LP-EGR이 적용된 디젤 엔진 인터쿨러용 알루미늄 튜브의 내식성 향상

안준(Joon Ahn),하석(Seok Ha),곽동호(Dongho Kwak),정병준(Byungjun Jung) 한국자동차공학회 2012 한국 자동차공학회논문집 Vol.20 No.6

목재 펠릿 연소 과정의 수치해석

안준(Joon Ahn),김혁주(Hyouck Ju Kim),박화춘(Hwa Choon Park) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.43

Combustion process of a wood pellet in a hot cross flow has been studied based on a series of unsteady simulations. Results show the pellet could be ignited with the cross flow temperature over 600℃. The locus of the ignition point changes depending on the free stream temperature, while the combustion of the char occurs throughout the pellet for all investigated temperature. Total combustion time as well as the time for the volatile decrease more rapidly for the inlet temperature change from 600℃ to 700℃ compared to the case for the change from 700℃ to 800℃.

가정용 열병합 스털링 엔진을 위한 예혼합 버너의 연소 특성

안준(Joon Ahn),이윤식(Youn Sik Lee),김혁주(Hyouck Ju Kim) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.2

화석 에너지 고갈에 따라 에너지의 합리적 이용이 요구되면서 가용 에너지를 고려한 열에너지의 계단식 활용이 적극적으로 검토되고 있다. 이와 같은 배경에서 1 ㎾ 급의 스털링 엔진을 기반으로 한열병합발전 시스템이 분산 에너지 시스템을 구축하는 단위로서 제안되었다. 1 ㎾ 의 용량은 가정용에 적합하며, 가정에서 활용하기 위해서는 공간을 작게 차지하도록 하면서도 소음과 유해가스의 배출을 철저하게 차단해야 한다. 이러한 조건들을 충족시키며 효율이 높은 시스템을 개발하기 위하여 슬롯형태의 예혼합 버너를 제안하였고 버너의 연소 특성을 파악하기 위하여 일련의 실험을 수행하였다. 본 연구에서는 화염의 형상을 촬영하여 연소부하 및 공기비에 따른 연소 모드를 관찰하였고 배가스를 분석하여 연소 모드에 따른 배기 특성을 연구하였다. The availability of thermal energy has been widely recognized recently, and the cascade usage of thermal energy from combustion has been encouraged. Within this framework, a 1-㎾-class Stirling-engine?based cogeneration system has been proposed as a unit of a distributed energy system. The capacity has been designed to be adequate for domestic usage, which requires high compactness as well as low emissions and noise. To develop a highly efficient system satisfying these requirements, a premixed slot-type short-flame burner has been proposed, and a series of experiments has been performed to understand its combustion characteristics. Flame images have been captured to observe the dependence of the flame mode on the combustion load and air/fuel ratio. The exhaust gas has been sampled and analyzed to study the emission characteristics for each flame mode.

제습냉방 공간의 온도와 환기 온도의 상관관계

안준(Joon Ahn),최호엽(Ho Yup Choi),김혜준(Hye Jun Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.열공학 No.-

나프타 개질로 벽면 파손 형태에 따른 화염전파 특성 수치해석

안준(Joon Ahn),장성일(Seongil Jang) 대한설비공학회 2015 대한설비공학회 학술발표대회논문집 Vol.2015 No.11

In the petrochemical plant to process the combustible material in the extreme conditions of high temperature and high pressure conditions. In particular, reformer of plant is the core to high-risk facilities and major equipment for decomposing naphtha. If the cracks in the pipes inside reformer, leakage and explosion accidents occur. In this study, the event of an accident by a leakage of the reformer inner tube, it was evaluated using a numerical analysis with respect to the occurrence and spread of the flame.

Gasket 방식 판형 열교환기의 고·저온부 유량 및 압력차에 따른 압력강하 특성

안준(Joon Ahn),김혁주(Hyouck Ju Kim),최규성(Kyu Sung Choi),송대석(Dae Seok Song) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

In a gas engine based cogeneration system, heat is recovered from two parts, which are jacket water and exhaust gas. The heat from the jacket water is often recovered by a plate type heat exchanger and used for the room heating and/or hot water supply. Depending on the operating conditions of engine and heat recovery system, there should be imbalance in the flow rate and supply pressure between engine and heat recovery side of the heat exchanger. The imbalance cause the deformation of the plate, which affects the pressure drop characteristics. In the present study, the pressure drop inside the heat exchanger has been investigated in a 1/5 scaled test rig and compare with the experimental correlations, which are used for the design.

에틸렌 반응로에 대한 복합 열전달 해석

안준(Joon Ahn),박진우(Jin Woo Park) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.10

Conjugate heat transfer analysis for an ethylene furnace was carried out based on numerical simulation. Detailed distributions of velocity vectors, chemical species, and temperature inside the furnace are presented and discussed. Von Mises stress and heat flux at the tube surface were also evaluated to elucidate mechanisms regarding failure of the tube. Maximum stress was found at the upstream elbow of the tube, which did not coincide with the location of maximum heat flux. This implies that thermal stress at a steady state would not be a dominant component of the stress. Degradation of the material, as well as the system arrangement, should be considered in order to accurately predict the lifetime of the tube material in the furnace.

