Tank Wall Research Articles

Comparative analysis of sloshing effects on elevated water tanks’ dynamic response using ANN and MARS

Important infrastructure elements like elevated water tanks are vulnerable to fluid sloshing brought on by earthquakes, which can seriously harm the structure. In order to precisely capture the fluid–structure interaction, this work uses a 3D finite element model based on the Coupled Eulerian–Lagrangian (CEL) approach to investigate the dynamic response of raised water tanks under seismic excitation. Seismic ground motions were applied to the model, and the displacements, accelerations, and stresses that resulted were examined. The results highlight how fluid sloshing significantly affects the dynamic response of the tank because sloshing waves increase structural stresses and deformations by imposing large hydrodynamic pressures on the tank walls. The water tank's performance as a tuned liquid damper (TLD) was also evaluated in the study. Multivariate Adaptive Regression Splines (MARS) and Artificial Neural Network (ANN) models were created and trained in order to further examine and forecast the dynamic response. According to statistical analysis and Taylor diagram evaluation, the ANN model outperformed the MARS model in forecasting the displacement response. The numerical simulations and precise results were made possible by the use of ABAQUS software, a potent finite element analysis tool. The study's conclusions can be used to improve the analysis and construction of elevated water tanks in order to reduce seismic risk. The impact of different tank geometries, fluid characteristics, and seismic ground motions on the dynamic response of raised water tanks may be investigated in future studies. This research innovatively employs ABAQUS software to simulate the stabilizing effect of sloshing in steel structures during earthquakes. By optimizing water levels to 60% capacity, the study explores sloshing as a potential damping mechanism to mitigate structural vibrations. In comparison to empty tanks, this leads to better damping throughout velocity, acceleration, and displacement responses, which speeds up stabilization and lowers dynamic loads. The study also demonstrates how well adjusted liquid dampers (TLDs) reduce vibrations in raised water tanks.

Analytical and numerical solutions to the problem of the influence of pipes for receipt and distribution on the stress-strain state of the tank wall

The article considers the problem of determining the stress-strain state of the tank wall in the area where it connects with receiving and dispensing pipes (PRP). One of the significant factors influencing the overall stress-strain state of the tank wall, which is a thin shell according to fundamental laws of structural mechanics, is the presence or absence of settlement of the bases and foundations of the structural elements of the tank.The article uses both classical structural mechanics methods, and existing analytical solutions. In addition to applying numerical methods, particularly the finite element method (FEM), implemented through the ANSYS software package The developed numerical model of the RVSP-20000 tank using the finite element method in ANSYS PC allowed to determine the displacements, deformations, and stresses in the structures in the junction area of the receiving and dispensing pipe and the RVSP tank wall. The numerical calculations revealed. As the numerical calculation in this article using the FEM complex has shown, the PRP, which has a connection with the reservoir at the level of maximum radial displacements of the wall from the hydrostatic pressure of the stored liquid, creates a significantly altered and potentially hazardous stress-strain state in the contact zone. This highlights the necessity of monitoring potential incompatible deformations in the foundations of both the PRP and the reservoir itself, and, if needed, implementing appropriate engineering measures.

ОСИММЕТРИЯЛЫҚ ҚАБЫҚШАЛАРДАҒЫ КЕРНЕУЛЕРДІ МОМЕНТСIЗ ТЕОРИЯ БОЙЫНША АНЫҚТАУ

In the Republic of Kazakhstan, a significant number of tanks are used for operations for the collection and storage of oil and oil products. The design of the tank is a vertical steel tank manufactured using roll or sheet assembly technology. Despite the longer use of the technology for the manufacture of such tanks, the risk of weld defects remains quite high. High voltage level, non-compliance with the technology and manufacturing mode during construction significantly affect the technological properties of the connection. Thin-walled shell theory is used to calculate steel tanks with wall and bottom elements of various thicknesses. Shells according to the shape of the axial section are divided into cylindrical, conical, spherical and drip structures. In this case, the use of the theory of wall instantaneous shells for the calculation of tanks should have features that take into account their design and operational features. The work provides for the use of the theory of unobstructed shells to study the stressed-deformed side of thin-walled shells of the tank wall.

