Combustion characteristics of gaseous inverse O₂/H₂ coaxial jet flames in a single-element model combustor

Kim, Tae Young,Choi, Sun,Kim, Young Hoo,Ahn, Yeong Jong,Kim, Hee Kyung,Kwon, Oh Chae Elsevier 2018 ENERGY Vol.155 No.-

<P><B>Abstract</B></P> <P>To effectively design hydrogen (H<SUB>2</SUB>)/oxygen (O<SUB>2</SUB>) liquid rocket engines through understanding the combustion characteristics of H<SUB>2</SUB>/O<SUB>2</SUB> bipropellants, fundamental studies for the bipropellants in different phases are needed. This study is focused on the combustion characteristics of inverse gaseous O<SUB>2</SUB>/H<SUB>2</SUB> coaxial jet flames in a single-element model combustor as a preliminary step for succeeding studies of injection at different phases in the combustor, visualizing flame structure by direct imaging, OH<SUP>∗</SUP> chemiluminescence and OH planar laser-induced fluorescence. With increasing Reynolds number (Re), the frequency of occurrence of the local flame extinction increases and the length of the disconnected OH reaction zone is extended. The OH layer thickness increases downstream, while it is almost constant where the local flame extinction occurs and decreases with increasing Re due to the enhanced strain and scalar-dissipation rates. The excessive flame wrinkledness increases the local flame strain rate and results in the local flame extinction, exhibiting the tendency of increasing and then decreasing flame surface density with increasing Re. The probability density function of OH intensity quantifies the fluctuation intensity of OH radicals and the possibility of the local flame extinction. A useful database is provided for modeling the combustion of H<SUB>2</SUB>/O<SUB>2</SUB> bipropellants under different phases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A useful database for modeling the H<SUB>2</SUB>/O<SUB>2</SUB> bipropellant combustion is provided. </LI> <LI> Local flame extinction frequently occurs at high Reynolds number (<I>Re</I>). </LI> <LI> OH probability density function indicates the possibility of local extinction. </LI> <LI> Flame surface density increases and then decreases with increasing <I>Re</I>. </LI> <LI> Strong burning of O<SUB>2</SUB>/H<SUB>2</SUB> causes laminar-like combustion near the injector lip. </LI> </UL> </P>

광합성세균 미생물막반응기에 의한 유기성폐수의 처리특성

오광근,이철우,전영중,이재홍 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.6

홍색비유황 광합성세균인 Rhodopseudomonas capsulata를 선택하여 porous ceramic bead를 충진시킨 충진형 반응기(Packed-bed reactor, PBR)와 분말활성탄을 현탁시킨 유동산 반응기(Fluidized-bed reactor, FBR)에서 미생물막을 형성하여 폐수처리를 비교한 결과 PBR이 FBR보다 BOD 부하량 변화에 더 안정적인 처리성을 보였다. 체류시간 (hydraulic retention time, HRT)에 따른 처리성은 유입폐수 농도를 각각 BOD 10,000, 20,000 mg/ℓ로 하였을 때, HRT 1일 이상에서 90% 이상의 처리효율을 가지며, 유출수의 BOD 농도는 각각 350, 800 mg/ℓ이었다. PBR에서 유입수의 BOD 농도변화에 다른 유출수의 농도를 측정하여 단위부피당 기질부하량 상수 (maximum specific BOD loading rate, P) 및 부착미생물 포화기질 제한농도 상수(half saturation constant, K_6)를 구한 결과, 각각 22.2 gBOD/ℓ·day, 1,750 mgBOD/ℓ이었고, 처리효율 90% 이상을 나타내는 BOD 용적부하(volumetric BOD loading rate)는 20 gBOD/ℓ·day 이상으로 표준활성오니법의 0.6 gBOD/ℓ·day에 비하여 30배가 넘는 값을 나타내었다. An efficient packed-bed type biofilm reactor charged with immobilized phototrophs was developed to treat organic wastewater at an extremely high volumetric loading rate. The packed bed reactor (PBR) charged with porous ceramic beads was superior to a fluidized-bed reactor suspended with activated carbon powders in terms of many aspects such as BOD removal efficiency, operational stability, and overall economics. For wastewater with BOD concentration as high as 20,000 mg/l, the BOD removal efficiency was maintained above 90% when the hydraulic retention time (HRT) was longer than 1 day. The allowable volumetric BOD loading rate of this reactor (20gBOD/l·day) is more than ten-folds higher than that of an ordinary activated sludge method. The behaviour of the reactor was represented well by a Monod type kinetic equation with a maximum specific BOD loading rate(P) of 22.2gBOD/l·day and a half saturation constant(K_s) of 1,750 mgBOD/l.

