• Journal of Advanced Marine Engineering and Technology
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• 제41권2호
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• pp.140-145
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• 2017

Newly designed vapor-injection heat pumps have been proposed and analyzed in the present study. An economizer-type vapor-injection (V-I) system has been employed as the standard system because of its reliability and simple control method. The V-I system has a re-cooler and re-heater for cooling and heating, respectively. Solar panels have been installed in the V-I heat pump as well as in the re-heater in order to enhance heating capacity and performance. R410A has been employed as a working fluid and performance analysis has been conducted under various conditions. Results are summarized as follows: (1) The V-I system with the re-cooler yielded a marginally higher coefficient of performance (COP) than the conventional V-I refrigeration system. (2) By increasing the re-cooler cooling capacity, enhanced system performance as compared to the conventional V-I system was observed. (3) The re-heater negatively affected the system performance; hence, the V-I heat pump with the re-heater yielded a lower COP than that of the conventional V-I heat pump used for heating. (4) Although the solar panels increased the system performance, this increase could not offset performance degradation by the re-heater.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.847-853
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• 2008

Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Circle fin exhaust pipes were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The designs adopted in this study were exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe Technique The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10nm), surface forces are increasingly important. Nanoparticles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^{4}$.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2311-2320
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• 2022

The main outcomes of the experiments H2P6 performed in the thermal-hydraulics large-scale PANDA facility at PSI in the frame of the OECD/NEA HYMERES-2 project are presented in this article. The experiments of the H2P6 series consists of two PANDA tests characterized by the activation of three (H2P6_1) or one (H2P6_2) cooler(s) in an initially stratified and pressurized containment atmosphere. The initial stratification is defined by a helium-rich region located in the upper part of the vessel and a steam/air atmosphere in the lower part. The activation of the cooler(s) results i) in the condensation of the steam in the vicinity of the cooler(s), ii) the corresponding activation of large scale natural circulation currents in the vessel atmosphere, with the result of iii) the re-distribution and mixing of the Helium stratification initially located in the upper half of the vessel and iv) the continuous pressure decay. The initial helium layer represents hydrogen generated in a postulated severe accident. The main question to be answered by the experiments is whether or not the interaction of the different, localized cooler units would be important for the application of numerical methods. The paper describes the initial and boundary conditions and the experimental results of the H2P6 series with the suggestion of simple scaling laws for both experiments in terms of i) the temperature difference(s) across the cooler(s), ii) the transient steam and helium content and iii) the pressure decay in the vessel. The outcomes of this scaling indicate that the interaction between separate, closely localized units does not play a prominent role for the present experiments. It is therefore reasonable to model several units as one large component with equivalent heat transfer area and total water flow rate.

• Journal of Advanced Marine Engineering and Technology
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• 제39권6호
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• pp.592-598
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• 2015

본 연구에서는 공랭식 VI(Vapour-Injection) 사이클을 적용한 R410A용 고성능 하절기 냉방 열펌프의 성능 특성을 실험적으로 규명하였다. 실험에 사용한 장치는 VI 압축기, 응축기, 유분리기, 판형열교환기, 에코노마이져(economizer), 증발기, 그리고 재냉기(re-cooler)로 구성하였다. 냉방 성능 실험 조건은 다음과 같이 3가지 사이클로 VI 사이클을 적용하고 증발기 출구 냉매와 VI사이클 흡입 냉매가 재냉기에서 서로 열교환 하지 않는 사이클(사이클 A)과 열교환을 하는 사이클(사이클 B), 그리고 VI 사이클도 적용하지 않고 증발기 출구 냉매와 VI 사이클 흡입 냉매와의 열교환도 없는 사이클(사이클 C)로 구분하였다. 분석 결과, 냉방 성능은 증발기 출구 냉매와 VI사이클 흡입 냉매가 서로 열교환하는 VI사이클(사이클 B)이 가장 높았으며 VI사이클을 적용하지 않은 사이클 C가 가장 낮음을 알 수 있었으며, 사이클B의 냉방성능계수($COP_C$)가 평균 3.5로 사이클A보다 8.6%, 사이클C보다 33% 높은 값을 나타내었다.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.134-142
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• 2011

Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Exhaust pipes with circular fin were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The gases examined in this study were oxides of nitrogen (NOx), carbon dioxide ($CO_2$) and carbon monoxide (CO). In addition, $O_2$ concentration in the exhaust was measured. The designs adopted in this study were about exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe technique. The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10 nm), surface forces are increasingly important. Nano particles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. The current tools for directly measuring interaction forces such as a surface force apparatus or atomic force microscopy (AFM) are limited to particles much larger than nano size. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^4$ by free convection and Re=$3.36{\times}10^4$ by forced air furnace.

• Journal of Advanced Marine Engineering and Technology
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• 제37권5호
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• pp.467-476
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• 2013

동결농축법은 열역학적 효율이 높고 에너지 소비량이 작으며 처리수를 재활용할 수 있는 장점을 가지고 있다. 본 연구에서는 중소규모로 상용화 가능한 동결농축폐수처리시스템을 설계하고, 각 시스템의 에너지 소비효율과 일일처리량을 비교하여 시스템 개발방향을 제안하고자 하였다. 시스템을 완속운전시스템과 급속운전시스템으로 각각 모델링하고 해석을 통해 소비동력과 운전시간을 계산하여 비교한 다음 설계처리량에 따른 변화를 추가 검토하였다. 연구결과 급속운전시스템의 소비전력량비가 0.6 Wh/kg 만큼 다소 높으나 일일처리량은 19 % 증가하였으며, 설계처리량이 큰 시스템일수록 소비전력량비가 작아지고 일일처리량이 큰 결과를 얻었다.

