37 research outputs found

    Technology for training creative graduates in engineering bachelor’s programs

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    This article is devoted to technologies of engineering education that produce the most in-demand professional qualities of graduates from Bachelor’s programs. a review of studies about introducing innovations to improve the educational process in practice-oriented Bachelor’s studies is carried out. The advantages and limitations of project-based and problem-based learning technologies are defined. The work presents the experience of developing and applying a unique teaching technology based on the integration of problem- and project-based training approaches, designed to enhance the creativity of the study process in engineering Bachelor’s programs. It is described with a focus on the mechanisms for the integrated use of the advantages of methods of problem- and project-based training in the formation of the professional competencies required for an engineer’s innovative activity in the development of a new product project. The data from an empirical study have been considered; they allow us to substantiate the conclusion that the integration of project- and problem-based learning in the form of a holistic technology is effective for developing students’ creative capacities. © 2019 Moscow Polytechnic University. All rights reserved

    The flows structure in unsteady gas flow in pipes with different cross-sections

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    The results of numerical simulation and experimental study of the structure of unsteady flows in pipes with different cross sections are presented in the article. It is shown that the unsteady gas flow in a circular pipe is axisymmetric without secondary currents. Steady vortex structures (secondary flows) are observed in pipes with cross sections in the form of a square and an equilateral triangle. It was found that these secondary flows have a significant impact on gas flows in pipes of complex configuration. On the basis of experimental researches it is established that the strong oscillatory phenomena exist in the inlet pipe of the piston engine arising after the closing of the intake valve. The placement of the profiled plots (with a cross section of a square or an equilateral triangle) in the intake pipe leads to the damping of the oscillatory phenomena and a more rapid stabilization of pulsating flow. This is due to the stabilizing effect of the vortex structures formed in the corners of this configuration

    Social Inequality as Global Challenge

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    Доступ до книги на сайті видавництва (copyright) https://www.riverpublishers.com/book_details.php?book_id=922У цій книзі обговорюються чинники нерівності, закладеної в наші соціальні, економічні та політичні системи. Соціальна нерівність особливо проявляється в секторах послуг у відмінності в доступі до охорони здоров’я, освіти, соціального захисту, системи житла, догляду за дітьми, догляду за літніми тощо. соціальним статусом певної групи, мовою, релігією, звичаями та нормами є ще одна поширена проблема. Ця книга намагається представити точну картину цих проблем на прикладах з різних країн. Здебільшого, коли ми говоримо про нерівність, акцент робиться на економічній нерівності; однак зберігається значна нерівність, особливо дискримінація за статтю, віком, походженням, етнічною приналежністю, інвалідністю, сексуальною орієнтацією, класом та релігією. Щоб покласти край цій ситуації, необхідно провести соціальні, економічні та політичні реформи. Поки маргіналізовані групи не отримають повноваження, проблему нерівності неможливо вирішити чи навіть мінімізувати. На основі різних тематичних досліджень ця книга заохочує нас переосмислити розвиток суспільства через призму зростаючої нерівності та диспропорції. У книзі представлені нові ідеї для оцінки прогресу соціального розвитку. Книга висвітлює сучасні проблеми соціальної нерівності. У сукупності ця збірка відредагованих статей дає комплексне розуміння питання «чому суспільство нерівне»? Ця книга націлена на тих зацікавлених сторін, які хочуть змінити та побудувати нерозділене, соціально інклюзивне суспільство або внести свій внесок у них, а також для тих, хто хоче зробити свій внесок у розширення прав і можливостей суспільства у ХХІ столітті.В этой книге обсуждаются факторы, лежащие в основе неравенства, присущего нашим социальным, экономическим и политическим системам. Социальное неравенство особенно заметно в секторах услуг - в различиях в доступе к здравоохранению, образованию, социальной защите, жилищным системам, уходу за детьми, уходу за престарелыми и т. д. Другой широко распространенной проблемой является социальный статус конкретных групп, их язык, религия, обычаи и нормы. В этой книге делается попытка представить точную картину этих проблем на примерах из разных стран. На основе различных тематических исследований эта книга побуждает нас переосмыслить социальное развитие через призму растущего неравенства и неравенства. В книге представлены новые идеи для оценки прогресса в социальном развитии. В книге освещаются современные проблемы социального неравенства. В совокупности этот сборник отредактированных статей дает комплексное понимание вопроса «почему общество неравно»? Эта книга адресована тем заинтересованным сторонам, которые хотят внести свой вклад в изменения и построить неразделенное, социально инклюзивное общество, а также тем, кто хочет внести свой вклад в расширение прав и возможностей общества в XXI веке.This book discusses the factors behind the inequalities embedded within our social, economic and political systems. Social inequalities are especially seen in the service sectors â  in the differences of access to healthcare, education, social protection, housing systems, childcare, elderly care etc. Cultural inequality, which segregates people from the mainstream based on recognition problems with a specific groups' social status, language, religion, customs and norms, is another widespread issue. This book tries to present an accurate picture of these issues with cases studies from various countries. Mostly, when we talk about inequality, the focus is on economic inequality; however, much inequality persists, especially discrimination due to gender, age, origin, ethnicity, disability, sexual orientation, class, and religion. To end this situation there is a need for social, economic, and political reform. Until or unless the marginalized groups are empowered, the inequality issue cannot be solved or even minimized. On the basis of various case studies, this book encourages us to rethink societal development through the lens of growing inequalities and disparities. The book presents new insights for evaluating the progress on social development. The book highlights the current challenges of social inequality. In combination this collection of edited papers gives an integrated understanding of the question of “why is society unequal”? This book is aimed at those stakeholders, who want to make or contribute to change and build an undivided, socially inclusive society, and to those who want to contribute to empowering society in the Twenty-First century

