STUDY OF GAS FUEL LEAKAGE AND EXPLOSION IN THE ENGINE ROOM OF A SMALL LNG-FUELED SHIP

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.

Simulation Study on the Influence of Injector Coupling Leakage on Fuel Injection

In order to study the effect of fuel leakage of an ultra-high pressure common rail injector control valve coupling on fuel injection performance, a simulation model was established by AMESim and the accuracy was verified by fuel injection test data. The leakage law of couples with different clearances was analyzed by using numerical simulation method and then the influence of control valve coupling on fuel injection performance was analyzed. The results demonstrate that the increase of the matching clearance of the slide valve coupling makes the start time of needle valve advanced and delay its end time. The injection rate and injection duration increase with the increase of the matching clearance of slide valve coupling. The increase of the matching clearance of the control plunger coupling keeps the start time of the needle valve unchanged at first, and then delay slightly, while the end time remains unchanged at first, and then show the trend of advance. The injection rate and injection duration decrease with the increase of the matching clearance of plunger coupling.

Crashworthiness of a Composite Bladder Fuel Tank for a Tilt Rotor Aircraft

The fulfilment of the crash is a demanding requirement for a Tiltrotor. Indeed, such a kind of aircraft, being a hybrid between an airplane and a helicopter, inherits the requirements mainly from helicopters (EASA CS 29) due to its hovering ability. In particular, the fuel storage system must be designed in such a manner that it is crash resistant, under prescribed airworthiness requirements, in order to avoid the fuel leakage during such an event, preventing fire and, thus, increasing the survival chances of the crew and the passengers. The present work deals with the evaluation of crashworthiness of the fuel storage system of a Tiltrotor (bladder tank), and, in particular, it aims at describing the adopted numerical approach and some specific results. Crash resistance requirements are considered from the earliest design stages, and for this reason they are mainly addressed from a numerical point of view and by simulations that treat both single components and small/medium size assemblies. The developed numerical models include all the main parts needed for simulating the structural behavior of the investigated wing section: the tank, the structural components of the wing, the fuel sub-systems (fuel lines, probes, etc.) and the fuel itself. During the crash event there are several parts inside the tanks that can come into contact with the tank structure; therefore, it is necessary to evaluate which of these parts can be a damage source for the tank itself and could generate fuel loss. The SPH approach has been adopted to discretise fuel and to estimate the interaction forces with respect to the tank structure. Experimental data were used to calibrate the fuel tank and foam material models and to define the acceleration time-history to be applied. Thanks to the optimized foam’s configuration, the amount of dissipated impact energy is remarkable, and the evaluation of tanks/fuel system stress distribution allows estimating any undesired failure due to a survivable crash event.

Environmental Risk Assessment of a Diesel Fuel Tank: A Case Study

The article deals with the application of the environmental damage assessment procedure and H&V index II method to the diesel fuel tank storage facility in a sand mining company using a case study. The procedures enabled the researchers to semi-quantitatively assess the operated diesel fuel tank’s impact on the selected environmental components and the possible damage risk by the leakage of stored fuel. It was discovered, by assessing the operating conditions, the state of the environment at the mining facility, and the risk of a diesel fuel leakage accident, that it is not necessary for the company to implement further steps in the field of environmental damage minimization. The H&V index II method examined both the impacts of diesel fuel leakage on soil, biotic component, groundwater, surface water, and the impact of flammable substances on the biotic environmental component in six steps. Slight or significant impacts were identified depending on the environmental component during the determination of the accident severity. The accident severity, together with the estimated probability, was plotted in the risk matrix which resulted in acceptable risks for all affected environmental components. The results of both approaches showed that the diesel fuel leakage in the mining company represents an acceptable environmental risk in relation to the countermeasures implemented so far.

