Three-dimensional Tank Research Articles

Lab-based scale measurements of internal storage of crude oil tank based on non-contact infrared thermography technique

Non-contact sludge measurement methods for storage tanks can address the challenge of measuring the volume of sedimented sludge during long-term storage. While infrared thermography technology can address the issue of liquid level detection, its measurement accuracy for the undulating interface of sludge is insufficient. This study designed and constructed experimental setups for measuring sludge in storage tanks. In this study, infrared images taken by an infrared camera were used to record the temperature distribution of the outer wall of the storage tank. The threshold segmentation method is used to determine the accurate sludge boundary line in image processing. Finally, the Three-Dimensional Tank Residue Recovery Algorithm (3D-TRRA) was applied to fit the 3D distribution of the sludge and calculate accurate sludge volumes. The results indicate that the best segmentation is achieved with a threshold of 170. The measurement error for sludge volume is less than 5%. Accurate visual positioning and recognition of sludge are achieved.

Numerical Investigation of Optimal Hydrodynamic Performance by Changing the Orifice Ratio and Relative Opening of a Land-Fixed Rectangular-based OWC

The energy that can be extracted from the ocean is inexhaustible. An oscillating water column (OWC) is a wave energy converter that extracts this energy. A numerical investigation has been conducted by altering relative opening (α) and orifice ratio (τ) to assess the maximal energy of a land-fixed rectangular-based OWC model in a nonlinear wave field. The power of OWC has also been evaluated by the wave steepness (H/L) alteration. The numeric analysis has been imposed to obtain the optimal power using Fluent software in a three-dimensional tank. Validation of the present numeric model’s result correlates with the printed empirical data. The Finite Volume Method (FVM) solves RANS equations, and the relevant waves are generated at the inlet of the numerical tank by the inlet velocity approach. The efficiency (η) increases with relative openings (α) increase. The efficiency (η) decreases with wave steepness (H/L) increase. The η reaches the optimum shown in the study at H/L = 0.02 and τ = 1.03% for entire values of α. The excellent energy of around 71.3% is attained at α =75% and H/L = 0.02. This study is a highly relevant source of information that finds the optimal efficiency of a land-fixed rectangular base OWC and gives prior knowledge of the performance of OWC before the real-life experiment.

The mechanism of switching direction of swirling sloshing waves

Swirling waves frequently occur in a three-dimensional tank under a nearly resonant excitation with oblique excitation angle. The oblique excitation produces two excitation components and the secondary component triggers rotational waves. The detailed mechanism of the switch in circular direction is clearly described in this study. The evolution of the hydrodynamic forces (Fz) on the tank walls presents a beating phenomenon and the switch direction always occurs at the peak and trough of the envelope of the Fz history. The external excitation moment changes the circulation intensity, and finally the swirling wave becomes a single-direction wave, but only for a short time. The profile of the single-direction wave was determined by the dominant sloshing mode and the instantaneous tank motion was found to be a key factor to determine the consequent swirling flow circulating direction.

Damping effects of dual vertical baffles on coupled surge-pitch sloshing in three-dimensional tanks: A numerical investigation

Present work aims to explore the inhibiting effects of dual vertical baffles (DVBs) on the coupled surge-pitch sloshing, and the wave behaviour and hydrodynamic load are parametrically identified by applying an in-house Navier-Stokes solver. After sufficient validations, the numerical model is then used to study the coupled surge-pitch sloshing where both surge and pitch are at the first-order resonance. The presentence of resonant pitch can dramatically reinforce the wave intensity of the surge-excited sloshing and cause heavy eccentric load, and special attention should be paid to the tank toe due to the remarkable pressure amplification. To lessen the adverse effect, the DVBs with various heights and widths are equipped in the middle of the tank length. It is found that they can shrink water into the spacing between the DVBs, then create pairs of strong vortices around the sharper tips of the DVBs to dissipate wave energy, and also block the movement of fluid at both baffle sides by separating the fluid domain into two compartments which thus yields less fluid bias. The increase of baffle width can lead to a decrease in the wave amplitude, pressure response as well as fluid bias; and the emersed DVBs are more effective than the submerged ones.

