난지도 매립지에서 침출수 거동에 관한 연구

조원철,강동희,구태훈 중앙대학교 기술과학연구소 2000 기술과학연구소 논문집 Vol.30 No.-

최근 난지도 매립지는 침출수로 인한 지하수오염이 심각한 매립지 중 하나로 부각되고 있다. 본 연구는 난지도 매립지에서의 침출수 거동을 3차원 지하수 흐름을 모사 할 수 있는 MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model)을 이용하여 분석하였고, 난지도 매립지에서의 침출수 발생량은 HELP(Hydraulic Evaluation of Landfill Performance)모델을 이용하여 추정하였다. 침출수 발생량은 최근 10년간의 기상 자료를 이용하여 산정 하였으며, 침출수 거동은 복토 전/후와 차수벽과 well 설치후의 시간 경과에 따른 침출수위의 변화를 계산하여 예측하였다. 본 연구는 난지도 매립지의 적절한 침출수 발생량과 침출수 거동을 예측하는데 있어 유용하게 사용될 것으로 사료된다. The Nanji landfill has recently became one of the most important site for groundwater contamination leachate transport. This study is to analyze the leachate transport in Nanji waste landfill using MODFLOW(A Modular 3-D Finite Different Groundwater Flow Model) model which can model three dimension groundwater flow. Leachate production rates are estimated by HELP(Hydraulic Evaluation of Landfill Performance) model and used weather records for recently 10 years. Leachate transport is predicted by a change of leachate level to after/before established HDPE, established slurry wall and wells. The purpose of this study is to predict appropriate leachate rates and leachate transport at Nanji waste landfill.

Investigations on CO2 hydrate slurry for transportation in carbon capture and storage

PRAHBENEDICT,윤린 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

The flow characteristics of CO 2 hydrate in the presence of Tween 80 in a scaled-up test facility were investigated in order to further elucidate the potential of CO 2 hydrate slurry transportation in carbon capture and storage technology. Two formation processes were used to generate sufficient hydrate slurry for flow in a circulation loop of a 108 mm inner diameter pipe. The effects of Tween 80 concentrations on the four hydrate slurry parameters of pressure, temperature, density, and flow rate were studied and discussed. The results of the CO 2 hydrate slurry transportation experiments indicated that 0.7 wt.% of Tween 80 showed the optimal results for slurry stability, slurry temperature, and slurry density, but had no significant effect on slurry temperature during flowing in the loop. In all experiments, hydrate circulation was performed for an average duration of 80 min under stable conditions. The results suggest the possibility of transporting hydrate slurry over long distances under stable conditions with the addition of chemical additives.

우수관로 내부 2상 유동 해석에 따른 한계소류력 관계식 제안

송양호(Song Yang Ho),윤린(Yun Rin),유재연(Yu Jae Yeon),공수창(Gong Soo Chang),이정호(Lee Jung Ho) 한국방재학회 2017 한국방재학회논문집 Vol.17 No.5

