• Title/Summary/Keyword: Cooler fouling

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The Effect of Cooling Efficiency on Fouling by EGR Cooler Internal Shape (EGR Cooler 내부 형상에 따른 Fouling이 냉각 성능에 미치는 영향)

  • Nam, Youn-Woo;Oh, Kwang-Chul;Lee, Chun-Hwan;Lee, Chun-Beom;Lee, Won-Nam
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.1
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    • pp.101-108
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    • 2011
  • Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of a EGR system. We develope a test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and shell & tube type. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in Shell & tube type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contact area as the EGR cooler fouling.

Evaluation of Catalyst Assisted EGR Cooler System for EGR Cooler Fouling Reduction (EGR Cooler Fouling 저감을 위한 촉매 장착 EGR Cooler System 평가)

  • Hong, Kwang-Seok;Park, Jung-Soo;Lee, Kyo-Seung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.5
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    • pp.76-81
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    • 2011
  • Exhaust gas recirculation is the well-known and widely used NOx reduction technology for diesel engines. More effective EGR cooler has been developed and applied to diesel engines to meet the reinforced emission regulation. However, the contaminated EGR cooler by diesel exhaust gas reduces the performance of the engine and NOx reduction rate. The buildup of deposits in EGR coolers cause significant degradation in heat transfer performance, often on the order of 20~30%. Deposits also increase pressure drop across coolers and thus may degrade engine efficiency under some operation conditions. In this study, as a solution for this problem, DOC assisted EGR cooler is designed and then investigated to reduce fouling and its impact on cooler performance. A single channel EGR cooler fouling test apparatus and soot particle generator were developed to represent the real EGR cooler and exhaust gas of diesel engine. EGR cooler effectiveness of the case with catalyst of pt 30g/ft3 decreased just up to 5%. This value was 45% less compared to the case without catalyst which decreased up to 9% after 10hours experiments.

A Study for Improving Spray Uniformity of the SECFR System for Vehicle Applications (SECFR 시스템의 차량적용을 위한 분무균일도향상에 관한 연구)

  • Shon, J.W.;Woo, S.C.;Kim, S.G.;Lee, K.H.
    • Journal of ILASS-Korea
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    • v.20 no.2
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    • pp.95-100
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    • 2015
  • Lower recirculated gas temperature at EGR system reduces NOx and PM emissions. However, EGR Cooler can be polluted by PM generated from recirculated EGR gas, and it reduces cooling efficiency and the amount of EGR gas simultaneously. The SECFR(Steam EGR Cooler Fouling Remover) system which uses the evaporated washer fluid steam caused by high temperature of EGR gas was manufactured for removing fouling generated on the cooler surface. Since an injection pressure of wind shield washer fluid in the vehicle is approximately 0.5 bar, it is not enough to atomize the injected washer fluid. Thus, it is necessary to apply a method to atomize the washer fluid. In this study, the impinging plate was used to promote the atomization of spray washer fluid for the purpose of apply SECFR system to vehicles and measured the DAR(Droplet Area Ratio) and DUI(Droplet Uniformity Index) through the spray visualization.

Effects of Pitch Length of Stack-type EGR Cooler on Heat Exchange Characteristics in a Diesel Engine (적층형 EGR Cooler의 Pitch 길이 변화가 열교환 특성에 미치는 영향)

  • Hwang, Se-Joon;Kim, Min-Chol;Jang, Sang-Hoon;Kim, Hyung-Man
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.135-140
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    • 2010
  • An important goal in diesel engine research is the development of a means to reduce the emissions of nitrogen oxides (NOX). The use of a cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for reducing nitrogen oxides. Since Particular Matter (PM) fouling reduces the efficiency of an EGR cooler, a trade-off exists between the amount of NOX and PM emissions, especially at high engine loads. In the present study, engine dynamometer experiments have been performed to investigate the heat exchange characteristics of the stack-type EGR coolers with wave fin pitches of 3.6 and 4.6 mm. The results show that the heat exchange effectiveness is decreased as surface area decrease with pitch of 4.6 mm due to PM fouling. As surface area increase at pitch of 3.6 mm, super-cooling happens in the recirculated exhaust gas.

