• 제목/요약/키워드: indirect flow

검색결과 240건 처리시간 0.029초

유동 방향이 간접 증발식 냉각기 성능에 미치는 영향 (Effects of flow direction on the performance of an indirect evaporative cooler)

  • 추현선;이관수;이대영
    • 대한설비공학회:학술대회논문집
    • /
    • 대한설비공학회 2006년도 하계학술발표대회 논문집
    • /
    • pp.743-748
    • /
    • 2006
  • Ren et al. analyzed the performance of the indirect evaporative cooler according to the direction of the flow considering evaporation water flow and wetness. However the effect of NTU of each channel on the performance of the indirect evaporative cooler according to the direction of the flow was not analyzed exactly. In this study the effect of the direction of the flow on the Indirect evaporative cooling performance changing NTU of each channel are investigated theoretically. The cooling process of the indirect evaporative cooler by flow direction is modeled into a set of linear differential equations and solved to obtain the exact solutions to the temperatures of the hot fluid, the moist air, and evaporation water. Based on the exact solution in the case of different NTU of each channel, we study the change of the distribution of the temperature according to each flow direction and at the same time analyze the effect of the flow direction on the cooling performance.

  • PDF

The Impact of Methods of Presenting Cash Flow Statement on Loan Decision: Evidence from Vietnam

  • NGUYEN, Dung Duc
    • The Journal of Asian Finance, Economics and Business
    • /
    • 제7권8호
    • /
    • pp.87-94
    • /
    • 2020
  • The paper aims to investigate the impact of presenting statements of cash flow using the direct method and the indirect method on loan decision by credit officers at Vietnamese banks. The data was collected from 150 credit officers of commercial banks in Vietnam based on the questionnaire about making loan decision when the cash flow statement is presented in different methods, namely, direct and indirect methods. This research uses T-tests to check whether using the direct or indirect method affects the accurate calculation of loan criteria, affects the loan decision by credit officers, and compare these two methods in the aspects of information provision. The research has pointed out that: 1) the direct method helps the calculation of indicators related to loans more accurately; 2) credit officers say that, while the direct method of presenting cash flow statement provides clearer information, the use of either the direct method or the indirect method does not affect the banks' loan decision. Since then, the author recommends that cash flow statements should be provided with information in a direct method to present the information needed for loan decision more accurately so as to improve the quality of cash flow statement.

통근통행에 의한 직·간접 흐름을 이용한 지역의 중심성 분석 (Analysis of Regional Centrality by Investigating Direct and Indirect Flows of Commuters)

  • 이종상;서덕수
    • 농촌지도와개발
    • /
    • 제27권3호
    • /
    • pp.125-134
    • /
    • 2020
  • The regional centrality plays a very important role in national and regional planning and it is measured by data such as people, goods, and information flows among regions. The inter-regional flows are usually considered by only direct flows, yet indirect flows, which are generated accordingly from direct flows, are not critically considered. Most centrality studies have also hardly reflected the indirect flow in the network analysis. This study demonstrates the significance of the indirect flows to enhance accuracy of the regional centrality. The nationwide dataset of inter-regional commuter traffic matrix is used in this study and analysed into two groups; one to consider only direct flow and the other both direct and indirect flows. The results indicate remarkable differences of centrality raking between two groups such as Yeongam of Jeonnam Province(+60th), Eumseong of Chungbuk Province(+57th), Gwacheon of Gyeonggi Province (-35th), and Nowon of Seoul (-32nd). It clearly shows the significant influence of indirect flow for regional centrality study. This also reveals regional centrality ranking in Korea by considering direct and indirect flows of commuters. Jung, Gangnam, and Jongno of Seoul are categorized in the highest rank group and Ulleung of Gyeongbuk, Ongjin of Incheon, and Jindo of Jeonnam are in the lowest group. The top group includes seven districts of Seoul, two of Busan, and one of Gyeonggi Province. The bottom group includes mostly island and costal areas. As this study shows an accurate method of centrality measurement, it has a significant implication to lead an effective regional planning.

