Holding Water Tank

The double-holding water tank system is a common non-linear control system that plays a crucial role in process control in the chemical industry. It consists of two cylindrical glass containers: the preset tank and the main tank. The main challenge in controlling this system is adjusting the main control valve to ensure that the actual liquid level of the main tank tracks the desired liquid level. This paper explores the zeroing dynamics (ZD) method and its application in tracking control. A non-linear model is developed for the double-holding water tank system, and the ZD method is used to design an effective controller (called the ZD controller) for tracking control. Additionally, the robustness of the double-holding water tank system in the presence of time-varying perturbations is investigated. In order to substantiate the effectiveness and robustness of the ZD controller, simulation experiments on four different tracking trajectories corresponding to four different practical situations, as well as an extra simulation experiment considering time-varying perturbations, are conducted. Furthermore, a comparative simulation experiment based on the backstepping method is conducted. The presented results successfully illustrate the feasibility and effectiveness of the ZD method for the tracking control of double-holding water tank systems.

Topological flow transformations in a universal vortex bioreactor

Research into the flow structure in an aerial vortex bioreactor is relevant for developing the methods to grow cell cultures. It is especially important in the case when, with the culture growth in the bioreactor, such parameters of the medium as density and viscosity can significantly change, accordingly altering the characteristic flow regimes. Since the cultivated culture is not transparent in most cases, it is impossible to visually determine the flow regime. Therefore, a detailed study of the regularities of flow regimes in an aerial vortex reactor is of great fundamental and applied interest. The research was carried out in an 8.5 L universal glass aerial vortex bioreactor, with a washer freely floating on its surface and stabilizing the motion of the working fluid. The regularities of the vortex motion of the culture medium depend on its volume and the rotation intensity of the activator generating vortex motion in the air. The air vortex generated by the impeller (activator) above the liquid surface spins the working fluid and a free-floating washer. The study reveals that despite the complex configuration of the flow stabilizing device (a free-floating washer), the observed vortex structure and its dynamics with increasing flow swirl intensity coincides with the structure of a confined vortex flow in a cylindrical container for both single-fluid and immiscible two-fluid configurations.

Designs of Corrosion Modules for Long-Term Corrosion Tests of Canister Materials in Aerobic and Anaerobic Underground Water

Corrosion modules simulating the engineered barrier system were designed in this study for long-term-corrosion (LTC) testing of canister materials under aerobic and anaerobic conditions. The LTC module for aerobic conditions was designed as a bath-type container with flowing underground water extracted from the Korea Underground Research Tunnel. Five types of metallic disks, that is, rolled Cu, Type 304 stainless steel (SS), Titanium Grade 2 (Ti-G2), cast iron (CI), and Cu coating, were embedded into bentonite and maintained at different temperatures. After 3 years of testing under aerobic conditions, the corrosion rates of CI and Cu were estimated to be 1.9 μm/year and 550 nm/year, respectively. The SS and Ti-G2 exhibited a better corrosion rate of 6 nm/year. The LTC module for anaerobic conditions was developed in a vessel-type cylindrical container to allow it to settle in the boreholes. Four coin-shaped disks of each metal were embedded in bentonite, which was subsequently stacked in the cylindrical vessel. The vessels were placed in boreholes at a depth of 300 m. The Cu corrosion rate after 6 months of LTC testing under anaerobic conditions was 280 nm/year. Longer LTC tests will provide a more exact corrosion rate.

Thermal behavior of CMC solutions under simulation of radio frequency pasteurization

Pasteurization and enzyme-inactivation are an economical and convenient way to provide safety and shelf-life stability. However, long heating time and non-uniform temperature distribution are the main issues of traditional thermal processing for enzyme-inactivation. Because of the volumetric heating and high heating rate, radio frequency (RF) treatment is considered as one of the most promising physical enzyme-inactivating methods. A 6 kW, 27.12 MHz RF heating system was applied to explore the effect of cylindrical container dimension and solution concentration on the thermal behavior of high-viscosity liquid food. Carboxymethylcellulose (CMC) solution as a non-Newtonian fluid was selected as a model liquid food in this study. The target temperature for enzyme inactivation was 70 °C. The experimental results showed that the electrode gap, container length, and container diameter affected the heating rate and uniformity of the liquid food. Furthermore, when the concentration of CMC solution increased from 0.5% to 2.0%, the heating rate of the solution firstly increased and then decreased, while the heating uniformity index of the solution increased from 0.008 ± 0.001 to 0.056 ± 0.002. The simulation results showed that the higher electric field strength led to a higher heating rate, temperature, and velocity of natural convection of the solution at the ends of the container. Then, the recirculation zones from the ends to the center of the container were formed, which was diminished with the increasing concentration solution, resulting in the increased maximum temperature difference of solution. The results of this research may provide useful data for subsequent continuous flow studies and information on potential RF enzyme-inactivation in high-viscosity liquid foods.

