Tank Model Research Articles

Comparative research on vapor injection heat pump with a novel flash tank

Two major problems for the vapor injection heat pump systems with the flash tank are the high discharge temperature and the lack of flash tank design theoretical basis, which would limit its wide application in extreme operating conditions. One possible way to overcome these problems is to effectively control the two-phase injection in the flash tank by optimizing its structure. The use of the proposed novel flash tank in the quasi-two-stage vapor injection cycle represents an economic and controllable solution. This research experimentally analyzes the influences of flash tank structure and volume on the system heating performance under different compressor frequencies and injection pressures at the ambient temperature of −10 °C. The comparative analysis is done finding that the novel flash tank could maximumly improve the system Coefficient of Performance (COPh) by 6.4% in this test, compared with the traditional type A flash tank cycle. In the meanwhile, a bad design of novel flash tank size could represent a loss of COPh improvement between 5.73% and 13.5%. Due to the particular structure, the implementation of the novel flash tank also allows the injection mass flow ratio can keep a linear relationship with the injection pressure. Moreover, the refrigerant liquid can be regularly injected into the compression chamber to control discharge temperature under 100 °C. From all the analysis, guidelines for optimizing the control strategy and the flash tank design are put forward, which can be used to perfect the real thermodynamic model of the flash tank rather than the ideal two-phase separation model.

Seismic responses of liquid storage tanks subjected to vertical excitation of near-fault earthquakes

This study aims to evaluate the effect of vertical seismic component on dynamic responses of liquid storage tanks, with a special focus on near-fault earthquakes. A shaking table test was performed on a 1:25 scaled steel tank, which was loaded by both far- and near-fault ground motions with horizontal unidirectional, vertical unidirectional, and combined horizontal and vertical bi-directional excitations. Seismic responses, including sloshing height and hydrodynamic pressure were recorded and compared. Subsequently, a refined finite element (FE) model of the scaled tank model was established by utilizing the structured Arbitrary-Lagrange-Eulerian (S-ALE) solver and Fluid-Structure Interaction (FSI) algorithm, which was verified by comparison with the test results. Afterward, the modeling methodology was further applied to a prototype large-scale liquefied natural gas (LNG) inner tank for seismic analysis. In addition, seismic responses of the LNG inner tank were compared with the recommendations given in seismic design codes for cylindrical tanks. The experimental and numerical findings showed that both the convective and impulsive motions of liquid was amplified by vertical excitations, especially under near-fault earthquakes. The peak sloshing heights under near- and far-fault earthquakes were increased by 14–142% and 8–56% due to the existence of vertical action, respectively. The LNG inner tank was more vulnerable to inelastic buckling due to the presence of vertical seismic component. Moreover, the effect of vertical excitations of near-fault earthquakes on hydrodynamic pressure and tank stresses was underestimated by the current seismic design codes.

Analytical 2D model for the liquid storage rectangular tank

This work aims to evaluate the free vibration of deformable fluid-filled rectangular tanks in two dimensions. These tanks are surrounded by soil, and consequently, the soil-fluid-structure interaction is taken into account. Here, the fluid is supposed to be compressible, non-rotational, and non-viscous. And, the soil is presumed to be cohesive. Besides the analytical solution, the formulation using finite elements to solve the problem is presented. For validating the suggested analytical solution, several numerical examples are examined. Additionally, a sensitivity analysis is performed to examine how various parameters affect the fluid–structure-soil system's natural frequencies and mode shapes. Findings have proven the correctness of the proposed solution.