    Thermal-mechanical characteristics of stationary and pulsating gas-flows in a gas-dynamic system: In relation the exhaust system of an engine

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    It is a relevant objective in thermal physics and in building reciprocating internal combustion engines (RICE) to obtain new information about the thermal-mechanical characteristics of both stationary and pulsating gas-flows in a complex gas-dynamic system. The article discusses the physical features of the gas dynamics and heat transfer of flows along the length of a gas-dynamic system typical for RICE exhaust systems. Both an experimental set-up and experimental techniques are described. An indirect method for determining the local heat transfer coefficient of gas-flows in pipe-lines with a constant temperature hot-wire anemometer is proposed. The regularities of changes in the instantaneous values of the flow rate and the local heat transfer coefficient in time for stationary and pulsating gas-flows in different elements of the gas-dynamic system are obtained. The regularities of the change in the turbulence number of stationary and pulsating gas-flows along the length of reciprocating internal combustion engines gas-dynamic systems are established (it is shown that the turbulence number for a pulsating gas-flow is 1.3-2.1 times higher than for a stationary flow). The regularities of changes in the heat transfer coefficient along the length of the engine?s gas-dynamic system for stationary and pulsating gas-flows were identified (it was established that the heat transfer coefficient for a stationary flow is 1.05-1.4 times higher than for a pulsating flow). Empirical equations are obtained to determine the turbulence number and heat transfer coefficient along the length of the gas-dynamic system.</jats:p

    Modernization of the Mechanical Fuel System of a Diesel Locomotive Engine through Physical and Numerical Modeling

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    Reducing harmful emissions from exhaust gases and increasing energy efficiency are urgent tasks when designing reciprocating internal combustion engines. In this experimental work, the fuel system of a diesel locomotive engine operating on the Miller cycle is improved. The purpose of the study is to improve the environmental and economic indicators of diesel engines at minimal financial cost. The article provides an overview of the main research on improving fuel supply, mixing and combustion. The features of engine operation are also briefly described. Numerical simulation of the diesel engine operating cycle was performed before the bench tests. The experiments were performed on a full-size diesel engine with a power of 1200 kW. The measuring equipment and experimental technique are described in the article. The technical solutions that made it possible to improve the fuel supply are described. A new design for the high-pressure fuel pump drive is proposed. The optimal fuel injection advance angles are determined. An original design for the fuel pump plunger was developed. The proposed technical solutions made it possible to reduce fuel consumption by up to 3% (from 217.8 to 211.4 g/kW&middot;h) and NOx emissions two-fold (from 19.4 to 8.8 g/kW&middot;h)

    Mathematical Description of the Aerodynamic Characteristics of Stationary Flows in a Vertical Conical Diffuser When Air Is Supplied through Various Tube Configurations

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    Conical diffusers of various configurations are used in many kinds of technical equipment and manufacturing processes. Therefore, it is a relevant objective to obtain reliable experimental and mathematical data on the aerodynamic characteristics of diffusers. This article presents experimental data on the aerodynamics of stationary flows in a vertical conical diffuser when air is supplied through tubes with various cross sections (circle, square, and triangle). Instantaneous values of air flow velocity are measured with a constant-temperature hot-wire anemometer. Data are obtained on the velocity fields and turbulence intensity along the height and the diameter of the diffuser’s cylindrical part when air is supplied through tubes of various configurations. It is established that air supply through profiled tubes has a significant effect on the shape of the velocity field and turbulence intensity in a vertical conical diffuser. For example, higher values of turbulence intensity are typical of air supplied through profiled tubes (the differences reach 50%). A mathematical formulation (linear and exponential equations) of the change in the average speed and intensity of air flow turbulence along the height of the diffuser’s cylindrical part for various initial conditions and supply tube configurations is presented. The obtained findings will make it possible to refine mathematical models and update algorithms for engineering the design of diffusers for various engineering processes and pieces of technical equipment.</jats:p

    The Influence of Gas-Dynamic Non-Stationarity of Air Flow on the Heat Transfer Coefficient in Round and Triangular Straight Pipes with Different Turbulence Intensities

