Features of thermomechanics of pulsating gas flows in inlet systems with grooves applicable to automotive engines

2021 ◽  
pp. 85-89
Author(s):  
L. V. Plotnikov ◽  
◽  
N. I. Grigoryev ◽  
L. E. Osipov ◽  
O. A. Plotnikov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
Primary Data ◽  
Gas Flows ◽  
Inlet System ◽  
Heat Engines ◽  
System A ◽  
High Dynamics ◽  
Secondary Vortices

Reciprocating internal combustion engines (RICE) are widely used as heat engines for converting the chemical energy of a fuel into mechanical work on the crankshaft. Aerodynamic and thermophysical processes in gas exchange systems significantly affect the efficiency of the RICE. This paper examines the possibility of influencing the gas dynamics and heat transfer of pulsating gas flows in the inlet system by placing a channel with grooves. It is known that the presence of grooves in the channel leads to the formation of significant secondary vortices, which radically change the physical picture of the gas flow. The studies were carried out on a laboratory bench, which was a singlecylinder model of a turbocharged RICE. A system of measurements of basic physical quantities is described, taking into account their high dynamics. Techniques for processing experimental data are presented. Primary data on instantaneous values of gas-dynamic and heatexchange characteristics of pulsating flows are presented. It was found that the presence of a channel with grooves in the inlet system leads to a decrease in the degree of turbulence to 40 % and an intensification of heat transfer in the range of 5–50 % compared to the basic inlet system. A positive effect is shown in the form of an increase in engine power by 3 % when using the modernized system.

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.

A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and its Usage for Calibrating Control Oriented and 1D Models at Early ICE Design Stages

2019 ◽  
Author(s):  
José Ramón Serrano ◽  
Francisco José Arnau ◽  
Luis Miguel García-Cuevas ◽  
Alejandro Gómez-Vilanova ◽  
Stephane Guilain ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
System Analysis ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Boost Pressure ◽  
Gas Temperature ◽  
Hot Gas ◽  
The Impact

Abstract Turbocharged engines are the standard architecture for designing efficient spark ignition and compression ignition reciprocating internal combustion engines (ICE). Turbochargers characterization and modeling are basic tasks for the analysis and prediction of the whole engine system performance and this information is needed in quite early stages of the engine design. Turbocharger characteristics (efficiency, pressure ratio, mass flow rates...) traditionally rely in maps of pseudo non-dimensional variables called reduced variables. These maps must be used by reciprocating ICE designer and modeler not only for benchmarking of the turbocharger, but for a multiplicity of purposes, i.e: assessing engine back-pressure, boost pressure, load transient response, after-treatment inlet temperature, intercooler inlet temperature, low pressure EGR temperature, ... Maps of reduced variables are measured in gas-stands with steady flow but non-standardized fluids conditioning; neither temperatures nor flows. In concrete: turbine inlet gas temperature; lubrication-oil flow and temperature; water-cooling flow and turbo-machinery external heat transfer are non-standardized variables which have a big impact in assessing said multiplicity of purposes. Moreover, adiabatic efficiency, heat losses and friction losses are important data, hidden in the maps of reduced variables, which depend on the testing conditions as much as on the auxiliary fluids temperature and flow rate. In this work it is proposed a methodology to standardize turbochargers testing based in measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or 1D-modelling the ICE. The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

Heat Transfer Characteristics of Turbulent Gas Flow Through Micro-Tubes

2010 ◽  
Author(s):  
Chungpyo Hong ◽  
Yuki Uchida ◽  
Takaharu Yamamoto ◽  
Yutaka Asako ◽  
Koichi Suzuki
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Wall Temperature ◽  
Transfer Rate ◽  
Gas Flow ◽  
Gas Flows ◽  
Heat Transfer Characteristics ◽  
Total Temperature ◽  
Flow Through ◽  
Turbulent Gas Flow

This paper presents experimental results on heat transfer characteristics of turbulent gas flows though a micro-tube with constant wall temperature. The experiments were performed for nitrogen gas flows through a micro-tube with 242μm in diameter and 50 mm in length. The wall temperature was maintained at 5K, 20K and 30K higher than the inlet temperature by circulating water around the micro-tube, respectively. In order to measure heat transfer rate of gas flow through a micro-tube, the total temperature at a micro-tube exit was measured. The stagnation pressure was chosen in such a way that the Reynolds number ranges from 3000 to 12000. The outlet pressure was fixed at the atmospheric condition. The total temperature at the outlet, the inlet stagnation temperature, the mass flow rate, and the inlet pressure were measured. The heat transfer rates obtained by the present study are higher than those of the incompressible flow. This is due to the additional heat transfer near the micro-tube outlet caused by the energy conversion into kinetic energy. A correlation for the prediction of the heat transfer rate of the turbulent gas flow through a micro-tube was proposed.

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

2019 ◽  
Vol 124 ◽  
pp. 01015
Author(s):  
L. V. Plotnikov ◽  
Y. M. Brodov ◽  
M. O. Misnik
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Exhaust System ◽  
Scale Model ◽  
Gas Flows ◽  
Exhaust Pipe ◽  
Piston Engine ◽  
Gas Dynamic ◽  
Valve Assembly

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.

