Experimental Study on Optimization of Polymer Preslug Viscosity of ASP Flooding in Interlayer Heterogeneous Well Group Artificial Sandstone Core

An artificial sandstone core model of large well group of positive rhythmic heterogeneous reservoir was designed and made for the simulation of ASP flooding experiment in the moderate heterogeneous reservoir. The well layout of one injection and one production was employed for the core model, to simulate the influence of polymer preslugs with different viscosity on ASP flooding effect. The experimental results show that the injectability of the polymer preslug and the effect of relieving the conflict of remaining oil production in each layer are related to the viscosity of the system. In the heterogeneous core model with the coefficient of variation of 0.65, under the constraint of the same amount of polymer agent, the ASP flooding effect of the 0.075 PV, 60 mPa·s polymer preslug was better than that of the 0.093 PV, 40 mPa·s and 0.064 PV, 80 mPa·s polymer preslugs. The change in the viscosity of the polymer preslug did not enable the ASP system to effectively exploit the low-permeability layer though. As the viscosity increased, the pressure difference between injection and production increased; the remaining oil could be exploited effectively at the bottom of the high-permeability layer and the medium-permeability layer as well as the injection end of the medium-permeability layer. If the viscosity is too small, the high-permeability area cannot be effectively blocked by the injected chemical agent, and if the viscosity is too large, the injected chemical agent cannot produce good elastic displacement relationship, which will lead to ineffective chemical agent flow. Therefore, the polymer preslug viscosity of the ASP flooding system should be moderate, and cores with different heterogeneity should have a reasonable viscosity matching range.

On Physical Modeling of the Current Measurements in a Jet of Fire Extinguishing Agent

In accordance with the current regulations for extinguishing a fire, including without disconnecting electric power supply of direct (alternating) current of industrial frequency, fire extinguishers are allowed with a leakage current in a jet of extinguishing agent of not more than 500 µA, which is measured with an applied potential difference of 36 kV. Therefore, the recommendations for preliminary disconnection of electric power supply do not cover fire extinguishers that are certified according to the level of safe leakage current. The article deals with fire extinguishing agents based on aqueous solutions. It is obvious that the development of such fire extinguishers requires additional analytical and experimental research. The purpose of this article is the computational and physical modeling of the current leakage process, and the justification of the requirements for the parameters of the extinguishing agent flow at the outlet of the exhaust nozzle. As a result of the conducted research, the calculation methodоlogy and a scheme of the physical model of a high-voltage test bench for measuring the leakage current were developed based on measuring the active resistance of fire extinguishing agent flow in a constant voltage field and the electric capacitance of the measuring space of the test bench. The developed methodology allows to increase the reliability of the calculated results and significantly reduce the cost of working out the nozzle design. Measured at an applied voltage of 36 kV of industrial frequency, the amount of current leakage in a jet of the extinguishing agent is satisfactorily consistent with the calculation. The obtained computational and experimental results allowed to determine the range of permissible values of the active resistance and the requirements to the length of the continuous section of the jet of the extinguishing agent, which ensure safe use of the fire extinguisher for fire-fighting, including without disconnecting the electric power supply of the constant (alternating) current of industrial frequency with a voltage up to 1000 V.

NUMERICAL SIMULATION AND EXPERIMENTAL STUDY OF INNER FLOW FIELD OF SEED PELLETING PREMIXER IN SPOUTED FLUIDIZED BED

In order to explore the temporal and spatial distribution and motion state of the grains of wheatgrass (Agropyron) seeds and powder in pelleting process, and to find the optimal inlet air speed of pelleting premixer, the pelleting forming mechanism was revealed. Based on Herz-Mindlin contact theory, the contact mechanics model of seed and powder was established. Besides, CPFD software was used to model and simulate the pelleting premixer, and the contact, collision and friction rules among particles were analysed. The simulation and experimental results show that with the increase of inlet wind speed, the bed expansion increases and the unit volume particle concentration decreases, while the air pressure difference only slightly increases. When the inlet wind speed is set at 3.5 m/s, the atomizing nozzle velocity is set at 4.1 m/s, and the seed coating agent flow rate is 0.36 L/min, the particles are suspended due to air isolation, forming a spouted fluidized bed. It is good for seed and powder contact and rapid prototyping. In this time, the pelleting qualified rate was 95.8%. The results provide theoretical basis and technical support for the research of small irregular seeds pelletizing technology.

