• Title/Summary/Keyword: 질량감소량 Mass Loss Rate

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Mass Loss and Air Entrainment Rate of Whirl Fire by Height of Fire Source (화점높이 변화에 따른 Whirl Fire의 질량감소 및 공기유입속도)

  • Park, Hyung-Ju
    • Fire Science and Engineering
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    • v.25 no.2
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    • pp.126-131
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    • 2011
  • This study is intended to understand mass loss rate and air entrainment rate of the whirl fire by height of fire source. Liquid fuels were methanol and n-Heptane which are used in many studies of whirl fire. Size of vessel was 100 mm ${\times}$ 100 mm ${\times}$ 50 mm and the vessel was made by stainless steel. When height of fire source changed from 0 cm to 30 cm, air entrainment rate showed the fastest in case of 0 cm. And in the same height of fire source, average and maximum air entrainment rate showed the fastest in 30 cm of anemometer. From the results of whirl fire for methanol and n-Heptane, mass loss rate and air entrainment rate of n-Heptane was found to faster 1.33 to 1.58 times and 4.38 to 5.44 times compared with methanol, respectively. Consequently, mass loss rate and air entrainment rate in whirl fire was able to identified decrease as height of fire source increases and the higher the heating value, increases the that's value.

Slurry Wear Test on the Liquid Jet (분류에 의한 SLURRY 마멸)

  • 우창기;조견식
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.5
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    • pp.88-92
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    • 2002
  • This research is about slurry wear of SM45C and SUS304, which using standard sand and KUM river sand. The results are as follows ; 1. Mass loss rates of both standard sand and KUM river sand were linearly increased as increasement of time and velocity. 2. The average diameter of sand from relatively, less wear rate and portion of larger particles. 3. Wear resistance was linear with time and velocity of liquid jet regardless of type of sand. Also, it was able to evaluate with the formula, $HV^2$/E calibrated with n, the velocity index. 4. The wear surface in liquid jet experiment was smooth. The maximum wear depth was observed at the location 2~4mm apart from the center in the condition of $90^{\circ}$ of collision angle 6mm of nozzle diameter, and 20mm of collision distance. The sectional shape in radial appeared as 'W'shape.

Slurry Wear of Sand from the Kum River (금강 토사에 의한 SLURRY 마멸)

  • 우창기;조견식;김대업;강동명;이하성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.798-801
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    • 2001
  • This research is about slurry wear of SM45C and SUS304, which using standard sand and KUM river sand. The results are as follows ; 1. Mass loss rates of both standard sand and KUM river sand were linearly increased as increasement of time and velocity. 2. The average diameter of sand from relatively, less wear rate and portion of larger particles. 3. Wear resistance was linear with time and velocity of liquid jet regardless of type of sand. Also it was able to evaluate with the formula, HV2/E calibrated with n, the velocity index. 4. The wear surface in liquid jet experiment was smooth. The maximum wear depth was observed at the location, 2~4mm apart from the center in the condition of 90$^{\circ}$of collision angle 6mm of nozzle diameter, and 20mm of collision distance. The sectional shape in radial appeared as 'W' shape.

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Effect of Flame Retardants on Flame Retardancy of Rigid Polyurethane Foam (난연제 종류에 따른 경질 폴리우레탄 폼의 난연 특성)

  • Kim, Keunyoung;Seo, Wonjin;Lee, Ju-Chan;Seo, Jung-Seok;Kim, Sangbum
    • Journal of the Korean Institute of Gas
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    • v.17 no.5
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    • pp.75-80
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    • 2013
  • In this study, the effect of phosphorus flame retardants on the flame retardancy of the rigid polyurethane foam(PUF) was studied. Tetramethylene bis(orthophos-phorylurea)[TBPU] and Tris(2-chloroethyl) phosphate[TCEP], Tris(2-chloropropyl)phosphate [TCPP], Triethyl phosphate[TEP] were used as flame retardant. It was found that TBPU added PUF exhibits low mean heat release rate(HRR), peak HRR, effective heat of combusion(EHC), mass loss rate (MLR), CO yield and $CO_2$ compared other flame retardants.

Changes in Fire Characteristics according to the Distance Between the Fire Source and Sidewall in a Reduced-Scale Compartment (축소 구획실에서 화원과 측벽의 거리에 따른 화재특성 변화)

  • Yun, Hong-Seok;Hwang, Cheol-Hong
    • Fire Science and Engineering
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    • v.33 no.1
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    • pp.50-59
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    • 2019
  • Experimental and numerical studies on the fire characteristics according to the distance between the fire source and sidewall under the over-ventilated fire conditions. A 1/3 reduced ISO 9705 room was constructed and spruce wood cribs were used as fuel. Fire Dynamics Simulator (FDS) was used for fire simulations to understand the phenomenon inside the compartment. As a result, the mass loss rate and heat release rate were increased due to the thermal feedback effect of the wall in the compartment fire compared to the open fire. As the distance between the fire source and sidewall was reduced, the major fire characteristics, such as maximum mass loss rate, heat release rate, fire growth rate, temperature, and heat flux, were increased despite the limitations of air entrainment into the flame. In particular, a significant change in these physical quantities was observed for the case of a fire source against the sidewall. In addition, the vertical distribution of temperature was changed considerably due to a change in the flow structure inside the compartment according to the distance between the fire source and sidewall.

