Liquid Cargo Research Articles

Effect of ultra-low temperature on some mechanical properties of painted and film-coated plywood

Plywood is used for insulation systems in liquid natural gas cargo ships because of its good thermal properties. However, there are only a few research investigating the mechanical properties of plywood exposed to ultra-low temperatures. This study aims to determine how plywood reacts when exposed to ultra-low temperatures, such as - 196 °C. To achieve this purpose, the present study investigated the bending strength, modulus of elasticity, and tensile-shear strength of painted and film-coated plywood under ultra-low temperatures. The mechanical properties of plywood were discovered to be significantly impacted by the ultra-low temperature as a result of this research. Moreover, not only the bending strength of the painted and film-coated plywood increased with decreasing temperature, but also the modules of elasticity of the painted and film-coated plywood increased. At decreasing temperature, the tensile shear strength of the painted and film-coated oven-dried plywood increased, but the ensile-shear strength of painted and film-coated air-dried plywood decreased. The tensile shear strength of air-dried plywood was determined to be more sensitive to the temperature change. Therefore, attention should be paid to plywood used in liquefied natural gas cargo ships with high humidity.

СИСТЕМА АВТОМАТИЗОВАНОГО КОНТРОЛЮ ВАНТАЖНИХ ОПЕРАЦІЙ ТАНКЕРА

Liquid cargo is transported by the tanker fleet in different climatic zones. Significant changes in ambient temperature are observed in these zones. At elevated temperatures, the volume of liquid cargo will increase. Consequently, there is a risk of spillage of the cargo onto the ship's deck. The International Convention for the Prevention of Pollution from Ships (MARPOL 73/78) and the International Safety Guide for Oil Tankers and Terminals (ISGOTT) regulate the filling of tanks when transporting liquid cargo. It is allowed to use only 98% of the volume of tanks, the remaining 2% is a reserve of tank volume for an unforeseen increase in the volume of the cargo when its temperature rises. The sender of the cargo must provide the tanker captain with complete information about the cargo and its properties. After receiving it, download operations can begin. The intensity of cargo operations when the tanker is loaded with various types of liquid cargo has led to an increase in the role of the "human factor" in ship power systems. Reducing the number of ship crews, in turn, contributes to the accumulation of fatigue, distraction of ship operators (masters) in the process of carrying out cargo operations on the ship. Watch assistants must constantly monitor the filling level of each tank, taking into account the weight, temperature and volume of the cargo. Statistics state that a significant proportion of accidents when loading a tanker occur as a result of loss of control over the volume of liquid cargo that is taken into each tank of the vessel. The operator's lack of accurate information about the filling status of each tank at the current moment in time leads to the risk of its overflow. Such an overflow, in turn, can lead to the spillage of liquid cargo, for example, petroleum products on the ship's deck and the water surface of the port's water area. At present, it is possible to monitor the level of liquid cargo in real-time using various models of liquid cargo level gauges: float, pneumatic, ultrasonic, magnetostrictive, microwave, and others. Creating a system that would allow for constant dynamic control of the volume of liquid cargo in tanks during tanker loading and would take into account all restrictions is a promising direction. Keywords: liquid cargo, tanker, level gauges, safety margin, loading control.

A scheme for capturing the kinetic energy of the flow liquid in a ship's cabin

The study proposes a solution for the energy capture of a sailing liquid cargo ship, which is essentially an organic combination of an Savonius turbine and a ship's rolling cabin. A model of the cabin turbine was simulated in ANSYS FLUENT from the perspective of the ship's roll and the rotor's rotational motion. Specifically, three cabin with opening lengths of 0.5, 1.0 and 1.5m were simulated to illustrate the sinusoidal trend of the axial velocity curves of the liquid at the cabin's opening position where the turbine is installed; When the burden of ship increases, the velocity at the opening decreases; when the burden is 90% and the ship's rolling angle is 20°, the peak axial velocity can reach 2.2 m/s, the average kinetic energy reaches 2.2 kJ and the flow rate reaches 1.38 m3/s. Then, the maximum values of the turbine's power coefficients are 0.21, 0.25 and 0.33 respectively, and their corresponding tip-speed rates are 1.0, 1.4 and 1.0. The torque coefficients decrease as the tip-speed rate increases. The velocity and pressure in the vicinity of the turbine present the non-stationary gradient images. Finally, the prediction of the power of turbine is discussed.