Finite Element Analysis and Improved Evaluation of Mechanical Response in Large Oil Storage Tanks Subjected to Non-Uniform Foundation Settlement

This study developed a finite element model to address the issue of non-uniform settlement in large crude oil storage tanks. The model consisted of four key components: the tank foundation, bottom plate, wall plate, and large fillet welds. The Ramberg-Osgood model was used to describe the material’s nonlinearity. Key factors such as the radius-to-thickness ratio, height-to-diameter ratio, harmonic number, and amplitude were evaluated for their impact on the radial deformation of the tank’s top wall. Two numerical models were developed—one accounting for the coupling effect between the foundation and the tank bottom, and the other without it. The differences in radial deformation between these models were analyzed, revealing that deformation was minimally influenced by the radius-to-thickness ratio, but increased with higher height-to-diameter ratios and harmonic amplitudes. At low liquid levels, radial deformation increased with harmonic number, but at high levels, it decreased once the harmonic number exceeded four due to the decoupling of the tank bottom from the foundation. The model considering foundation coupling exhibited less radial deformation compared to the one neglecting it, particularly as the harmonic number and amplitude increased. An improved evaluation method identified a critical range of harmonic amplitudes for a 100,000 m3 tank, within which the coupling effect can be reasonably neglected, allowing deformation to be calculated using the simpler model.

Vision-based weld detection and localization for climbing robots in large-scale storage tank inspections

Abstract Climbing robots are considered an effective solution for inspecting welds on the walls of large storage tanks. For these robotic systems, the efficient and accurate identification and localizing of weld seams are crucial prerequisites for ensuring precise weld seam tracking. In this paper, we investigate machine vision-based algorithms for feature recognition and localization of weld seams on tank walls for inspection of weld seams by a climbing robot. First, we designed the model of the image algorithm to extract the weld features of the tank walls. After extracting the weld features, we propose the novel idea of feature discretization and a Min-outer Rectangle Fitting Algorithm (MRFA), which will achieve the fitting of rectangular features on the discretized weld features. We constructed a mathematical model for calculating the orientation angle of the rectangular box based on the extracted rectangular boxes. This model allows for the real-time and efficient extraction of the rectangular feature’s pose information (x, y, θ). We also propose an efficient method for calculating the curvature of a curve trajectory. The experimental results demonstrate that the proposed image algorithm model and MRFA effectively identify weld features on the storage tank wall surface, while simultaneously achieving high-accuracy feature localization. Positioning errors are maintained within 3 mm for position and 3 degrees for azimuth, indicating both high precision and robustness. Additionally, the algorithm processes each image in approximately 80 milliseconds. The lightweight and efficient design of the proposed model allows it to be easily deployed on a climbing robot for weld seam detection and tracking on tank walls.

A Study on the Volume Expansion of Vanadium-Based Alloy Powders and Compacts During Hydrogen Sorption

Storing hydrogen in solid metal hydrides provides a safe and efficient storage approach. However, the large volume expansion of metal hydrides during hydrogen absorption imposes substantial stresses on the wall of a hydrogen storage tank. In this study, volume expansion behavior of a V-based hydrogen storage alloy, V61Cr24Ti12Ce3, with body-centered-cubic, was investigated using a self-developed in situ expansion testing device. The lattice expansion of the V61Cr24Ti12Ce3 alloy after full hydrogenation was determined to be 37.85% using X-ray diffraction(XRD). The powder bed, composed of alloy powder with an average size of 3.35 mm in diameter, displays a large volume expansion ratio of 131% at the first hydrogen absorption cycle and 40–45% in the following four cycles. The stable compact bed, made of alloy powders, organic silicone gel, and graphite flakes, shows significantly smaller volume expansion ratio, which is 97% at the first cycle and 21% at the second cycle, and stabilizes at 13% in the following cycles. Also, the compact bed shows similar hydrogen absorption capacity, but faster absorption kinetics compared to the powder bed.