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

2021 ◽  
pp. 146808742098736
Author(s):  
Leonid V Plotnikov
Keyword(s):  
Heat Transfer ◽  
Gas Dynamics ◽  
Gas Flow ◽  
Mechanical Characteristics ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Gas Flows ◽  
Intake System ◽  
Instantaneous Values ◽  
Technical Solutions

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%.

Frictional Characteristics of Microchannel Gas Flow

2003 ◽  
Author(s):  
Abdullahel Bari ◽  
Jae-Mo Koo ◽  
Linan Jiang ◽  
Jay Paidipati ◽  
Kenneth E. Goodson
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Friction Factor ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Hydraulic Diameter ◽  
Transition To Turbulence ◽  
Gas Flows ◽  
Design And Development ◽  
Predicted Values

The improved rates of heat transfer in microchannel gas flows are promising for the design and development of microfluidic systems. This research focuses on the flow characteristics of air in rectangular micro/minichannels at moderate velocities (∼100 m/sec). The 50.8 mm long channels vary from approximately 266 μm to 1090 μm in hydraulic diameter, and the aspect ratio ranges from 0.1 to 0.75. The value of Re ranged from 250 to 4300, with the intention of studying the transition to turbulence. The friction factor is found to be higher than predicted values for Re < 1400 and lower when Re > 1400 suggesting earlier transition to turbulence.

Non-Fourier Heat Transport in Microscale and Nanoscale Gas Flows

2009 ◽  
Author(s):  
R. S. Myong
Keyword(s):  
Heat Transfer ◽  
Heat Transport ◽  
Gas Flow ◽  
Constitutive Relations ◽  
Gas Flows ◽  
Nonlinear Relationship ◽  
Computationally Efficient ◽  
Thermal Nonequilibrium ◽  
Flow And Heat Transfer ◽  
Sophisticated Model

It is known that heat transport in microscale and nanoscale gas flows may deviate from the classical law of Fourier. A more sophisticated model may be needed to describe the gaseous and thermal transport in these cases. In this work, computationally efficient nonlinear coupled constitutive relations are presented and their properties in states removed far from thermal nonequilibrium are examined. In order to validate the new model, the force-driven Poiseuille gas flow in microchannel is considered. The emphasis will be placed on how coupled and nonlinear relationship affects the prediction of gas flow and heat transfer in microsystem.

Fully Developed Heat Transfer to a Gaseous Suspension of Particles Flowing Turbulently in Ducts of Different Size

1970 ◽  
Vol 12 (3) ◽  
pp. 191-200 ◽  
Author(s):  
R. G. Boothroyd ◽  
H. Haque
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Gas Flow ◽  
Eddy Diffusion ◽  
Gas Flows ◽  
Gas Flow Rate ◽  
Flow Conditions ◽  
Gaseous Suspension ◽  
Fractional Increase

This paper is a sequel to two earlier studies of friction (I)† and eddy diffusion (2) carried out for the same flow conditions as in the present study of heat transfer. Heat was transferred to an upward flowing suspension of 0-40 μ zinc particles in pipes of 1, 2 and 3 in bore. The solids/gas flow rate was in the range 0 < Ws/ W g< 17 and the pipe Reynolds number in the range 3·5 × 104< Re < 105. It was found that the fractional increase in heat transfer coefficient due to the presence of solids was always less than the increase in the friction factor. Minimum values of both these parameters are often observed in the range 1 < W s/ W q< 2·5. This paper gives further evidence that turbulence is suppressed by the particles, particularly when the duct is small and Re is large; in this case the wall Nusselt number, Nu s, is markedly reduced below the value when gas flows alone. However, when the pipe is large and Re is low, Nu s can be substantially higher than the value for gas alone. In this case the suspension is a superior coolant to the flow of gas alone.

The activity airflow detection of vehicle intake system using hot-film anemometry sensors instrument

2011 ◽  
Vol 225 (12) ◽  
pp. 2900-2906
Author(s):  
R-H Ma
Keyword(s):  
Internal Combustion Engines ◽  
Gas Flow ◽  
Alumina Substrate ◽  
Gas Flows ◽  
Process Technology ◽  
Airflow Velocity ◽  
Intake System ◽  
Sensor Resistance ◽  
Wind Velocities ◽  
Hot Film

The goal of this study is to develop an airflow meter sensor for the detection of vehicle intake system in internal combustion engines. The study uses micro-electromechanical process technology to develop a hot-film flow meter with an alumina substrate and platinum film heater; the hot-line method is used to create a micro-airflow anemometry meter sensor relying on variations in resistance of the platinum film corresponding to different wind velocities at the set temperatures. The alumina plate used in this study is produced by polishing an alumina substrate; a platinum film is then deposited on the plate to complete the micro-heater used in the sensor. Resistance on the sensor side varies as gas flows through the sensor, and the instrument determines airflow velocity on the basis of the changes in resistance caused by gas flow differences. Airflow velocities ranging from 10 to 60 m/s are used to test. Signals of change in resistance display a regular slope, indicating that the relationship between the changes in airflow velocity remains predictable throughout the sensing range. Therefore, the sensor can achieve its purpose of airflow measurement completely.

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