Influence of optimization model parameters on the main characteristics of the architectural and structural type of the combined vessel

Transportation of liquid cargo on specialized vessels has the disadvantage of not being able to reload. This is primarily due to the impossibility of placing dry cargo on the return trip in cargo tanks, both from the point of view of the need to clean up the latter, and from the point of view of access to cargo tanks with bulky or bulk cargo. This problem can be solved with the use of specialized cargo combined vessels, which have separate cargo spaces for dry cargo back loading, and traditional tanks for the transportation of liquid petroleum products. The above design solution reduces the carrying capacity of petroleum products compared to a "clean" tanker due to an increase in the weight of the hull, as well as due to the limitation of the permissible capacity, since, especially for river vessels and vessels of mixed (river-sea) navigation, there is no possibility of increasing the dimensions of the vessel. The article presents a mathematical model and the results of test calculations for the choice of an architectural and structural type of cargo combined vessel for inland and mixed (river-sea) transportation. It is shown that the so-called platform vessels have the greatest prospects both in terms of the profit they bring to the shipowner and in terms of minimum operating costs.

Export markets of Russian shipbuilding

Subject. I consider export capacity-building of civil shipbuilding products. Objectives. The focus is on the analysis of the current state of the Russian shipbuilding industry and consumer qualities of its production, exploration of current and future needs of potential foreign customers of civil shipbuilding products. Methods. The study rests on general scientific methods of research. Results. Products having high export capacity include liquid and dry cargo vessels of inland and mixed navigation, icebreakers, vessels for development of offshore oil and gas fields, high-speed hydrofoils and hovercraft, and floating power units. Conclusions. Products of civil shipbuilding are the main ones from the perspective of export growth. They are associated with cost-effective implementation of orders in large-scale manufacturing.

Study on Sloshing Characteristics in a Liquid Cargo Tank under Combination Excitation

Sloshing is a common flow phenomenon in liquid cargo tanks and has a great negative impact on the stability and safety of ship navigation. It is important to understand the sloshing process of tanks under the excitation of complex external conditions for the transportation of liquid cargo. In this paper, the sloshing characteristics of a liquid cargo tank are studied under the combination excitation conditions of roll and surge. The pressure distribution characteristics at different positions of the cargo tank are discussed, along with the influence of different excitation conditions on the pressure of the cargo tank. The results show that under the condition of combination excitation, the fluid sloshes along the diagonal direction of the tank, and the peak liquid height and peak pressure are located on the diagonal corner of the tank. The peak pressure at the lowest point on the diagonal of the tank is proportional to the amplitude of the roll angle and surge, and the change in roll angle amplitude has a significant impact on the pressure and liquid height at different positions.

A simulation model for evaluating the cargo transfer alternatives in liquid cargo terminals

Tanker ships arriving at liquid cargo terminals have to wait for getting service due to various operational restrictions in the terminal. Waiting time is the time passed until the tankers get service after the notice of readiness. The increase in the waiting times of tanker ships causes high demurrage costs. Reducing the waiting times of ships is of vital importance for the operational efficiency of the terminal. In this study, it is aimed to develop a simulation model in which alternative solutions in the cargo transfer operations can be tested to reduce the waiting times of tanker ships. The simulation model has several constraints that can be encountered in liquid cargo terminals, and it can be adapted to any liquid cargo terminal. The developed model was then applied to a liquid cargo terminal in Turkey.