증발수 유량이 간접 증발식 냉각기 성능에 미치는 영향 (Effects of Evaporation Water Flow Rate on the Performance of an Indirect Evaporative Cooler)

  • 추현선;이관수;이대영
    • 설비공학논문집
    • /
    • 제18권9호
    • /
    • pp.714-721
    • /
    • 2006
  • In evaporative cooling applications, the evaporation water is supplied usually sufficiently larger than the amount evaporated to enlarge contact surface between the water and the air. Especially in indirect evaporative coolers, however, if the evaporation water flow rate is excessively large, the evaporative cooling effect is not used for heat absorption from the hot fluid but spent to the sensible cooling of the evaporation water itself. This would result in a decrease in the cooling performance of the indirect evaporative cooler. In this study, the effects of the evaporation water flow rate on the cooling performance are investigated theoretically. The cooling process in an indirect evaporative cooler is modeled into a set of linear differential equations and solved to obtain the exact solutions to the temperatures of the hot fluid, the moist air, and the evaporation water. Based on the exact solutions, it is analyzed how much the cooling performance is affected by the evaporation water flow rate. The results show that the decrease in the cooling effectiveness is substantial even for a small flow rate of the evaporation water and the relative decrease is more serious for a high-performance evaporative cooler.

U형 직교 대향류 플라스틱/종이 재질 간접증발소자 (U-type Cross-Counter Indirect Evaporative Cooler made of Plastic/Paper)

  • 김내현
    • 한국산학기술학회논문지
    • /
    • 제17권11호
    • /
    • pp.732-739
    • /
    • 2016
  • 여름철이 무더운 대한민국에서는 냉방에 많은 전력을 소비한다. 이 경우 간접증발냉각을 동시에 적용하면 전기 사용을 줄일 수 있다. 본 연구에서는 플라스틱/종이 재질의 U형 직교대향류 간접증발소자를 개발하고 그 성능을 기존의 직교류소자와 비교하였다. 시료의 크기는 $500mm{\times}500mm{\times}1000mm$이었다. 직교대향류 소자의 간접증발효율은 직교류 소자의 간접증발효율보다 6~21% 크고 그 차이는 전방 풍속이 증가할수록 증가하였다. 이는 직교대향류 소자의 크기가 크고 (대향류의 2배) 직교 대향류의 유용도가 직교류의 유용도보다 크기 때문이다. 직교대향류 소자의 압력손실은 직교류 소자의 압력손실보다 2배 가량 컸다. 습채널의 압력손실도 건채널보다 51~66% 컸다. ${\epsilon}$-NTU 방식의 해석 모델은 실험 데이터를 ${\pm}10%$ 이내에서 예측하였다. 직교대향류 소자를 사용하였을 때 절약되는 전기에너지는 직교류 소자의 값보다 크고 그 차이는 풍속이 증가할수록 증가하였다. 하지만 직교대향류 소자의 크기가 직교류 소자에 비하여 2배 크므로 원가의 상승과 분무수 사용량의 증가가 예상된다.

간접냉각방식을 이용한 열원이 부착된 채널내의 열전달 촉진에 관한 연구 (The study on heat transfer enhancement using indirect cooling system in the channel with heat source)

  • 김광추;박만흥;윤준규
    • 설비공학논문집
    • /
    • 제11권3호
    • /
    • pp.321-331
    • /
    • 1999
  • A numerical study is carried out for increasing heat removal using indirect cooling system. Computation is performed for nine cases as variation of flow condition in the lower channel. As the result of this study, water is more effective than air at the same pressure loss in spite of the lower inlet velocity. In channel configuration, the vertical channel is more effective than horizontal channel because of the buoyancy effect. Under the condition that heat generation is the same, counter flow effectively decreases the temperature difference among blocks. Parallel flow is more effective than counter flow when average temperature of all blocks is considered. In the case of installing obstacles in the lower channel, it is desirable to install obstacles in the bottom of lower channel. Heat transfer rate increases as the height of obstacles increases.

  • PDF

간접 내부 개질형 용융탄산염 연료전지 anode 채널에서의 압력 강하 및 온도 조건 변경에 따른 유량 균일도에 관한 수치 해석적 연구 (Numerical analysis of the gas flow-rate uniformity in the anode flow channel of indirect internal reforming molten carbonate fuel cell (MCFC) under different pressure drop and temperature conditions)

  • 조준현;하태훈;김한상;민경덕;박종훈;장인갑;이태원
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2009년도 추계학술대회 논문집
    • /
    • pp.127-130
    • /
    • 2009
  • The uniform gas distribution between anode channels of the indirect internal reforming type molten carbonate fuel cell (MCFC) is crucial design parameter because of the electric performance and the durability problems. A three-dimensional computational fluid dynamics (CFD) analysis is performed to investigate flow characteristics in the anode channels and manifold under different pressure drop and channel temperature conditions. The combined meshes consists of hexadral meshes in the channels and polyhedral meshes in the manifold are adopted and chemical reactions inside the MCFC system are not included because of computational difficulties associated with the size and geometric complexity of the system. Results indicate that the uniformity in flow-rate is in the range of $\pm$ 0.048 % between the anode channels when the pressure drop of anode channel is about 150 Pa. A gas flow-rate uniformity decreases as the pressure drop of anode channels decreases and as the temperature difference between indirect internal reforming (IIR) channels and anode channels increases.