Enhancing Crude Oil Tank Inventory Stock Availability at PT Kilang Pertamina for National Fuel Security

In 2022, PT Kilang Pertamina International (KPI) Unit VI Balongan initiated the RDMP project to increase crude oil capacity to 150 MBSD (Million Barrels per Stream Day) by adding equipment to the CDU. However, refinery capacity growth faced challenges due to corrosion and leaks in the crude oil tank walls. Repairing these issues through welding while the tanks were onstream posed safety risks, including explosions. As an alternative, the COMPACT team implemented the FEA + Composite Patch solution, using a cold work method to minimize risk and avoid downtime. Laboratory testing confirmed that the repair increased material strength by up to 10%. Further structural analysis of tank 42-T-101B using standard fitness-for-service (FFS) procedures revealed that the tank initially failed to meet safety criteria due to metal loss. However, local defect analysis indicated that, if mitigated, the tank could meet the required standards. Proposed mitigation measures, such as reducing the maximum allowable fill height (MAFH) or adjusting the RSFa value, would ensure compliance. Composite patch repairs also showed significant improvements in the tank's ability to withstand collapse, extending its lifespan by up to 62 years, supporting the continued safe operation of the storage tank and contributing to national fuel security.

Analysis of thermal and mechanical properties with inventory level of the molten salt storage tank in central receiver concentrating solar power plants

Molten salt thermal energy storage (TES) tanks ensure steady power output of concentrating solar power (CSP) plants; however, recent tank failures have highlighted the need for further analysis. Current studies primarily focus on analyzing the molten salt flow, heat transfer, and thermal efficiency. Additionally, research on the latest tank structures is limited and lacks newest experimental validation. This study measures temperature and molten salt inventory levels in the high-temperature tank at a 50 MW central receiver CSP plant, connected to the power grid in 2019. A multi-physics model was developed to evaluate thermal and mechanical properties of TES tanks by combining computational fluid dynamics and finite element modeling using real plant data. Heat loss, temperature, displacement, and stress distribution of the tank at different inventory levels were investigated. Results show that ambient air velocity near the tank roof reaches 2.14 m/s, much higher than 0.2 m/s near the wall. The temperatures of inventory fluid and tank are close, varying slightly at different levels due to thermal conduction and radiation. Because the heat loss strongly depends on temperature, the total tank loss remains nearly constant across inventory levels. Larger temperature gradients and thermal stresses are primarily localized along the tank floor edge and the air-salt interface. Notably, the maximum thermal stress at the tank edge is three times higher than that at the interface. The magnitude of total stress changes by less than 5 MPa with and without thermal load, indicating that high temperatures exert only a minor impact on tank stress. In contrast, thermal load significantly affects tank deformation, particularly at the roof edge, where values exceed 150 mm. Despite the large variation in molten salt levels, tank wall temperatures and displacements present a minor change, suggesting a weak correlation with inventory levels. The findings obtained in this study provide important insights on the TES tank that could be used to optimize tank design and operation strategies.

Optimal Design of Rectangular Tank Walls With Ribs Using Numerical Models and Global Optimization

This paper addresses the optimization of the cross-section in rectangular above-ground tank walls, incorporating vertical ribs and an optional top ring. The objective is to minimize the volume of concrete used, while maintaining key performance criteria such as keeping the maximum tensile stress below the material’s allowable limit and minimizing deflections. The analysis is performed using the finite element method (FEM), with the optimization handled through a local gradient-based algorithm (trust region method), supported by a multistart technique to navigate the complexity of the design space and avoid suboptimal solutions. The results demonstrate that this approach effectively reduces concrete consumption without exceeding the tensile stress limits or causing excessive deflection, offering more efficient and cost-effective designs for rectangular tanks used in water storage applications. This method provides valuable insights into the balance between material usage and performance constraints, contributing to sustainable engineering practices.

Prediction of splash noise in a rectangular tank under longitudinal periodic excitation

Sloshing phenomena within fuel tanks have emerged as a significant contributor to noise in hybrid and high-end vehicles, particularly as other sources of noise, such as those from the engine and transmission system, minimized. The manifestation of noise during sloshing results from the dynamic interplay between the fluid within the tank and both its surrounding structures and the fluid itself. “Splash noise” is an acoustic phenomenon which arises due to pressure fluctuations induced by fluid-fluid interactions during sloshing. Thus, the generation of splash noise encompasses a multi-physics process involving fluid flow and acoustic radiation. Accurate prediction of splash noise is crucial for implementing measures to mitigate it during the design phase. The current paper proposes a hybrid approach for predicting splash noise within a rectangular tank. The first step in the methodology is to predict the flow field within the tank, from which acoustic sources are computed. These sources are then utilized to calculate the sound propagation based on the acoustic analogy. To emulate a regime dominated by fluid-fluid interactions, periodic longitudinal excitations are imposed on the rectangular tank, both with and without baffles. Parameters such as fluid free-surface profile, tank wall pressures, and radiated sound pressure levels are systematically calculated and subsequently validated against experimental results available in the existing literature.

