Influence of flow on thawing of underwater slopes and the pace coastal erosion of rivers, occurring in the permafrost zone

In the hydraulic laboratory of department of architecture & civil engineering RUDN University was performed studies of destruction of underwater and above-water coastal slopes in conditions simulating permafrost, depending on the soil type, the initial slope, and the slope angle. It was shown by authors, the speed of erosion of the underwater slope lags behind the speed of thawing of frozen ground. Water flow's influence is much higher than the impact of other factors (temperature, effect of wind, solar radiation), resulting in the formation of the washout niches. Thus, the main goal of the work was to identify the most important factors that affect on the changes of the river bed in permafrost zone.Keywords: experiment; frozen ground; erosion; water flow; permafrost zone

Mathematical rainfall model for hydrographic demarcation of Manabi (Ecuador)

To determine the average annual rainfall at a specific site in a basin, it is necessary to count with rainfall information in the study area and topographic information. Counting with base information, is comes to the filling of them data missing with the help of any of them methods statistical existing for the effect. Thiessen polygons are built. Based on this procedure, may be elaborated isohyet or curves of equal rainfall, that are an input that can help also to estimate of precipitation in a specific geographical site. Here is a methodology that allows creating with the help of geographic information systems (GIS), a mathematical model to estimate very accurately the values of rainfall based only on the geographical coordinates. To achieve this objective, the basins of the Hydrographic Demarcation of Manabí have been chosen to develop the indicated mathematical model, which can be applied to other basins in the world.Keywords: multiple regression; mathematical model; GIS; Hydrology; rainfall

Influence of the El Niño phenomena on the climate change of the Ecuadorian coast

The climate on the Ecuadorian coast depends mainly on the marine currents of Humboldt and El Niño, which appear in the dry and rainy seasons, respectively. The Humboldt current is distinguished by being cold, while that of El Niño is hot. The presence of the El Niño current causes an increase in the evaporation of ocean waters with the consequent appearance of the rainy season. There are anomalous seasons of the El Niño stream, when the water temperature rises above the norm, higher than 25.5 °C, which has been called El Niño phenomena. The appearance of this natural phenomena has proven to be decisive in the climate change of the coast of Ecuador. In order to have technical information, important for the planning, control and development of the water resources of the DHM, in this research a temporal analysis of the monthly rainfall during 55 years, 1963-2017 period, is carried out. The National Institute of Hydrology and Meteorology of Ecuador (Instituto National de Meteorología e Hidrología - INAMHI) at station M005, located in the Botanical Garden of the Technical University of Manabí in Portoviejo, obtained these records. An analysis of the monthly and annual patterns is made, establishing that the El Niño events occurred in 1983, 1997 and 1998, have established guidelines for the change in the production of rainwater in the levels of intensity and temporal distribution, increasing the months of drought, while precipitation levels increase, concentrating in fewer months, basically in February and March. This is a situation that increases the water deficit, especially when there is not enough infrastructure of hydraulic works for the storage and regulation of runoff

MODELING OF HYDRODYNAMICS OF THE PROCESS OF DRY WARM DESULPHURIZATION OF SYNTHESIS GAS IN A REACTOR WITH A CIRCULATING FLUIDIZED BED

In this paper, the hydrodynamics of the process of dry warm desulphurization of synthesis gas in a reactor with a CFB was simulated. The model was used to calculate the effect of the velocity, bed mass, and specific flow rate of solid particles over the reactor height on the solid phase concentration. The calculations were verified on a cold stand with a circulating fluidized bed.В настоящей работе произведено моделирование гидродинамики процесса сухой теплой сероочистки синтез-газа в реакторе с циркуляционным кипящим слоем (ЦКС). С помощью модели выполнены расчеты влияния скорости, массы слоя и удельного расхода твердых частиц по высоте реактора на концентрацию твердой фазы. Проведена верификация расчетов на холодном стенде с циркуляционным слоем