모듈형 2 t/h급 수관식 보일러의 열전달 특성

안준(Joon Ahn),황상순(Sang Soon Hwang),김종진(Jong Jin Kim),강새별(Sae Byul Kang) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.11

본 논문에서는 다중 버너를 채택한 2 t/h 급 수관식 보일러 휜(fin)이 설치된 증발관 모듈이 제안하였다. 휜의 형상은 보일러를 구성하는 각각의 모듈에서 고르게 증발이 이루어질 수 있도록 설계하였다. 이를 위해서 기존의 벌크 설계 과정이 아닌 각각의 열에 대해 에너지 보존을 고려하는 방식으로 설계를 수행하였다. 설계한 증발관 모듈로 2 t/h 급 수관식 보일러를 제작하여 성능을 실험하여 설계를 검증하였다. 설계 과정에서 고려되지 않은 입구 조건 등의 2, 3차원 효과를 파악하기 위하여 수치해석을 병행하였다. 수치해석은 휜 팁의 온도도 예측하기 위하여 증발관의 전도를 포함한 복합열전달해석을 하였다. 휜이 설치될 경우 휜의 크기와 밀도가 증가할수록 열전달 계수가 상관식보다 낮아졌고 수치해석으로 구한 휜 팁의 온도는 해석해로 예측한 값보다 높게 나타났다. A finned-tube-type evaporator module has been proposed for a 2 t/h-class water-tube-type industrial boiler with multiple burners. The geometry of the fins was changed at each module to equalize the evaporation. The modules were designed by considering the energy balance at each row rather than by following a conventional bulk design procedure. The designed module was built into a 2 t/h-class water-tube-type boiler, and its performance was tested. A numerical simulation was also conducted to evaluate the two- or three-dimensional effects of factors such as the inlet conditions. The numerical simulation also included the conjugate heat transfer problem to predict the fin tip temperature. The heat transfer coefficient with fins is lower than that obtained from the empirical correlation of a bare tube. The fin tip temperature from CFD is higher than that from the analytical solution.

순산소 재순환 연소를 채택한 3 ㎿급 CO₂ 회수형 보일러의 연소 특성

안준(Joon Ahn),김혁주(Hyuock Ju Kim),최규성(Kyu Sung Choi) 대한기계학회 2019 大韓機械學會論文集B Vol.43 No.3

본 연구에서는 공기 연소, 순산소 연소, 순산소 재순환 연소를 적용할 수 있는 동축형 버너를 개발하고 이를 3 ㎿급의 노통연관식 보일러에 설치하여 연소 및 배가스 특성을 실험하였다. 유사한 설계의 버너를 채택한 0.5 ㎿급의 보일러에서 얻은 결과와 비교하여 스케일 업 특성을 확인하고 안정된 화염을 얻을 수 있는 재순환율을 비교하였다. 연료공급량과 연료-산화제 비율을 변화하며 연소 특성을 파악하였고 각각의 조건에서 배가스를 분석하였다. 분석 결과 순산소 연소를 산업용 보일러에 적용함으로써 이산화탄소를 분리할 수 있고 질소 산화물의 배출을 크게 줄일 수 있음을 확인하였다. 그러나 순산소 연소를 적용할 경우 부분 부하 조건에서 안정된 화염을 얻기 어렵고 용량이 변화하면 안정된 화염을 얻을 수 있는 재순환율이 달라짐을 확인하였다. In this study, a coaxial type burner capable of applying air combustion, oxy-fuel combustion, and oxy-fuel oxygen combustion with FGR (flue gas recirculation) was developed and tested for combustion and exhaust gas characteristics by installing it in a 3 ㎿ class flame-tube type boiler. Compared with the results obtained from a 0.5 ㎿ class boiler with a similar burner, the scaled-up characteristics were verified and the recirculation rates for a stable flame were compared. Combustion characteristics were investigated by varying fuel supply rate and fuel-to-oxidizer ratio, and the flue gas was analyzed under each condition. Consequently, it was confirmed that carbon dioxide can be separated, and NOx emissions can be reduced by applying oxy-fuel combustion to industrial boilers. However, it was discovered that it is difficult to obtain a stable flame under partial load conditions when oxy-fuel combustion is applied and that this changes the recirculation rate that can yield a stable flame for a burner with a different capacity.

냉각공기 유속 측정에 기반한 철도차량용 공기압축기 열교환기의 열전달 특성 분석

안준(Joon Ahn),김무선(Moo Sun Kim),장성일(Seongil Jang) 대한설비공학회 2017 설비공학 논문집 Vol.29 No.9

In this study, local velocity distribution of cooling air in a heat exchanger used in an air compressor for a railway car was measured and heat transfer characteristics of the heat exchanger were analyzed. First, heat transfer coefficient and fin performance of the cooling air side were predicted and was checked if the fin of the heat exchanger was effectively used. Distribution of air flow rate at high temperature side was predicted through pipe network analysis and heat resistance at high temperature and low temperature side were predicted and compared. Spatial distribution of temperature in the interior and surface of the square channel constituting high-temperature side was predicted and appropriateness of the size of the heat exchanger was examined. As a result of the analysis, the present size of the heat exchanger could be reduced and it could be effective to promote heat transfer inside the heat exchanger rather than outside to improve performance of the heat exchanger.