발바닥 특정 부위 자극이 뇌파에 미치는 효과에 대한 비선형 분석

吳永仙,吳旼錫,宋泰元 대전대학교 한의학연구소 2001 한의학연구소 논문집 Vol.10 No.1

The brain is one of the most complex systems in nature. Brain waves, or the "EEG", are electrical signals that can be recorded from the brain, either directly or throught the scalp. The kind of brain wave recorded depends on the behavior of the animal, and is the visible evidence of the kind of neuronal (brain cell) processing necessary for that behavior. But, EEG had been considered as a virtually infinite-dimensional random signal. However, nonlinear dynamics light on dynamical aspects of the human EEG. The methods of nonlinear dynamics provide excellent tolls for the study of multi-variable, complex system such as EEG. In this study, 20 persons seperated in 2 groups were examined with EGG, one group stimulated on specific area of the sole of the foot with footbed inside the shoes. This experiment resulted in at the group stimulated on specific area of the sole of the fott correlation dimension of P4 and Ol channels increased significantly. Therefore, we obserbed that stimulation on specific area of the body had a constant effections on the specific channels.

저유량 마취를 위한 전자제어식 기화기 개발

오영택,박재훈,장인배 江原大學校 産業技術硏究所 2009 産業技術硏究 Vol.29 No.B

For the environmental safety of the operating room and patient healthcare, the closed type rebreathing system is widely adopted. In order to reduce the anesthesia gas during surgery, the mixing ratio of anesthesia gas with breathing air should be precisely controlled. Generally, the breathing air passes through the vaporizer to mix the anesthesia gas, but there is a difficulty in controlling the mixing ratio precisely. In this paper, the stand-alone style vaporizer is designed and the operating characteristics are investigated. The vaporizer measures the temperature and pressure in the vaporizing chamber and chamber temperature is precisely controlled by proportional controlled heater. Exact quantity of anesthesia media is feeded by PID controlled peristaltic pump and vaporized gas is mixed with breathing air flow by PWM controlled solenoid valve. The experimental result shows that the vaporizer has an excellent command following performances that it can be applied to the low flow anesthesia system.

기관골 신생증 1예

오영상,이은우,정종혁,문승원,김수현,김동한,양혁승,박정환,박경옥,강성수,이영직 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Tracheobronchopathia osteoplastica is a rare disorder of unknown cause characterized by the projection of numerous bony or cartilaginous submucosal nodules into the tracheobronchial lumen with sparing of the posterior membranous portion of tracheobronchial tree. In the past, most of the cases were diagnosed as secondary finding at autopsy. Nowaday, the key component of the evaluation is flexible fiberoptic laryngoscopy and bronchoscopy, which typically demonstrates irregular spicules of subrnucosal bone and cartilage projecting into the tracheobronchial lumen and causing various degrees of airway obstruction. A 45 years old man was visited Sunchon St. Carollo hospital due to discomfort on throat. We saw several nodules just below vocal cord via laryngoscope. The computed tomography revealed multiple small calcified nqdules on trachea and both main bronchi. Pathologic finding of bronchoscopic biopsy showed abnormal proliferation of bony and cartilagious nodules in the tracheal submucosa. These fingdings were consistent with tracheobronchopathia osteoplastica. We report here on a case of tracheobronchopathia osteoplastica with review of literature.