Evaluation of the susceptibility to erosion of materials used as a base of rigid pavements using a vertical shaking table

ABSTRACT Erosion of the base layers in rigid pavements is a complex hydro-mechanical process that rapidly reduces the structural integrity of these structures. This research revisits a vertical shaking table testing method to characterise the erosion susceptibility of the materials used on base layers in rigid pavements. The procedure consists of applying a vertical vibration to a cylindrical sample of the material under evaluation, which is partially immersed in water in a cylindrical metallic container with a high-strength concrete base. The vertical movement of the sample causes a radial flow of water on its base, which induces high shear forces that eventually erode the bottom of the sample. The volumetric loss of material from the testing sample under different water velocities and pressure conditions is used to quantify its susceptibility to erosion. After presenting the theoretical principles and the numerical formulation of the hydro-mechanical erosion processes occurring in this test, the experimental method was applied to characterise the erosion susceptibility of five different materials. The results suggest that the vertical shaking experimental technique is more versatile and accurate in quantifying the erosion susceptibility of base materials than available standardised tests.

Kinetics study on the catalytic recombination of non-premixed hydrogen–oxygen system: Effects of initial temperature, oxygen flow rate, and hydrogen diffusion time

Hydrogen-oxygen catalytic recombination reaction, as a promising technology for hydrogen elimination in the confined environment, can spontaneously eliminate the leaking hydrogen in the environment. However, the kinetics characteristics of this reaction process under different environmental factors have been poorly reported. A series of hydrogen–oxygen catalytic recombination experiments are performed in a little cylindrical container using Platinum-Carbon powder as the catalyst, to investigate the effects of the initial temperature, oxygen flow rate, and hydrogen diffusion time on the temperature characteristics. In addition, the amount of residual hydrogen at the end of the reaction is also taken into account. The results show that the reaction intensity increases with the increase of the initial temperature, and the first temperature peak PT1 is gradually smaller than PT2 and finally disappears. However, the intensity of temperature increase caused by the reaction exotherm does not enhance continuously with the increase of the reaction intensity. With the decrease in oxygen flow rate, the reaction temperature gradually reduces and the temperature peak gradually forms before the end of oxygen inflow. Nevertheless, the direction of temperature transfer is hardly affected by the oxygen flow rate and the heat is still accumulating below the catalyst. The effect of hydrogen diffusion time on the reaction at hydrogen-poor, stoichiometric ratio hydrogen, and hydrogen-rich is diverse and complex, but the temperature–time profile on the catalyst surface has been changed accordingly. In addition, under any conditions, the hydrogen can be completely reacted below the stoichiometric ratio.

Fluid mode spectroscopy for measuring kinematic viscosity of fluids in open cylindrical containers

On a daily basis, we stir tea or coffee with a spoon and leave it to rest. We know empirically the larger the stickiness, viscosity, of the fluid, the more rapidly its velocity slows down. It is surprising, therefore, that the variation, the decay rate of the velocity, has not been utilized for measuring (kinematic) viscosity of fluids. This study shows that a spectroscopy decomposing a velocity field into fluid modes (Stokes eigenmodes) allows us to accurately measure the kinematic viscosity. The method, fluid mode spectroscopy (FMS), is based on the fact that each Stokes eigenmode has its inherent decay rate of eigenvalue, and the dimensionless rate of the slowest decaying mode is constant, dependent only on the normalized shape of a fluid container, obtained analytically for some shapes including cylindrical containers. The FMS supplements major conventional measuring methods with each other, which is particularly useful for measuring relatively low kinematic viscosity and for a direct measurement of viscosity at zero shear rate without extrapolation. The method is validated by the experiments of water poured into an open cylindrical container, as well as by the corresponding numerical simulations.

Experimental study of the topological flow transformations in an aerial vortex bioreactor with a floating washer.

Research into the flow structure in an aerial vortex bioreactor is relevant for developing the methods for growing cell cultures. Determining the optimal cultivation condition for a certain process is especially important in the case when such parameters of the medium as density and viscosity significantly change with the culture growth in the bioreactor. The research of the flow dynamic was carried out in an 8.5 L universal aerial vortex bioreactor, with a washer freely floating on its surface and stabilizing the motion of the working fluid. The regularities of the vortex motion of the culture medium have been determined by Particle Image Velocimetry depending on its volume and the intensity of rotation of the activator, generating vortex motion in the air. The observed vortex structure and its dynamics at increasing flow swirl intensity are established to coincide with the structure of a confined vortex flow in a cylindrical container with no washer for both single and two-fluid configurations. This novel methodology of the flow optimization shows that an ascending swirling jet forms in the vicinity of the bioreactor axis, and a bubble-like vortex breakdown forms in the axial region. This article is protected by copyright. All rights reserved.