Analysis of the Impact of Partial Discharge Locations on Ultra-High Frequency Signal Propagation Characteristics

Transformers are critical devices for the functioning of power grids. Partial discharge, the leading cause of insulation failure, has consistently been a central focus in transformer fault detection and the assurance of safe operation. Among the various methods for detecting partial discharges, ultra-high frequency (UHF) is widely employed as measured quantities due to its outstanding sensitivity and strong resistance to interference. However, as UHF signals propagate within the transformer, internal components can easily obstruct them, leading to alterations in their propagation characteristics. These changes can hinder effective fault detection. Therefore, it is crucial to consider how the placement of the discharge source influences UHF signal transmission. In this study, an optimized model based on a real 110 kV device is developed through the Finite-Difference Time-Domain (FDTD) method to examine the dissemination of UHF waves generated by partial discharges. To evaluate the impact of different discharge source locations, simulations are conducted with examples of partial discharges occurring between the winding and the tank wall, as well as between windings. Drawing from the findings, the research investigates the propagation dynamics of UHF electromagnetic signals and analyzes how the discharge source location influences these characteristics.

Arbitrary Lagrangian-Eulerian finite element method for liquid sloshing with contact angle hysteresis in microgravity

Liquid sloshing in microgravity environment remains a focus of attention in space engineering. In this paper, an arbitrary Lagrangian-Eulerian finite element method is proposed to simulate the liquid sloshing dynamics with contact angle hysteresis, in which an infinitely small contact free-surface mesh method is used to implement the contact angle boundary condition. The contact angle hysteresis is accounted for by the relation between the contact angle and the advancing contact angle or the receding contact angle. This method not only guarantees the conformity between the numerical treatment and the actual liquid sloshing behavior, but also improves the accuracy of the numerical method. The numerical results of the free surface configurations, including the height of the contact line along the tank wall and the height of the free surface along the centerline, which are obtained by simulating the partially wetted liquid reorientation show good agreements with the correspongding experimental results. Then, the liquid sloshing in a spherical tank under microgravity is simulated, and the influences of the contact angle hysteresis on the free surface evolution are analyzed. The results show that it is of great significance to consider the contact angle hysteresis in microgravity environment.

Numerical study of liquid sloshing in three-dimensional flexible cylindrical tank under multi-directional seismic excitation

The present study aims to evaluate the effect of the flexibility of three-dimensional (3D) cylindrical tank on liquid sloshing inside the tank as well as the influence of the hydrodynamic forces on the structure's deformation. A ground-supported cylindrical flexible tank filled with water and subjected to seismic excitation is investigated using a numerical coupling methodology to take into account the fluid–structure interactions. The Navier–Stokes equations in the fluid domain are solved using the finite volume method, while the finite element method is used to solve the linear-elastic equations of the structure. The arbitrary Lagrangian–Eulerian formulation is applied for the moving mesh in two-phase flow system. The simulations are conducted using free open-source software: OpenFOAM for fluid dynamics and FEniCS for solid mechanics, both utilize the preCICE library for data exchanging and fluid–structure coupling. The numerical methodology is validated by the experimental and numerical results given in literature. A multi-directional earthquake ground motion is then considered as external loading, and the elasticity of the tank wall is varied to investigate the effect on the fluid sloshing. It has been shown that the more flexible the tank walls are, the greater will be both the sloshing height and the structural deformations during an earthquake event. Several flow field information and structural responses have been provided, such as the sloshing height, hydrodynamic pressure, structure deformations, and structural stress distribution. The potential elephant's foot buckling phenomenon at the lower part of tank can also be predicted.

