• 제목/요약/키워드: Secondary Air System

검색결과 272건 처리시간 0.027초

간접 냉동 시스템용 2차 냉매의 열전달과 압력강하 특성 (Heat Transfer and Pressure Drop Characteristics of Secondary Refrigerants Applying to Indirect Refrigeration System)

  • 오후규;손창효;조환;이문빈;전민주
    • 동력기계공학회지
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    • 제17권4호
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    • pp.45-50
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    • 2013
  • This paper presents the comparison of heat transfer and pressure drop of various secondary refrigerants (single-phase and two-phase) in the indirect refrigeration system. The main results were summarized as follows: In case of heat transfer, it is useful to use secondary refrigerants in low evaporating temperature region and the heat transfer coefficient of single-phase is larger than two-phase secondary refrigerants. In case of pressure drop, it is useful to use secondary refrigerants in high evaporating temperature region and the pressure drop of two-phase is smaller than single-phase secondary refrigerant. Also, $CO_2$ is the best useful because pressure drop of $CO_2$ among the secondary refrigerants is the smallest.

2차 공기 주입 조건 변화에 따른 소형 소각로 내부의 유동장 분석 (Analysis of the Gas Flow Field of Primary Combustion Chamber with the Conditions of Secondary Air Injection)

  • 최병대;김성준
    • 산업기술연구
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    • 제22권A호
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    • pp.9-17
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    • 2002
  • This analysis is aimed to find out how the conditions of secondary air injection affects the residence time and the turbulence energy of flue gas and flow field in a small incinerator. A commercial code, PHOENICS, is used to simulate the flow field of an Incinerator. The computational grid system is constructed in a cartesian coordinate system In this numerical experiment, an independent numerical variable is the conditions of secondary air injection and dependants are the residence time of flue gas and the mean value of turbulence energy in a primary combustion chamber. The flow field and the distribution of turbulence energy are analysed to evaluate the residence time of flue gas and the turbulence energy The computational results say that the tangential injection of secondary air make the residence time much longer than the radial injection and that the radial injection of secondary make turbulence much stronger than the tangential injection.

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2차 냉매로서 CO2를 사용하는 간접 냉동시스템의 열전달과 펌프 소비동력 (Heat Transfer and Pump Consumption Power of Indirect Refrigeration System Using CO2 as a Secondary Refrigerant)

  • 윤정인;최광환;손창효;이문빈
    • 동력기계공학회지
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    • 제18권2호
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    • pp.25-30
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    • 2014
  • In this paper, the heat transfer coefficient and pump consumption power of indirect refrigeration system using $CO_2$ as a secondary refrigerant were investigated experimentally. First, from the comparison of pump consumption powers of existing brines(EG, PG, EA etc.) and $CO_2$ as secondary refrigerants at the same experimental conditions, PG and $CO_2$ show the highest and lowest power, respectively. Second, the heat transfer coefficient of $CaCl_2$ is the highest, but PG is the lowest among other secondary refrigerants. From the above results, it is confirmed that $CO_2$ as the secondary refrigerant has excellent characteristics when comparing to existing brines. Thus, it is concluded that $CO_2$ is applicable as the secondary refrigerant of indirect refrigeration system.

2차 냉매로 천연냉매 R744를 사용하는 냉동시스템의 성능 특성 (Performance Characteristics of Refrigeration System Using R744 as a Secondary Refrigerant)

  • 이문빈;조환;윤정인;최인수;손창효
    • 동력기계공학회지
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    • 제18권4호
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    • pp.17-22
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    • 2014
  • In this paper, the performance characteristics of R404 indirect refrigeration system using R744 as a secondary refrigerant were investigated experimentally to obtain a optimum design data for this system. First, for the constant experimental conditions, the COP of R404A indirect refrigeration system using R744 as secondary refrigerants decreases with respect to the increases in R404A condensation temperature and temperature difference in R744 cooler. And, the COP of indirect refrigeration system using R744 as secondary refrigerants decreases slightly with decreasing the mass flowrate of R744.

스파크 점화기관에서 이차 공기 분사가 냉시동시 THC 배출량에 미치는 영향에 관한 실험적 연구 (Experimental Study of the Effect of Secondary Air Injection on the Cold Start Total Hydrocarbon Emissions in a Spark Ignition Engine)

  • 이승재;함윤영;전광민
    • 한국자동차공학회논문집
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    • 제11권1호
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    • pp.1-6
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    • 2003
  • Engine emission regulations are becoming more stringent nowadays. In cold transient regime, about 80% THC is exhausted to the atmosphere in the first 200s (US FTP cycles). Accordingly, reducing emission levels in the cold period immediately after the engine start before the catalysts reach their working temperature will be an especially critical factor in meeting more stringent regulations in the future. In this study, the total hydrocarbon quantities are measured using a Fast FID with gasoline fuel for a 4-cylinde. Sl engine, including Secondary Air Injection (SAI) system. Commercial SAI device's direction is reverse to the exhaust flow. In this study, a swirl flow type SAI system which is positioned between the exhaust manifold and exhaust port, was developed. We compared the swirl type secondary air injection with a commercial secondary air injection of .everse flow. The swirl type SAI showed better results in reducing HC by 26% than the commercial flow type SAI of reverse flow which was caused by the better mixing between the exhaust gas and the secondary air.