Analysis of silica gel desiccant application in fuel storage tanks model to reduce palm oil-based biodiesel degradation

Biodiesel fuel is subject to degradation as a result of its prolonged storage period. The degradation of biodiesel fuel can have a negative impact on its qualities as well as the performance of the engine. These four stages of degradation are hydrolysis, oxidation, thermal decomposition, and bacterial contamination. A consequence of the hygroscopic qualities of biodiesel is the possibility of hydrolysis processes, which might result in the creation of free fatty acids, which can lead to engine corrosion. The presence of water encourages bacterial development in biodiesel, which might result in the formation of deposits. This study aims to investigate the application of silica gel desiccant in fuel tanks with varying biodiesel concentrations. The total acid number is used as the degradation rate parameter, while the number of bacterial colonies is used as the bacterial growth rate parameter. The research was carried out through experiments using tank models over a period of six weeks, with six tank conditioning. With the experiment results, reducing humidity in the fuel tank by applying desiccant can lead to the reduction of biodiesel degradation rate and micro-bacteria growth.

Enhanced LSTM Model for Daily Runoff Prediction in the Upper Huai River Basin, China

Runoff prediction is of great significance to flood defense. However, due to the complexity and randomness of the runoff process, it is hard to predict daily runoff accurately, especially for peak runoff. To address this issue, this study proposes an enhanced long short-term memory (LSTM) model for runoff prediction, where novel loss functions are introduced and feature extractors are integrated. Two loss functions (peak error tanh (PET), peak error swish (PES)) are designed to strengthen the importance of the peak runoff's prediction while weakening the weight of the normal runoff's prediction. The feature extractor consisting of three LSTM networks is established for each meteorological station, aiming to extract temporal features of the input data at each station. Taking the upper Huai River Basin in China as a case study, daily runoff from 1960–2016 is predicted using the enhanced LSTM model. Results indicate that the enhanced LSTM model performed well, achieving Nash–Sutcliffe efficiency (NSE) coefficient ranging from 0.917–0.924 during the validation period (November 2005–December 2016), outperforming the widely used lumped hydrological models (Australian Water Balance Model (AWBM), Sacramento, SimHyd and Tank Model) and the data-driven models (artificial neural network (ANN), support vector regression (SVR), and gated recurrent units (GRU)). The enhanced LSTM with PES as loss function performed best on extreme runoff prediction with a mean NSE for floods of 0.873. In addition, precipitation at a meteorological station with a higher altitude contributes more runoff prediction than the closest stations. This study provides an effective tool for daily runoff prediction, which will benefit the basin's flood defense and water security management.

轮胎与土壤相互作用的离散元仿真参数标定

To carry out simulation research on tire-soil interaction, EDEM software was used to calibrate the test soil and the contact parameters between the tire and soil. The soil contact model was the Edinburgh Elasto-Plastic Adhesion (EEPA) model. Using the soil repose angle as the repose value, the contact plasticity ratio, the soil-soil rolling friction coefficient, and the tensile exponential (Tensile exp) were respectively calculated using the Plackett-Burman test, the steepest climbing test, and the Box-Behnken test, and the optimal combination of parameters was found to be E = 0.08, B = 0.1, and F = 4.8. The values of the remaining parameters were as follows: a soil-soil static friction coefficient of 0.45, a restitution coefficient of 0.5, a surface energy of 4, and a tangential stiffness multiplier of 0.35. Based on the slope sliding method, the coefficient of static friction between soil and rubber was calculated as 0.88. On this basis, a central combination test was designed to calibrate the rubber-soil rolling friction coefficient and coefficient of restitution, the optimal combination of which was found to be H = 0.18 and I = 0.55. A soil tank model was created using the optimal parameters, and the correctness of the established soil discrete element model and rubber-soil contact parameters was validated by comparing the simulation results and the results of an experiment of the tire driving process.

Effects of Climate Change on Streamflow in the Godavari Basin Simulated Using a Conceptual Model including CMIP6 Dataset