TECHNOLOGIES OF PREVENTION OF LOSSES (EMISSIONS) OF HYDROCARBONS FROM FUEL TANKS OF VEHICLES

This article is devoted to a comprehensive analysis of existing technologies and methods to prevent hydrocarbon losses from fuel tanks, taking into account the study of the advantages and disadvantages of these technologies that affect the effectiveness of emission prevention. The aim of the work is to identify the best technologies, systems, trends, features of capture and prevention of hydrocarbon losses from fuel tanks. The main causes of fuel losses from car fuel tanks are considered. Losses of hydrocarbons from fuel tanks due to large and small "breaths" are described. The physical properties of gasoline that characterize its evaporation and evaporation ability are described. The largest sources of emissions in the form of evaporation from vehicles are listed. Three separate mechanisms related to losses through the breathing valve of the fuel tank and fuel leakage are considered. Qualitative characteristics of the fuel-air mixture that evaporates from car tanks and emissions of pollutants during refueling of car fuel tanks are given. The causes, sources, consequences of fuel losses from car fuel tanks are considered and summarized in the figure. Also, the modern means of capturing hydrocarbon vapor from the fuel tanks of cars, which are relevant today, are summarized in the table. Based on a comprehensive situational analysis of current technologies and methods to prevent loss of hydrocarbons from fuel tanks, taking into account the study of the advantages and disadvantages of these technologies, we have identified the best technologies to prevent losses from large and small breaths. KEY WORDS: FUEL TANKS, PETROL, LOSSES, EMISSIONS, ANALYSIS, LOSS PREVENTION TECHNOLOGIES.

Application of laser scanning technology to control the state of protective constructions when transferring oil products

Laser scanning technology is actively used in various industries. Laser scanning has provenbe a highly precision method of collecting spatial data to solve various tasks. In the oil and gas industry, these are the tasks associated with the study of pipelines for degradation in order to prevent fuel leakage, study of tank state and assessment of their deformations due to various adverse factors, including soil subsidence, timely detection of mechanical damage to oil and gas infrastructure, assessment of the protective structure health, allowing to identify the degree of their reliability in case of emergencies. In order to use the laser scanning technology to identify most of the issues in a timely manner, as well as to assess their possible consequences, various studies are being carried out to develop data collection techniques, to increase the automation degree of the processing the surveying results and their accuracy, to develop methods of creating the final product, demonstrating the result of the processing in the desired form. These modern research trends in the laser scanning technology in order to control the state of protective constructions when transferring oil products are considered. Depending on a laser scanner position when surveying, 3 its types are distinguished: terrestrial, airborne and mobile. Recommendations of applying laser scanning types are discussed. The advantages of applying each type of laser scanning when monitoring various types of protective constructions are indicated. As an example, terrestrial and mobile laser scanning data are given for one site—the oil and gas condensate deposit area. Accuracy of laser scanning data and the reasons for possible errors in their pre-processing are analyzed. It is shown that additional surveying allows detecting changes in the state of various territory objects.

Research on Vision-based Position Measurement System for Rocket Propellant Loading

In the process of rocket propellant loading, the propellant's own gravity and wind pendulum may cause the connector to exert a large force on the rocket body, which may lead to connector disconnection and fuel leakage, or even damage to the rocket body. To improve the reliability and safety of rocket propellant loading, a position measurement system based on dynamic orientation detection alignment technology is proposed to achieve tracking of the rocket refueling port. In this paper, the two-dimensional position of the target in the camera plane is quickly extracted by identifying the direction of the target image and the size of the marker in the image, while the distance between the target and the camera is accurately obtained by a laser rangefinder. With this measurement solution, the deviation of the connector from the propellant filler port at the current moment can be modified in real time, thus reducing the forces on the rocket and increasing its launch reliability.

Investigation of electrical fuel – injection pump characteristics of petrol engines in simulation of basic fuel system problems

Technical state of electrical fuel-injection pumps of automobiles with petrol engines was evaluated with application of a multiple factor experiment, based on diagnostics test modes. There exist two main problems in the fuel system, connected with the fuel volume being injected into the fuel rail: clogging when the fuel flow to the rail and next to nozzles is hindered, wear out of elements in the pump part (due to an increasing clearance space between fuel-injection pump pulleys and casing the fuel flows over the tank, i.e., does not enter the system in sufficient volume). The studies showed that in the first case of fuel system problems the pump power circuit draws the current 4,6 А persistently depending on clogging extent. Such current rate is necessary for keeping high rotations of the pump elements, helping the pump to push through the necessary fuel volume into the fuel rail, making the essential pressure 310 кПа. In the second case the fuel does not enter the rail in sufficient amount either, but the current rate here is small (even smaller than the nominal reading). For example, in the largest fuel leakage it equals 2,5 A, power voltage being 12,5 V. The results and methods of experimental data treatment with MathCAD application are presented. The article materials are applicable for research, repair, technical maintenance organizations when they estimate technical state of fuel-injection low-pressure pumps ( including those which are installed on engines with microprocessor control system).

Study of Gas Fuel Leakage and Explosion in the Engine Room of a Small LNG-Fuelled Ship

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.