Investigations of transient sloshing induced impulsive hydrodynamics

Sloshing-induced impulsive pressures may be extremely high and of short rise time duration. A compressible Volume of Fluid (VoF) method was adopted to study these pressures in a partially filled three-dimensional tank with various oblique tank ceiling angles. Comparative available experimental model test measurements of free surface profiles and velocity and pressure time histories validated this numerical method. To obtain a sufficiently fine grid to yield converging predictions, grid sensitivity studies were performed. The influence of the oblique tank ceiling angle on sloshing-induced impulsive pressures was examined. Results demonstrated that the VoF method obtained accurate predictions of sloshing phenomena. The oblique tank ceiling angle dampened impulsive pressure and, therefore, this angle had to be accounted for in the design of the tank.

Efficient Simulation of Freezing of Water in Large Tanks Including Expansion of Ice

Abstract A liquid water-urea mixture is stored onboard diesel vehicles and used for exhaust aftertreatment. In cold weather conditions, the mixture may freeze and the freezing process may span over a day. In the first part of our study (Journal of Thermal Science and Engineering Applications—Transactions of the ASME, Vol. 13, p. 011008, 2021), it was shown that traditional computational methods are impractical for modeling such large-duration freezing processes because of restrictions in the time-step size posed by numerical stability and physical time scale considerations. A model, in which natural convection driven thermal transport is treated as a diffusive process, was developed and demonstrated. Since the flow field was not computed in this model, the computations were found to be orders of magnitude more efficient than traditional methods. This preliminary model did not account for the expansion of ice. Here, a new model that accounts for the expansion of ice, and the consequent rise of the initial air-water/ice interface (ice dome formation) is presented. An additional conservation equation for excess volume fraction is introduced to this end and is solved using the unstructured finite-volume procedure and sub-time-stepping. Since the flow field is not computed, the air-water/ice interface is tracked using a new algorithm similar to the traditional volume-of-fluid (VOF) method, but one that constructs fluxes using a diffusive formulation rather than an advective one. Validation studies in full-scale three-dimensional tanks show good agreement with measured temperature-time data. It is found that the air-water/ice interface first evolves to a concave shape before finally becoming a convex ice dome after full solidification.

NUMERICAL SIMULATION OF SLOSHING IN THE PRISMATIC TANK WITH VERTICAL BAFFLE USING SMOOTHED PARTICLE HYDRODYNAMICS

The capacity of LNG carriers is increasing year by year due to the demand for liquified natural gas (LNG). One of the types of LNG carriers is membrane type that the tank is prismatic. A natural phenomenon in a liquid carrier such as LNG is sloshing. Sloshing is a violent phenomenon in fluid dynamics caused by excitation force. The present study will conduct sloshing with a baffle shape to reduce the free surface inside the tank and impact pressure. In this study, a single vertical baffle and a double vertical baffle are used to reduce sloshing. In the present study, the meshless approach, so-called Smoothed particle hydrodynamics (SPH), is used to reproduce sloshing in the prismatic tank. The three-dimensional prismatic tank was used to capture sloshing with the baffle. Regular roll motion with one pressure sensor uses to validate the SPH results. The result shows that vertical baffle effectively reduced fluid movement inside the tank and impact pressure. As a result, the hydrodynamic force and moment decreased. The ratio of the baffle and the water depth 0.9 shows has significant influence to sloshing.

Numerical model of energy dissipation and shallow-water sloshing motions in tank under different coupled excitations

Shallow-water sloshing motions in a three-dimensional rectangular tank are investigated. The Boussinesq-type equations in terms of velocity potential and the finite-difference scheme are applied for the solutions of numerical model. Through linking the rate of decay of the wave amplitudes to the energy dissipation due to the friction at the tank walls, a linear damping term is proposed and added into the free surface boundary condition. Taking the tank under excited frequencies near the lowest natural frequency, the maximum transient wave amplitudes and steady-state wave amplitudes of sloshing motions at the tank wall are presented and verified by the experimental results given in the literature. The characteristics of sloshing motions in tank under different coupled excitations are studied. The results indicate that coupled surge-sway excitations lead to the weaker nonlinear sloshing motions in tank than the single degree of freedom excitations. The intersection of sloshing wave crest lines finally tend to the diagonal line of the tank under the coupled surge-sway excitations with different amplitudes. And the irregular free surface oscillations appear at the corners of the tank excited by the coupled surge-sway-roll-pitch-yaw harmonic motions.

