Container Geometry Research Articles

The Preventive Methodology: A priori modification of the containment geometry to boost the computational efficiency of GOTHIC 3D models

Historically, the deterministic safety analysis simulations for large dry containments of operating nuclear power plants have been done with nuclear legacy codes using the lumped parameter approach. In opposition, there are a limited number of calculations using 3D codes, due to several factors: (i) the necessity for more detailed data about the containment; (ii) the significantly increased effort required for model development; (iii) the necessity of a broad validation and verification process; and (iv) and the higher computational cost. These reasons emerge as primary impediments constraining a more extensive use of 3D analytical tools.During the last decade, the Universidad Politécnica de Madrid (UPM) has proposed different methodologies to address these challenges with the thermal–hydraulic code GOTHIC. This article presents an improved methodology with diverse solutions for the four limiting factors, with a particular emphasis on reducing the computational cost of the simulations. The work introduces a novel approach to define the containment geometry in GOTHIC which strategically avoids configurations that compromise the calculation stability.Comparative analyses have shown that the new models can reduce the computational cost of the simulations up to a factor 40, even when using a finer mesh. The article is concluded with a preliminary application case of a postulated severe accident sequence intended to prove the model readiness for performing comprehensive hydrogen risk analysis.

Exploring the potential and challenges of phase change materials in future heat storage systems via computations and experiments

The current work describes computational and experimental efforts to enable new heat storage technologies. Approximately 50% of the energy consumed globally is used to generate and manage heat. This is still predominantly acquired from the combustion of fossil fuels, consequently generating just over 40% of the total global CO2 emissions. To achieve a sustainable future, there is a need for sustainable, decarbonised and dependable energy sources. Heat storage is a key technology that could help achieving this goal. Recently published work by the current authors has shown the importance of heat storage in decarbonising heating (and cooling) of buildings using phase change materials (PCMs). The black-box approach followed evaluated the energetic, cost, and environmental impacts of a novel concept PCM storage scheme with microgeneration. The results obtained showed that this system had advantages over current and future competing heating technologies. However, PCM technology remains at low technological readiness levels because of the lack of understanding of the complex heat transfer physics associated with their phase change transition. For example, understanding and characterizing the propagation of the solid-liquid front during charging and discharging in such heat storage modules will be important in predicting and optimising their performance. In the current work, computations have been performed to understand and optimise the effects of container geometry and size on the charging and discharging heat flux profiles of a simple heat storage module. Furthermore, fundamental experiments have also been implemented to identify the complex governing mechanisms of heat transfer and storage in such materials during transient operation.

Early detection of deep-seated smouldering fires in wood waste storage using ERT

Incidents of waste and biofuel fires are common at all stages of the waste recycling chain and have grave implications for business, employees, firefighters, society, and environment. An early detection of waste and biofuel fires in the smouldering stage could save precious lives, resources, and our environment. Existing fire detection methodologies e.g. handheld temperature sensors, IR cameras, gas sensors, and video and satellite-based monitoring techniques have inherent limitations to efficiently detect smouldering fires. An attempt was made to explore the potential of electrical resistivity tomography (ERT) as an alternate tool to address the problem. In the experiments an externally powered resistive wire was employed to initiate the smouldering fire inside the test material (wood pellets, wood shavings, wood fines). Time series of ERT that followed the initiation and development of smouldering were recorded using an automated monitoring instrument setup. The actual geometry of the experimental sample container and electrode setup was integrated in the 3D finite element method (FEM) model grid to perform inverse numerical modelling (inversion) and to develop resistivity tomographic images. The study shows a sharp increase in ratio of resistivity (R/Ro ≥ 50 %) in the test material in the region of smouldering hotspot and demonstrates the potential use of ERT technique for the detection of smouldering hotspots in silos and pile storage of organic material such as wood-based fuels, wood waste, coal, municipal solid waste (MSW), recyclables etc. More research is however required for enabling the use of this technique at the practical scale for different storage conditions.