Методика и алгоритм расчета линейных потерь напора жидкости в трубопроводах

This article describes the methodology and algorithm for determining linear fluid pressure losses in pipeline. Liquid substances widely used in the national economy are usually stored in special tanks. To store a large amount of liquid product, separate tanks are combined into tank farms. Tank farms are being built at industrial enterprises and transshipment bases of various transport systems. An example of this is the storage of vegetable oils in the seaport of Yeysk (Russian Federation, Krasnodar territory). Pumps (mainly centrifugal), pipelines, auxiliary devices are used to transfer liquid cargo from a vehicle to a tank, or back. The design of liquid product storage is impossible without hydraulic calculation of this equipment. Pressure losses to overcome hydraulic resistances have a significant impact on the operation of pipeline systems. The methodology of calculating linear fluid pressure losses in pipelines includes the determination of the flow mode (laminar/turbulent), followed by the calculation of the Darcy friction coefficients. Based on the results obtained, the pressure loss along the flow length is calculated, taking into account the geometric characteristics of the pipeline (length, diameter) and the fluid velocity. The methodology was used to construct an algorithm for calculating linear fluid pressure losses. This algorithm can be applied as part of a previously created algorithm for calculating and selecting a pumping unit for storage of liquid products.

Optimization of a combined tanker/platform type vessel based on simulation modeling

Combined vessels of various architectural and structural types can be used to increase the efficiency of oil-loading transportation by water transport. On inland waterways, the most perspective vessels are the tanker/platform type, carrying the main (bulk) cargo in the hull and the return (dry) on the platform equipped on an open deck. The article presents a general mathematical model and an algorithm for selecting elements and characteristics of the specified type of vessels, allowing them to be optimized in various operating conditions with specified initial data. The carried out extensive test calculations, systematized and presented in the form of graphical dependencies, show the effect of the stroke speed on the coefficient of the overall completeness of the hull at various backloading volumes, the efficiency in the form of the relative profit of a combined vessel compared to a "clean" tanker from the share of backloading and the ratio of freight rates for dry and liquid cargo. The low dependence of the relative profit on the length of the lines of operation is also shown.

Equivalent linear roll damping of a FPSO coupled with liquid sloshing in a pair of two-row tanks

The increased risk of reduced transverse stability by free surfaces in cargo tanks in floating vessels such as Floating Production Storage and Offloading (FPSO) units, is well known. Roll decay testing remains the most common method for determining roll damping characteristics. Few works evaluating roll characteristics coupled with the effect of liquid motion exist. In this paper, a series of roll decay tests are carried out for a FPSO model with a pair of two-row prismatic tanks. The four compartment tanks are filled to different levels, and the equivalent linear damping is obtained using the Quasilinear (Logarithmic Decrement) method and the Froude Energy method. The effect of draft change for each loading condition is analyzed based on the average equivalent linear damping coefficient and the effect of the liquid cargo sloshing is also discussed. The results show that an increase in liquid cargo, the location of cargo load, and the geometry of the cargo tank affect the damping of the vessel.

Effect of percentage of reinforcement particulates on the corrosion behaviour of aluminium boron carbide composites

Aluminum based composites are generally used to build marine structures and liquid cargo containers because of its high strength and low weight. In the present investigation, the corrosion behaviour of B<sub>4</sub>C particle reinforced Al-6061 alloy has been studied. The aluminumboron carbide composite were prepared using stir casting method by varying percentage of reinforcement from 6 to 12% in steps of 2%. Salt spray method was adopted to investigate the corrosion behaviour of the composite. The test was conducted for a period of 240 hours and for every 48 hours the weight loss of the specimens was measured. The extent of corrosion was measured by using weight loss method. The results showed that the corrosion resistance of the composite decreases with the increase in the percentage of boron carbide particulates. The optical microscope was used to analyze the corroded surfaces and corrosion mechanism. The pit initiation side tends to the possibility of the accuracy corrosion on the interface between the hard reinforced particles and matrix alloy.