4-3-1 越波式波力発電装置開発に向けた2次元および3次元水槽を用いた実験に関する一考察

4-3-1 越波式波力発電装置開発に向けた2次元および3次元水槽を用いた実験に関する一考察

Numerical investigation of sloshing in a three-dimensional square tank under excitation using CFD code

ABSTRACT A numerical analysis and experimental validation of sloshing phenomenon in three-dimensional square tank with varying resonant frequency and amplitude of excitation is carried out in this study. Numerical simulations using fluid-structure interaction (FSI) was carried out and validated with experimental result. Square tank is numerically simulated with 50, 100 and 200 mm of water height excited at its 25%, 50%, 75% and 100% of resonance frequencies. Numerical study has been extended to study sloshing phenomenon at different ratio of resonance frequencies to that of varying amplitudes 30, 40 and 60 mm. Pressure of liquid in container during excitation were recorded at specific intervals of time and analysed. Increase in amplitude and frequency of excitation is directly proportional to pressure of liquid in tank. Sudden impulse of velocity of tank has an impact over the pressure built inside tank. The sloshing phenomenon in vertical and horizontal baffle configuration is also examined.

Pogo Stability Approaches for the Strap-On Launch Vehicle with Staged Combustion Cycle Engines

According to the new characteristics of the solid–liquid strap-on launch vehicle and the liquid oxygen/kerosene staged combustion cycle engines, a finite element model of the launch vehicle propulsion–structure coupled system subjected to pogo was presented in this paper. In the model, the structure was represented by a longitudinal–lateral–torsional integrated finite element model with a three-dimensional tank and one-dimensional beam–spring–mass. The propulsion system was represented by a transfer matrix model, which was fitted by the vector fitting method and transformed into a second-order differential equation. By assembling the structure dynamic equations and propulsion system, the governing equation of the coupled system can be established. After that, pogo stability was analyzed by solving the complex eigenvalues of the governing equations. The method developed in this paper can also be expanded to other liquid launch vehicles.

Numerical investigation on the effect of baffles on liquid sloshing in 3D rectangular tanks based on nonlinear boundary element method

The numerical simulation of liquid sloshing in the three-dimensional tanks under horizontal excitation and roll excitation was carried out, and the inhibition effect of different baffles on the sloshing phenomenon was investigated. The numerical calculations were carried out by the nonlinear Boundary Element Method (BEM) with Green's theorem based on the potential flow, which was conducted with the governing equation corresponding to the boundaries of each region. The validity of the method was verified by comparing with experimental values and published literatures. The horizontal baffle, the vertical baffle and the T-shaped baffle in the sloshing tanks were investigated respectively, and the baffles' position, dimension and the liquid depth were provided and discussed in detail. It is drawn that the baffle shape plays a non-negligible role in the tank sloshing. The vertical baffle is a more effective way to reduce the sloshing amplitude when the tank is under a horizontal harmonic excitation while the horizontal baffle is a more effective way when the tank is under a roll excitation. The amplitude of free surface elevation at right tank wall decreases with the increasing of the horizontal baffle length and the vertical baffle height. Although the T-shaped baffle has the best suppression effect on tank sloshing under horizontal excitation, it has limited suppression effect under roll excitation and will complicate the sloshing phenomenon when changing baffle height.

Experimental and numerical study of convective flow structure above heated horizontal plates of different sizes

Free thermal convection above heated plates formed in circles of different diameters is studied within our paper. Experimental and numerical studies are carried out in a three-dimensional tank filled with water under specified boundary conditions. The initial stage of thermal convection development is mainly considered. The study of liquid flow structure is particularly observed, as well as evolution of temperature field in a plane of the central section of the working sections. Within the study different heating conditions are considered: the diameter of the round source is in the range from 0.010 to 0.024 m, and the Rayleigh number varies in the range from 1.0·102 to 1.30·105. The standard system of Navier-Stokes equations is numerically solved by finite element method to study systematically convection from heat sources of various sizes by the software package COMSOL Multiphysics. Values of the control parameter are estimated in the course of the work. At the control parameter the transition from one flow regime to another one is observed. In addition, an experimental study is carried out to verify the results of numerical simulation. As a result, a qualitative agreement has been obtained between the calculated and observed flow structures during the experiments.

