소형 디젤 엔진의 연소실 및 인젝터 노즐 형상에 따른 연비 및 배기 특성

강승우 ( Seungwoo Kang ),홍동우 ( Dongwoo Hong ),배충식 ( Choongsik Bae ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-

The penetrations of the sprays from the injectors were increased with adoption of high pressure injection system in a light-duty diesel engine. Because the combustion chamber of a light-duty diesel engine is smaller than the heavy-duty, the interaction between spray and combustion chamber is much important in a light-duty diesel engine. The combustion process and the position at which the combustion occurs vary depending on the combustion chamber geometry and spray. Also, in the case of a small diesel engine, the ratio of the heat loss caused by combustion to the piston and the liner is large. It is therefore important to improve combustion and reduce heat loss through optimization of injector nozzles and combustion chamber geometry of small diesel engines. In this study, fuel efficiency and exhaust characteristics of a small diesel engine according to the shape of injector nozzle were examined in two types of combustion chambers. The effect of the nozzle diameter and the number of holes was studied. The nozzle diameter was 100um to 117um and the number of nozzles was in the range of 8 to 12. The shape of the re-entrance combustion chamber tends to improve the fuel efficiency and exhaust gas when the nozzle diameter is larger and the number of holes is increased. This is because the air utilization in the combustion chamber increased when the momentum of the spray was larger. However, when the nozzle diameter increases beyond a certain nozzle diameter, the penetration distance of the liquid spray becomes longer, so that the wetting of the liquid spray occurs and the particulate matter emission increased. On the other hand, in the case where the depth of the combustion chamber shape is deep and making the spray using the air toward the edge of the combustion chamber, the fuel consumption and exhaust are deteriorated when the nozzle diameter is large and the number of holes is increased,. Compared to the combustion chamber shape in which the spray is re-entrant to the center of the combustion chamber, the larger the spray momentum did not help to improve the air utilization rate, and the microscopic mixing of the air and the fuel due to improved atomization of the spray improved the combustion and exhaust. In this experiment the formation of the injector nozzle and spray required for each combustion chamber shape in the case of the small diesel engine is changed. Therefore, it was concluded that optimization of injector shape, injection strategy and optimization of combustion chamber shape should be performed at the same time.

실물형 연소기의 형상에 따른 연소특성속도 비교

김종규(Jonggyu Kim),한영민(Yeoung-Min Han),안규복(Kyubok Ahn),김문기(Munki Kim),서성현(Seonghyeon Seo),최환석(Hwan-Seok Choi) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.5

30톤급 액체로켓엔진 실물형 연소기의 형상에 따른 연소특성속도에 대한 연구를 수행하였다. 본 연구에서 연소기의 형상은 연소기 헤드와 분리가 가능한 내열재 및 채널 냉각형 연소실(ε=3.2), 그리고 일체형인 팽창비가 각각 3.5와 12인 재생냉각형 연소기이다. 연소압력은 약 53~60 bar 그리고 추진제 유량은 약 89 kg/s이고, 적용된 분사기는 리세스수가 1.0인 동축 와류형이다. 설계점 연소시험에서 팽창비가 12인 일체형 재생냉각 방식의 연소기가 가장 큰 연소특성속도를 보였는데 이는 추진제인 케로신이 분무되기 전 챔버 냉각으로 인한 온도 상승에 따른 엔탈피의 증가 및 연소압력의 증가에 기인한 것이다. Effects of chamber configuration on combustion characteristic velocity of full-scale combustion chamber for 30-tonf-class liquid rocket engine were studied. The configurations of combustion chamber are ablative and channel cooling chamber (ε=3.2) which have detachable mixing head, and single body regenerative cooling chamber which has nozzle expansion ratio of 3.5 and 12, respectively. The combustion chambers have chamber pressure of 53~60 bar and propellant mass flow rate of 89 kg/s, and the injectors of all combustion chamber have recess number 1.0 and double-swirl characteristics. The hot firing test results at design point show that the combustion characteristic velocity of the regenerative cooling chamber which has nozzle expansion ratio of 12 is higher than that of other combustion chambers. The reasons for the above result are the increases of combustion pressure and enthalpy of kerosene which is heated due to cooling of the chamber wall before injection into the combustion field.