• 자원리싸이클링
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• 제8권5호
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• pp.51-58
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• 1999

석탄화력 발전소에서 발생하는 수백만 톤의 석탄회는 콘크리트 혼화재 및 건축자재로 재활용이 가능함에도 불구하고 과다한 미연탄소 함량으로 인해 대부분 회사장(Ash Pond) 되는데, 이로 인해 환경오염유발, 회사장 포화에 따른 발전소의 수명 감소, 그리고 재활용 가능한 자원의 낭비와 같은 문제가 발생한다. 본 연구는 석탄회 내의 미연탄소분을 분리하여 미연탄소분 함량이 낮은 고순도 석탄회를 회수하기 위해 직류관 믹서(In-Line Mixer) 발생기키는 역류형 컬럼부선기를 이용하였다. 이때 입자 표면에 소수성의 특성을 강화시키는 포스제의 증가에 따른 석탄회와 미연탄소 입자의 분리 특성을 분석하였다. 석탕회 톤당 8ι의 포수제를 사용한 역류형 컬럼 부선기를 이용하여 미연탄소분 함유량이 7%인 석탄회를 분리 실험한 결과 미연탄소분 함유량 0.5%인 고순도 석탄회를 88.2% 회수하였다. 그리고 질량 평균입경이 21.2$mu extrm{m}$인 석탄회를 분리 실험하여 입도를 분석한 결과 분리 정도에 따라 입도는 뚜렷하게 구별되어 나타났는데, 분리효율이 증가할수록 정제 석탄회의 경우 입도는 조대해져 입도 분포의 양극화 현상이 뚜렷하게 나타났다. 포수제의 투입량이 증대함에 따라 미연탄소 입자의 계면에 소수성이 강화되어 분리 특성이 향상되었으며, 이때 회수한 고순도 석탄회의 입도는 미세화 되는 경향이 나타났다.

• 자원리싸이클링
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• 제8권5호
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• pp.44-50
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• 1999

동 매트 중에 함유된 불순물 중 단순한 산화정련으로는 제거하기 어려워 제련 후 조동에 함유되어 동의 순도와 기계적 성질을 저하시키는 Ni와 Sb를 매트제련 동안에 제거하기 위한 기초 자료를 제시하고자 공기 송풍에 의한 합성 동 매트의 용련 반응을 통하여 반응 생성물인 매트와 슬래그 그리고 조동에 함유된 Ni와 Sb의 거동 및 상호 연관성을 조사하였다. 공기 송풍에 따른 합성 매트의 용련동안 생성된 반응 생성물에 대한 Ni와 Sb의 분배비로부터 Sb가 Ni과 공존 시 Ni의 슬래그화를 촉진하는 역할을 하며, 또한 Ni은 Sb와 공존시 조동 중으로의 Sb 이동을 저해하고 슬래그화를 촉진시키는 것으로 나타났다. 따라서 Ni와 Sb의 슬래그화를 유도하기 위해서는 Ni와 Sb의 공존이 필요한 것으로 생각된다.

• 한국제4기학회지
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• 제11권1호
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• pp.57-68
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• 1997

Climatic change of the late-Quaternary period has been record-ed in the loess deposits of the central Great plains and the record of such change is extractable using a number of approaches and parameters. The stratigraphy of loess deposits which have been investigated on Fort Riley exhibits the same sequence of loess units and intercalated buried soils as is found elsewhere in the re-gion but adds detail unique to the reservation Upland late-Qua-ternary composite stratigraphy preserved on the reservation con-sists of the basal Sangamon soil of the Last interglacial(c. 120-110ka), Gilman Canyon Formation(c. >40 -20ka), Peoria loess(c. 20 -10ka) Brady soil(c. 11 -10ka) Bignell loess(c. 9-\ulcornerka). and mod-ern surface soil. Application of magnetic analyses has provided proxy data sets that represent a time series of climatically regulated pedogenesis/weathering and botanical composition. magetic data have yielded an impression of the variation in climate from Sangamon time to the late Holocene through a reconstruction of the history of pedogenesis/weathering. Sangamon soil formation dominated the reservation durin the Last interglacial as indicated by magnetic parameters. During Gil-man Canyon time loess influx was usually sufficiently slow as to permit pedogenesis which appears to have been at a maximum twice during that time. Warm season grasses were important dur-ing soil formation but diminished in importance during the peri-ods of more rapid loess fall which were cooler and perhaps wet-ter. Peoria loess fall a function of the deterioration of climate during the last Glacial Maximum thinly blanketed the reservation with thickest accumulations occurring to the north-west(Bala Cemetery site)proximal to the source region. Long-term surface stability did not apparently occur within Peoria time but short-term stability may be indicaed by the presence of thin weathering zones(incipient soils) in the Peoria loess. Re-gional landscape stability prevailed during the environmental shift at the Pleistocene/Holocene transition resulting in forma-tion of the well expressed Brady soil. One or more weak soils developed in the Bignell loess as it ac-cumulated. A notable feature of the Bignell loess is the appear-ance of the Altithermal dry period: the loess experienced little weathering and was dominated by warm season grasses until the latter of the Holocene.