Hydrological reaction to climate change anticipates water cycle alterations. To ensure long-term water availability and accessibility, it is essential to develop sustainable water management strategies and better hydrological models that can simulate peak flow. These efforts will aid in water resource planning, management, and climate change mitigation. This study develops and compares Sacramento, Australian Water Balance Model (AWBM), TANK, and SIMHYD conceptual models to simulate daily streamflow at Rajegaon station of the Pranhita subbasin in the Godavari basin of India. The study uses daily Indian Meteorological Department (IMD) gridded rainfall and temperature datasets. For 1987–2019, 70% of the models were calibrated and 30% validated. Pearson correlation (CC), Nash Sutcliffe efficiency (NSE), Root mean square error (RMSE), and coefficient of determination (CD) between the observed and simulated streamflow to evaluate model efficacy. The best conceptual (Sacramento) model selected to forecast future streamflow for the SSP126, SSP245, SSP370, and SSP585 scenarios for the near (2021–2040), middle (2041–2070), and far future (2071–2100) using EC-Earth3 data was resampled and bias-corrected using distribution mapping. In the far future, the SSP585 scenario had the most significant relative rainfall change (55.02%) and absolute rise in the annual mean temperature (3.29 °C). In the middle and far future, the 95th percentile of monthly streamflow in the wettest July is anticipated to rise 40.09% to 127.06% and 73.90% to 215.13%. SSP370 and SSP585 scenarios predicted the largest streamflow increases in all three time periods. In the near, middle, and far future, the SSP585 scenario projects yearly relative streamflow changes of 72.49%, 93.80%, and 150.76%. Overall, the findings emphasize the importance of considering the potential impacts of future scenarios on water resources to develop effective and sustainable water management practices.

Effects of different inlet configurations on the performance of solar storage tanks: A three-dimensional unsteady CFD simulation

A validated three-dimensional unsteady computational fluid dynamics analysis is performed in this study to investigate the effects of the inlet flow conditions on the thermal performance of solar storage tanks. First, effects of different mass flow rates on the thermal performance of a simple tank (Model 1, single inlet and single outlet) are investigated. The results show that higher mass flow rates deteriorate thermocline and thermal stratification which is desirable. To reduce the unfavorable effects of inlet jet mixing with stagnant fluid, the mass flow rates are divided equally between two inlet ports in the next model (Model 2). The results show that this model acts better than previous model form heat transfer point of view. In the next model (Model 3), the simple inlet port is replaced by a circular truncated cone shaped diffuser to reduce the momentum of the jet and impede unwanted mixing in the tank. The effects of the diffuser aspect ratio are analysed at fixed mass flow rates. The results reveal that small aspect ratios improve the performance of the tank while higher aspect ratios deteriorate the performance because of strongly adverse pressure gradient occurred inside the diffuser, which consequently results in a high-speed core flow, that contradicts with the idea of employing a diffuser. The outcomes indicate that only the aspect ratios between 1.0 and 1.5 have positive effects. In the final section, the study continues by modifying Model 3 through examining different orientations of the inlet port with respect to horizon (Model 4). Different angels including −30°, −15°, 15°, 30° are considered and the results show that changing inlet orientation is not as effective as the previous modifications.

The Optimal Daily Dispatch of Ice-Storage Air-Conditioning Systems

In this paper, the Ant-based Radial Basis Function Network (ARBFN) is proposed to determine the optimal daily dispatch of ice-storage air-conditioning systems. ARBFN is a novel algorithm that is integrated into the Ant Colony Optimization and Radial Basis Function Network. ARBFN is used to construct the function of the cost and operation for each chiller and ice-storage tank and is used to simulate the polynomial function of the cooling load and the cost of power consumption. The best learning rate in the training process is adjusted in ARBFN to improve the accuracy of constructing models for chillers and ice-storage tanks. The electricity savings are thus 4.130% on a summer day and 7.381% on a non-summer day. The results have shown that ARBFN can more accurately calculate the actual power consumption and cooling capability of each chiller and ice-storage tank. Lastly, ACO is used to calculate the daily dispatch of the ice-storage air-conditioning system. The results demonstrated the optimization of energy savings and efficiency for the operation of the ice-storage air-conditioning system.

