Thermodynamic Performance Simulation of Diesel EGR Cooler with Finned Tube

2010 ◽  
Vol 97-101 ◽  
pp. 3345-3348
Author(s):  
Yan Song Wang ◽  
Hui He ◽  
Zhen Hua Xu ◽  
Jiang Hua Liu
Keyword(s):  
Finned Tube ◽  
Finite Element Models ◽  
Exhaust Gas ◽  
Performance Simulation ◽  
Pressure Fields ◽  
Thermodynamic Performance ◽  
Cooling Tube ◽  
Egr Cooler ◽  
Gas Recirculation ◽  
Pressure Boundary Conditions

Exhaust gas recirculation (EGR) cooler plays an important role in reducing the nitrogen oxides (NOx) emission of diesel engines. By using the CFDesign software, in this paper, the finite element models are established for analyzing the thermodynamic performance of an EGR cooler. The temperature, velocity and pressure fields of the fluids in the EGR cooler are simulated and verified. Based on these models, furthermore, the thermodynamic performance of the EGR cooler with different structures of cooling tube are analyzed, compared and discussed. The results show that, under the fixed pressure boundary conditions, the EGR cooling efficiency can be significantly increased by properly design the fin number of the cooling tube in EGR coolers.

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.

Mechanism of Void Formation during Brazing of Ni Paste Brazing Filler Metal

2021 ◽  
Vol 1016 ◽  
pp. 1218-1222
Author(s):  
Mana Sakai ◽  
Tatsuya Sasaki ◽  
Yasuyuki Miyazawa
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Void Formation ◽  
Inert Atmosphere ◽  
Exhaust Gas ◽  
Vacuum Atmosphere ◽  
Brazed Joint ◽  
Egr Cooler ◽  
Debinding Process ◽  
Gas Recirculation

Automobiles are equipped with EGR (Exhaust Gas Recirculation) coolers to improve fuel economy and exhaust gas suppression performance. Inside the EGR cooler, the moisture in the gas is condensed by cooling the hot exhaust gas. This condensed water is highly corrosive because sulfur oxides dissolve. Therefore, stainless steel and Ni-based brazing metal having excellent corrosion resistance are used for the EGR cooler.Until now, stainless steel has been brazed under a vacuum atmosphere. However, there are increasing opportunities to braze stainless steel in an inert atmosphere gas at atmosphere for cost reduction and mass production. In this case, a paste-type brazing filler metal consisted of a powder brazing filler metal and a binder is used. As is well known, a debinding process that volatilizes the binder is needed. From previous research in this laboratory, it is clarified that the binder causes voids. In addition, it is said that the size and location of voids generated at the brazed joint affect the product performance. On the other hand, the detailed investigation about the influence which the installation position of a paste type brazing filler metal on the void formation process has not yet been made. Therefore, in this study, the arrangement method and influence on heating rate and debinder temperature on void formation were investigated by X-ray CT.

The Semi-Closed Recuperated Cycle With Intercooled Compressors

2014 ◽  
Author(s):  
Hans E. Wettstein
Keyword(s):  
Fossil Fuels ◽  
Combined Cycle ◽  
Component Technology ◽  
Exhaust Gas ◽  
Combustion Gas ◽  
Electric Power Supply ◽  
Thermodynamic Performance ◽  
Low Load ◽  
Fierce Competition ◽  
Gas Recirculation

The Gas Turbine Combined Cycle (GTCC) is the best currently available choice, if gaps in the renewable electric power supply need being filled at short notice with power from fossil fuels. The GTCC manufacturers are in a fierce competition responding to these needs, especially for the best part load efficiency, the fastest load ramp capability and for the lowest low load power parking at an acceptable NOx and CO emission level. But there is an option outperforming the GTCC technology for the above mentioned requirements, which is theoretically known since years but it has not yet been practically developed. It is the Semi-Closed Recuperated Cycle (SCRC). The author has described this recently in an article [1] with the title “The air breathing semi-closed recuperated cycle and its super chargeable predecessors”. The SCRC does not require any component technology, which is not yet proven in operating commercial GTCC or GT plants. But of course the cycle integration is a different one, requiring a specific design of the components. An inherent side feature of the SCRC is the exhaust gas composition, which corresponds to a near-stoichiometric combustion gas. This allows comparing the SCRC with a (CO2-) capture ready GTCC having exhaust gas recirculation. The above mentioned article [1] describes the thermodynamic performance analysis of a SCRC with an adiabatic compressor. But the cycle becomes even more attractive with an intercooling stage in each of the two compressors. Here this is quantified with another detailed thermodynamic analysis. Additionally also an ideal case with isothermal compression is analyzed. The latter is of course unrealistic for a practical realization. But it indicates the potential of using more than one intercooling stage per compressor. The aim of this paper is to quantitatively compare the three variants with adiabatic, intercooled and isothermal compressors. In all three cases the same turbine and recuperator temperature limitations are used while some other cycle data assumptions are adapted to the compressor technology in order to achieve an optimal performance level for each variant. The thermodynamic results have been cross-checked with a breakdown of the exergy losses in the three variants. The final results for base load operation indicate that the intercooled variant could become the best choice.

Cooling Challenges of Modern Truck Diesel Engines

2005 ◽  
Author(s):  
John P. Bowman ◽  
Sivakumar S. Krishnan ◽  
Razi Nalim
Keyword(s):  
Cooling System ◽  
Emissions Reduction ◽  
Exhaust Gas ◽  
Counter Flow ◽  
Cost Constraints ◽  
Additional Costs ◽  
Egr Cooler ◽  
Gas Recirculation ◽  
System Designs ◽  
Truck Engine

Efficient cooling system designs are required for the modern diesel truck engine to meet new standards of increased efficiency and reduced emissions. Often, emissions reduction requires substantial cooled exhaust gas recirculation (EGR) to decrease peak combustion temperatures. This extra heat rejection imposes additional costs on the cooling system, and may not comply with application space constraints. Space and cost constraints require minimization of EGR cooler size and the risks from coolant boiling and exhaust condensation, while restraining growth in radiator frontal area, pumping power, and fan power. These objectives are usually contradictory, and a careful optimization is needed. This paper examines the effect of a coolant flow rate and peak temperature on these objectives, in parallel-flow and counter-flow arrangements of EGR cooler systems. It is concluded that these systems are likely to be inadequate, and alternative configurations may be necessary.

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
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