Effects of operating parameters on co-gasification of coconut petioles and refuse-derived fuel

Coconut agro-industry in the western region of Thailand generates a large amount of residues. This study investigated the energy production potential of discarded coconut petioles, with a focus on co-gasification with refuse-derived fuel (RDF). Gasification tests involving petioles, RDFs and their mixtures (25%, 50%, 75% or 100% by weight) were conducted in a laboratory-scale fixed bed reactor. Fuel samples of 5 g were gasified at 700°C–900°C for 60 minutes, using simulated air (79% N2 to 21% O2, by volume) as a gasifying agent. Gasification of petioles generated producer gas with lower heating values, estimated at 0.43–0.75 MJ Nm−3, while RDF produced 0.92–1.39 MJ Nm−3. Adding greater quantities of RDF to the fuel mixture resulted in an increase in the heating value of the producer gas and cold gas efficiency. The operating temperatures and gasifying-agent flow rates affected the efficiency of process differently, depending on the fuel composition. However, the maximum cold gas efficiency from both fuels was detected in tests conducted at 800°C. In co-gasification and pure refuse-derived-fuel tests, higher temperatures and gasifying-agent flow rates led to outputs with higher energy yields. Our findings suggested that co-gasification of petiole is a viable alternative waste-treatment technology for this region.

Experimental and statistical analysis research of the triticale grain drying process when countercurrent-direct-flow blowing of the grain layer

Experimental studies of the kinetics of the process of drying triticale grain during counter-current-direct blowing of the grain layer were carried out. In the experimental installation, a programmed change in the direction of the drying agent flow through the grain layer was carried out and the actual conditions of the drying agent supply through the supply and discharge boxes of the shaft grain dryer were emitted. Analysis of drying curves and drying rate of triticale grain showed the presence of only a period of decreasing drying rate, in which the intensity of moisture diffusion is significantly less than the intensity of moisture exchange. The organization of the experiment made it possible to fully adapt it to industrial mine grain dryers, in which the drying process is carried out in a continuous mode. Based on the results of the study, an empirical model of the drying process is proposed in the form of an exponential function, which establishes a unique functional relationship between the current moisture of the grain and the main parameters of the process: temperature, speed, moisture content of the drying agent and the thickness of the blown layer. Taking into ac-count the requirements to the process modes of grain drying, the triticale analyzes the ratio between the grain temperature and its humidity at various values of the mode parameters, which is proposed to be used as a restriction on the drying temperature mode.

Magnetic Refrigeration: emerging technology for sustainable refrigeration

This article presents the magnetic refrigeration technology that is based on the magnetocaloric effect, heating or cooling of a magnetic material when the applied magnetic field changes. The first part of the paper shows an introductory study of the evolution of this technology over the years, continuing with the presentation of the magnetic regenerator model, which is composed of two heat exchangers with parallel plates of magnetocaloric material, gadolinium and are separated by heat transfer agent flow channels. The benefits and advantages of this technology are described, in the context of the current stage of development.

DEVELOPMENT OF THE AERODYNAMIC DRYING METHOD FOR THE CHOPPED VEGETAL MASS

The article presents the theoretical study and elaborates the calculation methodology of the technological and constructive parameters of the aerodynamic dryers: the saltation speed of the vegetal mass particles, the speed of the thermal agent flow, the length of the dryer pipes and the duration of the moist particles contact with the thermal agent. The comparative analysis of the aerodynamic dryers was performed: with direct and vortex flow. The advantages of vortex dryers, recommended for implementation in production, are theoretically argued. In the research of the developed conical shape dryer, it has been identified a phenomenon of vortex flow parameters self-regulation to the material to be dried inside the dryer, under the condition of varying the amount of material feeding the dryer, allowing automatic creation of optimal drying conditions, when the supply of raw material and/or its humidity were changed within the studied limits. It has been demonstrated the possibility to increase up to 12-15 times the duration of contact of the raw material particles with the thermal agent and, respectively, to reduce the overall dimensions of the developed vortex dryer, compared to the known ones, which have direct air flow.

