비열플라즈마와 라디칼을 이용한 디젤엔진의 매연 및 NO 제거 특성

장영준,최승환,김규보,전충환,Jang, Yeong-Jun,Choe, Seung-Hwan,Kim, Gyu-Bo,Jeon, Chung-Hwan 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.4

We are facing the serious environmental pollution difficulties such as acid rain, green house effects, etc. The gaseous matter NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the emissions strictly, especially the exhaust emissions from a Diesel engine without an aftertreatment device. The objective of this study is to find out soot and NO removal characteristics focused on the emissions of a Diesel engine by using nonthermal plasma for each engine speeds and loads. Electrostatic precipitator(wire-to-plate type reactor) is used for soot removal. Radicals generated from outer air and put into a mixing chamber in the end of exhaust line are used for NO removal. Concentration of exhaust emissions is analyzed from the gas analyzer(KaneMay) and FTIR to estimate by-products.

강의평가 설문 결과를 이용한 양생기공 교육의 효과 분석

장영준(Yeong Jun Jang),이장원(Jang Won Lee),채한(Han Chae),권영규(Young Kyu Kwon),허광호(Kwang Ho Heo),이금산(Guem San Lee),황의형(Eui Hyoung Hwang) 한의병리학회 2013 동의생리병리학회지 Vol.27 No.4

비응축성 기체 존재 시 수직관 외벽에서의 응축 열전달계수 상관식 개발

장영준(Yeong-Jun Jang),최동재(Dong-Jae Choi),김신(Sin Kim),정동욱(Dong Wook Jerng),이연건(Yeon-Gun Lee) 대한기계학회 2018 大韓機械學會論文集B Vol.42 No.3

본 연구에서는 비응축성 기체(공기)가 존재할 때, 10 mm의 직경을 갖는 수직 튜브 외벽에서의 응축 열전달계수를 측정하였다. 압력 2~5 bar, 공기 질량분율 10~75 %의 범위에서 실험을 수행하였다. 응축튜브 직경의 차이가 열전달계수에 미치는 영향을 평가하기 위해 측정 결과를 외경 40 mm의 응축튜브로부터 얻은 Lee의 실험 결과와 비교하였다. 본 연구의 측정결과와 Lee, 그리고 Dehbi의 실험결과를 이용하여 전열관의 직경에 의한 영향을 고려할 수 있는 실험적 상관식을 제안하였다. 제안된 상관식의 검증을 위해 Kawakubo의 실험결과와 예측값을 비교하였고, 평균 표준편차는 약 27 %로 나타났다. In this study, condensation heat transfer coefficients are measured in the presence of noncondensable gas (i.e., air) on a vertical tube with a 10-mm outer diameter. Experiments are conducted at pressures ranging from 2 to 5 bar and an air-mass fraction from 10 to 75 %. The experimental results are compared to the heat transfer coefficients obtained on a 40-mm O.D. tube, researched by Lee et al. Using the consolidated data from this study and Lee"s and Dehbi"s tests, a new empirical correlation for the condensation heat transfer coefficient of an air-steam mixture is developed. The proposed correlation is assessed against Kawakubo"s experimental results, and the mean standard deviation is ~27 %.

