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Conceptual Design for a Kerosene Fuel-rich Gas-generator of a Turbopump-fed Liquid Rocket Engine

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Journal of Thermal Science 2012年第5期21卷 428-434页

作者： Min Son Jaye Koo won Kook cho Eun Seok Lee Graduate Student Korea Aerospace UniversityGoyang Republic of Korea School of Aerospace and Mechanical Engineering Korea Aerospace UniversityGoyang Republic of Korea Korea Aerospace Research Institute Daejeon Republic of Korea

A design method for a kerosene fuel-rich gas-generator of a liquid rocket engine using turbopumps to supply propellant was performed at a conceptual level. The gas-generator creates hot gases, enabling the turbine to operate the turbopumps. A chemical non-equilibrium analysis and a droplet vaporization model were used for the estimation of the burnt gas properties and characteristic chamber length. A premixed counter-flow flame analysis was performed for the prediction of the burnt gas properties, namely the temperature, the specific heat ratio and heat capacity, and the chemical reaction time. To predict the vaporization time, the Spalding model, using a single droplet in convective condition, was used. The minimum residence time in the chamber and the characteristic length were calculated by adding the reaction time and the vaporization time. Using the characteristic length, the design methods for the fuel-rich gas-generator were established. Finally, a parametric study was achieved for the effects of the O/F ratio, mass flow rate, chamber pressure, initial droplet temperature, initial droplet diameter and initial droplet velocity.

关键词： Liquid rocket engine Conceptual design Fuel-rich gas-generator Sensitivity analysis

High Oil-absorptive Composites Prepared from Non-woven Fiber and Sponges with 4-tert- butylstyrene-EPDM-divinylbenzene Graft Polymer

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Journal of Donghua University(English Edition) 2001年第1期18卷 6-10页

作者：周美华 cho won-Jei Environment Science and Engineering College Dong Hua University Shanghai 200051 Department of Polymer Science and Engineering Pusan National University Pusan 609 - 735 South Korea

4-tert-butylstyrene-EPDM-divinylbenzene graft terpolymer (PBED) was prepared by graft cross-polymerization in toluene using BPO as an initiator. The gel-PBED and solPBED were isolated from extraction of tetrahydrofuran (THF), and then they were identified by IR spectroscopy. The maximum oil-absorptivity of gel-PBED produced from the optinum reaction conditions was 8 420% but its swelling rate was very low. The highest oil-absorptivity of photocrosslinked sol-PBED film was 5 800%. Although its oil absorbency was not as high as gel-PBED' s, swelling rate was higher than that of gelPBED and was suitable for commercial purpose. After swelling in oil, neither gel PBED nor photocrosslinked sol-PBED film having high oil-absorptivity had sufficient mechanical strength to be taken out of oil wholly. As is known, composite technique is one of the useful methods for reinforcing them. Fibers, sponges and non-woven cloths were used as reinforcers or supporters in this work. Oil-absorptivities and swelling kinetics were evaluated by method ASTM (F726 - 81 ) and an experimental equation. The mechanical properties and the morphologies of some composites were measured by tensile tester and SEM , respectively.

关键词： 4-tert-butylstyrene-EPDM-divinylbenzene graft terpolymer (PBED), fiber, non-woven cloth, sponge, oilabsorptive composite.

Beach stabilization by the laying of a drainage layer

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Science China(Technological Sciences) 2012年第9期55卷 2625-2639页

作者： HUR Dong-Soo LEE Woo-Dong cho won-Chul Department of Ocean Civil Engineering(Institute of Marine Industry) Gyeongsang National University445 Inpyeong-dongTongyeong 650-160Korea Department of Ocean Civil Engineering Gyeongsang National University445 Inpyeong-dongTongyeong 650-160Korea Department of Civil and Environmental Engineering Chung-Ang University221 Heuksuk-dong Dongjak-guSeoul 156-756Korea

In the present study, the stabilization effects of the laying of a drainage layer in a sandy beach were analyzed. The numerical model developed by Hur et al. （2011） was used to examine the characteristics of wave-sandy beach interaction with/without a drainage layer. This numericai model directly simulates Wave-Structure-Seabed/Sandy （WASS） beach interaction by consid- ering flow through a porous medium with inertia, laminar and turbulent resistances, and determines the eddy viscosity with the Large Eddy Simulation （LES） turbulent model in a 3-D wave field （LES-WASS-3D）. Based on the numerical results, it ap- pears that the installation of a drainage layer in the beach results in a decrease in both the mean groundwater level around the foreshore and the flow moving offshore on the beach surface. Spatial distributions of the mean groundwater level and wave setup around the foreshore with various arrangements of the drainage layer and conditions of the incident wave are also discussed in this paper.

