• 제목/요약/키워드: Amount of Heat

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환경조절장치용 미세유로형 증발열교환기의 성능특성 연구 (A Study on Performance Characteristics of an Evaporative Heat Exchanger with Mini-channels)

  • 이형주;유영준;민성기;황기영
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2011년도 제37회 추계학술대회논문집
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    • pp.247-253
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    • 2011
  • 본 논문에서는 항공기 탑재용 환경조절장치에 사용하기 위한 미세유로형 증발열교환기의 성능 특성에 관한 연구결과를 제시하였다. 미세유로형 증발열교환기는 가능한한 적은 양의 냉매로 고온부의 열량을 흡수할 수 있도록 저온부 냉매의 증발잠열을 이용하고 단위 체적당 열전달 면적의 극대화를 위해 미세유로를 이용하는 개념이다. 설계된 공기 및 냉각수 유로를 에칭을 통해 가공하고, 이들을 적층하여 브레이징으로 접합한 후 입출구 포트를 용접함으로써 열교환기를 제작하였다. 제작된 열교환기는 기본 성능시험을 통해 요구조건대로 설계/제작되었음을 확인하였고, 다양한 운용조건에 대한 성능 맵 시험을 수행하여 입구 공기온도, 공기 유량 및 냉각수 유량 변화에 따른 열교환 성능특성을 정량적으로 파악하였다.

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CBR의 제조(製造) 및 이를 자동차(自動車) Tyre에 활용(活用)하는데 관(關)한 연구(硏究)(제4보(第四報)) Diene Rubber와 Alfin Rubber와의 Blend에 관(關)하여 (Studies on It's Practical Application to Auto Pneumatic Tyre and Manufacture of CBR (Cis-1,4-Polybutadiene Rubber) (Part. 4) On the Blend of Diene rubber and Alfin rubber)

  • 이현오;이영길;김기엽
    • Elastomers and Composites
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    • 제8권1호
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    • pp.33-51
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    • 1973
  • We have studied the blending effects of Diene NF 35 R and Alfin 1530 at various blending ratios, 100/0, 70/30, 50/50, 30/70, 0/100, and of carbon black HAF-HS and ISAF-HS at various compounding ratios of 45 PHR, 55 PHR, 65 PHR, for tyre tread rubber. As the results, it was found that; 1. For tyre tread rubber, as the blending ratio, AR 1530/Diene NF 35R, indicated 70/30, the physical properties we examined were most excellent. 2. Excellent result was obtained in the case of carbon black compounding ratio of 55 PHR. The compounding of ISAF-HS made better result than that of HAF-HS for tensile strength, but the compounding of HAF-HS made better result than that of ISAF-HS for tearing strength and best result for abrasion quantity. 3. Heat buildup obtained from compounding carbon black HAF-HS indicated low temperature than that from compounding carbon black HAP-HS. As the compounding amount of carbon black increased, and as the blending amount of AR 1530 decreased, the heat buildup increased. 4. Carbon black was more efficient to AR 1630 than io Diene NF 35 R. 5. In the physical properties, mooney viscosity and mooney scorch time, as the compounding amount of carbon black increased, the values of mooney viscosity increased, but that of mooney scorch time had a max. point at the compoundiug amount of carbon black, 55 PHR.

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당근의 열충격 유전자 발현의 번역과정에서의 조절 (Translational Control of The Heat Shock Gene Expression in Carrot)

  • Cheol Ho HWANG
    • 식물조직배양학회지
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    • 제22권1호
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    • pp.19-23
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    • 1995
  • 당근의 현탁배양 캘러스 세포가 고온에 노출되었을때 다른 식물에서 알려진 것과 유사한 열충격반응을 나타낸다. 이는 기존의 유전자의 발현을 억제하고 새로운 열충격단백질을 생산하기 위한 열충격유전자의 발현을 촉진한다. 이러한 열충격유전자의 고온조건에서의 발현은 주로 전사과정에서 이루어지는 것으로 알려져 있다. 그러나 몇가지의 경우에서 이들 열충격 유전자의 발현이 번역과정에서 조절되는 것으로 보고된 바 있다. 본 고에서는 열충격 과정과는 무관한 토끼의 적혈구로 만들어진 시험관 내 번역시스템과 2차원단백질분리 시스템을 이용하여 생성된 단백질의 양을 통해, 번역에 사용된 mRNA의 양을 추정하였다. 이를 생체내에서 같은 조건에서 만들어진 단백질의 양과 비교할 때에 당근세포내의 특정 mRNA의 양과 해당 열충격단백질의 양이 $ 30^{\circ}C$에서 불일치함을 확인하였다. 이를 통해 당근의 캘러스 세포가 열충격 반응을 나타내는 가장 낮은 온도인 $30^{\circ}C$에서 mRNA의 양과는 다소 무관하게 해당 열충격단백질을 번역을 촉진하는 과정이 있음을 추정할 수 있었다.