  • PDF

Echocardiographic features of indirect Gerbode defect in a cat

  • Lee, Sang-Kwon;Lee, Namsoon;Cho, Kyoung-Oh;Soliman, Mahmoud;Yun, Munsu;Choi, Jihye
    • 대한수의학회지
    • /
    • 제59권3호
    • /
    • pp.161-163
    • /
    • 2019
  • This report describes the echocardiographic features of an indirect Gerbode defect in a young cat. Echocardiography revealed high-velocity, turbulent systolic flow directed from left ventricle to right ventricle through a ventricular septal defect. The flow immediately entered the right atrium through a tricuspid septal leaflet. The indirect-type Gerbode defect was confirmed through necropsy. When a high-velocity turbulent flow in the RA without pulmonary hypertension is observed on echocardiography, Gerbode defect should be considered.

인터랙티브 드라마의 시청동기, 몰입, 시청만족도, 시청충성도 간 관계에 관한 연구: 중국 시청자를 중심으로 (A Study on the Relationships among Audience Motivation, Viewing Flow, Satisfaction, and Loyalty in Watching Interactive Drama: Focused on Chinese Audience)

  • 두정;김성경;임성준
    • 아태비즈니스연구
    • /
    • 제13권3호
    • /
    • pp.157-170
    • /
    • 2022
  • Purpose - The purpose of this study is to understand the motivating factors of Chinese audience who watch the interactive drama, and suggest the effects of audience' motivation on viewing flow, satisfaction, and loyalty. Design/methodology/approach - To achieve the purpose of the study, a questionnaire survey on the Internet was conducted from September 26, 2021 to October 14, 2021, and data from 332 Chinese respondents were collected. Findings - Findings of this study are 1) audience motivation of watching the interactive drama is composed of 6 factors including the pursuit of entertainment and information, curiosity, interaction, sense of control and indirect experience; 2) the pursuit of entertainment and information, interaction and indirect experience have positive effects on viewing flow; 3) all six factors of audience motivation have positive effects on audience satisfaction; 4) four motivating factors including the pursuit of entertainment, curiosity, interaction and indirect experience have positive effects on audience loyalty. 5) viewing flow and audience satisfaction respectively has some partial mediating effects on the relationship between audience motivation and audience loyalty. Research implications or Originality - Results of this study suggest that in order to increase audience loyalty to interactive dramas, in addition to fulfilling the pursuit of entertainment, which is the basic motive for watching any drama, it is important to fulfill motivating factors related to the unique characteristics of interactive dramas such as curiosity, interaction, and indirect experience. In order for these motivating factors to lead to audience loyalty, it is more effective when viewing flow and audience satisfaction are accompanied.

체험형 패션 매장에서의 쇼핑몰입이 브랜드 옹호행동에 미치는 영향 - 감정반응과 경험적 쇼핑가치 및 점포애착의 순차적 다중매개 효과 검증 - (Effects of Shopping Flow in Experiential Fashion Stores on Brand Advocacy - Multi-mediating Effects of Emotional Response, Experimental Shopping Value, and Store Attachment -)

  • 최미영;김우빈
    • 한국의류산업학회지
    • /
    • 제24권4호
    • /
    • pp.431-442
    • /
    • 2022
  • Despite the rapid reorganization of the center of consumption online, the fashion industry is still strengthening brand marketing using offline stores. This study investigates the psychological mechanisms of shopping flow by three mediators that influence the e-word of mouth(e-WOM) as a marketing performance variable in recent marketing. Data collection was conducted online for 241 women in their 20s and 30s. The significance of multi-mediated pathways was verified using Process 3.5 Model 6. The results for multiple mediation paths are as follows. First, the direct effect of shopping flow on brand advocacy was not significant. Second, analysis of the significance of the indirect effect via simple mediation found that the path mediated by shopping value in the path from the shopping flow to brand advocacy was significant. Third, analysis of the indirect effect by double mediation revealed all three double mediating effects of shopping flow on brand advocacy were significant(emotional response and shopping value, emotional response and store attachment, shopping value and store attachment). Fourth, analysis of the significance of the indirect effect by sequential multiple mediation established the indirect effect leading to emotional response, shopping value, and store attachment was significant. These results indicate that the operation of an experiential fashion store is not just a means for sales, but a communication tool that improves and promotes the brand advocacy by providing brand experience in a store.