A Numerical Study of the Effect of Water Speed on the Melting Process of Phase Change Materials Inside a Vertical Cylindrical Container

The present work offers a thorough analysis of the impact of water velocity on phase change material (PCM) melting in a vertical cylindrical container. A detailed quantitative analysis uses sophisticated numerical techniques, namely the ANSYS/FLUENT 16 program, to clarify the complex relationship between enthalpy and porosity during the melting process. The experimental focus is on phase transition materials based on paraffin wax, particularly Rubitherm RT42. This study’s primary goal is to evaluate the effects of different water velocities (that is, at velocities of 0.01 m/s, 0.1 m/s, and 1 m/s) on the PCM’s melting behavior at a constant temperature of 333 K. This work intends to make a substantial contribution to the development of thermal energy storage systems by investigating new perspectives on PCM behavior under various flow circumstances. The study’s key findings highlight the possible ramifications for improving PCM-based thermal energy storage devices by revealing significant differences in melting rates and behavior that correlate to changes in water velocities. Future research is recommended to explore the impact of temperature variations, container geometries, and experimental validation to improve the accuracy and practicality of the results and to advance the creation of sustainable and effective energy storage solutions.

MATRESHCA: Microtesla Apparatus for Transfer of Resonance Enhancement of Spin Hyperpolarization via Chemical Exchange and Addition.

We present an integrated, open-source device for parahydrogen-based hyperpolarization processes in the microtesla field regime with a cost of components of less than $7000. The device is designed to produce a batch of 13C and 15N hyperpolarized (HP) compounds via hydrogenative or non-hydrogenative parahydrogen-induced polarization methods that employ microtesla magnetic fields for efficient polarization transfer of parahydrogen-derived spin order to X-nuclei (e.g., 13C and 15N). The apparatus employs a layered structure (reminiscent of a Russian doll "Matryoshka") that includes a nonmagnetic variable-temperature sample chamber, a microtesla magnetic field coil (operating in the range of 0.02-75 microtesla), a three-layered mu-metal shield (to attenuate the ambient magnetic field), and a magnetic shield degaussing coil placed in the overall device enclosure. The gas-handling manifold allows for parahydrogen-gas flow and pressure control (up to 9.2 bar of total parahydrogen pressure). The sample temperature can be varied either using a water bath or a PID-controlled heat exchanger in the range from -12 to 80 °C. This benchtop device measures 62 cm (length) × 47 cm (width) × 47 cm (height), weighs 30 kg, and requires only connections to a high-pressure parahydrogen gas supply and a single 110/220 VAC power source. The utility of the device has been demonstrated using an example of parahydrogen pairwise addition to form HP ethyl [1-13C]acetate (P13C = 7%, [c] = 1 M). Moreover, the Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) technique was employed to demonstrate efficient hyperpolarization of 13C and 15N spins in a wide range of biologically relevant molecules, including [1-13C]pyruvate (P13C = 14%, [c] = 27 mM), [1-13C]-α-ketoglutarate (P13C = 17%), [1-13C]ketoisocaproate (P13C = 18%), [15N3]metronidazole (P15N = 13%, [c] = 20 mM), and others. While the vast majority of the utility studies have been performed in standard 5 mm NMR tubes, the sample chamber of the device can accommodate a wide range of sample container sizes and geometries of up to 1 L sample volume. The device establishes an integrated, simple, inexpensive, and versatile equipment gateway needed to facilitate parahydrogen-based hyperpolarization experiments ranging from basic science to preclinical applications; indeed, detailed technical drawings and a bill of materials are provided to support the ready translation of this design to other laboratories.

Geometry optimization of microwavable food to improve heating uniformity

Food geometry affects microwave heating, posing a challenge for uniform heating. In this study, numerical geometry optimization models of 3-D microwave heating were developed using the coefficient of variation of the absorbed power as the optimization objective to obtain the best geometry. These models were verified by comparing the surface temperature distribution and point temperatures from the experiments and simulations. The optimized geometry exhibited better heating uniformity than the non-optimized geometry. After geometry optimization, the static heating uniformity of a single sample and multiple sample combinations was improved by up to 109.93% and 53.95%, respectively. Similar geometry features were obtained after geometry optimization of potato, beef, and tilapia samples at defined positions. In addition, rotational heating enhanced temperature uniformity for each sample during simultaneous heating. This study provides a flexible and effective method for designing microwaveable food and container geometries.