우수관거의 치수능력을 유지하고 홍수시 침수를 방지하기 위해 관거 내부에서의 더 많은 흐름특성을 이해하는 것은 매우 중요하다. 관 내부의 유출량 거동에 영향을 미치는 요소에는 관거 내부로 함께 유입되는 토사 슬러리가 있으며 이송·침전 과정을 거쳐 퇴적층을 형성할 때 통수능 저하에 따른 문제를 야기시킨다. 토사 슬러리는 유체와 혼합된 상태로 관거로 유입된다. 관 내부에서의 난류 에너지와 에너지 소산으로 인해 분리현상을 일으키며 하상에 퇴적을 형성할 경우 관거 통수능 저하의 주요 문제점이 된다. 우수관거로 유입되는 토사 슬러리에 대한 거동 특성을 파악하고 이송·침전의 원인을 분석할 필요가 있다. 본 연구에서는 우수관거 내부로 유입되는 토사 슬러리를 고려하여 관거 내부의 유체와 토사 슬러리를 동시에 고려한 2상 유동 흐름의 분석조건을 난류흐름의 관점에서 도출하고자한다. 우수관거 내부 흐름에 대한 수치해석 모델링을 실시하였으며, Navier-Stokes 방정식과 k-ε 난류모델의 반영을 통해 실제 우수관거 내부에서의 유체와 토사 슬러리의 흐름에 대하여 분석하였다. 우수관 내부 토사 슬러리의 이송·침전 현상을 검토하였으며, 결과들을 바탕으로 한계소류력 산정을 통해 관 내부에서 발생하는 이송·침전에 대한 기준을 제안하였다. It’s important to understand a lot more flow properties in sewer conduit in order to maintain the flood control capacity, and to prevent flooding an urban inundation. There is soil slurry flowing inside the conduit together in the influencing elements on runoff behavior and causes a problem consequent on the decline in discharge capacity when it forms a sedimentary layer through the transport·deposition process. Soil slurry flows in conduit in a state mixed with a fluid. There arises a separation phenomenon due to the turbulent energy and energy dissipation inside the conduit, and in case sedimentation forms in a bed, it becomes a major problem of the decline in discharge capacity. Therefore, it is there is a need to grasp the behavior property of soil slurry, and to analyze the reason for its transport·deposition process. In this study, the soil slurry incoming the storm sewer conduit was considered, two-phase flow analytical conditions considering both the fluid and soil slurry in the conduit are to be derived from the perspective of the turbulent flow. This study conducted the numerical value analysis modeling of the internal flow and analyzed both the fluid and soil slurry inside an actual conduit through the reflection of Navier-Strokes equation and k-ε turbulence model. This study examined the transport·deposition phenomenon occurring inside the conduit, and proposed the standard of the transport·deposition occurring inside the conduit through the critical tractive force assessment on the basis of results.

A FIELD APPLICATION CASE OF THE DIRECT ICE SLURRY TRANSPORTING SYSTEM FOR DISTRICT COOLING

Yoo, Ho-Seon,Lee, Sang-Hoon,Lee, Yoon-Pyo The Society of Air-Conditioning and Refrigerating 2010 International Journal Of Air-Conditioning and Refr Vol.18 No.1

In order to investigate the feasibility of the direct ice slurry transporting system for the purpose of district cooling, a case study of field application is performed. The research aims to include the field measurement of ice packing factor, the performance of cold energy delivery, and the branching characteristics of ice slurry in which the additive is propylene glycol wt 10%. Two representative types of pipe branch are dealt with in this work. For the slurry flow with ice volume fraction of 0.16 or less, the pipe blocking due to aggregation is not observed. It is confirmed that the mass flow rate of ice slurry per unit cooling load markedly decreases with the increase of the ice content. The pumping power also decreases, but remains unchanged when the ice fractions are higher than a certain level.

A FIELD APPLICATION CASE OF THE DIRECT ICE SLURRY TRANSPORTING SYSTEM FOR DISTRICT COOLING

유호선,SANG HOON LEE,이윤표 대한설비공학회 2010 International Journal Of Air-Conditioning and Refr Vol.18 No.1

In order to investigate the feasibility of the direct ice slurry transporting system for the purpose of district cooling, a case study of field application is performed. The research aims to include the ¯eld measurement of ice packing factor, the performance of cold energy delivery, and the branching characteristics of ice slurry in which the additive is propylene glycol wt 10%. Two representative types of pipe branch are dealt with in this work. For the slurry flow with ice volume fraction of 0.16 or less, the pipe blocking due to aggregation is not observed. It is con¯rmed that the mass flow rate of ice slurry per unit cooling load markedly decreases with the increase of the ice content. The pumping power also decreases, but remains unchanged when the ice fractions are higher than a certain level.