A Study on Heat Exchange Efficiency of EGR Cooler for Diesel Engine to Meet Euro-5 Emission Regulation (Euro-5 대응 디젤엔진용 EGR 쿨러의 열교환 효율 연구)

  • Lee, Joon;Han, Chang-Suk
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.3
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    • pp.183-188
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    • 2007
  • Recently, diesel engine has been frequently applied to RV, SUV and light duty truck due to the good fuel economy and high thermal efficiency. $NO_x$ and PM, environmental pollution materials are basically produced in diesel combustion process. The most important target in diesel engine research is the development of system to reduce the emissions of $NO_x$ and PM. Cooled EGR system is an effective method for the reduction of $NO_x$ emission and PM emission from a diesel engine and EGR cooler is the key component of the system. This study investigates the EGR cooler of oval gas tubes compared with the EGR cooler of shell & tubes to verify the heat exchange efficiency of cooler by means of engine dynamometer tests, rig performance tests and numerical analyses.

NOx Emission Characteristic according to Aging of EGR Cooler in Non-Road Diesel Engine (EGR 적용 비도로 엔진의 쿨러 열화에 따른 질소산화물 배출특성)

  • Lee, Kyoung-Bok;Oh, Kwang-Chul
    • Journal of Power System Engineering
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    • v.20 no.5
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    • pp.37-45
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    • 2016
  • Exhaust gas recirculation has the advantage of being low-cost and easy to control of NOx emission. Therefore, it is most generally used to reduce NOx emission according to strengthen regulation. In the case of a non-road engine, such as the agricultural engine, since it mainly operate a middle or high-load state, NOx emission is decreased in accordance with the mapping range of the EGR rate, but results in an increase in the particulate matter which is caused to deposit and fouling problem of the EGR system. This problem has become an important issue for maintaining the performance of the engine, as well as emission performance. This study had examined the effects of cooler aging on the performance of heat transfer efficiency and NOx emission in non-road diesel engine. As a result of the EGR cooler aging during 200 hours engine operation, the cooling performance decreased about 25% compared with that of fresh cooler and the NOx emission increased about 14.6% on NRSC(non-road steady cycle) and 20% on NRTC(non-road transient cycle) compared with that of fresh cooler respectively.

Numerical Simulations on the Thermal Flow and Particle Behaviors in the Gas Reversal Chamber of a Syngas Cooler for IGCC (IGCC 합성가스 냉각기 GRC의 열유동 및 입자거동 특성에 대한 전산해석 연구)

  • Park, Sangbin;Ye, Insoo;Ryu, Changkook;Kim, Bongkeun
    • Journal of the Korean Society of Combustion
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    • v.18 no.1
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    • pp.21-26
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    • 2013
  • In the Shell coal gasification process, the syngas produced in a gasifier passes through a syngas cooler for steam production and temperature control for gas cleaning. Fly slag present in the syngas may cause major operational problems such as erosion, slagging, and corrosion, especially in the upper part of the syngas cooler (gas reversal chamber, GRC). This study investigates the flow, heat transfer and particle behaviors in the GRC for a 300 MWe IGCC process using computational fluid dynamics. Three operational loads of 100%, 75% and 50% were considered. The gas and particle flows directly impinged on the wall opposite to the syngas inlet, which may lead to erosion of the membrane wall. The heat transfer to the wall was mainly by convection which was larger on the side wall at the inlet level due to the expansion of the cross-section. In the evaporator below the GRC, the particles were concentrated more on the outer channels, which needs to be considered for alleviation of fouling and blockage.

Numerical Analysis on the Heat Transfer Characteristics of Syngas Cooling System of an IGCC Process (IGCC 합성가스 냉각 시스템의 열전달 특성 연구)

  • Oh, Junho;Ye, In-soo;Park, Sangbin;Ryu, Changkook;Park, Sungku
    • 한국연소학회:학술대회논문집
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    • 2013.06a
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    • pp.65-68
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    • 2013
  • In a syngas cooling system of coal gasification process, fly slag carried by syngas deposit on the surface of heat exchanger. The deposited materials form a fouling layer with several millimeters thickness, disturbing heat transfer between steam and syngas. This study investigates flow and heat transfer characteristics of syngas in helical coil heat exchanger using computational fluid dynamics under clean and fouled surface condition. Process model were also designed and its results are in good agreement with CFD results.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.