Study on Heat Exchanger Efficiency of EGR Cooler with Dimpled Rectangular Tube Shape for Application of Diesel Vehicles

2008 ◽  
Vol 32 (10) ◽  
pp. 769-775 ◽  
Author(s):  
Young-Ho Seo ◽  
Seong-Chan Heo ◽  
Tae-Wan Ku ◽  
Woo-Jin Song ◽  
Jeong Kim ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Diesel Vehicles ◽  
Rectangular Tube ◽  
Tube Shape ◽  
Egr Cooler

scholarly journals Parametric Study on EGR Cooler Fouling Mechanism Using Model Gas and Light-Duty Diesel Engine Exhaust Gas

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3161 ◽  
Author(s):  
Sangjun Park ◽  
Kyo Lee ◽  
Jungsoo Park
Keyword(s):  
Heat Exchanger ◽  
Diesel Engine ◽  
Laboratory Experiment ◽  
Flow Rate ◽  
Parametric Study ◽  
Gas Flow ◽  
Exhaust Gas ◽  
Gas Flow Rate ◽  
Engine Exhaust ◽  
Egr Cooler

Exhaust gas recirculation (EGR) and high-pressure fuel injection are key technologies for reducing diesel engine emissions in the face of reinforced regulations. With the increasing need for advanced EGR technologies to achieve low-temperature combustion and low emission, the adverse etableffects of EGR must be addressed. One of the main problems is fouling of the EGR cooler, which involves the deposition of particulate matter (PM) due to the thermophoretic force between the cooler wall and flow field. A large amount of deposited PM can reduce the effectiveness of the heat exchanger in the EGR cooler and the de-NOx efficiency. In the present study, the effects of the variables that affect EGR cooler fouling are investigated by a comparison of laboratory-based and engine-based experiments. In the laboratory experiment, a soot generator that could readily provide separate control of the variables was used to generate the model EGR gas. Through control of the soot generator, it was possible to perform a parametric study by varying the particle size, the EGR gas flow rate, and the coolant temperature as the dominant parameters. A decrease in these factors caused an increase in the mass of the deposit and a drop in the effectiveness of the heat exchanger, related to fouling of the EGR cooler. In the engine-based experiment, engine-like conditions were provided to analyze real exhaust gas without a soot generator. Different variables were found to induce fouling of the EGR cooler, and the results of the engine-based experiment differed from those of the laboratory experiment. For example, in the engine-based experiment, a decrease in the EGR gas flow rate did not lead to a more pronounced drop in the effectiveness of the heat exchanger because of the increase in the concentration of PM in the EGR gas. This result shows that the conditions of the engine exhaust gas are different from those of the soot generator.

Effects of the Internal Shape of EGR Cooler on Heat Exchanger Efficiencies

2007 ◽  
Author(s):  
Sang-Ki Park ◽  
Kap-Seung Choi ◽  
Hak-Min Wang ◽  
Hyung-Man Kim ◽  
Dae-Hee Lee ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Egr Cooler

Effect of tube shape on the performance of a fin and tube heat exchanger

2020 ◽  
Vol 14 (2) ◽  
pp. 6709-6718
Author(s):  
Djamel Sahel ◽  
Houari Ameur ◽  
Mustapha Mellal
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Finned Tube ◽  
Moderate Pressure ◽  
Tube Heat Exchanger ◽  
Finned Tube Heat Exchanger ◽  
Tube Shape ◽  
Different Shapes

A numerical study is carried out to test the effect of tube shape on heat transfer and fluid flow in a finned tube heat exchanger. The effects of different shapes (circular, flat, elliptical and oval in both orientations: left and right) are analyzed. The simulations are carried out for two-dimensional and external flow of an incompressible fluid with Reynolds numbers varying between 3000 and 20000. The results obtained indicate that the shape of the tube directly affects the thermal and dynamic behaviors of a fin and tube heat exchanger. Where the circular tube ensures higher heat transfer coefficient of about 18% than the flat tube, and it generate a moderate pressure drop of about 10% in the same conditions. Also, some reliable empirical correlations are proposed to predict the Nusselt number and the friction factor.

Combined Enhancement Techniques on Double Tube Heat Exchanger Using Nanofluid and Helicoid Tube Shape

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Yousef Alhendal ◽  
Abdalla Gomaa ◽  
Mahmoud Abdelmagied
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Design Parameters ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Points Of Interest ◽  
Level Of Details ◽  
Tube Shape

Abstract The thermofluid characteristics of Al2O3–water nanofluid in the annulus of double-helical coiled tubes were experimentally and numerically carried out. The purpose was to investigate the effect of combined enhancement techniques of nanofluid and helicoid tube shape on the performance of a double tube heat exchanger. The effects of concentration of nanoparticles, Reynolds number, coil curvature ratio, and flow arrangement through the annulus of double-helical coiled tube were the main points of interest. Three coiled tube heat exchangers were manufactured and experimentally tested to study the design parameters on the performance of such a heat exchanger. A three-dimensional numerical computational fluid dynamic (CFD) model was developed to get additional insights on the thermal performance of double helically coiled tubes with nanofluid on a level of details not always available in experiments. It was found that the Al2O3–water nanofluid achieved an enhancement by 32% on the overall heat transfer coefficient. The heat exchanger effectiveness, heat transfer per unit pumping power, and the Nusselt number were also presented for different design parameters.

Effect of Engine Operating Conditions and Coolant Temperature on the Physical and Chemical Properties of Deposits From an Automotive Exhaust Gas Recirculation Cooler

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Bhaskar Prabhakar ◽  
André L. Boehman
Keyword(s):  
Heat Exchanger ◽  
Load Condition ◽  
Exhaust Gas Recirculation ◽  
Control Flow ◽  
Operating Conditions ◽  
Coolant Temperature ◽  
Exhaust Gas ◽  
Low Load ◽  
Egr Cooler ◽  
Gas Recirculation

The effect of engine operating conditions on exhaust gas recirculation (EGR) cooler fouling was studied using a 6.4 L V-8 common rail turbodiesel engine. An experimental setup, which included a custom-made shell and tube heat exchanger (EGR cooler) with six surrogate tubes, was designed to control flow variables independently. The engine was operated at 2150 rpm, 203 Nm and 1400 rpm, 81 Nm, representing medium and low load conditions, respectively, and the coolant to the heat exchanger was circulated at 85 °C and 40 °C. Heat exchanger effectiveness and pressure drop was monitored throughout the tests. Deposits from the EGR cooler were collected every 1.5 h for a total of 9 h, and their microstructure was analyzed using a scanning electron microscope while their chemical composition was analyzed using a pyrolysis GC-MS apparatus, and the elemental weight percentages were obtained using a CHN analyzer. The results of these analyses showed that the effectiveness of the EGR cooler drops rapidly initially and asymptotes in a few hours. The medium load condition had a higher effectiveness loss due to a greater accumulation of deposits inside the EGR cooler, mostly due to increased thermophoresis, and produced smaller and coarse particles. The low load condition had lower effectiveness loss but produced bigger particles mostly due to excess hydrocarbons. Coolant temperature played a significant role in altering the deposit microstructure and in increasing the amount of condensed hydrocarbons. More deposits were produced for the cold coolant condition, indicating that lower coolant temperature promotes greater hydrocarbon condensation and thermophoresis. These results indicate the complex nature of fouling in automotive heat exchangers.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

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