준설토 이송고효율화를 위한 유동특성의 실험적 분석

김유승(Yu-Seung Kim),이명한(Myung-Han Lee),이수연(Su-Yeon Lee) 한국지반신소재학회 2016 한국지반신소재학회 논문집 Vol.15 No.1

준설토 이송 시 윤활층에 전자기장을 인가하여 이송 동력을 절감하고, 송토량을 증가시키는 연구의 일환으로, 이런 전자기장장치의 실제 적용성을 검증하고자 실현장 8.5km의 이송거리의 준설현장에 전자기장 장치를 설치하여 그 효과를 검증하였다. 이송 유속에 관계되는 운전 조건 및 토질상태와 유동상태를 모니터링하고, 획득한 데이터를 송토량과 동력 사이의 관계로 정리하여 전자기장 인가 후 약 30%의 동력대비 이송량 증가가 있음을 확인하였고, 이를 통해 전자기장 인가가 준설토 이송시 동력절감에 효과가 있음을 확인하였다. To evaluate the effects of magnetic force for transporting the dredged soil, magnetic energy inducing device was installed at the dredger. The whole length of transporting pipeline reaches more than 8.5km and the efficiency of the system and the characteristics of the flow are critical factors. The main parameters which govern the flow are flow-rate, velocity, concentration and slip-layer’s condition, so in the field test monitoring system was applied to check the real time conditions of the closed circuit flow and the main parameters. From analyzing the relation between the dredged soil amounts and the pump power, it can be concluded that the magnetic forces effect on the transporting system, increase the transporting quantities of dredged soil and decrease power consumption of the pump.

우수관로 슬러리 이송에 따른 난류 전단경계층 검토

송양호(Song Yang Ho),윤린(Yun Rin),이정호(Lee Jung Ho) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.2

슬러리의 이송과정은 대게 유체와 함께 흘러가는 부유사나 하상 저면에 가라앉은 퇴적물로 분류되지만 두 현상의 경계를 명확히 구분한 사례는 드물다. 경계층은 퇴적물의 이송능력을 판단할 수 있는 중요 요소이다. 우수관거 내부로 유입되는 유출량의 경우 대부분 강우 발생에 따른 토사 슬러리와의 혼합물의 형태로 유입되며 난류흐름 조건을 갖는 특징을 갖는다. 본 연구에서는 수치해석 모형을 바탕으로 실제 우수관로 내 토사 슬리러의 흐름을 예측할 수 있는 분석모델을 수립하고 퇴적물 흐름의 경계층 추정방법을 제안하였다. 분석모델을 검증하기 위해 유사 실험연구 사례를 토대로 관 내부에서의 체적농도 를 비교하였다. 퇴적물의 이송과정을 검토하고자 대상유량 조건별 슬러리를 포함한 관 내부의 유속장과 체적농도를 살펴보았다. 결과를 토대로 관 내부 전단유속과 입자의 침강속도를 활용하여 전단경계층 형성에 대한 기준을 수식적으로 표현하였다. In the classification of the slurry transportation processes, sediment has been mostly classified as suspended sediment flowing with fluid or sediment sank to the bottom of riverbed, though there have been few cases of clarifying the boundary of the two phenomena. A boundary layer is a major factor in determining the capability of transferring sediment. In case of discharges flowed into sewer pipes, most of them flow into as a mixture fluid and soil slurry based on the occurrence of rainfall, and show characteristics of turbulent flows. In this study, an analysis model capable of predicting soil slurry flows within actual sewer pipes based on a numerical analysis model, and proposed a method of estimating boundary layers in the sediment flow. To verify the analysis model, the volume fractions in the pipes were compared based on cases of similar studies. To review the process of transferring sediment, the velocity field and volume fraction by flow conditions including slurry inside of pipes was studied. Based on the result, criteria on the formation of a shear boundary layer were expressed as for figural style by using shear velocity rates and settling velocity rate of particles in pipes.

