• Title/Summary/Keyword: Volume Variation

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Spatial Distribution Characteristics of Small LRE-injector's Spray-droplet According to the Variation of Fuel-injection Pressure (소형 액체로켓엔진 인젝터 분무의 연료분사압력 변이에 따른 액적의 공간분포 특성)

  • Jung, Hun;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.5
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    • pp.1-8
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    • 2008
  • Dual-mode Phase Doppler Anemometry (DPDA) was used to scrutinize the spatial distribution characteristics of spray emanating from a small Liquid-Rocket Engine (LRE) injector. Droplet size and velocity were measured according to the variation of injection pressure along the plane normal to the spray stream and then the spray characteristic parameters such as Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), number density, span of drop size distribution, and volume flux were deduced for an investigation of spray breakup characteristics. As the injection pressure increases, the number density, span, and volume flux of spray droplets become higher, whereas the AMD gets smaller.

Volume Resistivity Properties of Polyethylene Terephthalate Film due to Temperature Variation (온도변화에 따른 폴리에틸렌텔레프탈레이트 박막의 체적고유저항 특성)

  • Youn, J.I.;Ko, K.Y.;Shin, H.T.;Shin, J.Y.;Lee, C.H.;Hong, J.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.224-227
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    • 2002
  • In this paper, we have investigated the physical properties and electrical conduction properties of polyethylene terephthalate film due to temperature variation, and the measurement of volume resistivity used to highmegohm meter is measured from 1 to 10 minutes when the specimen applied the voltage accroding to the step voltage appling method. From FT-IR spectrum as an analysis of physical properties, the strong absorption in wavenumbers $1019[cm^{-1}]$, $1266[cm^{-1}]$ and $1752[cm^{-1}]$ observed by the C=O and benzene ring. From the analysis of DSC, the crystalline melting points of the specimen observed in the temperature $80[^{\circ}C]$ and $263[^{\circ}C]$, respectively.

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Preliminary Design Conditions for a Thermally Actuated Refrigerator Based on the Vuilleumier Cycle (Vuilleumier 사이클로 작동되는 열구동 냉동기의 예비설계조건)

  • 유호선;강병하
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.12
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    • pp.2358-2367
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    • 1992
  • This paper deals with preliminary design conditions for a thermally actuated Vuilleumier refrigerator/heat pump. The previously reported approximate adiabatic analysis which is based on the 8-volume model makes it possible to evaluate exchanged heats per cycle as well as cyclic pressure, temperature and mass variation of each working volume. Calculated results reveal not only there exists an optimum value for the phase angle and the swept volume ratio maximizing a specific thermal output, but also design parameters can be determined independently of each other. Under a given combination of operating temperature levels, the optimum conditions for refrigeration are different from those for heat pumping and the differences between two operating modes become larger with decreasing the dead volume ratio. Both the optimum phase angle and the optimum swept volume ratio are increased asymptotically toward 0.5 pi and 1.0 respectively, as the dead volume ratio approaches to unity. When a VM machine is used for cooling and heating simultaneously, the design parameters should be carefully determined to reach the best performance.

Measurement and analysis of the cyclic combustion variability in as SI engine (전기점화기관에서 연소의 사이클 변화 측정 및 해석)

  • 이종화;김응서
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.90-101
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    • 1992
  • An experimental study was carried out to investigate the characteristics of cyclic variability of combustion in a single cylinder spark ignition engine. Cylinder pressure of 240 consecutive cycles were measured for various engine operating conditions. From these data, a thermody-n amic analysis was performed for the typical cases in order to identify the cause and effect re -lation of the cyclic variation. In determining the number of cycles required for estimating the coefficient of variation of IMEP and so on, the oprating conditions must be cosidered to fit the objective of the analysis. It is thought that the variation in early flame stage is amplified through the flame propagation and results in the phase change between pressure and volume, which can be the major reason of cyclic variation of IMEP in case of lean operation.

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Thermal buckling of FGM beams having parabolic thickness variation and temperature dependent materials

  • Arioui, Othman;Belakhdar, Khalil;Kaci, Abdelhakim;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.27 no.6
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    • pp.777-788
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    • 2018
  • An investigation on the thermal buckling resistance of simply supported FGM beams having parabolic-concave thickness variation and temperature dependent material properties is presented in this paper. An analytical formulation based on the first order beam theory is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. a function of thickness variation is introduced which controls the parabolic variation intensity of the beam thickness without changing its original material volume. The results showed the high importance of taking into account the temperature-dependent material properties in the thermal buckling analysis of such critical beam sections. Different Influencing parametric on the thermal stability are studied which may help in design guidelines of such complex structures.