The choice of ice conditions for ice model tests to support the industrial development of the Оb’ Вay

The Ob’ Bay has long been the main center for the development of the Russian oil industry in the Arctic region. The rapid growth of shipping and the active creation of port infrastructure in this area are an integral part of the strategy for the development of the Russian Arctic. The main feature of the hydrometeorological regime of the Ob’ Bay is the annual presence of ice for a long time. Determining the ice performance of icebreakers, tugboats and heavy-tonnage vessels designed for the region, as well as ice loads on marine platforms and hydraulic structures, is a most important task in the creation thereof.The paper describes research carried out in the ice model tank of the Krylov State Research Centre over the past twenty years. The research supports the design and operation of new technical facilities intended for the industrial development of the Ob’ Bay. In the completed study, two main areas of research can be distinguished, namely the interaction of ships and engineering structures with ice formations in the Ob’ Bay. The paper emphasizes a significant dependence of the possibility of conducting ice tests and proper analysis of findings on the quality of the initial data, primarily hydrology and ice parameters.The results of ice model tests analysis, especially the ice impact on offshore and hydraulic structures for the Ob’ Bay, show the need to change approaches to determining theoretical ice loads and, as a result, to expand ice model testing programs. The simulation of the worst-case scenario, when all ice parameters are determined for a given probability and are not consistent with each other, leads to a significant overestimation of ice loads and the physical modeling of unrealistic combinations of ice conditions.Each ice impact scenario should contain the maximum value of only one main ice parameter corresponding to the probability. The main ice parameters include the thickness, the flexural strength or compression strength and the speed of ice drift. In this case, ice parameters should be selected in accordance with the chosen main one in the modeling scenario. It should not be the result of the same maximum value calculation for the given observation period as for the main ice parameter.

Determination of Thermocline Heat Transfer Coefficient by Using CFD Simulation

This article deals with a thermal energy storage system in the form of a water tank with a thermocline. The well-known thermocline phenomenon is modeled using computational fluid dynamics (CFD). However, the reservoir model proposed in this article is zero-dimensional. This is due to the fact that the aim of this article is to build a mathematical model that will be more useful in mathematical models of complex energy systems in which a hot water tank is one of many elements of the system. In such a zero-dimensional mathematical model, the hot water tank will be modeled using equations describing heat transfer, and the thermocline itself will be treated as a heat transfer surface with known dimensions and heat transfer coefficient. A novelty of this paper is that it addresses heat loss across the thermocline as defined in this manner. A CFD model of a thermal storage tank is created, validated with available experimental data, and used to obtain the heat transfer coefficient U. The resulting value is then analyzed quantitatively and qualitatively and the changes in the thickness of the thermocline are accounted for in the equation. The results from this groundbreaking work can be used to analyze heat storage in the form of thermocline water tanks at the level of system modeling, e.g., for the purpose of configuring the structure of other devices and control systems.

Towards fast and safe hydrogen filling for the fuel vehicle: A variable mass flow filling strategy based on a real-time thermodynamic model

Dealing with the conflict between the temperature/pressure rise and the total mass of hydrogen is a key challenge for rapid hydrogen filling of the hydrogen storage tank (HST). The temperature/pressure rise and total mass of hydrogen cause safety risks because of the former and limited cruise as the result of the latter. Therefore, safe hydrogen filling strategy is essential for the promotion of hydrogen fuel cell vehicles (FCVs). The existing thermodynamic model of the hydrogen storage tank is simplified either in the hydrogen state or the heat conduction of the HST wall, which can be hardly used as the real-time and accurate references for developing the filling strategy. To solve this problem, this paper works out the mathematical expression of a HST thermodynamic model. With the proposed HST thermodynamic model, a variable mass flow hydrogen filling strategy is developed. The results show that at the mass flow (12 g/s), the errors of the thermodynamic model are 7.1% and 6.8% for the temperature and pressure rise, compared with the computational fluid dynamics (CFD) model. At the mass flow (4.84 g/s), the thermodynamic model errors are 8.3% and 7.1% for the temperature and pressure rise, compared with the experimental data. Also, compared with the rule-based hydrogen filling strategies, the final state of charge (SoC) with the new filling strategy improve by 3%, 3.7%, and 2.7% at different initial temperatures, different volumes, and initial SoCs, respectively.