Effect of equivalence ratio and mixing time on combustion of ammonia/ oxygen/argon mixture using a constant volume combustion chamber with sub-chamber

Bin Guo,Mitsuhisa Ichiyanagi,Takuma Ohashi,Qinyue Zheng,Takashi Suzuki 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Ammonia has received significant attention as a fuel due to its carbon-free molecular structure. However, burning ammonia is challenging because of its low laminar burning velocity. To promote the combustion velocity, the authors propose a constant volume combustion chamber with a sub-chamber. This study investigated the effects of the mixing time and equivalence ratio of the ammonia/oxygen/argon mixture on combustion. The mean velocity of the ejection from the sub-chamber can be calculated by evaluating the combustion pressure, mass fraction burned, and volume fraction burned. It was clarified that with the sub-chamber structure, the ejection from the sub-chamber improved the compression and turbulence of unburned gas in the main chamber and increased the mean flame velocity of ammonia combustion. The appropriate glow plug temperature could improve the ignitability of the fuel mixture, leading to increased combustion efficiency, maximum combustion pressure, and reduced combustion time.

전남지역 마한․백제 토기가마 변천과 파급

이정민 동아시아고대학회 2019 동아시아고대학 Vol.0 No.53

The purpose of this study is to examine the structural characteris tics of pottery kilns in Chonnam area and to examine the relationship between them and the early Sueki kiln based on the process of change. The structural characteristics of the pottery kiln in Chonnam area were examined. Seven types of structural features were established based on the shape of firing chamber, the presence of stepped structure of combustion chamber, and the existence of the stepped structure at the side wall formed in the combustion chamber and firing chamber. Based on this, set up branch of pottery kiln in Chonnam area and figure out the change pattern. The pottery kiln in Chonnam area has the largest width of the firing chamber in the first half or the middle half, and it has a flat oval shape and no existence of stepped structure of combustion chamber. In the 5th century, stepped structure exists between combustion chamber and firing chamber. After the middle of the 6th century, when the Gaebe(serving vessel) of Sabi period was discovered, only the type with stepped structure of combustion chamber is the long elliptical shape (the maximum width of the firing chamber is in the middle) near the rectangular shape is confirmed. The early sueki kilns of Japan, the TG232 step ∼ TK73 step corresponds to the start of the fourth century at Deai site in Hyogo. The maximum width of the firing chamber is the long elliptical flat oval shape with the middle half, and the combustion chamber has a mixed wedge with and without. The structure of the pottery kiln and the early sueki kiln in Chonnam area has a common point such as the combination of shape of the firing chamber and the presence or absence of stepped structure of combustion chamber. It also shows similarities in the proliferation process, such as small-scale operations in each region in the 3rd and 4th centuries, specific regional operations in the mid-5th century, large-scale production in the late 5th century, and increased operations within the province. It can be assumed that the relation ship between ancient Chonnam area and Japan is close to each other in view of the relationship between the structure of the kiln and the diffusion process that is based on the social and cultural aspects. 본고는 전남지역 토기가마의 구조적 특징을 파악함으로써 형식을 설정하고 변천과정을 바탕으로 초기 스에키가마와의 관련성을 살펴보고자 하였다. 전남지역의 토기가마에서 확인되는 구조적 특징을 각각 검토하여 그중 소성실 평면형태와 연소실 불턱 단 유무, 그리고 연소실과 소성실에 형성된 측벽 단 유무를 기준으로 7가지의 형식을 설정하였다. 이를 바탕으로 전남지역 토기가마의 분기를 설정하여 변화양상을 파악하였다. 전남지역 토기가마는 소성실의 최대너비가 전반부 혹은 중반부에 있는 장타원형 평면형태이며 연소실 불턱 단이 없는 것에서 있는 것으로 변화하면서 규모가 커지고 다양한 형식이 운영되는 5세기대에는 연소실과 소성실에 측벽 단이 형성된다. 사비기 개배가 확인되는 6세기 중엽 이후가 되면 장방형에 가까운 장타원형(소성실 최대너비가 중반부에 위치)에 연소실 불턱 단이 있는 형식만이 확인되고 있다. 일본의 초기 스에키가마는 4세기 말의 효고현 데아이유적을 시작으로 TG232단계∼TK73단계가 해당된다. 소성실의 최대너비가 중반부에 있는 장타원형 평면형태이며 연소실 불턱 단이 있는 것과 없는 것이 혼재되어 있다. 전남지역 토기가마와 초기 스에키가마의 구조는 소성실 평면형태 및 연소실 불턱 단 유무의 혼재 등 공통점을 띤다. 또한 3∼4세기대의 각 지역별 소규모 조업, 5세기 전․중반의 특정지역 중심 조업, 5세기 후반에 대규모 생산체제 및 지방 내에서의 조업이 증가되는 등 확산 과정에서도 유사성을 보인다. 가마의 구조적 속성뿐 아니라 사회․문화적 양상이 바탕이 되는 확산 과정에서의 관련성으로 보아 고대 전남지역과 일본과의 교류가 긴밀했음을 추정해 볼 수 있다.