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그린하우스 열환경 조절을 위한 파라핀계 화합물(CnH2n+2)의 잠열 축열 특성 (Latent Heat Storage Characteristics of Some Paraffins(CnH2n+2) for Thermal Environment Control of Greenhouse)

  • 송현갑;유영선
    • Journal of Biosystems Engineering
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    • 제21권1호
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    • pp.84-93
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    • 1996
  • Several paraffins(CnH2n +2) can be used as the thermal energy storage medium because of their large amount of latent heat and their flexibility of phase change temperature. But they have not been used in the thermal energy storage system because their long term stability have not been verified. Paraffins(CnH2n+2) which the values of n are 23, 24, 26 and 28 were selected for this experimental research. And this research was peformed to apply them to the practical systems. The results were summarized as follows. (1) The increase of phase change cycles had no effect on their phase change temperatures. (2) According as the values of n increased from 23 to 28, the specific heats of paraffins(CnH2n+2) increased, and were in the range of 0.47 0.75 ㎉/$kg^circ C$. (3) Thermal conductivities of them were in the range of 0.14 0.17 W/$m^circ C$. and specific gravities of them were in the range of 765800 kg/m3. (4) The density of paraffins was in the range of 765 800 kg/$m^circ C$ , and the density of solid phase was larger than that of liquid phase. (5) When the number of phase change cycles was 1, 500 cycles, the latent heat of paraffins was 90% of the initial value.

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고출력 18650 리튬이온 배터리의 발열인자 해석 및 실험적 검증 (Analysis and Experiment Verification of Heat Generation Factor of High Power 18650 Lithium-ion Cell)

  • 강태우;유기수;김종훈
    • 전력전자학회논문지
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    • 제24권5호
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    • pp.365-371
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    • 2019
  • This study shows the feasibility of the parameter of the 1st RC parallel equivalent circuit as a factor of the heat generation of lithium-ion cell. The internal resistance of a lithium-ion cell consists of ohmic and polarization resistances. The internal resistances at various SOCs of the lithium-ion cell are obtained via an electrical characteristic test. The internal resistance is inversely obtained through the amount of heat generated during the experiment. By comparing the resistances obtained using the two methods, the summation of ohmic and polarization resistances is identified as the heating factor of lithium-ion battery. Finally, the amounts of heat generated from the 2C, 3C, and 4C-rate discharge experiments and the COMSOL multiphysics simulation using the summation of ohmic and polarization resistances as the heating parameter are compared. The comparison shows the feasibility of the electrical parameters of the 1st RC parallel equivalent circuit as the heating factor.

Influence of heat treatments on electrical properties of ZnO films grown by molecular-beam epitaxy

  • 오동철;김동진;배창환;구경완;박승환;야오다까후미
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.34-34
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    • 2010
  • We report on the influence of heat treatments on the electrical properties of ZnO films grown by molecular-beam epitaxy. We note that the electrical resistance of the ZnO films is significantly changed by the heat treatments: the electrical resistance increases with the increase of ambient temperature, but above a critical temperature the resistance decreases with the increase of temperature, irrespective of ambient gases. On the other hand, it is found that the large amount of photocurrent is generated in the ZnO films, exposed to white sources: the photocurrent decreases with the increase of the obtained resistance, and the current increases with the decrease of the resistance. Also, it is shown that the X-ray diffraction linewidth of the ZnO films is significantly decreased by the heat treatments. These indicate that the increase/decrease of the electrical resistance is ascribed to the annihilation/formation of the residual donor-type defects in the ZnO films by the heat treatments. It is suggested that the increase of the electrical resistance is due to the annihilation of Zni-complex defects, while the decrease of the electrical resistance is due to the formation of VO-complex defects.