The impact of ultrasound on Janus capsules at gel-liquid interface

Ultrasound-responsive Janus capsules gain increasing recognition in the scientific world due to the wide spectrum of their potential applications. Spherical structures with the heterogeneous shells composed of two kinds of fused polymeric microparticles can be particularly useful when the cargo should be released in a strictly controlled manner. Distinct physical properties of individual hemispheres have a significant impact on the course of the payload release process. In this paper we deal with the problem of the influence of high-frequency and low intensity ultrasound on the behaviour of Janus capsules placed at the gel-liquid interface. Such a boundary between two phases can simulate the natural barriers occurring for example in biological systems. We show that 1 MHz acoustic waves are able to liberate the content from Janus capsule and push the freed liquid cargo through the interface so that it penetrates into the gel medium. We demonstrate that the size of the Janus capsule and, above all, its orientation at the interface in relation to the direction of acoustic wave propagation, are the key factors determining the progress of payload release and its transfer to the gel medium. Shell region that is mechanically weaker tends to break faster, which defines the initial path of payload release. Presented results contribute to a better understanding of physical phenomena occurring during the interaction of ultrasound with particle capsules. They can also become a source of inspiration not only for further experimental research, but also for theoretical analysis.

Artificial neural network based prediction of ultimate buckling strength of liquid natural gas cargo containment system under sloshing loads considering onboard boundary conditions

In this study, the ultimate buckling strength of a GTT NO96 liquid natural gas (LNG) cargo containment system under a sloshing impact load was investigated while considering the design environmental conditions thereof, such as the cryogenic temperature and flexible boundary conditions owing to the inner hull structures. As the dynamic buckling capacities of LNG cargo containment boxes show a large nonlinearity against several design parameters, we applied an artificial neural network to generalize the numerical analysis results and develop design ultimate capacities of the system for early design purposes. Through one-hot encoding, a character variable was converted into a variable form suitable for the artificial neural network, and a prediction model optimized for the current system was constructed through a model optimization process. A comparison of the design values with finite element (FE) simulation results shows a very good agreement. Finally, we provide a prediction model: a GitHub repository, BUNO96, which is suitable for the calculation of ultimate buckling strength of NO96 box.

Resilience evaluation of maritime liquid cargo emergency response by integrating FRAM and a BN: A case study of a propylene leakage emergency scenario

A novel model is proposed to evaluate the resilience involved in maritime liquid cargo emergency response. The model integrates the superiorities of the function resonance analysis method (FRAM), a directed complex network (CN) and a probabilistic-based Bayesian network (BN) within the resilience engineering framework. The FRAM is employed to qualitatively describe the emergency response process on the basis of function, variability and coupling identification to establish a topological network, which can be considered the prototype of BN and directed CN. The improved K-shell decomposition algorithm is employed to obtain the prior probability of the root nodes based on the developed directed CN, while the conditional probability tables for the BN model simulation are calculated according to the probability distribution of the root nodes. Finally, the developed BN is simulated with AgenaRisk software, and then different emergency scenarios and node sensitivity are investigated. The results show that the proposed probabilistic-based methodology can compensate well for the constraints of the traditional FRAM model by aggregating the quantitative analysis method and can be effectively used to evaluate the resilience involved in the maritime emergency response process. Moreover, the application potential of this methodology can be expanded to other similar industries.

A Chronological Overview of Scientific Research on Ship Grounding Frequency Estimation Models