광합성세균에 의한 미생물막의 형성

오광근,이철우,전영중,이재홍 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.6

홍색비유황 광합성세균인 Rhodopseudomonas capsulata를 선택하여 packed-bed reactor에서 미생물막을 형성할 때, porous ceramic bead가 다른 담체에 비해 우수하였고, 일정한 유입농도하에서 체류시간(hydraulic retention tiem, HRT)이 짧을수록 미생물막 형성이 양호하였으며, 그 때 반응기내의 세포농도는 11,400mg/l로 현탁처리시의 세포농도에 비하여 3~8배 증가하였다. PBR에서 미생물막의 형성은 cell attachment, microcolony formation, biofilm formation의 단계를 거쳐 형성되는 것으로 관찰되었으며, PBR이 FBR보다 안정적인 미생물 부착을 보였고 특히 PBR에서는 BOD용적 부하가 15gBOD/ℓ·day 이상이 되어도 미생물막의 부착비율은 90% 이상을 유지하였다. 전자현미경으로 담체의 표면 및 내부에 고정화된 광합성세균을 확인할 수 있었다. The formation of microbial films(biofilm) by a non-sulfur phototrophic bacteria, Rhodopseudomonas capsulata, on inorganic media was studied. Porous ceramic beads(PCB) were superior to other immobilizing media for the biofilm formation in a packed-bed reactor. It was found that the formation of microbial films favored a lower hydraulic retention time, showing a higher ratio of cells attatched to the media to those suspended in the solution. The cell concentration in the biofilm reactor was as high as 11,400 mg/ℓ, which is 8-folds of the cell concentration in a ordinary suspended treatment. It was observed that the formation of microbial film by R. capsulata followed a general serial process of cell attachment, microcolony formation, and biofilm formation. The microbial films thus formed was very stable even for an extremely high volumetric BOD loading rate of 15 gBOD/ℓ·day. The scanning electron micrographs of the microbial films showed that the cells were attached to both the surface and pores of the media.

새고막을 이용한 분말조미료 가공

오영열,강동수,김해섭,김경은,최옥수,배태진 여수대학교 산업기술지역개발연구소 2000 産業基術硏究所 論文集 Vol.9 No.-

Conditions for processing dried condiments with bloody clam were investigated. The enzymatic hydrolysis for 1 hour was more profitable than hydrothermal extraction to develop flavoring matters from bloody clam. As a result of omission tests, nucleotides were predominated in the taste compounds of bloody clam hydrolysates rather than free amino acids, and the contribution of nucleotides and free amino acids to the taste of bloody clam hydrolysates was remarkable. The major flavoring components of bloody clam hydrolysates were free amino acids and oligopeptides below 500 dalton. When bloody clam hydrolysates were separated with membrane(molecular weight cutoff 500 dalton) for recovering flavor, recovering yields of amino type nitrogen were 92.4%. Proximate compositions of dried condiments prepared with protease hydrolyzed bloody clam were moisture content 3.6%, total nitrogen were 71.2% amino nitrogen were 47.8%. And drying yield, solubility and absorption rates at Aw 0.88 were 21.4%. 86.3% and 6.6%, respectively.

「金鰲新話」에 굴절된 恨의 고찰

文永午 동국대학교 한국문학연구소 1987 한국문학연구 Vol.0 No.10

조속기 삼중화 출력모듈 설계에 관한 연구

강영선,오성보 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

This paper presents the design of fault-tolerant governor system. There are a lot of troubles in the system of power plant. Also, they occasionally occur in turbine governor system. Therefore, we consider development of the fault-tolerant governor control system about fault detection, fault containment, fault location, fault recovery and fault masking. To construct to system using TMR(triple modular redundancy), we design digital output module with voter, analog output module with voter and flux summing module. Consequently, we achieved good response from simulation of the proposed output module of TMR governor system. We will apply it to the Gas Turbine No. 3 Unit in Cheju Power Plant.

전기응집에 의한 페수의 크롬 제거

김영관,오미영 대한상하수도학회 2001 상하수도학회지 Vol.15 No.6

This research was carried out to investigate the removal of chromium from wastewater by electrocoagulation. The electrochemical reactor was manufactured to enhance settling of the electro-generated sludge. Aluminum and graphite were used as electrode materials. In the electrochemical reaction of synthetic chromium wastewater using aluminum electrodes, chromium removal increased with both the applied electrical current and retention time. Chromium removal over 90% was obtained and further removal as low as 0.45㎎/ℓ could be attained by successive electrochemical treatment. However, increased residual aluminum concentration in the treated effluent should be considered for the application of the successive treatment scheme. As an anodic material, graphite resulted in a greater chromium removal by enhanced production of H^+ and OH^- which eventually accelerated the precipitation reaction. In the electrochemical treatment of the plating wastewater, some selected heavy metals showed removal efficiencies in the range of 70-94%.