액체 로켓 엔진 연소불안정 현상 모사를 위한 비원통형 연소실 설계 및 검증

오정화,신민규,차정열,김지운,이대연,고영성 한국항공우주학회 2024 韓國航空宇宙學會誌 Vol.52 No.3

액체 로켓 엔진의 연소불안정 현상을 모사할 수 있는 방법에 대한 연구를 진행하였다. 추진제로는 케로신/액체산소를 사용하며, 연소 압력은 60 bar일 때 1T 모드를 모사하고자 하였다. 본 논문에서는 모사 장치의 주요 파트인, 직육면체 형상의 비원통형 연소실의 설계 및 검증을 수행하였다. 일반적인 원통형 연소실이 아니므로, 설계 시 구조적인 검토 및 고유 진동수 분석을 수행하였으며, 연소실의 검증은 10 bar, 60 bar 연소 시험 순으로 진행하였다. 시험 결과 안정적인 점화 및 연소 압력을 형성하였으며, 연소실의 구조적인 손상이 없었으므로, 최종적으로 비원통형 연소실의 검증이 완료된 것으로 판단하였다. Research was conducted on methods to simulate combustion instability in a liquid rocket engine. Kerosene/liquid oxygen was used as the propellant, and the goal was to simulate the 1T mode at a combustion pressure of 60 bar. In this paper, the design and validation of the non-cylindrical combustion chamber, which has a rectangular cuboid shape and is a key component of the simulation device, were performed. Since it is not a typical cylindrical combustion chamber, structural reviews and a natural frequency analysis were conducted during the design process. Validation of the combustion chamber was carried out through combustion tests at both 10 bar and 60 bar. The test results showed stable ignition and combustion pressure, and there was no structural damage to the combustion chamber. Therefore, it was concluded that the validation of the non-cylindrical combustion chamber was successfully completed.

A numerical study on the soot and combustion performance of a diesel engine with pip shape

이상열,김민재,김하진 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.12

The shape of the combustion chamber plays an important role in the formation of the air-fuel mixture in the chamber, which has a great influence on the combustion efficiency and emission formation. The pip is a protruding shape at the center of the combustion chamber, and its importance has been evaluated to be relatively low. There has also been little research on off-highway diesel engines in comparison with on-highway diesel engines. When a high-pressure injection system is used in an off-highway diesel engine, which injects more fuel than on-highway engines, the shape of the pip greatly affects the mixture spray momentum and air flow in the combustion chamber. In this study, the pip geometry of a 2.4-liter off-highway engine was modified using three shapes: a step cone, W shape, and egg shape. We used 3-D combustion simulations to analyze the effects of the pip geometry on the mixture formation and combustion efficiency. We also analyzed the influence of the height and corner angle of the pip on the combustion and emission based on the egg shape, which was the most efficient. The results of this study could be used as a guide in designing combustion chambers for diesel engines.

정적연소실을 이용한 메탄올 혼합연료의 연소특성에 관한 연구

조행묵(Haeng Muk Cho),이창식(Chang Sik Lee) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

This work is to obtain the combustion characteristics of methanol-blended fuel in a constant volume combustion chamber. The combustion characteristics of methanol-blended fuel in a constant volume combustion chamber are investigated for various conditions of equivalence ratio, initial pressure, and pre-mixture temperature of mixture. The results of combustion experiment show that the combustion pressure is increased in accordance with the increase of initial pressure in the chamber. The combustion duration of blended fuel is increased with the decrease of air 뺈uel equivalence ratio of methanol-blended fuel.