The effect of outer container geometry on the thermal management of lithium-ion batteries with a combination of phase change material and metal foam

The use of PCM for thermal management of the batteries has an important place among passive cooling methods because it does not require pump or fan power. In battery cooling applications with PCM, it was aimed to increase the thermal conductivity of the PCM and to cool the battery better by using fins, nanoparticles, and metal foam. The novelty of this study is to investigate the effect of outer container geometry on battery temperature in battery cooling with PCM + metal foam composition. In this direction, five different container geometries affecting the heat transfer by conduction and convection were analyzed. The parametric study was carried out for different values of convection heat transfer coefficient, heat generation in the battery, PCM amount, and porosity. The lowest battery temperature for a given discharge time was obtained in triangular container geometry. With the use of a triangular container, the battery temperature was reduced between 0.4 % and 14.42 % compared to the use of a circular container, depending on the parameter values. The analysis findings revealed that the outer container geometry is more effective in the thermal management of the battery for conditions with low convection heat transfer coefficient and high heat generation.

Numerical simulation of melting of phase change material within thermal storage spiral container in existence of nanoparticles

The period of melting process should be managed according to application. The rate of melting can be increased with improvement of the geometry of container and melting the properties of paraffin. The current storage unit utilizes spiral tubes filled with hot hybrid nanomaterial, which is heated by the sun. To efficiently use this heat, a spiral pipe filled with paraffin was employed in the storage unit. Two configurations, both with equal paraffin volume, were implemented using this setup. The present study employed spiral tubes as a storage unit filled with hot hybrid nanomaterial, which was heated by solar energy. To optimize heat transfer, a spiral pipe was used instead of a straight one. Two configurations with equal paraffin volume were tested, differing only in the location where the hybrid fluid exits the unit. Both types have the same volume of paraffin. The inlet and outlet section exist in top left side in type 1 while the type 2 represent the arrangement which inlet section is position in left bottom side while outlet section is positioned in right upper side. In the current study, two geometries have been examined. In the first geometry (Type 1), the nanofluid section's inlet and outlet were positioned on the left side. In the second geometry (Type 2), the inlet section was located on the right side, while the outlet section remained on the left side. The governing equations were achieved based on approximation of single phase model for nanomaterial. For simulating of this unsteady problem, finite volume method has been implemented which is verified based on previous publication. The grid independency and optimized value of time step have been applied. The outcomes were analyzed to determine the most effective configuration. In Type 1 configuration, the SF changed from 0.638 to 0.094 as the time increased from 10 to 30 min.

Inertial wave attractors in librating cuboids

Perturbed rapidly rotating flows are dominated by inertial oscillations, with restricted group velocity directions, due to the restorative nature of the Coriolis force. In containers with some boundaries oblique to the rotation axis, the inertial oscillations may focus upon reflections, whereby their energy increases whilst their wavelength decreases and their trajectories focus onto attractor regions. In a linear inviscid setting, these attractors are Delta-like distributions. The linear inviscid setting is obtained formally by setting both Ekman number ${E}$ (ratio of inertial to viscous time scales) and Rossby number ${Ro}$ (non-dimensional amplitude of the forcing that drives the inertial oscillations) to zero. These settings raise fundamental questions, in particular concerning the nature of energy dissipation in the vanishing Ekman number regime. Here, we consider a simple container geometry, a rectangular cuboid, in which the direction of the rotation axis is oblique to four of its walls, subject to librational forcing (small-amplitude harmonic oscillations of the rotation rate). This geometry allows for accurate and efficient direct numerical simulations of the three-dimensional incompressible Navier–Stokes equations with no-slip boundary conditions using a spectral-Galerkin spatial discretisation along with a third-order temporal discretisation. Solutions with Ekman and Rossby numbers as small as ${E}={Ro}=10^{-8}$ reveal many details of how the inertial oscillations focus, at the libration frequency considered, onto attractors, and how the focusing leads to increased localised nonlinear and dissipative processes as ${E}$ and ${Ro}$ are reduced. Even for extremely small forcing amplitudes, nonlinear effects have important dynamic consequences for the attractors.