해상공사에 투입된 예·부선 용선계약의 문제점과 개선방안에 관한 연구

장영준(Yeong-Jun Jang) 한국항해항만학회 2014 한국항해항만학회지 Vol.38 No.5

일반적으로 해상공사에 투입된 예인선의 용선계약은 정기용선계약으로 이루어지고 있고, 부선의 용선계약은 선체용선계약의 형태로 이루어진다. 현재 사용되는 예·부선의 용선계약에는 표준화된 서식이 존재하지 않아 계약 당사자간 임의적으로 내용을 정하고 있으므로 운항 중 사고 발생시 책임주체를 명확히 하고 있는 조항이 미비된 경우가 많다. 또한 계약서에 사용되는 용어가 현행 상법상의 용어와 달라 혼란을 야기하고 있다. 이는 계약 당사자간에 용선계약의 성질에 대한 합의를 분명히 하고 계약서의 표제 명칭과 용어를 상법상의 용어와 일치시키는 것만으로도 상당부분 해결 가능할 것이다. 또한 이를 위하여 표준계약서의 작성이 추진되어야 할 것이다. 본 연구는 해상공사 현장에 투입된 예·부선의 용선계약의 실태를 알아보고 그 문제점을 검토하여 이를 개선하는 방안을 제시하는 것을 목적으로 한다. 이를 위하여 본 연구에서는 먼저 실제 발생한 관련 사고에서 계약서의 흠결로 그 책임관계가 논란의 대상이 되었던 사고 사례를 살펴보고 이를 해결하기 위한 방안으로 표준계약서의 작성을 제안한 다음 표준계약서 작성에 있어 유의할 점을 살펴보고자 한다. In general, a regular charterparty form is used as a charterparty for tugboats which are employed in marine construction and a bareboat charter form is generally used for barge boat charterparty. As the tug-barge charterparty which are currently used do not have a standardised form, contracting parties arbitrarily decide on the terms and conditions of the contract. As a result, provisions of the charterparty usually do not specify in the contract which party bears the burden of liability in case of accident. Furthermore, the terminologies used in the charterparty are different from legal terms of current commercial law which causes confusion. These problems can be solved mostly by clarifying the legal character of the charterparty between the contracting parties and by conforming the terminologies. In addition, endeavour to standardise the contract form must be carried forward at the same time. This research purports to study actual condition of current charterparty for tug-barge ship which are employed to marine construction and to suggest systematic improvement plan. For this purpose, this research focuses on studying cases in which dispute arose due to lack of clarity in the provisions of the contract with regard to which party bears the burden of liability in case of accident. This research also purports to suggest forming the standardised contract terms of the charterparty as one way of solution and examine matters to be attended in writing a standardised form.

해상공사에 투입된 부선의 안전관리 책임에 대한 연구

장영준(Yeong-Jun Jang) 한국항해항만학회 2015 한국항해항만학회지 Vol.39 No.1

해상공사 현장에서 용선한 부선 안전관리의 책임 소재와 관련한 논란과 법적 문제가 빈번히 발생하고 있다. 일반적으로 해상공사에 투입된 부선의 용선계약은 소위 ‘선원부 선체용선계약’의 형식으로 계약이 이루어진다. 우리 상법 제5편 해상편에서는 정기용선계약이나 선체용선계약을 규정하고 있지만 여기에 명시된 내용으로는 해상공사에 투입된 부선의 안전에 대한 책임소재가 불분명하다. 또한 이로 인하여 실제로 사고 발생 시 그 책임소재에 관한 논쟁이 발생하고 있으며 실무에서도 그 책임소재가 불분명하여 서로 책임을 전가하는 현상이 나타나고 있고 그로 인한 유사 사고의 위험성이 높은 상황이다. 그러나 부선의 관리를 맡고 있는 선두는 법적으로 자격요건이 정해진 바가 없으며 평소의 업무 내용을 고려해 볼 때 선두에게 해기사로서의 전문적인 판단을 요구하는 업무를 요구할 수 없다. 또한 해상공사 현장에 투입된 부선은 장비임대차계약 또는 선체용선의 형태로 건설공사에 투입되었으므로 용선자의 공사현장 안전관리 조직의 관리대상이므로 용선자가 부선을 안전하게 관리하여야 하는 주의의무가 있다. 따라서 선체용선한 부선의 사용 중 손해가 발생한 경우에는 기본적으로는 선체용선자의 책임이 된다. At marine construction sites, there are problems with regard to dispute on the responsibility of safety management of chartered barge and its legal issues. In general, demise charter with crew is used for barge charterparty which is committed to the marine construction. Although Chapter 5 of the Korean Commercial Act enact provisions regulating a Time Chargerparty and a Bareboat Charterparty, it is difficult to clarify where the responsibility lies with regard to the safety control of the chartered barge. For this reason, disputes on accountability arise when accident occurs in effect. As a result, parties of the charterparty shift the responsibility on each other and there is increased risk for occurrence of similar accidents. There is no legally required qualification for a head of barge workers who is in charge of barge management. It is not possible to demand the head of barge workers to take charge of tasks which requires professional judgment as a marine technician considering his daily work scope. Furthermore, the barge committed to the marine construction as a form of bareboat charter or equipment charterage is an object which should be managed by safety supervisor of the charterer’s marine construction. The charterer bears a duty to manage the safety of the barge. Therefore, the charterer is generally liable for the damage incurred in the course of using the chartered barge.