Experimental study on fireproof of aviation lubrication oil tank

Abstract This paper presents an experimental study on the fireproof performance of aeroengine lubrication oil tanks. By constructing a simplified lubrication oil tank model and simulating the harsh operating conditions of engine fires, the oil tank was exposed to flames generated by a standard burner for testing. The study monitored and recorded key parameters such as temperature, pressure, flow rate, and phase changes within the tank. The results indicate significant differences in the temperature distribution characteristics of the tank walls under different inlet temperatures and flow conditions. In the rigorous 15-minute flame test, all tests successfully completed the fire verification process.

Lumped Parameter Analysis of Autogenous Propellant Pressurization System for Nuclear Thermal Rocket

This work proposes a new propellant management configuration for an ammonia-fueled nuclear thermal propulsion system. The suggested configuration maximizes the advantage deriving from the autogenous pressurization of ammonia by exploiting the thermal power lost by the nuclear reactor toward the vacuum space due to leaking radiation. In this layout, a tank containing ammonia in saturated conditions is placed near the nuclear reactor and receives an input thermal power proportional to the dose of gamma rays and neutrons absorbed by the tank walls and the ammonia itself. Such a thermal power accelerates the vaporization process of the saturated ammonia, thus increasing the pressure in the tank. A pressure regulator valve exploits this overpressure to pressurize the ammonia propellant contained in a run tank to the level required by the mission by connecting the two ammonia volumes. The pressure achieved inside the run tank pushes the propellant with an adequate mass flow rate inside the nuclear reactor. The developed lumped parameter analysis shows how this propellant management system can provide a constant mass flow to the nuclear reactor without using a turbopump assembly. Moreover, it is shown how the proposed concept allows for a reduction in the radiation shield mass.

Building a model of oil tank water cooling in the case of fire

The object of this study is the process of liquid combustion in spillage, and the subject is the temperature distribution along the wall of a vertical steel tank when it is heated under the thermal influence of fire and cooled by water. A system of equations describing the water cooling of the wall of a vertical steel tank under the conditions of the thermal effect of a fire spilling a flammable liquid has been constructed. The system consists of a heat balance equation for the tank wall, a heat balance equation for the water film flowing over the wall, and a mass balance equation for the water film. The equations take into account the radiative heat exchange with the flame, the environment, the internal space of the tank, as well as the convective heat exchange with the surrounding air, the vapor-air mixture, and the liquid inside the tank, as well as between the water film and the wall. The joint solution to the system of equations makes it possible to determine the temperature distribution along the tank wall and the water film at an arbitrary time point, as well as to determine the thickness and flow rate of the water film at a certain point. The finite difference method was used to solve the system of heat and mass balance equations. It is shown that the insufficient intensity of water supply for cooling leads to boiling of water from the film, as a result of which the wall temperature in such areas can reach 300 °C. A delay in the supply of water, even with sufficient intensity, could lead to the establishment of a film-like mode of boiling. In such a situation, the water film is thrown away from the wall, as a result of which the part of the wall below the film boiling zone remains without cooling. The practical significance of the built model is the possibility of determining the necessary intensity of water supply for cooling the tank and the limit time for the start of cooling

Collective phase transitions in confined fish schools

The collective patterns that emerge in schooling fish are often analyzed using models of self-propelled particles in unbounded domains. However, while schooling fish in both field and laboratory settings interact with domain boundaries, these effects are typically ignored. Here, we propose a model that incorporates geometric confinement, by accounting for both flow and wall interactions, into existing data-driven behavioral rules. We show that new collective phases emerge where the school of fish "follows the tank wall" or "double mills." Importantly, confinement induces repeated switching between two collective states, schooling and milling. We describe the group dynamics probabilistically, uncovering bistable collective states along with unintuitive bifurcations driving phase transitions. Our findings support the hypothesis that collective transitions in fish schools could occur spontaneously, with no adjustment at the individual level, and opens venues to control and engineer emergent collective patterns in biological and synthetic systems that operate far from equilibrium.