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    Unsteady gas-dynamic phenomena in pipelines of complex configuration are widespread in heat exchange and power equipment. Therefore, studying the heat transfer level of pulsating air flows in round and triangular pipes with different turbulence intensities is a relevant and significant task for the development of science and technology. The studies were conducted on a laboratory stand based on the thermal anemometry method and an automated system for collecting and processing experimental data. Rectilinear round and triangular pipes with identical cross-sectional areas were used in the work. Flow pulsations from 3 to 15.8 Hz were generated by means of a rotating flap. The turbulence intensity (TI) of the pulsating flows varied from 0.03 to 0.15 by installing stationary flat turbulators. The working medium was air with a temperature of 22 ± 1 °C moving at a speed from 5 to 75 m/s. It was established that the presence of gas-dynamic unsteadiness leads to an increase in the TI by 47–72% in a round pipe and by 36–86% in a triangular pipe. The presence of gas-dynamic unsteadiness causes a heat transfer intensification in a round pipe by 26–35.5% and by 24–36% in a triangular pipe. It was shown that a significant increase in the TI of pulsating flows leads to an increase in the heat transfer coefficient by 11–16% in a round pipe and a decrease in the heat transfer coefficient by 7–24% in a triangular pipe. The obtained results can be used in the design of heat exchangers and gas exchange systems in power machines, as well as in the creation of devices and apparatuses of pulse action

    Preparation and Analysis of Experimental Findings on the Thermal and Mechanical Characteristics of Pulsating Gas Flows in the Intake System of a Piston Engine for Modelling and Machine Learning

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    Today, reciprocating internal combustion engines are used in many branches of the economy (power engineering, machine engineering, transportation, and others). In order for piston engines to meet stringent environmental and economic regulations, it is necessary to develop complex and accurate control systems for the physical processes in engine elements based on digital twins, machine learning, and artificial intelligence algorithms. This article is aimed at preparing and analysing experimental data on the gas dynamics and heat transfer of pulsating air flows in a piston engine’s intake system for modelling and machine learning. The key studies were carried out on a full-scale model of a single-cylinder piston engine under dynamic conditions. Some experimental findings on the gas-dynamic and heat-exchange characteristics of the flows were obtained with the thermal anemometry method and a corresponding measuring system. The effects of the inlet channel diameter on the air flow, the intensity of turbulence, and the heat transfer coefficient of pulsating air flows in a piston engine’s inlet system are shown. A mathematical description of the dependences of the turbulence intensity, heat transfer coefficient, and Nusselt number on operation factors (crankshaft speed, air flow velocity, Reynolds number) and the inlet channel’s geometric dimensions are proposed. Based on the mathematical modelling of the thermodynamic cycle, the operational and environmental performance of a piston engine with intake systems containing channels with different diameters were assessed. The presented data could be useful for refining engineering calculations and mathematical models, as well as for developing digital twins and engine control systems

    Experimental research into the methods for controlling the thermal-mechanical characteristics of pulsating gas flows in the intake system of a turbocharged engine model

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    It is a relevant objective in thermal physics and piston engine construction to develop technical solutions for controlling the gas dynamics and heat exchange of gas flows in the intake system of turbocharged engines in order to improve performance. The article presents other authors’ data on the improvement of processes in the gas exchange systems of piston engines. It also provides a description of experimental set-ups, instruments, measurement tools and research methods for establishing the thermal-mechanical characteristics of pulsating flows in the intake system of a turbocharged engine. The instantaneous values of the gas flow rate and the local heat transfer coefficient were determined using the measured results by applying a constant temperature hot-wire anemometer (H-WA). The article describes technical solutions for influencing the gas dynamics and heat exchange of gas flows by stabilising and turbulising the flow. The regularities of changes in the instantaneous values of the flow velocity, pressure and the local heat transfer coefficient in time for a pulsating gas flow with different intake system configurations are obtained. It is shown that the installation of a levelling grid in the compressor outlet channel leads to the stabilisation of the flow and the suppression of heat transfer in the engine intake system by an average of 15% compared to the base system. It was found that the presence of a channel with grooves in the intake system leads to flow turbulisation and the intensification of heat transfer in the intake system by an average of 25%. </jats:p

    Integrated modernization of the gas-and-air system of a turbocharged diesel engine (21/21)

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    Improving the exploitative and environmental performance of piston engines (PICE) is an urgent task for many engineers and scientists. The article presents the results of the upgrade of a gas-and-air system of a diesel PICE, carried out through changing the turbocharging system’s configuration and modernizing the design of the admittance collector. The authors present a review of studies on the given subject and a description of the object of the research. The study was conducted on the basis of bench tests at a manufacturing plant and mathematical modeling using ACTUS program. The results of experimental studies on the main indicators of a basic and upgraded PICEs are presented. The gas exchange processes in the PICE under examination were studied in detail using mathematical modeling. For the given diesel PICE, improvement of the gas-and-air system leads to a growth in charging efficiency by 2.45-3.92%, a decrease in scavenging factor by 3.11-6.31% and a reduction of specific fuel consumption up to 3.33%. In the conclusion, new directions for increasing the efficiency of the given PICE are offered
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