Влияние гранулометрического состава песка на глубину проникновения дизельного топлива

Deployment of tanks for temporary storage of fuel on sand layer (a sand blanket) is an effective method to protect the soil from process-related spills. Asessment of the required thickness of the sand layer is important in practice, as it determines the layer’s protective properties when oil droplets fall on the surface. This paper investigates the dependences of the speed and depth of ingress of DT-Z-K5 diesel fuel on the grain size composition of the sand used as a protective layer. Substantiation has been given for the approach to the evaluation of the kinetics and to the depth of ingress of petroleum products into the sand, such approach being based upon the probabilistic movement of the fluid flow boundaries in the protective layer. It is proposed to describe the ingress of fuel into the sand layer in the coordinate system of the square root of the process time. Based on the results of the study, there have been established the dependences of the speed and depth of ingress of DT-Z-K5 fuel into the protective layer on the sand grain size and on the quantity of petroleum product leaked on the surface. It has been established that to create a protective layer preventing the ingress of fuel into the soil in the event of process-related leaks in temporary fuel storage tanks, it is optimal to use sand with 0.8 mm grain. Размещение резервуаров для временного хранения горючего на слое песка (песчаной подушке) является эффективным способом защиты грунта от технологических проливов. Практическое значение имеет оценка необходимой толщины песчаного слоя, которая определяет его защитные свойства при попадании на поверхность капель нефтепродукта. В настоящей работе исследованы зависимости скорости и глубины проникновения дизельного топлива ДТ-З-К5 от гранулометрического состава частиц песка, используемого в качестве защитного слоя. Обоснован подход к оценке кинетики и глубины проникновения нефтепродукта в песок, основу которого составляет вероятностное движение границ потока жидкости в защитном слое. Предложено описывать проникновение топлива в слой песка в системе координат корня квадратного из времени процесса. По результатам исследования установлены зависимости скорости и глубины проникновения ДТ-З-К5 в защитный слой от размера частиц песка и количества вносимого на поверхность нефтепродукта. Определено, что для создания защитного слоя, исключающего проникновение топлива в почву при возникновении технологических протечек резервуаров временного хранения горючего, оптимально использовать песок с размером частиц от 0,8 мм. Предложенный подход по получению зависимостей глубины проникновения топлива от условного времени можно использовать для оценки распределения топлива в слоях песка с различными размерами частиц.

Computational analysis of mixture(LPG/Air) formation and performancein a dual fuel diesel engine

This paper focuseson the use of CFD in advancing the LPG/air blend development of a dual fueled IC engine (Diesel and LPG). LPG is introduced through a secondary gas tube to the intake duct of the engine, keeping up 45° point to the flow direction. The variations in the stream boundaries change the output of the engine. Thus there is apossibility for gas tube design to position it and to get an optimized performance. From the previous literatures, CFD tool can be utilized to streamline the gas flow boundaries to improve execution. Familiar programming has been utilized to tackle this issue and approved with trial results. The outcomes show that the streamlined flow boundaries by FLUENT demonstrate 3% improvement in performance of the engine and 11% decrease in NOx emission.

Coherent Particle Structures in High-Prandtl-Number Liquid Bridges

Clustering of small rigid spherical particles into particle accumulation structures (PAS) is studied numerically for a high-Prandtl-number (Pr = 68) thermocapillary liquid bridge. The one-way-coupling approach is used for calculation of the particle motion, modeling PAS as an attractor for a single particle. The attractor is created by dissipative forces acting on the particle near the boundary due to the finite size of the particle. These forces can dramatically deflect the particle trajectory from a fluid pathline and transfer it to certain tubular flow structures, called Kolmogorov–Arnold–Moser (KAM) tori, in which the particle is focused and from which it might not escape anymore. The transfer of particles can take place if a KAM torus, which is a property of the flow without particles, enters the narrow boundary layer on the flow boundaries in which the particle experiences extra forces. Since the PAS obtained in this system depends mainly on the finite particle size, it can be classified as a finite-size coherent structure (FSCS).

Appraising and developing ST-X field determination of uncertainties by DST analysis

A subsurface uncertainties is a possible future event, which, if occurs, would affect project objectives either negatively or positively. For any given model or event, the uncertainty is the range of variation of the component parts and possible outcomes. It could be quantified approximately by either analytical model or in a more cumbersome one such as numerical approach. This paper summarizes thedetermination ofuncertainties by DST analysis in appraising and developing the ST-X gas condensate field, which is offshore Vietnam in Block 15-1O. Drill Stem Test (DST) results show that the S field has moderate to low permeability, multiple flow boundaries/barriers, and at least 2 PVT regions. To understand the impact of these and other important reservoir parameters on ultimate gas and condensate recovery and well count, the uncertainties has to be well evaluated and understood. The study demonstrates that there is a wide range of possible ultimate gas and condensate recoveries and well counts. The top causes for this wide range are permeability and flow boundaries/barriers. In addition to the subsurface risks, drilling cost of a ST-X well is very high. The high well cost in combination with the field being offshore, having low permeability and possibly numerous reservoir compartments dramatically increase the risk of a full field development.

Determination of Flow Units in Carbonate Reservoir With Multiscale Karst Morphology

The Tahe reservoir, one of the largest scale carbonate reservoirs in western China, has very special cavities and fractures. The size of the cavities ranges from millimeter to meter scale, and the size of the fractures ranges from hundreds micrometers to millimeters scale. The length of some cavities can even reach kilometers. However, based on views of core testing results, there is insignificant flow in the rock matrix. This paper introduces a new and refined method to determine flow units in such Karst carbonate reservoirs. Based on fractal theory, fluid flow patterns can be divided into three types by using production data of the Tahe reservoir. Through porosity and permeability statistics of production layers on the established geological model, flow boundaries of different flow patterns were proposed. Flow units were classified in terms of the flow boundaries. As for refined flow units, subcategory flow units were determined by three graphical tools: the limit of dynamic synthesis coefficient (DSCL) method, modified flow coefficient (MS1 and MS2, which are derived by the Forchheimer equation) curve, and the stratigraphic modified Lorenz plot (SMLP). All the parameters of graphical tools help to reconcile geology to fluid flow by illustrating the important link between geology, petrophysics, and reservoir engineering. The use of this technique is illustrated with data from a specific block of the Tahe reservoir.