On the Thermoelastic Influence of Fluid-Gas Phase Transition Pressure on the Closed Structural Storage Container

The current paper presents a finite element method (FEM) axisymmetric solution based on commercial software for an isotropic closed-ended container filled with fluid, located in the triple point phase (liquefied gas) while being converted into gas through a phase transition to critical point phase by a simultaneously rapid change of pressure and temperature to their critical values. The whole chemical process will be simulated through thermo-elastic analysis that is controlled by temperature-displacement dynamic coupling and subjected to step function boundary conditions alongside liquefied triple point initial conditions. In the process, the maximum principal stresses will be determined and illustrated as dependent on the container thickness. In the process, investigation will be carried out for prominent parameters, like, container hollow geometry type (spherical, ellipsoidal, and cylindrical) and raw material of the container. Commercial software solution calibration against existing literature solutions has been performed. Also, the solution accuracy was examined by element size mesh analysis to be coherent. In conclusion, the best materials to use were Molybdenum TZM and Tungsten while the preferred shape is the ellipsoidal shape. However, a typical vessel that is still durable with sufficient thermal strength for gas storage purposes is a cylinder body container with spherical ended cups made from Aluminum 6061 T6.

Impact of container geometry and hydraulic properties of coir dust, perlite, and their blends used as growing media, on growth, photosynthesis, and yield of Golden Thistle (S. hispanicus L.)

Soilless cultivation is an expanding greenhouse cropping system with the potential to maintain and increase food security in challenging environments and under the eminent climate crisis, and to diversify our diet with crops that could not be sustainably cultivated in open fields. The replacement of soil with blends of organic and inorganic substrates has provided solutions but has also created challenges and opportunities, such as the need to match crop irrigation with their hydraulic properties and the specific requirements of each crop species. In this context, here we investigate the effects of the container type (growbag or pot) and the growing media used to cultivate Golden Thistle (Scolymus hispanicus L.) on crop performance and physiological parameters that may be affected by water and air availability in the root zone. The tested growing media were perlite and coir dust at ratios 4:0, 3:1, 2:2, 1:3, and 0:4, denoted as 4P0C, 3P1C, 2P2C, 1P3C, and 0P4C, respectively. To characterize substrates in terms of their hydraulic properties, the hydraulic conductivity (K), easily available water (EAW), and actual water content (AWC) in the substrate profile at container capacity were determined using HYPROP2. The cultivation of S. hispanicus L. on the blends 4C0P and 3C1Pincreased total plant fresh weight of both leaves and roots (FWL and FWR, respectively) compared to cultivation on sole perlite, while the use of shorter (growbag) container increased FWL:FWR ratio and, concomitantly, decreased in higher container (pot). Results show that the EAW significantly increases when the fraction of coir dust increases in the mixture, while K and AWC decrease considerably when the container height increases from 5 to 25 cm. These results show that in substrate-grown crops, both the substrate and the container geometry have a crucial impact on water flux and water availability, and thus their proper manipulation can greatly contribute to maintenance of an optimal water and air status in the root zone of the plants. In conclusion, accurate estimation of the moisture retention curve (MRC) of substrates used in soilless culture is essential to design proper irrigation schedules tailored to crop water and aeration needs. Furthermore, the current study provides valuable information about the agronomic responses of tuberous species such as S. hispanicus L. to the hydraulic characteristics and the container geometry of growing media used in soilless culture systems.

Energy and exergy analysis of a bidirectional solar thermoelectric generator combining thermal energy storage

In this paper, energy and exergy analysis of a bidirectional solar thermoelectric generator (STEG) coupled to a latent heat storage and cooling system (LHSCS) has been carried out. The effect of various parameters of LHSCS on energy and exergy efficiencies of STEG have been analysed under climatic conditions of Chile’s Atacama Desert. It is found that the most relevant design parameter to improve the energy and exergy efficiencies of the thermoelectric generator (TEG) is the container insulation, followed by heat sink at the TEG hot side, fin thickness and the aspect ratio of the container. The results showed that an optimally designed insulation container can improve the energy and exergy efficiencies of LHSCS by 30% and 200%, respectively, and the TEG conversion efficiency by 30% during nighttime. Further, inclusion of heat sink at TEG hot side during reverse operation of TEG at night can improve the TEG efficiency by 20%. The optimal fin thickness can improve the TEG conversion efficiency by 20% during the night and LHSCS energy and exergy efficiencies by 30% and 23%, respectively. The container geometry should have higher aspect ratios. This study may help in optimal design of LHSCS for solar energy conversion applications in the desert locations.

