Influence of Gas-Dynamical Nonstationarity on Local Heat Transfer in the Gas–Air Passages of Piston Internal-Combustion Engines

2018 ◽  
Vol 91 (6) ◽  
pp. 1444-1451 ◽  
Author(s):  
L. V. Plotnikov ◽  
B. P. Zhilkin
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Local Heat Transfer ◽  
Internal Combustion ◽  
Local Heat ◽  
Combustion Engines

Influence of High-Frequency Gas-Dynamic Unsteadiness on Heat Transfer in Gas Flows of Internal Combustion Engines

2014 ◽  
Vol 698 ◽  
pp. 631-636 ◽  
Author(s):  
L.V. Plotnikov ◽  
B.P. Zhilkin ◽  
Y.M. Brodov
Keyword(s):  
Heat Transfer ◽  
High Frequency ◽  
Internal Combustion Engines ◽  
Rotation Angle ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Gas Flows ◽  
Combustion Engines ◽  
Instantaneous Values ◽  
Crankshaft Rotation

The results of experimental research of the influence of high-frequency gas-dynamical nonstationarity on the intensity of heat transfer in the intake and exhaust tract of piston engines are presented in the article. Experimental setup and methods of the experiments are described in the article. Dependences of instantaneous values of flow velocity and the local heat transfer coefficient in the intake and exhaust tract of the engine from the crankshaft rotation angle are presented in the article.

scholarly journals Features of heat and mechanical characteristics of pulsating flows in gas-air paths of piston engines with turbocharging

2019 ◽  
Vol 21 (4) ◽  
pp. 77-84
Author(s):  
L. V. Plotnikov ◽  
Y. M. Brodov ◽  
B. P. Zhilkin ◽  
N. I. Grigoriev
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Original Method ◽  
Combustion Engines ◽  
Gas Dynamic ◽  
Exchange Processes ◽  
Turbo Compressor

This article provides a comparative analysis of unsteady gas dynamics and instantaneous local heat transfer of pulsating flows in the intake and exhaust systems of reciprocating internal combustion engines in the case of a turbo-compressor installed without it and based on the results of experimental studies. Experimental studies were carried out on full-scale laboratory stands under the conditions of gas-dynamic nonstationarity. The article provides an original method for determining the instantaneous values of the local heat transfer coefficient in pipes, and describes the procedure for conducting experiments. It has been established that the presence of a turbo compressor in the gas-air system of a piston engine leads to significant differences in the patterns of changes in the gas-dynamic and heat exchange characteristics of pulsating flows. The obtained new data can be used to improve engineering methods for calculating the quality indicators of gas exchange processes, to refine the working processes of the engine when installing a turbocharger, as well as to develop advanced gas-air ICE systems with turbocharging.

Improvement of operational indicators of automobile internal combustion engines by development of thermogasdynamics in intake system

2020 ◽  
pp. 47-51
Author(s):  
Leonid Valeryevich Plotnikov ◽  
◽  
Nikita Igorevich Grigoryev ◽  
Nikolay Sergeevich Kochev ◽  
Leonid Evgenyevich Osipov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Local Heat Transfer ◽  
Internal Combustion ◽  
Flow Speed ◽  
Boost Pressure ◽  
Combustion Engines ◽  
Original Design ◽  
Charge System ◽  
Intake System

Piston internal combustion engines (ICE) are the most widespread sources of energy among heat engines. The ICEs are widely used as power installations on road transport. Nowadays, most of the ICEs are equipped with the boost-pressure charge system. Thermal and mechanical improvement of processes in intake system largely affects the efficiency of piston engines. The paper proposes a method of stabilization of pulsing flows in the intake system by the installation of the equalizing frame in the output channel of the turbocharger (TC). Investigations were carried out on an experimental installation that consisted of single-cylinder engine (8.2/7.1) and boost-pressure charge system (ТКR-6). Determination of instantaneous values of air flow speed and local heat transfer coefficient was conducted by the use of constant-temperature heat loss anemometer with an original design. It is established that the presence of the equalizing frame in the intake system leads to the decrease of turbulence level up to 25 % in comparison with the basic intake system (with preservation of metering characteristics). It is shown that the installation of the equalizing frame in the intake system of the ICE with TC also leads to the decrease in heat transfer intensity up to 15 % in comparison with the basic system. As a result, the authors determined values of breakdown intensity and probability of failure-free operation of engine with basic and modernized intake system.

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

2017 ◽  
Vol 19 (10) ◽  
pp. 1005-1023 ◽  
Author(s):  
Jerald A Caton
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Thermodynamic Evaluation ◽  
Combustion Engines ◽  
Automotive Engine ◽  
Specific Heats ◽  
Cycle Simulation

The thermodynamic limitation for the maximum efficiencies of internal combustion engines is an important consideration for the design and development of future engines. Knowing these limits helps direct resources to those areas with the most potential for improvements. Using an engine cycle simulation which includes the first and second laws of thermodynamics, this study has determined the fundamental thermodynamics that are responsible for these limits. This work has considered an automotive engine and has quantified the maximum efficiencies starting with the most ideal conditions. These ideal conditions included no heat losses, no mechanical friction, lean operation, and short burn durations. Then, each of these idealizations is removed in a step-by-step fashion until a configuration that represents current engines is obtained. During this process, a systematic thermodynamic evaluation was completed to determine the fundamental reasons for the limitations of the maximum efficiencies. For the most ideal assumptions, for compression ratios of 20 and 30, the thermal efficiencies were 62.5% and 66.9%, respectively. These limits are largely a result of the combustion irreversibilities. As each of the idealizations is relaxed, the thermal efficiencies continue to decrease. High compression ratios are identified as an important aspect for high-efficiency engines. Cylinder heat transfer was found to be one of the largest impediments to high efficiency. Reducing cylinder heat transfer, however, is difficult and may not result in much direct increases of piston work due to decreases of the ratio of specific heats. Throughout this work, the importance of high values of the ratio of specific heats was identified as important for achieving high thermal efficiencies. Depending on the selection of constraints, different values may be given for the maximum thermal efficiency. These constraints include the allowed values for compression ratio, heat transfer, friction, stoichiometry, cylinder pressure, and pressure rise rate.

Thermophysical Properties of Working Substance and Heat Transfer in a Hydrogen Combustion Engine

2003 ◽  
Author(s):  
T. Shudo ◽  
H. Oka
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Heat Loss ◽  
Thermophysical Properties ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Spark Ignition ◽  
Hydrogen Combustion ◽  
Spark Ignition Engine ◽  
Combustion Engines

Hydrogen is a clean alternative to fossil fuels for internal combustion engines and can be easily used in spark-ignition engines. However, the characteristics of the engines fueled with hydrogen are largely different from those with conventional hydrocarbon fuels. A higher burning velocity and a shorter quenching distance for hydrogen as compared with hydrocarbons bring a higher degree of constant volume and a larger heat transfer from the burning gas to the combustion chamber wall of the engines. Because of the large heat loss, the thermal efficiency of an engine fueled with hydrogen is sometimes lower than that with hydrocarbons. Therefore, the analysis and the reduction of the heat loss are crucial for the efficient utilization of hydrogen in internal combustion engines. The empirical correlations to describe the total heat transferred from the burning gas to the combustion chamber walls are often used to calculate the heat loss in internal combustion engines. However, the previous research by one of the authors has shown that the widely used heat transfer correlations cannot be properly applied to the hydrogen combustion even with adjusting the constants in them. For this background, this research analyzes the relationship between characteristics of thermophysical properties of working substance and heat transfer to the wall in a spark-ignition engine fueled with hydrogen.

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