Heat transfer research on the cooling process of waxy crude oil storage in the vault tank based on VOF model

This paper focuses on the static cooling process for waxy crude oil stored in dome roof tanks. For the three phases of gas on top, liquid crude oil, and bottom water in storage tank, the VOF method is used to describe the evolution of physical quantities at the “oil–water”/“oil–gas” interface. The porous medium method is used to quantitatively characterize the sol–gel conversion process for waxy crude oil. A physical and mathematical models are established to describe the flow-heat transfer coupling behavior of the three-phase medium of crude oil, gas on top, and water at the bottom of the dome roof tank. In terms of the overall cooling process,The gas at the top of the tank has the simplest and fastest physical field evolution. It has the most uneven distribution (average temperature variance of 4 °C2), the strongest flow (average flow velocity of 0.4 m/s), the highest cooling rate (0.632 °C/h), and the lowest temperature (14.84 °C at the end). Its physical field is influenced by both the atmosphere and crude oil. The evolution of the physical field of crude oil is the most complex. It lags behind the gas at the top of tank and is directly effectted by it. Based on the evolution characteristics of the flow field of crude oil, the cooling process is divided into three stages: Stage I (0–––10 h) is the stage of convection generation and evolution in the crude oil region; Stage II (10 h − 34 h) is the stage of convection stability in the crude oil region; Stage III (after 35 h) is the stage of flow field transformation of crude oil. In stages I and II, the flow and momentum exchange at the oil–gas interface are significant. Crude oil is jointly influenced by the natural convection of the gas at the top of the tank and its own natural convection, forming a counterclockwise large vortex structure. The low-temperature area is near the central axis boundary of storage tank, oil–gas interface, and tank wall. The high-temperature area is within a range of 0.1 m − 3.3 m from the tank wall. After entering stage III, the flow and momentum exchange at the oil–gas interface weaken. The flow field of crude oil is only controlled by its own natural convection and transforms into a clockwise large vortex dominated. The low-temperature area is concentrated in the enclosed area of “oil–gas interface − tank wall” and “oil–water interface − tank wall”. The temperature field changes accordingly. Eventually, the high-temperature area is concentrated in the area slightly above the center of the tank. The physical field evolution of bottom water lags behind crude oil and is most unstable. Its cooling rate is 0.164 °C/h, slightly higher than crude oil’s 0.157 °C/h. The temperature is always slightly lower (33.47 °C at the end), and the physical field is the most uniform (average temperature variance of 0.0003 °C2), affected by the tank bottom environment and liquid crude oil.

Strengthening Transformer Tank Structural Integrity through Economic Stiffener Design Configurations Using Computational Analysis

Power transformers play a vital role in adjusting voltage levels during transmission. This study focuses on optimizing the structural design of power transformer tanks, particularly high-voltage (HV) tank walls, to enhance their mechanical robustness, performance, and operational reliability. This research investigates various stiffener designs and their impact on stress distribution and deformation through finite element analysis (FEA). Ten different configurations of stiffeners, including thickness, width, type, and position variations, were evaluated to identify the optimal design that minimizes stress and deflection while considering weight constraints. The results indicate that specific configurations, particularly those incorporating 16 mm thick H beams, significantly enhance structural integrity. Experimental validation through pressure testing corroborated the simulation findings, ensuring the practical applicability of the optimized designs. This study’s findings have implications for enhancing the longevity and reliability of power transformers, ultimately contributing to more efficient and resilient power transmission systems.

Simulation of resonant liquid sloshing in a tank with vertical baffles

The material presents the results of numerical modeling of internal fluid flows geometry in tanks that are subject to fluctuations due to external force influences. Similar applied problems occur when transporting large volumes of liquid, for example, in tanker ships. Given the rather significant moving masses within the reservoirs (tanks), as a rule, there are shock pressures on the walls and internal structures of the guiding devices, which can cause their deformation and even destruction, which leads to serious emergency situations.Numerous studies devoted to the determination of the force effects of liquid flows on the walls of tanks came to the conclusion that the presented phenomena are of a strongly nonlinear nature, depend not only on the amount of liquid and the directions of its movement within the tank, but also on the formation of velocity and pressure fields over time. The specified parameters are decisive in predicting possible resonance phenomena in tanks, which in turn can become the main factor in the design of means of damping or control of inertial fluid flows.The proposed work is devoted to the mathematical modeling of the mentioned phenomena in tanks, as well as the analysis of the force effect of internal inertial flows, which cause the occurrence of shock pressures on internal structures. On the basis of the indicated research results, it is possible to propose rational from the point of view of damping the design of guide devices in the form of flat rigid baffles.