Evaluation of the feasibility of log file-based three-dimensional independent dose verification system in quality assurance of intensity-modulated radiation therapy

Objective To assess the feasibility of the log file-based three-dimensional independent dose verification system for the quality assurance of clinical radiotherapy. Methods The statistical values of the percentage depth dose, off-axis curves and output factor calculated by the Mobius system were statistically compared with the measured data by three-dimensional water tank. The three-dimensional independent dose verification in clinical radiotherapy plan and the acceleratr log file-based three-dimensional dose verification during the treatment were performed in 17 patients with nasopharyngeal cancer. The accuracy of dose calculation and reconstruction of Mobius system was assessed. A statistical analysis was performed on the intra-fractionalγpass rate (3%/3 mm) for each patient to evaluate the stability of intra-fractional radiotherapy. Results The percentage depth dose, off-axis curve and output factor statistically calculated by the Mobius system matched well with the data measured by three-dimensional water tank. The dose-volume histogram (DVH) parameters between the target area and organ at risk during clinical radiotherapy plan were statistically compared in 17 patients with nasopharyngeal cancer. The maximum deviation was-2.16% for the three-dimensional independent dose verification in the clinical radiotherapy plan, and 0.18 Gy for the accelerator log file-based three-dimensional dose verification. The averageγpass rate for 17 nasopharyngeal cancer patients was 99.26%, and the maximum deviation of intra-fractional radiotherapy was below 0.5%. Conclusions The function of dose reconstruction and independent calculation of the Mobius system yeilds the same accuracy with the treatment planning system, which can quickly perform three-dimensional independent dose verification in the clinical radiotherapy plan and accelerator log file-based three-dimensional dose verification throughout the treatment, thereby guarantting and providing the safe and reliable technical support for clinical treatment. Key words: Intensity-modulated radiotherapy; Dose verification; Quality control

An investigation of the basic situation of radiotherapy in mainland China in 2015

Objective To conduct the 7th investigation by Chinese Society of Radiation Oncology, Chinese Medical Association, and to further investigate the current situation of radiotherapy in mainland China, reasonably allocate personnel and equipment resources, and promote the development of radiotherapy in China. Methods From October 8, 2015 to December 2015, the office for investigation of radiotherapy information was established, the list and contact information of radiotherapy units were provided by each province, and a special data submission system was used for a complete, rapid, and efficient investigation through the Internet. Results As of January 20, 2016, there were 1413 radiotherapy units in the mainland China with 52, 496 employees in total, among which there were 15 839 radiotherapy physicians (4824 with senior professional titles), 8452 technical therapists (260 with senior professional titles), 3292 physicists (562 with senior professional titles), and 938 maintenance engineers (120 with senior professional titles). In the aspect of radiotherapy equipment, there were 1930 linear accelerators, 96 Co-60 teletherapy units, 173 X-knife units, 212 γ-knife units, 382 Ir-192 brachytherapy units, 436 Co-60 brachytherapy units, 1051 X-ray simulators, 1353 CT simulators, 642 MRI simulators, 978 sets of multileaf collimators, 1922 sets of treatment planning systems, and 974 sets of radiotherapy network systems. As for quality control devices, there were 1792 dosimeters, 2143 ionization chambers, 935 two-dimensional array dosimeters, 540 three-dimensional dosimetric verification systems, 596 three-dimensional water tanks, 844 anthropomorphic phantoms, and 1168 water equivalent phantoms. In the aspect of therapeutic situation, there were 102, 170 beds (including beds in departments of oncology in general hospitals), 76612 episodes per day, and 919339 episodes per year. Conclusions The results of this investigation show significant increases in radiotherapy units, personnel, and equipment in recent years in mainland China. The distribution of radiotherapy units and equipment and the structure of radiotherapy personnel are becoming more reasonable, but there are still some problems. In some regions, current radiotherapy equipment cannot meet the medical needs, and there is a lack of professional technical personnel. Key words: Radiotherapy; Radiotherapy units; Allocation of Radiotherapy; Radiotherapy personnel

Synthesis, crystal structure, thermal analysis, vibrational study dielectric behaviour and Hirshfeld surface analysis of [C6H10(NH3)2)]2 SnCl6 (Cl)2