In the global maritime industry, ship grounding represents about one-third of commercial groundings. Grounding is a type of accident where the hull of a ship strikes the seabed, causing damage to the hull. This type of accident can lead to damage to the hull and water penetration, but also to the pollution of the marine environment by the spillage of ship fuel or some liquid cargo carried by the ship. This paper presents a chronological overview of the contribution of ship grounding frequency, where one of the first ideas of grounding probability was presented by Macduff (1974) and Fuji (1974) in their models. Their ideas, such as grounding candidates and causing probability, laid the foundation for the development of future models. After their models, years later, other models continued to be developed; e.g., analytically (Macduff, Fujii, Amrowitcz, etc.) and statistically (Pedersen, Simonsen, etc.). To find the probability of grounding in an area of interest or in a scenario, it is necessary to have the number of grounding candidates and the causing probability. There are different internal and external factors that affect both probabilities, and in this paper, we analyze how various authors approach their grounding models and have tried to show the actual event as faithfully as possible and thus contribute to greater safety in maritime transport. The number of grounding frequency models significantly complicates their selection in practice; accordingly, the review of models in this paper should facilitate this, but also it should facilitate future research on this topic.

Incorporating multi-scenario underreporting rates into MICE for underreported maritime accident record analysis

This study attempts to incorporate multi-scenario underreporting rates into multivariate imputation using chain equation (MICE) to address underreporting issues in maritime accident records. In addition, the Tobit regression model is utilized to evaluate the economic loss of maritime accidents for both the original and supplemented data. With ten years’ maritime accident data in Fujian waters, one empirical study is created to testify the effectiveness of the proposed method. The marginal effect results from the proposed method significantly differ from the conventional Tobit regression model. The proposed method could significantly correct the over- or underestimated impacts related to various variables (e.g., serious/non-serious accident types, fishing vessels, other ships, and liquid cargo ships). This reveals that the proposed method is capable of correcting the systematic deviation of the analysis results to a satisfactory extent.

CFD Simulation and Experimental Study on Coupled Motion Response of Ship with Tank in Beam Waves

Tank sloshing is widely present in many engineering fields, especially in the field of marine. Due to the trend of large-scale liquid cargo ships, it is of great significance to study the coupled motion response of ships with tanks in beam waves. In this study, the CFD (Computational Fluid Dynamics) method and experiments are used to study the response of a ship with/without a tank in beam waves. All the computations are performed by an in-house CFD solver, which is used to solve RANS (Reynold Average Navier-Stokes) equations coupled with six degrees-of-freedom solid-body motion equations. The Level Set Method is used to solve the free surface. Verification work on the grid number and time step size has been conducted. The simulation results agree with the experimental results well, which shows that the numerical method is accurate enough. In this paper, several different working conditions are set up, and the effects of the liquid height in the tank, the size of the tank and the wavelength ratio of the incident wave on the ship’s motion are studied. The results show the effect of tank sloshing on the ship’s motion in different working conditions.

Outlier analysis of sloshing impact loads on liquid ship cargo

This paper introduces an outlier analysis which can improve the convergence of the statistical analysis results of sloshing model test data. The paper classify possible outliers in the sloshing model test into three categories and present a treatment method for each outlier. The developed outlier analysis is adapted to the model test results for the cargo of the liquefied-natural-gas (LNG) carrier in operation. The results of the present new method are compared with those of the conventional procedure, particularly focusing on long-term sloshing prediction. Through this study, the effectiveness of the present method is observed, and it is found that the present method provides is robust and reliable results in the application of experimental data for load prediction.

Liquid cargo effect on load transfer under orthogonal accelerations

A methodology is proposed for the experimental analysis of the liquid cargo effect under combined orthogonal accelerations. To simultaneously subject the vehicle-cargo system to longitudinal and lateral accelerations, the vehicle is set obliquely on a tilt table. The experimental outputs suggest that there is a significant effect of the liquid cargo on the lateral load transfer ratio (LTR), on the order of 20%, which is attributable to the resulting shifting of the liquid cargo's centre of gravity. That is, the peak LTR values due exclusively to sloshing were not significant, in such a way that the liquid cargo would only pose a safety risk under a steady acceleration input. Also, the inverse of the product of the magnitude of the acceleration times the free surface length, correlates with the liquid cargo effect. That is, the magnitude of the input acceleration is not fully determinant for greater load transfers.

Liquid cargo effect on load transfer under orthogonal accelerations

Liquid cargo effect on load transfer under orthogonal accelerations