밀폐 연소실내의 메탄-공기 예혼합기의 연소 및 라디칼 특성에 관한 연구 (1)

전충환,장영준,Jeon, Chung-Hwan,Jang, Yeong-Jun 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.2

To clarify the effects of equivalence ratio, initial pressure and temperature on the flame propagation and radicals characteristics, a series of the experimental study were conducted in a quiescent methane-air premixture using a constant volume chamber. The development of the flame was visualized following the start of ignition using high speed schlieren photo and radical images by intensified CCD camera. Combustion pressure and ion current were recorded simultaneously according to the experimental conditions which were equivalence ratio with 0.7 to 1.2, initial pressure with 0.08 MPa to 0.40 MPa and initial premixture temperature with 3l3.2K to 403.2K. The results showed that the flame speed by ion current and mass fraction burned by combustion pressure characterized the effects of flame propagation very well. And increased combustion duration due to lean combustion condition that was below equivalence ratio, 0.8 caused cycle variation and decreasing the power of engine.

SCV를 장착한 2밸브 Sl 가시화기관의 연소특성에 관한 연구

정구섭,전충환,장영준,Jeong, Gu-Seop,Jeon, Chung-Hwan,Jang, Yeong-Jun 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.12

This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve SI optically accessible engine with swirl control valve(SCV). It adapted three different types of SCV(open ratio 72.5%, 78%, 59%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt) were calculated to explain burn rate and flame speed. From acquired flame images, we inspected the flame propagation direction, flame area, and flame centroid. Flame propagation direction showed different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame images at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

밀폐 연소실 내의 메탄-공기 예혼합기의 연소 및 라디칼 특성에 관한 연구(II)

최수진,전충환,장영준,Choe, Su-Jin,Jeon, Chung-Hwan,Jang, Yeong-Jun 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.5

In order to evaluate the effects of equivalence ratio, initial pressure and temperature on the laminar flame propagation process, and combustion radicals characteristics, experimental approaches are carried out in methane-air premixture using a constant volume chamber. Local and average radical intensities were measured to determine the time and spatial correlations between each radicals; C $H^{*}$(431 nm), $C_{2}$$^{*}$ (517 nm) and O $H^{*}$(309 nm) . The results are showed that two kinds of equation were proposed for the cases of continuous flame and intermittent flame type to evaluate actual equivalence ratio using relative intensities with each radicals. Both equations were agreed with actual equivalence ratio within 10% errors range. And schlieren photo and CCD image were compared with flame sizes at equivalence ratio 1.0.o 1.0.

모형가스터빈 연소기내 연소불안정성에 대한 연구

이종호,이연주,전충환,장영준,Lee, Jong-Ho,Lee, Yeon-Ju,Jeon, Chung-Hwan,Jang, Yeong-Jun 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.9

Combustion instabilities are an important concern associated with lean premixed combustion. Laboratory-scale dump combustor was used to understand the underlying mechanisms causing combustion instabilities. Experiments were conducted at atmospheric pressure and sound level meter was used to track the pressure fluctuations inside the combustor. Instability maps and phase-resolved OH chemiluminescence images were obtained at several conditions to investigate the mechanism of combustion instability and relations between pressure wave and heat release rate. It showed that combustion instability was susceptible to occur at higher value of equivalence ratio (>0.6) as the mean velocity was decreased. Instabilities exhibited a longitudinal mode with a dominant frequency of ∼341.8 Hz, which corresponded to a quarter wave mode of combustor. Heat release and pressure waves were in-phase when instabilities occurred. Rayleigh index distribution gave a hint about the location where the strong coherence of pressure and heat release existed. These results also give an insight to the control scheme of combustion instabilities. Emission test revealed that NOx emissions were affected by not only equivalence ratio but also combustion instability.

선회도가 평면화염버너의 유동과 연소 특성에 미치는 영향

정용기,김경천,전충환,장영준,Jeong, Yong-Gi,Kim, Gyeong-Cheon,Jeon, Chung-Hwan,Jang, Yeong-Jun 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.2

In this study, the flow and combustion characteristics of flat flame burner with twirler were investigated. There are several factors that define the characteristics of burner. Among them, the experiments was focused on swirl effect by four types of twirler in terms of flow structure, distribution of temperature and emission characteristics. In PIV(Particle Image Velocimetry) experiment, the less of swirl number, axial flow is dominant at the center. As swirl number increases, the flow develops along the burner tile and backward flow becomes stronger at center. From the combustion characteristics, as long as combustion load increases, blow-off limit was improved. But at the higher swirl number, the limit is decreased. At swirl number 0, the temperature is shown typical distribution of long flame burner. but swirl number increases, the temperature distribution is uniform in front of round tile. Therefore, the temperature distribution is coincided with flow structure. As excess air ratio increases, NO concentrations are high. But high swirl number gives rise to become low NO concentrations. The flame characteristics are comprised in wrinkled laminar-flame regime according to turbulence Reynolds number(Rel) and Damkohler number(Da).