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Combustion Characteristics of Hinoki Cypress Louver after Pressure Impregnation with Boric Acid, Borax and Ammonium Phosphate (붕사, 붕산 및 인산암모늄을 가압 함침한 편백 루버의 연소특성)

  • Park, Hyung-Ju
    • Fire Science and Engineering
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    • v.29 no.6
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    • pp.1-5
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    • 2015

  • In this study, the combustion characteristics of Hinoki Cypress Louver were measured after performing pressure impregnation with aqueous solution of boric acid, borax, and ammonium phosphate. The characteristics measured include ignition time, critical heat flux, and mass loss rate by incident hear flux (25, 30 and $50kW/m^2$). The samples used for the test were $100{\times}100{\times}10mm$, and the 5 min variation for each incident heat flux was measured 3 times. The results show that the ignition time for incident heat flux of $25kW/m^2$ showed a delay effect of 17.4 to 21.3% except for Type C-H. There was no significant difference at 35 and $50kW/m^2$ in the average mass loss rate in Types A-H and D-H, which had lower rates than Type N-H, which was predicted to be higher than that of Type N-H ($10.7kW/m^2$) by 38.22 to 60.46%. It is thus expected that at the time of initial primary fire, there would be a delay effect against fire spread.

  • https://doi.org/10.7731/KIFSE.2015.29.6.001 인용 PDF KSCI

Effects of Heat Input and Bead Generation Methods on Finite Element Analysis of Cylindrical Multi-Pass Welding Process of Metals (열원 입력과 비드 생성 방법이 원통형 다층 금속 용접 과정의 유한요소해석에 미치는 영향)

  • Park, Won Dong;Bahn, Chi Bum;Kim, Ji Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.6
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    • pp.455-467
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    • 2017

  • In this study, a finite element analysis of a cylindrical multi-pass weldment for dissimilar metals was performed. The effects of the heat input method and weld bead generation method were considered. We compared two heat input methods: the heat flux method and the temperature method. We also compared two weld bead generation methods: the element birth method and the quiet element method. Although the results of the thermal analysis show deviations between the two heat input methods, the welding residual stresses were similar. Because the areas exposed to high temperature were similar and the strength of the material was very low in high temperature (above the $1000^{\circ}C$), the effects of the weld bead temperature were insignificant. The distributions of the welding residual stress were similar to each other. However, gaps and overlaps occurred on the welding boundary surfaces when the element birth method was applied. The quiet element method is more suitable for a large deformation model in order to simulate a more accurate weld shape.

  • https://doi.org/10.3795/KSME-A.2017.41.6.455 인용 PDF KSCI

A Study on the Utilization of potential heat sources for Heat Pumps to District Heating System in Urban (도시 내 지역난방 Heat Pump용 잠재열원 이용에 관한 연구)

  • Oh, Kwang Min;Kim, Lae Hyun
    • Korean Chemical Engineering Research
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    • v.56 no.6
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    • pp.841-855
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    • 2018

  • The purpose of this study is to estimate the available potential heat source for heat pump in the district heating supply area in the city. Unused energy potentials were estimated and integrated based on open source based data. In particular, geographical spatial analysis of recoverable heat energy density and heat demand in the heat source area of large retailers and public sauna facilities in the DH network located in the southern part of the metropolitan area (Pyeongtaek-si) was conducted. As a result of the study, the DH network area had a total potential energy of 1,741.7 toe/year for the two heat sources of large retailers and public saunas. It is estimated that 1,006.9 toe/year, which is 57.8% of the total, can be linked to the district heating. The large retailers showed a positive correlation with the floor area and energy use of 0.4937. The recoverable energy intensity was estimated to be $0.0017toe/m^2$ per unit area and $0.0069tCO_2/m^2$ for greenhouse gas emissions. In addition, public saunas were analyzed by comparing the empirical case with the theoretical calculation, and it was estimated that energy conservation estimate of 80% was $0.0315toe/m^2$ per bath area and $0.1183tCO_2/m^2$ for greenhouse gas emissions. The total potential energy amount of this area was positively correlated with the heat demand of apartment house by administrative district, and it was confirmed that it had a relatively high potential energy especially in traffic and commercial center.

  • https://doi.org/10.9713/kcer.2018.56.6.841 인용 PDF KSCI HTML