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중탄소강의 기계적성질에 미치는 잔류오스테나이트의 영향 (Effect of retained austenite on mechanical properties in medium carbon steel)

  • 선철곤;김영훈;김한군
    • 열처리공학회지
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    • 제8권3호
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    • pp.229-235
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    • 1995
  • We were studied to the effect of alloying element and retained austenite on a mechnical properties and that used steels were composed three types composition. According to the soaking temperature, a retained austenite was pricipitated in the bainitic ferrite matrix and it was pricipitated to a flake type of about $2{\mu}m$, a mixture of massive and bar type and a flake type of about $1{\mu}m$ size. Through x-ray diffraction analysis, the amount of retained austenite was increased with addition of Si and Ni for equal heat treatment condition and it was best abundanted in the soaking temperature of $855^{\circ}C$. The balance value of strength and elongation were complexly controlled not only a retained austenite formation but also a formation characteristic and shape of the retained austenite and bainite. The balance value of strength and elongation were most satisfactory obtained with "B" and "C" specimens in a firstly heat treated at $855^{\circ}C$ and the best result was that a $2840kg/mm^2.%$ with the heat teratment condition of $855^{\circ}C-400^{\circ}C$ used for "C" specimen.

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SI 열화학 수소 생산 공정 요오드 결정화기 열-물질 수지 계산 (Calculation of Mass-Heat Balance on the Iodine Crystallizer for SI Thermochemical Hydrogen Production Process)

  • 이평종;박병흥
    • 융복합기술연구소 논문집
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    • 제5권1호
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    • pp.1-5
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    • 2015
  • SI thermochemical hydrogen production process achieves water splitting into hydrogen and oxygen through three chemical reactions. The process is comprised of three sections and one of them is HI decomposition into $H_2$ and $I_2$ called as Section III. The production of $H_2$ included processes involving EED for concentrating a product stream from Section I. Additionally an $I_2$ crystallization would be considered to reduce burden on EED by removing certain amount of $I_2$ out of a process stream prior to EED. In this study, the current thermodynamic model of SI process was briefly described and the calculation results of the applied Electrolytes NRTL model for phase equilibrium calculations was illustrated for ternary systems of Section III. We calculated temperature and heat duty of an $I_2$ crystallizer and heat duty of heaters using UVa model and heat balance equation of simulation tool. The results were expected to be used as operation information in optimizing HI decomposition process and setting up material balance throughout SI process.

날아가는 섬광탄이 연료탱크 수평핀에 미치는 복사열전달 연구 (An Investigation of Radiation Heat Transfer on The Horizontal Fin of An External Fuel Tank by Flame of a Flying Flare)

  • 정대한;강치행;김시태
    • 한국군사과학기술학회지
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    • 제17권2호
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    • pp.197-203
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    • 2014
  • In this paper, the effect of unsteady radiation on the horizontal fin of an external fuel tank by flame of a flying flare was analysed to see the temperature increase of the fin and the thermal impact on the fin. Radiation between two surfaces was calculated using the concept of radiation resistance of surface and space including radiation, irradiation and shape factor for two flying trajectories of a flare, maximum temperature of 2200 K, emissivity of 0.95, flying velocity of 30 m/s, and thermal surface area of $0.01m^2$. The result shows that the temperature increase of the fin is 0.236 K, and the thermal effect on the fin is ignorable. And it was found that temperature is increased a little because small amount of heat energy can be radiated due to the short exposure time to the heat source.

프레온 냉동장치의 과열도에 관한 성능 특성 연구 (열교환기 타입별 비교) (The Study on Performance Characteristics due to the Degree of Superheat in Freon Refrigerating System (The Comparison of Heat Exchanger Types))

  • 정송태;하경수;김양현;박찬수;하옥남;이승재
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2005년도 동계학술발표대회 논문집
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    • pp.486-491
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    • 2005
  • Nowadays heat exchangers that have been applied for freon refrigerating systems, a shell and tube type condenser, but because of their large size, large space for installation and more amount of refrigerants are needed. Therefore, in this study, we will find the most suitable operating condition through the comparison of performance between the shell & tube type and shell & disk type heat exchanger with R22. The experiments are carried out for the condensing pressure of refrigeration system from 1500kPa to 1600kPa and for the degree of superheat from 0 to $1^{\circ}C$ at each condensing pressure. As a result of experiment, if the shell & disk type heat exchanger is applied for R22 refrigerating systems, minimized input of refrigerants and space required for installation will be secured, which will have a great contribute to financial improvement for industry.

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