A new organotin (IV), bis 1-2 diammonium cyclohexane octachlorotin dichloride, have been synthesized. The molecular structures of the complexes have been determined using single crystal X-ray diffraction analysis reveals that complexes crystallizes in orthorhombic space group P4/n with a = 13.014(3)Å, b = 13.014(3), c = 16.822(4)Å, V = 2849.0(11)Å3. The structure consists of three-dimensional tanks framework. They show further that the tin (IV) ion is octahedral surrounded by six atoms with six chloride ligands, tow [C6H10(NH3)2]2+ cations and tow isolated chloride ion Cl−.The new compound has been characterized by differential scanning calorimetric (DSC) technique, 13C MAS-NMR, FT-IR, RAMAN spectroscopic studies and dielectric properties are detected in the frequency interval of 209 Hz–5 MHz and in the temperature interval of 313–373 K, have been carried out in order to characterize the complexes, the Hirschfeld surface analysis have been performed to gain insight into the behavior of these weak interactions.

Fully nonlinear analysis of second-order sloshing resonance in a three-dimensional tank

The 3D boundary element method (BEM) based on the potential flow theory is developed to study the second-order resonance problems in rectangular sloshing tanks. Fully-nonlinear free-surface boundary conditions are considered. A local surface fitting method is used to calculate tangential derivatives. A shared-memory parallel procedure based on OpenMP is adopted for the efficiency improvement. Both 2D and 3D sloshing cases are studied. It is found that the second-order resonance may occur due to the interaction among natural frequencies and excitations frequencies. The second-order resonance becomes obvious after a sufficient long time length. After increasing the excitation amplitude, the second-order resonance emerges much earlier. For 3D situations, the second-order resonance in rectangular tanks with either equal or unequal length and width sides are investigated. The second-order resonances due to the interaction of two orthogonal plane waves in length and width directions are observed.

New Pogo Analysis Method Using Rational Fitting and Three-Dimensional Tank Modeling

Considering the flexibility of a liquid rocket propellant tank and the importance of the relationship between oscillatory pressure and outflow near the tank outlet, a three-dimensional modeling technique is developed to provide a more accurate tank simulation. This paper also presents a rational function fitting method that could be used to transform transcendental equations of a feed-line transfer function into a homogeneous second-order matrix form. It is shown that this form of feed-line transfer function can be easily coupled together with governing equations of a liquid rocket structural system, which could be further solved for system stability using mature eigenvalue solvers. By comparison with the telemetry data and traditional methods, this pogo stability method proves to be highly accurate and efficient.

Sloshing in a rectangular tank based on SPH simulation

A ship would generate significant sloshing when subjected to underwater explosion loads; the sloshing will reduce the ship's stability and even cause the ship to capsize when coupled with internal liquid sloshing. It is of great significance to research on the characteristics of the sloshing loads in a tank to improve the ship's stability and security. The liquid sloshing in a tank is a complex process characterized with nonlinearity and strong randomness, and large amplitude sloshing is a great challenge for both theoretical models and numerical algorithms. Yet as a meshfree method, Smoothed particle hydrodynamics (SPH) has great advantages of solving such large deformation problems because of the nature of self-adaptiveness and Lagrangian. This paper focuses on the SPH core issues, such as the accuracy and the stability of the kernel function and boundary treatments. Firstly, the accuracy and computational stability of four common SPH kernel functions are simply investigated by two simple cases, and a more appropriate kernel function is selected. Secondly, the dummy particles and a novel boundary treatment considering the boundary motion are applied. Furthermore, the laws of impact pressure of the two-dimensional tank under forced rolling with different excitation frequencies and excitation angles are studied. Then, the influences of a baffle for the liquid sloshing in a two-dimensional tank under forced surging are analyzed, and the action mechanisms of the baffle are summarized. Finally, the coupled motion of swaying and surging for a three-dimensional tank is studied, which aims to lay a foundation for further study on the influence of sloshing loads on real ship motions.

THREE-DIMENSIONAL SIMULATION THE RUNUP OF NONLINEAR SURFACE GRAVITY WAVES ON SHALLOW COAST

The paper is devoted to three-dimensional numerical modeling of a runup of nonlinear surface gravity waves based on Navier-Stokes equations. The three-dimensional problem is stated, boundary and initial conditions are described. Using split method for physical processes, there has been constructed the discrete model with consideration of cell filling coefficient. The peculiarities of the modeled three-dimensional tank structure are described. There are pre- sented three-dimensional models of stepwise runup of the surface gravity wave upon a sloping shore.