Thermal buckling resistance of simply supported FGM plates with parabolic-concave thickness variation

  • Benlahcen, Fouad;Belakhdar, Khalil;Sellami, Mohammed;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.29 no.5
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    • pp.591-602
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    • 2018
  • This research presents an investigation on the thermal buckling resistance of FGM plates having parabolic-concave thickness variation exposed to uniform and gradient temperature change. An analytical formulation is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. A specific function of thickness variation is introduced where it controls the parabolic variation intensity of the thickness without changing the original material volume. The results indicated that the loss ratio in buckling resistance is the same for any gradient temperature profile. Influencing geometrical and material parameters on the loss ratio in the thermal resistance buckling are investigated which may help in design guidelines of such complex structures.

Humidity Variation by Green Space Calculation Method (녹지의 산출방법이 습도변화에 미치는 영향)

  • Yoon, Yong-Han;Park, Heon
    • Asian Journal of Turfgrass Science
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    • v.16 no.1
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    • pp.41-47
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    • 2002
  • For this study grasp quantitative humidity variation with planting stratification to various green space of calculation method, observed humidity distribution in the green space. with this data, coverage condition and humidity distribution, planting calculation method and humidity, planting stratification calculation method and humidity, analyzed by revolution analysis. In this result, as well as coverage condition, planting stratification effect humidity variation. increasing planting ratio (area) and planting volume (capacity) effect higher humidity. especially, if we compared between planting stratification calculation method and higher humidity, effect by a revolution coefficient and a correlation coefficient, effect relatively planting volume (capacity) higher than stratification ratio (area). today, in the index of higher humidity, planting calculation propose application of capacity method.

Damage Behaviors by Particle Impact Energy of $Al_2O_3-TiO_2$ Coated Glass Specimen ($Al_2O_3-TiO_2$ 용사코팅된 유리의 입자충격 에너지에 따른 손상거동)

  • Lee, Moon-Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.6
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    • pp.107-114
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    • 2012
  • Fracture of brittle material due to dynamic load such a particle impact has been reported by many researchers as the fracture behavior by variation of stress for a short minute. Especially, the brittle material, such a ceramic, applied to the structural component of machine, is considered as the important project. In order to evaluate the improvement of impact resistance, the particle impact test for the $Al_2O_3-TiO_2$ coated glass is practiced. And then, the damage variation according to the impact energy of steel ball was evaluated. There was a large improvement by the ceramic coating on the surface of a glass substrate. The damage volume was especially imported to evaluate damage behavior in quantity. These data were plotted on logarithmic coordinate and experimental equations were induced by data analysis based on test results. And the variation of critical energy for crack initiation was analyzed with critical impact energy when each crack occurs.

Study on the Density and Volume Change Property of Petroleum Products according to Temperature Variation (석유제품의 온도 변화에 따른 밀도 및 부피 변화 특성 연구)

  • Hwang, In-ha;Doe, Jin-woo;Kang, Hyung-kyu;Sung, Sang-rae;Ha, Jong-han;Na, Byung-ki
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.4
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    • pp.1112-1120
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    • 2017
  • Petroleum products are composed of various types of hydrocarbon compounds. Like other types of liquids, they presented the variation of density and volume according to temperature change. The method of measuring the density of petroleum products in a liquid phase is based on experimental data obtained mainly for each fractionally distilled petroleum product. In this study, the density and volume changes of kerosene and automotive diesel according to temperature change were measured and the property of change were analyzed. The conversion values were calculated using the density volume conversion table proposed by international standard ASTM. In addition, we analyzed the differences between the reference values and the measured values for the temperature changes specified in the domestic metering law.

Automated Cold Volume Calibration of Temperature Variation in Cryogenic Hydrogen Isotope Sorption Isotherm (극저온(20K) 수소동위원소 흡착 등온선의 온도 변화에 대한 자동 저온 부피 교정)

  • Park, Jawoo;Oh, Hyunchul
    • Korean Journal of Materials Research
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    • v.29 no.5
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    • pp.336-341
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    • 2019
  • The gas adsorption isotherm requires accurate measurement for the analysis of porous materials and is used as an index of surface area, pore distribution, and adsorption amount of gas. Basically, adsorption isotherms of porous materials are measured conventionally at 77K and 87K using liquid nitrogen and liquid argon. The cold volume calibration in this conventional method is done simply by splitting a sample cell into two zones (cold and warm volumes) by controlling the level sensor in a Dewar filled with liquid nitrogen or argon. As a result, BET measurement for textural properties is mainly limited to liquefied gases (i.e. $N_2$ or Ar) at atmospheric pressure. In order to independently investigate other gases (e.g. hydrogen isotopes) at cryogenic temperature, a novel temperature control system in the sample cell is required, and consequently cold volume calibration at various temperatures becomes more important. In this study, a cryocooler system is installed in a commercially available BET device to control the sample cell temperature, and the automated cold volume calibration method of temperature variation is introduced. This developed calibration method presents a reliable and reproducible method of cryogenic measurement for hydrogen isotope separation in porous materials, and also provides large flexibility for evaluating various other gases at various temperature.