Influence of channels transverse profiling on the heat transfer intensity in the intake system of internal combustion engine

Gas-dynamic perfection and intensity of heat exchange of intake systems determine the efficiency of the piston engine. The results of numerical simulation and experimental study of the heat transfer of gas streams in the intake system of engines having different configurations are presented in the article. Methods of modeling, experimental setup, geometric configuration of pipelines and measuring base are described in the paper. The investigations were carried out under steady-state air flow in the system. The results of mathematical modeling were verified using experimental studies. It is established that the use of profiled sections in the intake system leads to a decrease in the heat transfer rate up to 20 % at low air flow rates (up to 40 m/s) and an increase in the heat transfer rate up to 9 % at high speeds. © Published under licence by IOP Publishing Ltd.The work has been supported by the Russian Science Foundation (grant No. 18-79-10003)

Heat transfer intensity of pulsating gas flows in the exhaust system elements of a piston engine

Internal combustion engines are the most common sources of energy among heat engines. Therefore, the improvement of their design and workflow is an urgent task in the development of world energy. Thermal-mechanical perfection of the exhaust system has a significant impact on the technical and economic performance of piston engines. The article presents the results of experimental studies of gas-dynamics and heat exchange of pulsating gas flows in the exhaust system of a piston engine. Studies were carried out on a full-scale model of a single-cylinder engine. The article describes the instrument-measuring base and methods of experiments. The heat transfer intensity was estimated in different elements of the exhaust system: the exhaust pipe, the channel in the cylinder head, the valve assembly. Heat transfer studies were carried out taking into account the gas-dynamic nonstationarity characteristic of gas exchange processes in engines. The article presents data on the influence of gas-dynamic and regime factors on the heat transfer intensity. It is shown that the restructuring of the gas flow structure in the exhaust system occurs depending on the engine crankshaft speed, this has a significant impact on the local heat transfer coefficient. It has been established that the heat transfer intensity in the valve assembly is 2-3 times lower than in other elements of the exhaust system. © The Authors, published by EDP Sciences.Russian Science Foundation, RSF: 18-79-10003The work has been supported by the Russian Science Foundation (grant No. 18-79-10003)

Numerical simulation of gas dynamics and heat transfer in the intake system of the piston ICE in stationary conditions

The results of numerical simulation of gas dynamics and heat transfer in the intake systems of different configurations with respect to the piston engine are presented in this article. It is shown that the transverse profiling of the intake pipe leads to a significant change of flow structure in the intake system, stabilization of the flow (reduction of stagnant zones, leveling velocity field) in the intake system and the cylinder of the piston engine, reduce the intensity of heat transfer up to 15 % with flow velocities up to 40 m/s and increase the intensity of heat transfer up to 5% at high speeds.В данной статье представлены результаты численного моделирования газодинамики и теплообмена во впускных системах разной конфигурации применительно к поршневым двигателям. Показано, что поперечное профилирование впускного трубопровода приводит к существенному изменению структуры течения во впускной системе, стабилизации течения (сокращению застойных зон, выравниванию поля скоростей) во впускной системе и цилиндре ДВС, снижению интенсивности теплоотдачи вплоть до 15 % при скоростях потока воздуха до 40 м/с и росту интенсивности теплоотдачи до 5 % при высоких скоростях

ДІАГНОСТИКА ТА ЛІКУВАННЯ ФУНКЦІОНАЛЬНИХ ЗАХВОРЮВАНЬ КИШЕЧНИКА У ДІТЕЙ РАННЬОГО ВІКУ (КЛІНІЧНІ РЕКОМЕНДАЦІЇ)

Функціональні захворювання кишечника  (ФЗК) займають одне з провідних місць в структурі патології органів травлення у дітей раннього віку і характеризуються різноманітними клінічними проявами. У клінічних рекомендаціях на підставі сучасних доказових даних показано, що однією з причин розвитку ФЗК у дітей будь – якої вікової групи є зрушення кількісних і якісних характеристик кишкової мікробіоти та запропоновані практичні підходи до їх корекції. Найбільш перспективним є застосування біотерапевтичних формул, що містять як пробіотичні мікробні штами, так і синергічні пребіотики, та мають доведену клінічну ефективність і безпечність (статуси GRAS та QPS), активують ріст і метаболічну активність корисної мікрофлори. Впровадження запропонованих медичних технологій в комплексній терапії ФЗК дозволить попередити або провести своєчасну корекцію ФЗК у дітей грудного віку. Клінічні рекомендації призначені для лікарів-педіатрів, лікарів загальної практики-сімейної медицини, гастроентерологів

Strategic Methods for Managing Risk Insurance in Crop Production

Doing any entrepreneurial activity takes place under conditions of risk and uncertainty. Agricultural production is distinguished by a special risk environment, since it manifests natural and climatic risks that are very dangerous and have the maximum effect on the final results of operations. At the same time, the economic damage caused by them is not only comparable to the scale of the financial results of commodity producers, but periodically exceeds them. Households also suffer losses as a result of the risks that are traditional for any commercial activity (production, marketing, financial): the size of these losses is large, difficult to estimate, and the consequences are disastrous. Therefore, the complex impact of agricultural risks obliges commodity producers to put stability and guaranteed result in the first place in the system of their interests

Numerical Simulation of Gas Dynamics and Heat Transfer in the Exhaust System of the Piston Engine with 8.2/7.1 Dimensions

The paper presents the results of the physical and mathematical modeling of gas dynamics and heat transfer in the exhaust system of a piston internal combustion engine of 8.2/7.1 dimension. The description of the configuration of the studied exhaust system and the physical features of the developed mathematical model are given. The results obtained during the simulation are in qualitative agreement with the data of other authors. The developed mathematical model can be applied at designing and finishing of exhaust systems of piston internal combustion engines.В статье представлены результаты физико-математического моделирования газодинамики и теплоотдачи в выпускной системе поршневого двигателя внутреннего сгорания размерности 8,2/7,1. Приводится описание конфигурации исследуемой системы выпуска и физические особенности разработанной математической модели. Результаты, полученные в ходе моделирования, качественно согласуются с данными других авторов. Разработанная математическая модель может применяться при проектировании и доводке выпускных систем поршневых ДВС

Forecasting the financial results from enterprase activity

Statistical equations of dependence have been used in this article to forecast the financial activity of an enterprise. The selection of 6 primary factors of production is grounded, as directly affecting the effectiveness of financial resources, other current assets, bills payable. The results of the research show that the current financial situation of the enterprise is stable. According to the estimates the net profit will increase in the future. At the same time, of all these factors cash resources and other current assets had the maximum impact on net profit increase

Physical and numerical simulation of the thermal and mechanical characteristics of stationary flows in the gasair paths of piston engines

Thermomechanical perfection of intake and exhaust systems largely determine the efficiency of the working process of reciprocating engines (ICE). The article presents the results of numerical simulation and experimental study of the heat transfer of gas flows in profiled gas- air systems of ICEs. A description of the numerical simulation technique, experimental setup, configurations of the studied hydraulic systems, measuring base and features of the experiments are given. On the basis of numerical modeling, it has been established that the use of profiled sections with cross sections in the shape of a square or a triangle in exhaust systems of an ICEs leads to a decrease in the heat transfer coefficient by 5-11%. It is shown that the use of similar profiled sections in the intake system of reciprocating engines also leads to a decrease in the heat transfer coefficient to 10 % at low air flow rates (up to 40 m/s) and an increase in the heat transfer coefficient to 7% at high speeds. Experimental studies qualitatively confirm the simulation results