Combustion Characteristics of Pool Fire by Height of Fire Source (화점높이 변화에 따른 Pool Fire의 연소특성)

  • Park, Hyung-Ju;Cha, Jong-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.11
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    • pp.4671-4676
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    • 2010
  • This study is intended to understand flame behavior of the pool fire by height of fire source. Liquid fuels were methanol and n-Heptane which are used in many studies of pool fire. Size of vessel was $100mm{\times}100mm{\times}50mm$ and the vessel was made by stainless steel. Combustion time, mass loss rate, flame temperature, flame height and air entrainment rate from the outside to flame were measured, and flame behavior was visualized with video camera. Based on the experiment, it was found that combustion characteristics of pool fire was decreased according to increase of height of fire source because entrainment volume of relative cold air was increased from the outside to flame.

The Relationship between Flash Point and Fire Properties of Flammable Liquids (가연성 액체의 인화점과 화재특성치와의 관계)

  • Song, Young-Ho;Ha, Dong-Myeong
    • Journal of the Korean Institute of Gas
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    • v.11 no.2 s.35
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    • pp.10-14
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    • 2007
  • Flash point is one of the major physical properties used to evaluate fire hazards of the combustible liquids. Properties showing relative fire hazards of the combustible liquids are heat release rate(HRR), peak heat release rate(PHRR), time to ignition(TTI), mass loss rate, and yield of $CO/CO_2$. The relationships between flash points and fire properties of the combustible liquids were examined in this study. For this study, mass loss rate and time to ignition were measured to calculate fire properties of the combustible liquids. The results showed that good correlations could be found between flash point and time to ignition, time to peak heat release rate, and the propensity to flashover. From a presented results, the parameters can be used to evaluate relative hazards of the combustible liquids on fire.

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Effect of Flame Retardants on Flame Retardancy of Flexible Polyurethane Foam (난연제 종류에 따른 연질 폴리우레탄 폼의 난연 특성에 대한 연구)

  • Kwon, Ohdeok;Lee, Ju-Chan;Seo, Ki-Seog;Seo, Chung-Seok;Kim, Sang Bum
    • Applied Chemistry for Engineering
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    • v.24 no.2
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    • pp.208-213
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    • 2013
  • In this study, the effect of phosphorus flame retardants on the flame retardancy of the flexible polyurethane foam (PUF) was investigated. Tetramethylene bis(orthophosphorylurea) [TBPU] and phosphinyl alkylphosphate ester [CR-530], resorcinol bis diphenylphosphate [RDP], triethyl phosphate [TEP] were used as flame retardants. The results of thermogravimetric analysis (TGA) indicate that TBPU added PUF produces more charred residues than the other flame retardant added PUF. It was found that TBPU added PUF exhibits low mean heat release rate (HRR), peak HRR, effective heat of combusion (EHC), mass loss rate (MLR), CO yield and $CO_2$ compared to those other flame retardants.

Study on Flame Retardancy and Thermal Resistance Properties of Phenolic Foam and Polyurethane Foam (페놀 폼과 폴리우레탄 폼의 난연 및 내열성 연구)

  • Lee, Ju-Chan;Seo, Jung-Seok;Kim, Sang Bum
    • Journal of the Korean Institute of Gas
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    • v.17 no.1
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    • pp.35-41
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    • 2013
  • In this study, flame retardancy of polyurethane foam and phenolic foam were investigated by addition of phosphorous flame retardants. The thermal degradation behavior of polyurethane foam and phenolic foam in the presence of flame retardants has been studied by thermogravimetric analysis(TGA). Heat release rate(HRR), mean HRR, mass loss rate(MLR), total smoke released(TSR) and limited oxygen index(LOI) were tested by cone calorimeter. From the test results, Phenolic foam showed low HRR, MLR and TSR than polyurethane foam.

Analysis on the Effects of the Heat Loss Coefficient on the Operation Time of Sprinkler in Compartment Fire (구획 화재에서 스프링클러 열 손실계수 변화에 따른 작동 시간 분석)

  • You, Woo Jun
    • Fire Science and Engineering
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    • v.32 no.5
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    • pp.34-39
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    • 2018
  • In this study, the experiment conditions for the variation of heat release rate in compartment space were constructed to analyze the effects of fire spread and the operation time of sprinkler in accordance with the heat loss of the sprinkler's heat element. The compartment composed of fire board (width = 0.3 m, height = 0.5 m, length = 3.0 m), are manufactured to measure the temperature distributions in the inner space, the mass loss rate and heat release rate during the experiment of N-heptane pool fire test. Also, the operation time of sprinkler is analyzed with the installation of sprinkler and C-factor using Fire Dynamics Simulator Ver.6 under the experiment conditions. The results show that the operation time of sprinkler, which has RTI $100(m{\cdot}s)^{0.5}$ operating temperature $70^{\circ}C$, is 30 s~60 s for C-factor = 0 and 1, 62 s~92 s for C-factor = 3, and 120 s over for C-factor = 5, respectively.