SIMULATION OF NITROGEN OXIDE FORMATION DURING SYNGAS GAS TURBINE OPERATION

In this paper, we applied a new method for estimating the concentrations of nitrogen oxides during combustion of synthesis gas in the combustion chamber of a gas turbine. it allowed us to link the complete detailed mechanism of the Grimech 3.0 parallel reaction array with the equations of computer hydrodynamics. Verification calculations were carried out on a model combustion chamber of a gas turbine in the range of values of the fuel excess factor of 0,5–2. The new method was used to determine nitrogen oxide emissions and the maximum temperature of the flame tube wall of an industrial combustion chamber.В настоящей работе был применен новый метод оценки концентраций оксидов азота при горении синтез газа в камере сгорания газовой турбины, который позволил связать полный детальный механизм массива параллельных реакций Grimech 3.0 с уравнениями компьютерной гидродинамики. Проведены верификационные расчеты на модельной камере сгорания газовой турбины в интервале значений коэффициента избытка топлива 0,5–2. Новая методика была применена при определении выбросов оксида азота и максимальной температуры стенки пламенной трубы промышленной камеры сгорания

Cogeneration plant based on gasifier and fuel cell

Fuel cell synthesis gas is produced in gas generator of steam Borodinskiy charcoal gasification. Gross efficiency, anode temperature, loses with outgoing gases and to the environment throughthermal isolation, electromotive force of fuel cell, fuel consumption on heat-and-power production are calculated in this study.Синтез-газ для электрохимического генератора производится в газогенераторе паровой газификацией полукокса бородинского угля. В работы рассчитаны: электрическийкоэффициент полезного действия (брутто), температура в аноде, потери с уходящими газами и в окружающую среду через тепловую изоляцию, электродвижущая сила топливного элемента, удельные расходы условного топлива на выработку электрической энергии и теплоты

Catalytic Reactor of Methane Conversion with Fluidized Bed

The design of a thermochemical reactor for oxygen-free vapor conversion of methane with partial oxidation of conversion products has been developed to ensure autothermal process. The reactor is divided into a lower zone of a bed with a catalytic packing in which methane conversion takes place and an upper one where a part of the conversion products is withdrawn from the reactor and the remaining part is oxidized to provide the required bed temperature. The experimental results studies of the reactor are presented. A stationary one-dimensional model of methane vapor conversion in a homogeneous fluidized bed, braked by a catalytic packing, has been developed.Разработана конструкция термохимического реактора для бескислородной паровой конверсии метана с частичным окислением продуктов конверсии с целью обеспечения автотермичности процесса. Реактор разделен на нижнюю зону слоя с каталитической насадкой, в которой происходит конверсия метана, и верхнюю, где организован отвод из реактора части продуктов конверсии и окисление оставшейся части для обеспечения необходимой температуры слоя. Представлены результаты экспериментальных исследований реактора. Разработана стационарная одномерная модель паровой конверсии метана в однородном псевдоожиженном слое, заторможенном каталитической насадкой

ОСОБЕННОСТИ УПРАВЛЕНИЯ ЭЛЕКТРОПНЕВМАТИЧЕСКИМИ КЛАПАНАМИ ИСПОЛНИТЕЛЬНОГО МЕХАНИЗМА УПРАВЛЕНИЯ СЦЕПЛЕНИЕМ С УСКОРИТЕЛЬНЫМ КЛАПАНОМ