关键词： drainage layer groundwater level foreshore LES-WASS-3D (3-D numerical simulation) beach stabilization swash zone

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO_2 absorption

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Journal of Environmental Sciences 2012年第5期24卷 897-902页

作者： Sang-Sup Lee Seong-Man Mun won-Joon choi Byoung-Moo Min Sang-won cho Kwang-Joong Oh Department of Environmental Engineering Chungbuk National University Department of Environmental Engineering Pusan National University Corporate R&D Institute Fuel Cell System Development Team Doosan Heavy Industries & Construction Greenhouse Gas Research Center Korea Institute of Energy Research Department of Energy and Environment Korea Polytechnic VII College

Aqueous 1,8-diamino-p-menthane （KIER-C3） and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol （AMP） solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine （MEA） and ammonia （NH3）, respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation： k2,AMP/C3 = 7.702×106 exp （-2248.03/T）. A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.

关键词： carbon dioxide absorption rate and capacity 1 8-diamino-p-menthane 2-amino-2-methyl-1-propanol

Oil Gels Based on Styrene Butadiene Rubber

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Journal of Donghua University(English Edition) 2004年第1期21卷 51-56页

作者：周美华徐静波 won-jei cho Environmental Science and Engineering College Donghua University Shanghai 200051 College of Electronic and Electrical Engineering Shanghai University of Science and Technology Shanghai 200336 Department of Polymer Science and Engineering Pusan National University Pusan 609-735 South Koreaour oil absorbents based on styrene butadiene (SBR) i.e. pure SBR (PS) 4. tert-butylstyrene-SBR (PBS) EPDM-SBR network (PES) and 4.tert-butylstyrene-EPDMSBR (PBES) were produced from crosslinking polymerization of uncured styrene butadiene rubber (SBR) 4-tert-butylstyrene (tBS) and ethylene-propylenc-diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a pre-polymer and a crosslink agent in this work and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with the method ASTM (F726-81). The order of maximum oil absorbency was PBES>PBS>PES>PS. The maximum values of oil absorbency of PBES and PBS were 74.0g/g and 69.5g/g respectively. Gel fractions and swelling kinetic constants however had the opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49. 97×10~(-2)h~(-1).

Four oil absorbents based on styrene butadiene (SBR), i.e., pure SBR (PS), 4. tert-butylstyrene-SBR (PBS), EPDM-SBR network (PES) and ***-butylstyrene-EPDMSBR (PBES), were produced from crosslinking polymerization of uncured styrene butadiene rubber (SBR), 4-tert-butylstyrene (tBS) and ethylene-propylenc-diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a pre-polymer and a crosslink agent in this work, and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with the method ASTM (F726-81). The order of maximum oil absorbency was PBES>PBS>PES>PS. The maximum values of oil absorbency of PBES and PBS were 74.0g/g and 69.5g/g, respectively. Gel fractions and swelling kinetic constants, however, had the opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49. 97×10^(-2)h^(-1).

关键词： oil gel styrene butadiene rubber swelling kinetic constant

Development of Preliminary Design Program for Combustor of Regenerative Cooled Liquid Rocket Engine

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Journal of Thermal Science 2011年第5期20卷 467-473页

作者： won Kook cho Woo Seok Seol Min Son Min Kyo Seo Jaye Koo Korea Aerospace Research Institute DaejoenRepublic of Korea Graduate Student Korea Aerospace UniversityGoyangRepublic of Korea School of Aerospace and Mechanical Engineering Korea Aerospace UniversityGoyangRepublic of Korea

An integrated program was established to design a combustor for a liquid rocket engine and to analyze regenerative cooling results on a preliminary design *** of burnt gas from a kerosene-LOx mixture in the combustor and rocket performance were calculated from CEA which is the code for the calculation of chemical *** heat transfer of regenerative cooling was analyzed by using SUPERTRAPP code for coolant properties and by one-dimensional correlations of the heat transfer coefficient from the combustor liner to the *** of the combustors of F-1 and RS-27A engines were designed from similar input data and the present results were compared to actual data for ***,the combustors of 30 tonf class,75 tonf class and 150 tonf class were designed from the required thrust,combustion chamber,exit pressure and mixture ratio of *** wall temperature,heat flux and pressure drop were calculated for heat transfer analysis of regenerative cooling using the profiles.