발전용 커먼레일 디젤엔진에 적합한 최적화 연소실형상 설계를 위한 수치해석

김승철(Seung Chul Kim) 한국가스학회 2016 한국가스학회지 Vol.20 No.4

본 연구는 연소실 형상 변화에 따른 디젤연소와 배출가스의 특성에 대해 살펴보았다. 발전용 커먼레일 디젤엔진의 최적화 설계를 위한 연소실형상을 제시하기 위해 5가지 타입형상을 연비 측면에서 계산하였다. 연소실 형상은 연소 시 분무면적을 변화시킴으로서 연소특성에 영향을 주었으며 이러한 주요요소는 연소실 형상 비였다. 이러한 수치해석의 결과는 연소실 형상의 변화는 발전기의 연비 개선을 가능하도록 한다고 판단되었다. This paper presents characteristics of diesel combustion and emissions according to adoption of various combustion chamber geometry. In order to suggest suitable combustion chamber geometry of the common rail diesel engine for electric generative use, 5 type of geometry chamber was found performance for combustion chamber to respond fuel efficiency. Combustion chamber geometry affects combustion characteristics due to change target area of spray in the combustion chamber and the main factor was the bowl aspect ratio of combustion chamber. Using the results of simulation, the effects of the variable combustion chamber can be improved the fuel efficiency for electric generation.

75톤급 연소기 연소시험설비 테스트 스탠드 구축 현황

임지혁(Ji-Hyuk Im),우성필(Seongphil Woo),이무근(Mookeun Yi),김승한(Seung-Han Kim),이광진(Kwang-Jin Lee),한영민(Yeoung-Min Han) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.5

75톤급 연소기 연소시험설비는 한국형발사체(KSLV-II) 적용되는 75톤급 연소기, 7톤급 연소기, 75톤급 가스발생기의 지상 환경에서의 연소성능평가를 목적으로 구축되었다. 테스트 스탠드는 제어/계측 및 유공압 등의 설비와 연소기 사이의 인터페이스를 담당하고 연소기에서 발생하는 추력을 측정 및 지탱하는 역할을 한다. 75톤급 연소기 연소시험설비는 고추력 및 저추력 테스트 스탠드로 구성되고 고추력 테스트 스탠드에서는 75톤급 연소기의 연소시험이 가능하며 저추력 테스트 스탠드는 7톤급 연소기와 75톤급 가스발생기의 연소시험을 수행할 수 있다. 본 논문에서는 75톤급 연소기 연소시험설비 테스트 스탠드의 구축 현황과 단독시험 결과를 소개하였다. 75 tonf-class Combustion Chamber Test Facility(CCTF) is constructed for hot-firing performance evaluation of 75 tonf-class combustion chamber, 7 tonf-class combustion chamber and 75 tonf-class gas generator of KSLV-II. Test stand provides interfaces between control measurement system and hydro-pneumatic system, and combustion chamber. Also, test stand holds and measure the thrust generated by combustion chamber. Test Stand is consisted of high thrust and low thrust test stand. In high thrust test stand, it is possible to perform hot-firing tests for 75 tonf-class combustion chamber. Hot-firing tests for 7 tonf- class combustion chamber and 75 tonf-class gas generator can be conducted in low thrust test stand. This paper introduces the construction status of CCTF test stand and the autonomous tests results.

연소실 압력 변화에 따른 연소기 압력 섭동 분석

안규복(Kyubok Ahn),임병직(Byoungjik Lim),김종규(Jong-Gyu Kim),한영민(Yeoung-Min Han),최환석(Hwan-Seok Choi) 한국추진공학회 2010 한국추진공학회지 Vol.14 No.5

For the development of a liquid rocket engine, hot-firing tests of a regeneratively cooled thrust chamber were performed at chamber pressures of approximately 30 and 60 bars. In the paper, pressure fluctuation data, which were obtained from the dynamic pressure transducers installed in propellant manifolds and combustion chamber, were analyzed. Compared to the data at chamber pressure of 60 bar, the results at chamber pressure of 30 bar showed low-frequency oscillations around 150 Hz in the combustion chamber. The low-frequency waves in the combustion chamber were coupled with those in the manifolds. However, the RMS values of the chamber pressure fluctuations at chamber pressure of 30 bar were only 0.8% of the chamber pressures. Thus, it can be inferred that the thrust chamber operates in the stability boundary even at low chamber pressure.