Application of the multi-stage centrifugal compressor 1D loss model in the adiabatic compressed air energy storage

A compressor is the core equipment used to convert and store energy in an adiabatic compressed air energy storage system. However, existing compressor models cannot be used for design and detailed loss analyses, which in turn makes simulations of the energy storage process inadequate. In response to this problem, a 1D loss model was developed and applied to an adiabatic compressed air energy storage system to realize compressor design and simulate the compression process. In the design section, based on the 1D loss model and novel optimization algorithms for the stage distribution and single-stage compressor design, we achieved detailed geometric dimensioning of every single-stage compressor and analyzed the energy loss distribution in each representative single-stage compressor. In the simulation session, we generated performance maps of the single-stage and multi-stage compressors under both speed and variable inlet guide vane regulations. Furthermore, the performance maps were combined with heat exchanger and air storage tank models to simulate the entire energy-storage process. The results show that through variable inlet guide vane regulation, the adiabatic compressed air energy storage system has good flexibility to meet different demands under fluctuating renewable energy flows.

Seismic performance of a base-isolated flexible liquid storage tank equipped with a novel rate-independent damping device

Conventional base-isolation systems can significantly reduce the hydrodynamic pressure on the walls of large liquid storage tanks, but they have limited or even adverse effects on the sloshing response of liquids because the sloshing period is comparable to the isolation period. In this study, a combined base-isolation system consisting of natural rubber bearings and a novel rate-independent damping device was developed to achieve a simultaneous reduction in the hydrodynamic pressures and sloshing heights of liquid storage tanks. Using an analytical flexible tank model considering higher sloshing modes, the seismic responses of liquid storage tanks equipped with the proposed combined base-isolation system under strong ground motions were investigated. The influence of tank flexibility, higher sloshing modes, and liquid heights on the seismic responses of the controlled storage tank were evaluated quantitatively. The effectiveness of the proposed combined base-isolation system was verified, and its advantages over conventional base-isolation systems were identified. The proposed system can achieve a larger reduction in base shear, overturning moment, and sloshing height than conventional systems without increasing the isolator displacements.

Effect of simplified wind girder modelling on MNA-LBA analysis of open steel tanks

The MNA/LBA design methodology for metal shells, including open-top tank steel shells, plays an important role in the European Standard on Strength and Stability of Shell Structures. However, when using this design format, particular doubts as to the correctness of the obtained results may arise when simplifications are used in modelling of key elements of tank structures in order to improve modelling and numerical calculation processes. This paper presents the results of numerical studies that address the question of how the simplifications in the modelling of the primary wind girder affect the values of the elastic buckling resistance and the plastic reference resistance determined from linear bifurcation analysis (LBA) and materially nonlinear analysis (MNA), respectively. Forty-two computational models of wind-loaded open storage tanks with three height-to-diameter ratios and with variable or constant wall thickness of a cylindrical shell, equipped with six different representations of the wind girder, were investigated in order to provide guidelines in the above-mentioned scope. It has been proven that the applied simplifications in the modelling of the primary wind girder allows for relatively faithful representation of the reference models, i.e. models in which the stiffening ring was modelled using shell finite elements, in the LBA analysis. In turn, a varied influence of the applied simplifications in modelling on the results of the MNA analysis was observed. The obtained results indicated a limited range of applicability of the results of the materially nonlinear analysis for the formal assessment of the relative overall slenderness of the considered shells. Finally the obtained results allowed for the formulation of practical conclusions for the purposes of design of open-top steel tanks using the MNA/LBA methodology.

Experimental study on hydrodynamic response of a floating rigid fish tank model with slosh suppression blocks

The development of slosh suppression blocks is an important step forward for mitigating sloshing in floating closed containment fish tanks and makes the tanks suitable for operating in a broader range of wave conditions. This experimental study investigates the motion and sloshing response of a scaled floating rigid containment tank model under regular wave action in a wave flume. The tank is fitted with slosh suppression blocks of different dimensions to investigate their effectiveness in mitigating sloshing while considering the state of the internal fluid for fish well-being. This study shows that by sacrificing moderately higher sloshing amplitudes at lower excitation periods, slosh suppression blocks are able to reduce the overall sloshing amplitudes and mitigate the build-up to large sloshing amplitudes. By letting fluid overtop onto the slosh suppression block disturbances to the main fluid volume are minimised, thereby preserving a calm living environment for the fish below. Effective slosh mitigation allows for deploying these closed containment systems in higher energy fish farming sites as the aquaculture industry expands operations into more spacious offshore sites.