Experimental Study Of Helium Stratification In Multi-Compartment Containment Studies Facility

Abstract A significant amount of hydrogen may be released inside the containment of water cooled nuclear power reactor under postulated accident conditions. Its distribution in the multi-compartment containment geometry must be known to manage and mitigate the local hydrogen concentration in combustible pockets. An experimental study to characterize the behavior of a lighter gas (helium in place of hydrogen) in a multi-compartment Containment Studies Facility (CSF) has been pursued. Helium distribution experiments have been performed in CSF by varying important accident parameters like helium release rate, duration and injection area. The experimental studies performed in CSF depict helium stratification in the upper dome region. Stratification in terms of stratification/effective stratification factor determined for a range of experiments. The present experimental studies are important for understanding hydrogen distribution characteristics in multi-compartment containment geometry and benchmarking of CFD codes. Based on these studies some important prevailing practices for recombiner placement were endorsed.

Repetitive Acoustic Streaming Patterns in Sinusoidal Shaped Microchannels

Geometry of the fluid container plays a key role in the shape of acoustic streaming patterns. Inadvertent vortices can be troublesome in some cases, but if treated properly, the problem turns into a very useful parameter in acoustic tweezing or micromixing applications. In this paper, the effects of sinusoidal boundaries of a microchannel on acoustic streaming patterns are studied. The results show that while top and bottom sinusoidal walls are vertically actuated at the resonance frequency of basic hypothetical rectangular microchannel, some repetitive acoustic streaming patterns are recognised in classifiable cases. Such patterns can never be produced in the rectangular geometry with flat boundaries. Relations between geometrical parameters and emerging acoustic streaming patterns lead us to propose formulas in order to predict more cases. Such results and formulations were not trivial at a glance.

Kristallenmiş Çiçek Balının Sıvılaşma Hızının Artırılmasının Deneysel İncelenmesi

After the honey is harvested from the bee colony, it is removed from the honeycomb with mechanization and stored as a liquid in cans or barrels. Honey crystallizes depending on the chemical structure, type of its, and impurity or ambient temperature. In Turkey, liquid (wax) honey is generally not consumed as crystallized. For this reason, honey is liquefied and packaged again. When the honey crystallizes, which is stored in tin cans, an air oven or hot water pool is usually used as a liquefaction medium. The liquefaction time of honey depends on the type of its, melting medium, the ambient temperature, and the geometry of the honey container. As the ambient temperature and melting time increase, both chemical and color-taste changes occur in honey. In this experimental study, crystallized honey stored in tin cans (18 dm3) was liquefied in an air-type oven at 50oC using two different methods (conventional and mechanical vibratory). During liquefaction, time-dependent temperature changes were determined in honey’s x and y axes. Moisture, diastase, proline, and HMF (Hidroksimetilfurfural) changes in the heat-treated honey were measured. As a result of the obtained data, it was determined that the mechanical vibration liquefaction time was 35% shorter than the conventional liquefaction time. At the end of the heat treatment with both methods, the change of chemical values in honey was found to be in accordance with the Turkish Food Code.

Energy-efficient and quality-aware part placement in robotic additive manufacturing

The advancements in autonomous robots for additive manufacturing (AM) are opening new horizons in the manufacturing industry, especially in aerospace and construction applications. The use of multiple robots and collaborative work in AM has rapidly gained attention in the industry and research community. Addressing the process planning challenges for single-robotic AM is foundational in addressing more advanced challenges at the collaborative multi-robotic level for AM. Among these challenges include the part placement problem which explores the optimal positioning of the part within the robot’s reach volume. The majority of the existing part placement algorithms take into account the part accuracy and manufacturing time for decision-making, while neglecting the implications of such decisions on energy efficiency and environmental sustainability. To address this gap, this paper presents a methodology for energy-efficient, high-quality part placement (EEHQPP) in robotic additive manufacturing. An energy-quality map is formulated and established to characterize the energy and quality variations across the robot’s workspace to inform the decision-making process. Two case studies (a container and a spur gear) are considered, and the performance of the proposed approach compared to the benchmark (i.e., default part placement by the 3D printing software) are evaluated. The proposed algorithm reduces both the energy consumption and maximum deviation error of the container (6.5% and 19.4%, respectively) and spur gear (1.4% and 32.7%, respectively) geometries manufactured by the robotic additive manufacturing system.