Computational Fluid Dynamics Study of Superselective Intra-arterial Chemotherapy for Oral Cancer: Flow Simulation of Anticancer Agent in the Linguofacial Trunk

Superselective intra-arterial chemotherapy (SSIAC) for oral cancer can deliver a higher concentration of anticancer agent into a tumor-feeding artery than intravenous systemic chemotherapy. However, the agent distribution between the lingual artery and facial artery (FA) is not clear in SSIAC for patients with the linguofacial trunk. The agent distribution in the SSIAC method was investigated using computational fluid dynamics (CFD). Ten three-dimensional vessel models were created from CT images of two patients with oral cancer (patients A and B) with the linguofacial trunk. Catheter models were combined with vessel models to mimic intra-arterial infusion, and the agent flow was analyzed. In patient A models, the agent distribution varied depending on the catheter tip position in the linguofacial trunk, while all anticancer agents flowed into the FA only in patient B models. This study revealed that the behavior of the agent in the common trunk is determined by the blood flow field which depends on the topography of the vessels in each patient. Therefore, the catheter tip position should be changed according to the vessel topography to deliver anticancer agents into the tumor-feeding artery. Moreover, CFD can be a useful method to predict the agent flow for each patient before SSIAC.

Rotation of Bruchid Weevil in Drying Agent Flow around Longitudinal Axis from Position 0 to Position 1 at its Movement from Deck to Sсreen

В зерноуборочных комбайнах, применяемых в настоящее время, очень велики затраты энергии на выделение зёрен из колосьев. Для уменьшения затрат энергии предлагается комбайн, который производил бы выделение зёрен из колосьев методом вытирания. При перемещении верхней части растения лентой верхнего транспортёра по деке происходит выделение зёрен из колосьев. Сквозь отверстия деки проваливается зерновой ворох, содержащий зерновки, частицы соломы, полову, семена сорных растений, пыль и другие компоненты. Первичную очистку зернового вороха от примесей с одновременным снятием с зерна поверхностной влаги целесообразно осуществлять потоком агента сушки. Агент сушки поступает в пространство между декой и расположенным под ней решетом. Перемещение зерновки в потоке агента сушки от деки к решету разбито на этапы с шагом поворота зерновки относительно продольной оси 15°. Начальный этап перемещения зерновки в потоке агента сушки от деки к решету –из положения 0 в положение 1. Рассмотрены силы, воздействующие на зерновку в начале перемещения на начальном этапе. На основе анализа сил и методом построений рассчитаны кинематические параметры зерновки при её повороте относительно продольной оси в процессе перемещения из положения 0 в положение 1. Полученные кинематические параметры зерновки в потоке агента сушки, её траектория от деки до поверхности решета создают возможность проектирования рациональной конструкции комбайна. In combine harvester threshers currently used energy costs for the extraction of grains from ears are very high. To reduce energy costs, a combine is proposed that would extract grains from the ears by grinding method. When the upper part of the plant is moved by the belt of the upper conveyor along the deck, grains are extracted from the ears. Grain heap containing bruchid weevils, straw particles, chaff, weed seeds, dust and other components falls through the holes of the deck. Primary cleaning of grain heap from impurities with simultaneous removal of surface moisture from grain is advisable to be carried out by flow of drying agent. The drying agent enters the space between the deck and the underlying screen. Bruchid weevil displacement in drying agent flow from deck to screen is divided into stages with bruchid weevil pitch relative to longitudinal axis 15°. Initial stage of bruchid weevil movement in drying agent flow from deck to screen is from position 0 to position 1. Forces acting on bruchid weevil at the beginning of movement at the initial stage are considered. Based on the analysis of forces and the method of constructions, kinematic parameters of bruchid weevil are calculated when it turns relative to the longitudinal axis in the process of moving from position 0 to position 1. The obtained kinematic parameters of the bruchid weevil in the flow of the drying agent, its trajectory from the deck to the surface of the screen create the possibility of designing a rational design of the combine.