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%.

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 Nonstationary gas-dynamics and local heat transfer in the output channel of the turbocharger compressor

2019 ◽  
Vol 196 ◽  
pp. 00007 ◽  
Author(s):  
Leonid Plotnikov ◽  
Nikita Grigor'ev ◽  
Nikolaj Kochev
Keyword(s):  
Heat Transfer ◽  
Gas Dynamics ◽  
Gas Flow ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Measuring System ◽  
Rotor Speed ◽  
Outlet Channel ◽  
Thermomechanical Characteristics ◽  
Channel Configuration

Thermomechanical characteristics of the gas flow at the turbocharger compressor outlet largely determine the quality of the intake process in piston engines with boost. The article presents the results of an experimental study of gas-dynamics and heat transfer of gas flows after compression in a turbocharger centrifugal compressor. A brief description of the experimental setup, the configuration of pipes under investigation, the measuring system and the experimental features are given. The studies were carried out on a free compressor, i.e. without considering the piston part. Different conditions in the compressor outlet channel were created by installing special nozzles with different hydraulic resistances. It has been established that the local heat transfer increases from 23 to 46 % with an increase in the turbocharger rotor speed, depending on the outlet channel configuration. It should be noted that an increase in rotor speed is also accompanied by an increase in air flow through the channel. The increase in flow rate was from 10 to 42 %.

Annular Liquid Film Flow Under Local Heating in Microchannel

2005 ◽  
Author(s):  
Elizaveta Ya. Gatapova ◽  
Vladimir V. Kuznetsov ◽  
Oleg A. Kabov ◽  
Jean-Claude Legros
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Biot Number ◽  
Gas Flow ◽  
Film Flow ◽  
Local Heating ◽  
Local Heat Transfer ◽  
Flow Region ◽  
Local Heat ◽  
Liquid Film Flow

In our previous investigations the formation of liquid bump of locally heated laminar liquid film with co-current gas flow was obtained [1,2]. The evaporation of liquid was left out of account. Heat transfer to the gas phase was approximately specified by a constant Biot number [2,3]. The aim of this work is an investigation of the evaporation effect, the hydrodynamics and the heat transfer of liquid film flow in a channel 0.2–1 mm height. The 2-D model of locally heated liquid film moving under gravity and the action of co-current gas flow with low viscosity in a channel are considered. The channel can be inclined at an angle with respect to horizon. It is supposed that the height of the channel is much less than its width. Surface tension is assumed to depend on temperature. The velocity profiles for gas and liquid regions are found from problem of joint motion of isothermal non-deformable liquid film and gas flow. Using the findings the joint solution of heat transfer and diffusion problem with corresponding boundary condition is calculated. Having the temperature field in the whole of liquid and gas flow region we find a local heat transfer coefficient on the gas-liquid interface and Biot number as a function of flow parameters and spatial variables.

scholarly journals Thermal-mechanical characteristics of stationary and pulsating gas flows in a gas-dynamic system (in relation to the exhaust system of an engine)

2021 ◽  
pp. 171-171
Author(s):  
Leonid Plotnikov
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Dynamic System ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Stationary Flow ◽  
Local Heat ◽  
Gas Flows ◽  
Gas Dynamic ◽  
The Heat Transfer Coefficient

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 pipelines 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 RICE 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.

The Transition From Turbulent to Laminar Gas Flow in a Heated Pipe

1970 ◽  
Vol 92 (4) ◽  
pp. 569-579 ◽  
Author(s):  
C. A. Bankston
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Heat Fluxes ◽  
External Boundary ◽  
Transfer Coefficients ◽  
Adiabatic Flow ◽  
Heat Transfer Coefficients

Experimental results are reported on the heat transfer and fluid friction of heated hydrogen and helium gas flows undergoing transition from turbulent to laminar flow in a circular tube. The entering Reynolds numbers range from 2350 to 12,500 and the nondimensional heat-flux parameter ranges from 0.0021 to 0.0061. Local heat-transfer coefficients and friction factors are obtained, and the flow transition, which is evident in these results, is verified at small heat fluxes by measuring directly the turbulence intensity at the center line with a hot-wire anemometer. At large heat fluxes, laminarization is found to occur at local bulk Reynolds numbers well in excess of the minimum number for fully turbulent adiabatic flow, and the resulting heat-transfer coefficients are much lower than those associated with fully turbulent flow at the same Reynolds number. The relation between laminarization in heated tubes and in severely accelerated external boundary layers is investigated and some similarities are noted. The acceleration and pressure-gradient parameters used to predict boundary-layer laminarization are modified for tube flow and used to correlate the initiation and completion of laminarization in the heated tube.

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