关键词： Liquid rocket engine Preliminary design of Combustor Regenerative cooling

Fatigue crack in large-scale tubular joints for offshore structures

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Science China(Technological Sciences) 2011年第3期54卷 705-714页

作者： Chul-Hee JO Sung-Woo IM won-Chul cho Kwan-Kyu PARK Department of Naval Architecture and Ocean Engineering Inha University Research Institute of Industrial Science and Technology Department of Civil & Environmental Engineering Chung-Ang University Samsung Heavy Industry Inc.

Tubular members have been used for constructing offshore structures. Large-scale fatigue tests of welded tubular K-joints under the balanced in-plane bending brace were carried out to investigate the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The experimental results were verified by numerical approaches and compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The test results based on the hot spot stress were in agreement with the design curves. The SCF factor for tubular K-joint was also obtained. The numerical parametric study of the K-joint (using the finite element program) was described and its results were compared with experimental results. The stress effects of various parameters including α, β, γ, τ and θ on the stress in the K-joint were investigated. The stress distribution for each parameter was introduced. The study showed that the maximum stress of the joint varied according to the variation of joint parameters.

关键词： tubular K-joint API 2W Gr.50 hot spot stress SCF fatigue through-thickness crack S-N curve numerical parametric study

Path to the fabrication of efficient, stable and commercially viable large-area organic solar cells

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Materials Futures

Materials Futures 2023年第3期2卷 38-52页

作者： Shafket Rasool Jiwoo Yeop Hye won cho Woojin Lee Jae won Kim Dohun Yuk JinYoung Kim School of Energy and Chemical Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Graduate School of Carbon Neutrality Ulsan National Institute of Science and TechnologyUlsan44919Republic of Korea

Organic solar cells(OSCs)have reached an outstanding certified power conversion efficiency(PCE)of over 19%in single junction and 20%in tandem architecture *** high PCEs have emerged with outstanding Y-shaped Y6 non-fullerene acceptors(NFAs),together with PM6 electron donor *** are on the rise for small-area ***,large-area OSC sub-modules are still unable to achieve such high PCEs,and the highest certified PCE reported so far is∼12%having an area of 58 *** fabricate efficient large-area OSCs,new custom-designed NFAs for large-area systems are imminent along with improvements in the sub-module fabrication ***,the search for stable yet efficient OSCs is still in *** this review,progress in small-area OSCs is presented with reference to the advancement in the chemical structure of NFAs and donor ***,the life-cycle assessment of OSCs is presented and the energy payback time of the efficient and stable OSCs is discussed and lastly,an outlook for the OSCs is given.

关键词： organic solar cells non-fullerene acceptors OSC morphology interfacial modification light-soaking stability solar energy large-area OSCs

Porously Reduced 2-Dimensional Bi_(2)O_(2)CO_(3) Petals for Strain-Mediated Electrochemical CO_(2) Reduction to HCOOH

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Energy & Environmental Materials 2024年第1期7卷 215-221页

作者： won Seok cho Dae Myung Hong Wan Jae Dong Tae Hyung Lee Chul Jong Yoo Donghwa Lee Ho won Jang Jong-Lam Lee Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)Pohang Gyungbuk 37673Korea Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National UniversitySeoul 08826Korea

Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO_(2)to formic acid(HCOOH),which are composed of petal-shaped Bi_(2)O_(2)CO_(3)(BOC)that spontaneously formed from Bi thin film in aqueous carbonate solution at room *** the electrochemical reduction process,the BOC petals transform to reduced BOC(R-BOC)consisting of individual BOC and Bi *** mismatch between both domains induces biaxial strain at the *** functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the*Ocho intermediate,reducing the thermodynamic barrier toward CO_(2)conversion to *** with the thermodynamic benefit and the unique nanoporous petal-shaped morphology,R-BOC petals have a superior Faradaic efficiency of 95.9%at-0.8 V_(RHE)for the electrochemical conversion of CO_(2)to *** work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO_(2)reduction reaction;such a strategy can be applicable in design of various electrocatalysts.

关键词： bismuth carbon dioxide reduction formic acid heterointerfaces strain