The article deals with one of the ways to control an actuator of the automated clutch control system. The aim is to design control of the electropneumatic actuator, to control its coupling with the acceleration valve on the basis of experimental research as well as to provide rational parameters of the automated clutch control system for the robotic transmission. The feature of the system is an acceleration valve in the design of the electropneumatic actuator to control the clutch. New links demand to adjust the way to control the actuator. The connection of Pulse-Width Modulation (PWM) with single power supply pulses to control electropneumatic valves is substantiated. The quantitative characteristics of single control pulses and PWM ones are determined. The error of operation accuracy for various ways of the control of the electropneumatic actuator to control the clutch of the robotic transmission is determined. Obtained separate PWM area is designed to suppress the initial hysteresis when the rod of the clutch actuator is moved. An algorithm for the operation of a clutch control system is proposed, taking into account the use of two modes of operation of solenoid valves. A graphical interpretation of the clutch control algorithm is presented, which gives an idea of the location of the constant signal feeding zones to the solenoid valve, as well as the operation areas of the solenoid valve in PWM mode. The control algorithm of the clutch booster provides a mode of guaranteed absence of excess pressure in the pneumatic cylinder after releasing the clutch pedal, provided that two normally closed solenoid valves are used. This configuration of the electro-pneumatic clutch control system allows the use of an emergency clutch release system in case of voltage absence. The reference algorithm for filtering the array of data coming from the feedback sensor, as well as the numerical values of the delay caused by the presence of a filter, are given.В статье рассмотрен один из способов управления исполнительным механизмом автоматизированной системы управления сцеплением. На основе экспериментальных исследований предложены способ управления электропневматическим исполнительным устройством управления сцеплением с ускорительным клапаном, а также рациональные параметры автоматизированной системы управления сцеплением для роботизированной трансмиссии. Особенностью рассматриваемой системы является наличие в конструкции электропневматического исполнительного механизма управления сцеплением ускорительного клапана. Наличие новых связей требует корректировки способа управления исполнительным механизмом. Обосновано объединение широтно-импульсной модуляции с одиночными импульсами питания для управления электропневматическими клапанами. Определены количественные характеристики управляющих импульсов как для случая одиночных, так и в случае использования широтно-импульсной модуляции. Определена ошибка точности работы во время разных способов управления электропневматическим исполнительным устройством управления сцеплением роботизированной трансмиссии. Выделена отдельная зона широтно-импульсной модуляции, предназначенная для подавления начального гистерезиса при перемещении штока исполнительного устройства управления сцеплением. Предложен алгоритм работы системы управления сцеплением с учетом использования двух режимов работы электромагнитных клапанов. Представлена графическая интерпретация алгоритма управления сцеплением, дающая представление о расположении зон подачи постоянного сигнала на электромагнитный клапан, а также зон работы электромагнитного клапана в режиме широтно-импульсной модуляции. В алгоритме управления усилителем предусмотрен режим гарантированного сброса давления из пневматического цилиндра после отпускания педали сцепления при условии использования двух нормально закрытых электромагнитных клапанов. Такая конфигурация электропневматической системы управления сцеплением позволяет задействовать систему аварийного выключения сцепления при отсутствии электропитания. Приведены опорный алгоритм фильтрации массива данных, поступающих от датчика обратной связи, а также численные значения запаздывания, вызванного наличием фильтра

MATHEMATICAL MODEL TO DETERMINE THE AVERAGE ANNUAL PRECIPITATION USING RASTER AND OTHER GIS ELEMENTS

In this paper it is developed a mathematical model, based on the use of geographic information systems (GIS) to calculate the average annual precipitation by geographical coordinates. The case of the hydrographic demarcation of Manabi (Ecuador) is analyzed

Hydrological safety and risk assessment of hydraulic structures

Hydraulic structures (HS) are engineering structures of major hazard, intended for use of water resources and prevention of negative impact of water and pollutants, operating tens or hundreds of years and have proven to be generally stable structures. Hydrological safety is understood as stability of hydraulic structures during its operation against extreme hydrological impacts of natural and maninduced nature. Most of the HS are built based on modern projects in accordance with current regulatory documents, but the probability of accidents in hydroelectric facilities tends to grow, especially after 30-40 years of operation. Most severe emergency situations (ES) occur when hydraulic structures, such as dams of large reservoirs, let over-estimated discharge through, especially if it is associated with inept exploitation. This is evidenced by the materials of the International Commission on Large Dams, according to which about 3000 accidents of different degrees occur in hydropower stations worldwide every year. Most of the accidents associated with breaking waterfront of dam could be avoided by monitoring the technical condition of HS and ensuring necessary training of operating personnel