상업용 소각로 연소실 성능예측을 위한 수치해석 연구 (Numerical Analysis for the Performance Prediction of Combustion Chamber of Commercial Incinerator)

  • 이진욱;박병수;윤용승;서정대;허일상
    • 한국연소학회지
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    • 제4권1호
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    • pp.141-153
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    • 1999
  • Numerical analysis for the combustion flow in the combustion chamber of incineration system has been carried out in order to acquire the basic design capability of incineration system. Established mathematical model was applied to the performance prediction of the pre-designed combustion chamber of commercial plant. Especially, combustion characteristics and the variation of flow pattern have been deeply discussed in accordance with secondary air injection. Secondary air injection was effective for the turbulent mixing between air and carbon monoxide/volatile matter resulting in considerably reduced CO content at the exit. Secondary air injection was found to be one of the key design parameters because the size of recirculation zone could be changed with the variation of injection characteristics.

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2차 공기 공급 시스템을 채택한 촉매 변환기 내 냉 시동 구간 배기가스 해석 (Emission Analysis in Catalytic Converter Adopted Secondary Air Injection System for Cold Start Period)

  • 윤정의
    • 한국자동차공학회논문집
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    • 제18권6호
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    • pp.46-52
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    • 2010
  • In this paper, emission analysis during cold start period of CVS-75 mode in LPG vehicle was performed to find out proper operating conditions of SAI(Secondary Air Injection) system. In order to meet SULEV target, the simulated emission system had a SAI system as well as a MCC(Manifold Catalytic Converter) and a UCC(Under body Catalytic Converter). Using commercial 1-D code AMESIM, in which 7 step global surface chemical reactions of Langmuir-Hinshelwood type were adopted, transient emission analysis in the exhaust system during cold start period of CVS-75 mode were carried out to figure out the effects of flow rate, duration of supply air on HC, CO, NO emission.

2차 공기 주입각이 소각로 내부의 온도 분포 균일도에 미치는 영향 (Effects of the angle of secondary air inlet on the uniformity of temperature distribution inside an incinerator)

  • 김성준;민인홍;박명호;박민주
    • 한국전산유체공학회지
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    • 제5권3호
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    • pp.8-15
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    • 2000
  • This research is aimed to find out how the inlet angle of secondary air affects the uniformity of temperature distribution inside a small incinerator. A commercial code, PHOENICS, is used to simulate the thermal-flow field of an incinerator. The computational grid system is constructed by Multi-Block technique provided by PHOENICS. Numerical experiments are done with the five different angles of secondary air inlet. The uniformity of temperature distribution is evaluated by checking the standard deviation of temperature distribution in an incinerator. The computational results show that there is the minimum value of standard deviation at the certain angle of secondary air inlet, which means that there is an optimum angle of secondary air inlet that could improve the uniformity of temperature distribution in an incinerator. The optimum angle of secondary air inlet is between 30 degree and 45 degree in this particular case.

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역방향 2차 공기 주입 방식을 적용한 소각 연소로의 Thermal NOx 및 CO 배출특성에 대한 축소모형실험 연구 (Experimental Study on Thermal NOx and CO Emission in a Laboratory-Scale Incinerator with Reversed Secondary Air Jet Injection)

  • 최종균;최우성;신동훈
    • 대한기계학회논문집B
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    • 제40권8호
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    • pp.503-510
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    • 2016
  • 일반적으로 연소로는 연료의 연소과정에서 NOx, CO등의 공해물질을 배출한다. 본 연구는 소각연소로를 대상으로 2차 공기를 연소가스 흐름의 역방향으로 주입시키는 방법의 NOx 및 CO 배출특성에 대한 연구를 수행하였다. 연구의 주요변수는 1, 2차 공기의 유량비와 2차 공기의 투입 방향으로 설정하였다. 변수에 따른 NOx 및 CO 배출특성을 묘사하기 위해서 축소모형실험 연구를 수행하였다. 실험결과 1차 공기유량이 감소하고 2차 공기유량이 증가할수록 NOx가 감소되다가 일정 유량비 이상에서 다시 NOx가 다소 증가하는 형태가 나타났다. 역방향으로 빠른 유속의 2차 공기가 투입될 때 연소로 내부에 유동 재순환이 발생하여 혼합이 증가하고 이로 인해서 온도 영역이 고르게 분포되는 것으로 나타났으며 그 결과로서 thermal NOx의 저감 효과를 확인할 수 있었다. CO는 2차 공기가 역방향에서 높은 비율로 투입되는 조건이외에서는 측정되지 않았다. 측정된 경우도 CO의 농도는 2 ppm 이내로 안정적인 연소 조건으로 나타났다.

2차 공기 분사 위치에 따른 촉매 내 공급 공기 분포에 대한 전산 유동해석 (CFD Analysis on the Fresh Air Distribution in the Catalytic Converter Varying Secondary Air Injector Position)

  • 윤정의
    • 한국자동차공학회논문집
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    • 제18권5호
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    • pp.31-36
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    • 2010
  • SAI(Secondary Air Injection) system has been studied widely as one of the promising countermeasure for reducing HC emission at cold start. In this paper, in order to find out the optimal position of SAI, computational thermal fluid analysis on exhaust system adapted SAI system is performed using commercial 3-D CFD code, CFX. The present results showed that SAI position strongly affected the uniformity of air distribution in front of catalyst. And also through the decision process of optimal position of SAI, new index, uniformity of air distribution($U_{\phi}$) is proposed to define it quantitively. Because $U_{\phi}$ is very simple equation and similar with flow uniformity, it is very easy to figure out the physical meaning and to apply it to practices. Finally, we applied the index $U_{\phi}$ to the decision process of the optimal position of SAI, so that we could get the clear comparison results.