A parameter study of strato-rotational low-frequency modulations: impacts on momentum transfer and energy distribution.

Previous comparisons of experimental data with nonlinear numerical simulations of density stratified Taylor-Couette (TC) flows revealed nonlinear interactions of strato-rotational instability (SRI) modes that lead to periodic changes in the SRI spirals and their axial propagation. These pattern changes are associated with low-frequency velocity modulations that are related to the dynamics of two competing spiral wave modes propagating in opposite directions. In the present paper, a parameter study of the SRI is performed using direct numerical simulations to evaluate the influence of the Reynolds numbers, the stratification, and of the container geometry on these SRI low-frequency modulations and spiral pattern changes. The results of this parameter study show that the modulations can be considered as a secondary instability that are not observed for all SRI unstable regimes. The findings are of interest when the TC model is related to star formation processes in accretion discs. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (Part 2)'.

Impulsive impact of a body fully submerged in an open container

An impulsively starting motion of a cylindrical body submerged below a calm water surface in an open container of arbitrary shape is considered. This work generalizes the case of an infinite-depth liquid studied by Semenov et al. (J. Fluid Mech., vol. 919, 2021, R4). Particular attention is paid to the interaction between the body, the free surface and the container. The integral hodograph method is employed to derive the complex velocity potential in a parameter plane. The boundary-value problem is reduced to a system of integral equations, which is solved numerically. The velocity field, the pressure impulse on the body and the container wall and the added mass just after the impact are determined for a wide range of depths of submergence and container geometries and for various cross-sectional shapes of the body, such as a flat plate, a circle and a rectangle.

Improving the Radon Adsorption Capacity of Activated Carbon by Liquid Nitrogen Modification

Radon is a naturally occurring radioactive inert gas that poses a significant threat to the human health. Coconut shell activated carbon has been verified to be the best radon adsorbing material, but its radon adsorption capacity still cannot meet the requirement of industrial applications. Activated carbon modification using liquid nitrogen is an effective method for improving the radon adsorption capacity, but it is necessary to determine the conditions for large-scale production. In this study, the influence of environmental temperature, container geometry, and amount of activated carbon and liquid nitrogen on the modification effect are examined. The results show that the activated carbon has the best modification effect when the container is placed in a water bath at 50 °C. The container geometry and activated carbon mass have a minor influence on the modification effect. Further, the radon adsorption capacity is increased by 36% when 6.5 L of liquid nitrogen is added to 1 kg of activated carbon. The characterization results reveal that the chemical structure and elemental content of the activated carbon do not change after modification, but the number of micropores is significantly increased, especially the micropores with a size of 0.5-0.6 nm, which is related to the radon adsorption capacity of the modified activated carbon. Overall, the liquid-nitrogen-based modification is a simple, environment-friendly, and low-cost method to improve the radon adsorption capacity of activated carbon, which can be used in the large-scale production of highly efficient radon adsorbents.

Geometry effect of phase change material container on waste heat recovery enhancement

Waste heat recovery from industrial exhaust gases is a key method to reduce fuel consumption and improve system energy efficiency. Phase change materials (PCMs) are one of the major media in the waste heat storing and recovering processes. The PCM container geometry is a crucial design factor but attracts less attention for its effect on the PCM melting and heat storage operation. This study simulates the melting behaviour and heat storage performance in the PCM storage containers with the same cross area but different configurations with the rectangular shape and ones with concave folded sidewalls and protruding folded sidewalls. The geometry variation on PCM containers influences both the contact area with the hot airflow and natural convection in the melting phase of PCMs. The three-dimensional transient modelling indicates that the natural convection currents enhance the PCM melting and thermal storage rates. The PCM container design angle, α, shows a remarkable impact on the natural convection strength, PCM melting time, and energy storage rate. The protruding-shaped container with α at 133.8∘ presents the least melting time of 4,645 s, reducing 24.9% of the melting time in comparison to the rectangular chamber as the baseline with α= 90 ∘. The study can inspire the design of PCM storage geometries with efficient waste heat recovery in the industrial applications.