Smoothed particle hydrodynamics study of a heaving point absorber in various waves using wave tank and calm-water models

In this research, the influence of wave parameters on the response of a tuned point absorber was evaluated using the smoothed particle hydrodynamics (SPH) wave tank and calm-water models. In the first model, the device response was obtained under the effect of waves generated by a wavemaker. In the calm-water model, the added mass and hydrodynamic damping coefficients of the device were calculated from a short-time SPH-free decaying test. Then, using the Runge–Kutta method, the governing equation of motion was solved in MATLAB. Both models were verified by previously published experimental tests. Considering the viscous damping makes calm-water model superior to potential-flow models. Meanwhile, the computation time of this model is very lower than wave tank model. For wave steepness values below 8.5% which is more than the upper limit of wave steepness for deep-water waves, both models predicted a direct relationship between wave height and device motion. However, wave tank simulations showed that for steeper waves, the device motion was not significantly affected by the wave height. Moreover, the device response decreased as the wave period moved away from the device's natural period. The predictions of the two models had an average difference below 10%. While in linear conditions, the calm-water model predicted a slightly larger response than the wave tank model; in nonlinear cases, wave tank model predicted slightly higher device motions. This research shows that using the SPH calm water model is an efficient way to investigate wave-point absorber interactions.

Youth’s engagement and perceptions of disposable e-cigarettes: a UK focus group study

ObjectivesEvidence suggests that use of flavoured disposable electronic cigarettes (e-cigarettes) is increasing. Considering the growing popularity and rapid evolution of e-cigarettes, we explored youth’s perceptions and engagement with disposable e-cigarettes.DesignTwenty...

Electrostatic potential simulation and safety countermeasures in the tank of hazardous chemicals tanker

In this paper, taking a benzene transport vehicle as an example, a cylindrical tank model is established according to the relevant standards, and the electrostatic potential distribution in the tank of dangerous chemicals is numerically simulated. The potential distribution in the tank is calculated by numerical calculation software, and the three-dimensional distribution map of the electrostatic potential of the medium in the tank is obtained. The general rules between the electrostatic potential distribution in the tank of a hazardous chemical tanker and the filling rate, the number of Anti-wave plates, and the two phases of gas and liquid were analyzed. The relationship between volume, Anti-wave plate area, and electrostatic potential was further analyzed by studying the relationship between electrostatic potential and medium parameters. A model of an elliptical cylindrical tank was also constructed, and corresponding anti-static measures were proposed.

Input-to-State Stability of Time-Delay Systems With Hybrid Impulses and Continuous Subdynamics Based on Vector Lyapunov Function

This article focuses on input-to-state stability (ISS) of impulsive time-delay systems where the hybrid effect of impulses with time-dependent multiple jump maps in different subsystems is fully considered. By virtue of M-matrix and vector Lyapunov function, some theorems for ISS are established for Krasovskii-type conditions which avoid the common threshold of impulses in subsystems and allow the simultaneous existence of stable and unstable continuous subdynamics. If the time intervals between impulses are bounded, the ISS of time-delay systems can be ensured even though hybrid impulses exist in each subsystem, which determines the robustness of stable time-delay systems with respect to hybrid impulses. The unstable time-delay systems with different subdynamics can be stabilized in input-to-state-stability sense by involving hybrid impulses. In addition, several extended criteria are presented to bridge the results derived via vector Lyapunov function, scalar Lyapunov function, and comparison principle. At last, the theoretical results are validated by numerical example and a simplified model of sewage treatment tank.