Improvement of Thermal and Mechanic Flow Characteristics in the Intake System of the Piston Engine with Turbocharging

Currently the turbocharging is actively used in piston engines to increase their technical and economic indicators. The efficiency of piston engines with turbocharging significantly depends on perfection of processes in the intake and exhaust systems. Results of experimental researches of unsteady gas dynamics and heat transfer in the intake system of the piston engine with a turbocharger are presented in the article. Studies were conducted on full-scale model of the single-cylinder engine with a turbocharger. It is shown that significant pulsations of pressure and flow occur in the intake system of the piston engine during the entire working cycle. The method of stabilization of flows in the intake system due to the controlled discharge of excess air after the turbocharger is proposed. This method will reduce the difference in the cylinders of multi-cylinder engine, reduce noise, increase reliability, and increase the efficiency of the turbocharger

The shock-acoustic waves generated by earthquakes

We investigate the form and dynamics of shock-acoustic waves generated by earthquakes. We use the method for detecting and locating the sources of ionospheric impulsive disturbances, based on using data from a global network of receivers of the GPS navigation system and requiring no a priori information about the place and time of associated effects. The practical implementation of the method is illustrated by a case study of earthquake effects in Turkey (August 17, and November 12, 1999), in Southern Sumatera (June 4, 2000), and off the coast of Central America (January 13, 2001). It was found that in all instances the time period of the ionospheric response is 180-390 s, and the amplitude exceeds by a factor of two as a minimum the standard deviation of background fluctuations in total electron content in this range of periods under quiet and moderate geomagnetic conditions. The elevation of the wave vector varies through a range of 20-44 degree, and the phase velocity (1100-1300 m/s) approaches the sound velocity at the heights of the ionospheric F-region maximum. The calculated (by neglecting refraction corrections) location of the source roughly corresponds to the earthquake epicenter. Our data are consistent with the present views that shock-acoustic waves are caused by a piston-like movement of the Earth surface in the zone of an earthquake epicenter.Comment: EmTeX-386, 30 pages, 4 figures, 3 tabl

Improving the process of release of the piston internal combustion engine

В работе представлены результаты экспериментального исследования режимных факторов поршневых двигателей на процессы газообмена. Опыты проводились на натурных моделях одноцилиндрового ДВС. Описаны установки и методика проведения экспериментов. Представлены зависимости изменения мгновенной скорости и давления потока в газовоздушных трактах двигателя от угла поворота коленчатого вала. Данные получены при различных коэффициентах сопротивления впускных и выпускных систем и разных частотах вращения коленчатого вала. На основе полученных данных были сделаны выводы о динамических особенностях процессов газообмена в двигателе при различных условиях.Experimental study results of operation conditions influence of piston engines on gas exchange processes are presented in the paper. The experimental investigations were carried out on full-sized model of combustion engine. The experimental unit and research methods are described. Dependence of change of instantaneous velocity and pressure of the flow in the gas-air channels of engine from the angle of rotation of a cranked shaft are presented. Data were obtained with different the resistance coefficients of the intake and exhaust systems and different rotation crankshaft frequencies. Based on the findings, conclusions on the dynamic features of the processes of gas exchange in the engine under different conditions were drawn.Программа развития УрФУ на 2013 год (п.2.1.2.1

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)

An Indirect Method for Determining the Local Heat Transfer Coefficient of Gas Flows in Pipelines

An indirect method and procedure for determining the local heat transfer coefficient in experimental studies on the intensity of heat transfer at a gas–surface interface is described. The article provides an overview of modern approaches and technical devices for determining the heat flux or friction stresses on surfaces in the study of thermophysical processes. The proposed method uses a constant-temperature hot-wire anemometer and a sensor with a thread sensitive element fixed on the surface of a fluoroplastic substrate. A substrate with the sensor’s sensitive element was mounted flush with the wall of the investigated pipeline. This method is based on the Kutateladze–Leontiev approach (the laws of friction and heat transfer) and the hydrodynamic analogy of heat transfer (the Reynolds analogy): this is an assumption about the unity of momentum and heat transfer in a turbulent flow, which establishes a quantitative relationship between friction stresses on the heat exchange surface and heat transfer through this surface. The article presents a method for determining the speed of the developed measuring system. An example of a successful application of the proposed method in relation to the study of thermomechanical processes in the gas exchange systems of reciprocating internal combustion engines is described. © 2022 by the authors.Ministry of Education and Science of the Russian Federation, MinobrnaukaThe research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program) is gratefully acknowledged

Improving the technical and environmental performance of piston engines by upgrading the fuel system

The article presents the results of an experimental study of the dispersion of superheated water through cylindrical channels and nozzles of piston internal combustion engines under different initial conditions. The advantages and disadvantages of modern diesel engine fuel systems are discussed in the article. The process of explosive boiling in relation to the fuel system of a piston engine is formulated and briefly described. A description of the laboratory setup and methods of conducting experiments is given in the article. The results of the visualization of sprayed superheated water through a cylindrical channel and through a diesel engine nozzle of 21/21 dimension are presented. The original scheme of the fuel system for a diesel engine using the effect of explosive boiling is proposed. Preliminary estimates have shown that the use of such a fuel system will increase the reliability of the combustion chamber elements of a piston engine, reduce specific fuel consumption (up to 2%) and reduce the amount of harmful substances in exhaust gases (an average of 12% compared with traditional fuel systems). © The Authors, published by EDP Sciences

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)

Evaluation of the effect of Miller cycle on the main parameters of a diesel engine using mathematical modeling

The influence of the angles of closure of the intake valves on the technical, economic and ecological parameters of a diesel engine was studied by numerical simulation. The study was carried out in the program complex Diesel-RK developed by the MGTU named after N. E. Bauman. Diesel 12DM-185 was chosen as the base engine for the study. It is shown that application of the Miller cycle (early valve closing) has a significant impact on the performance of diesel. It is established that the optimum closing angles of the intake valves for the diesel when using the Miller cycle is 25 degrees before BDC.В данной статье на основе численного моделирования было исследовано влияние углов закрытия впускных клапанов на технико-экономические и экологические показатели дизельного двигателя. Исследование выполнено в программном комплексе Дизель-РК, разработанном в МГТУ имени Н. Э. Баумана. В качестве базового двигателя для исследования был выбран дизель 12ДМ-185. Показано, что применение цикла Миллера (раннее закрытие клапана) оказывает существенное влияние на показатели дизеля. Установлено, что оптимальные углы закрытия впускных клапанов для исследуемого дизеля при использовании цикла Миллера составляют 25 градусов до НМТ