Numerical simulation of cooling performance of an exhaust gas recirculation (EGR) cooler using nano-fluids

2017 ◽  
Vol 110 ◽  
pp. 244-252 ◽  
Author(s):  
Hojjat Shabgard ◽  
Saeid Kheradmand ◽  
Hamed Farzaneh ◽  
Choongsik Bae
Keyword(s):  
Numerical Simulation ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Cooling Performance ◽  
Egr Cooler ◽  
Gas Recirculation ◽  
Nano Fluids

Analysis of the Exhaust Gas Recirculation System Performance in Modern Diesel Engines

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Stefano d'Ambrosio ◽  
Alessandro Ferrari ◽  
Ezio Spessa
Keyword(s):  
Control Valve ◽  
Experimental Tests ◽  
Detailed Comparison ◽  
Exhaust Gas Recirculation ◽  
Valve Lift ◽  
Exhaust Gas ◽  
Flow Area ◽  
Tube Type ◽  
Egr Cooler ◽  
Gas Recirculation

Exhaust gas recirculation (EGR) is extensively employed in diesel combustion engines to achieve nitrogen oxides emission targets. The EGR is often cooled in order to increase the effectiveness of the strategy, even though this leads to a further undesired impact on particulate matter and hydrocarbons. Experimental tests were carried out on a diesel engine at a dynamometer rig under steady-state speed and load working conditions that were considered relevant for the New European Driving Cycle. Two different shell and tube-type EGR coolers were compared, in terms of the pressure and temperature of the exhaust and intake lines, to evaluate thermal effectiveness and induced pumping losses. All the relevant engine parameters were acquired along EGR trade-off curves, in order to perform a detailed comparison of the two coolers. The effect of intake throttling operation on increasing the EGR ratio was also investigated. A purposely designed aging procedure was run in order to characterize the deterioration of the thermal effectiveness and verify whether clogging of the EGR cooler occurred. The EGR mass flow-rate dependence on the pressure and temperature upstream of the turbine as well as the pressure downstream of the EGR control valve was modeled by means of the expression for convergent nozzles. The restricted flow-area at the valve-seat passage and the discharge coefficient were accurately determined as functions of the valve lift.

A Comprehensive Physics-Based Model for Medium-Duty Diesel Engine With Exhaust Gas Recirculation

2007 ◽  
Author(s):  
Alok A. Joshi ◽  
Scott James ◽  
Peter Meckl ◽  
Galen King ◽  
Kristofer Jennings
Keyword(s):  
Heat Transfer ◽  
Exhaust Gas Recirculation ◽  
Boost Pressure ◽  
Exhaust Gas ◽  
Variable Geometry ◽  
Transfer Effects ◽  
Variable Geometry Turbine ◽  
Heat Transfer Effects ◽  
Egr Cooler ◽  
Gas Recirculation

Physics-based models of diesel engines with exhaust gas recirculation and a variable geometry turbine (EGR/VGT) have been developed extensively in the control system design community. However, these models omit the heat transfer effects of the charge-air cooler and the recirculated exhaust gas cooler in order to avoid the added complexity in model order for online implementation. Generally, there is no need to include these effects if the purpose of the model is to control the target variables, such as boost pressure and air-to-fuel ratio. In this paper, after surveying the existing state of physics-based models for the EGR/VGT subsystem, a comprehensive model of the EGR/VGT subsystem is developed. This model includes heat transfer effects in the coolers, pressure drops across air filters and pipes, and mass flow rate calculations for a variable geometry turbine and an exhaust gas recirculation control valve. The purpose and scope of this work is offline modeling-for-diagnostics. Such models, though complex, will assist in the fault sensitivity analysis of a subsystem while avoiding any destructive testing when a major design modification in the EGR/VGT subsystem is proposed. For example, the impact of charge-water or EGR cooler degradation on the boost pressure and the air-to-fuel ratio can be studied with such models to further help in designing diagnostic reasoning strategies. Simulation performed using the proposed physicsbased model demonstrates a dominant failure effect of an EGR cooler coolant leak over a charge-water cooler water leak on the properties of the intake air.

A Simplified Model for Deposition and Removal of Soot Particles in an Exhaust Gas Recirculation Cooler

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
A. Reza Razmavar ◽  
M. Reza Malayeri
Keyword(s):  
Maximum Velocity ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Rolling Moment ◽  
Soot Particles ◽  
Exhaust Gases ◽  
Particulate Fouling ◽  
Efficient Performance ◽  
Egr Cooler ◽  
Gas Recirculation

Nitrogen oxides (NOx) emissions from diesel engines can profoundly be suppressed if a portion of exhaust gases is cooled through a heat exchanger known as exhaust gas recirculation (EGR) cooler and returned to the intake of the combustion chamber. One major hurdle though for the efficient performance of EGR coolers is the deposition of various species, i.e., particulate matter (PM) on the surface of EGR coolers. In this study, a model is proposed for the deposition and removal of soot particles carried by the exhaust gases in a tubular cooler. The model takes thermophoresis into account as the primary deposition mechanism. Several removal mechanisms of incident particle impact, shear force, and rolling moment (RM) have rigorously been examined to obtain the critical velocity that is the maximum velocity at which the particulate fouling can profoundly be suppressed. The results show that the dominant removal mechanism changes from one to another based particle size and gas velocity. Based on particle mass and energy conservation equations, a model for the fouling resistance has also been developed which shows satisfactory agreement when compared with the fouling experimental results.

Development and performance estimation of an exhaust gas recirculation cooler with dimpled rectangular tubes

2011 ◽  
Vol 225 (3) ◽  
pp. 384-397
Author(s):  
Y-H Seo ◽  
S-C Heo ◽  
T-W Ku ◽  
J Kim ◽  
B-S Kang
Keyword(s):  
Heat Exchange ◽  
Structural Integrity ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Exhaust Gas ◽  
Core Tube ◽  
Egr Cooler ◽  
Gas Recirculation ◽  
Rectangular Tubes

In this study, an exhaust gas recirculation (EGR) cooler with dimpled rectangular tubes, whose heat exchange effectiveness is higher than that of a conventional cooler, is developed. To maximize the heat transfer between the exhaust gas and coolant, the dimples are formed on the surface of the heat exchange tubes. A dimpled-tube manufacturing process is established that comprises: dimple shape forming, edge bending, centre v-notch bending, compression, and plasma welding. The high effectiveness of the dimple-type EGR cooler is confirmed by the effectiveness-NTU method and experimental approaches under normal operating conditions. It is also important to verify the structural integrity, in view of the practical uses of the dimple-type EGR cooler. In order to confirm the safety of the EGR cooler, finite element analyses are carried out for each component, such as the oval core tube with a dimpled shape. The structural integrity under thermal stress and pressure, which are caused by gas and coolant flows in the shell and tubes, is evaluated through thermal and structural analyses.

The study of heat transfer for nanofluid with carbon nano particle in an exhaust gas recirculation (EGR) cooler

2013 ◽  
Vol 49 (7) ◽  
pp. 1051-1055 ◽  
Author(s):  
Seongsoo Kim ◽  
Hanshik Chung ◽  
Hyomin Jeong ◽  
Byungho Lee ◽  
Bayanjargal Ochirkhuyag ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Nano Particle ◽  
Egr Cooler ◽  
Gas Recirculation

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.

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