물-토사 혼합물의 관 내 슬러리 유동특성에 대한 수치적 연구

송양호(Song Yang Ho),윤린(Yun Rin),이정호(Lee Jung Ho) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.2

본 논문은 수치 해석적 관점에서 우수관거로 유입되는 토사 슬러리 이송ㆍ침전 현상에 대하여 기술하였다. 본 연구에 앞서 우수관거에 내부 흐름에 대하여 유동특성을 검토한 연구사례가 존재한다. 기존 연구들의 경우 관로 내 단일 유체의 흐름을 고려한 실험 및 해석을 진행하였다. 그러나 본 연구에서는 토사 슬러리를 고려한 2상유동 해석을 진행하였고 관 내부에서의 이송ㆍ침전 경향을 검토할 수 있는 유속과 체적분율의 변화와 퇴적 특성에 대한 연구결과를 도출하고자 하였다. 더불어 우수관거 내부 유동해석을 바탕으로 향후 관로 내 퇴적에 대한 설계기준을 뒷받침하는 이론 및 분석적 근거가 필요한 현실이다. 토사 슬러리를 고려한 2상유동의 관측 및 해석의 어려움으로 인해 연구결과가 드물어 해당 부분이 본 연구에서 검토하고자 함이 연구목표이다. 따라서 실제 맨홀로 유입되는 토사 슬러리의 경우 유출에 따른 유량과 혼합된 형태로 유입되는 것을 반영하여 관거 내부에서 발생하는 유동특성을 검토하였다. 관 내부에서 발생하는 퇴적에 따른 통수능의 영향정도를 살펴보고 기존에 제안된 우수관로 내 임계 퇴적고 예측모델을 개선하였다. 기존 제안된 모델과의 비교 결과 더 높은 상관율을 갖음을 확인하였다. This study described the phenomena of transport and sedimentation of soil slurry flowed in storm sewers from the perspective of numerical analysis. There have been some research cases reviewing the characteristics of flows inside of storm sewers. Most existing researches have performed experiments and analyses based on a flow of single fluid in conduits. However, this study tried to interpret such a flows as a two-phase flow by taking into account soil slurry, and it also tried to deduce results on the change of flow velocity and volume fraction, as well as characteristics of sedimentation to study the tendency of transport and sedimentation inside of the conduits. In addition, it should be necessary to produce theories and analytical basis which can support design criteria for sedimentation inside of conduits based on the analysis of internal flows in storm sewers. Because of difficulties in observing and interpreting two-phase flows made of soil slurry, there have been few studies on this subject, the objective of this study was to examine this part. Accordingly, in case of soil slurry flowed into real manholes, this study reviewed the characteristics of flows generated inside of conduits by reflecting the rate of flow caused by outflow and that of inflow occurred in mixed forms. This study also checked the scope of impact of discharge capacity caused by sedimentation occurred inside of conduits, and improved the already proposed prediction model of critical sediment depth within storm sewers. When comparing with the proposed model, it was confirmed that this new model showed higher correlation ratio.

Hydraulic transport of sand-water mixtures in pipelines Part I. Experiment

김창희,이만수,한철희 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.12

The hydraulic transport characteristics of sand-water mixtures in circular and square pipelines are experimentally investigated by changing the Reynolds number and volumetric delivered concentration. The hydraulic gradients are increased along with the Reynolds number. When the mean velocity is larger than the critical velocity, the hydraulic gradient of sand-water mixture in the square duct is larger than that in the circular pipe. The deposition-limit velocity in the square duct is smaller than that in the circular pipe. Thus, it can be concluded that the square duct transports sands more effectively than the circular pipe in a low operating range of velocity. The empirical correlation between the hydraulic gradient and the Reynolds number is obtained. It is believed that the present data and empirical equation can be used to validate the numerical methods developed for the analysis of the transport characteristics of slurry in the circular and square pipelines.

아이스슬러리형 빙축열 시스템을 이용한 냉각 시스템의 특성 분석

이동원(Dong-Won Lee),이순명(Soon-Myung Lee) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.6

To clarify the hydraulic and thermal characteristics of ice slurry which made from 6.5% ethylene glycol-water solution flow in the double tube and plate type heat exchanger, experimental studies were performed. The mass flux and ice fraction of ice slurry were varied from 800 to 3,500 ㎏/㎡s(or 7 to 17 ㎏/min) and from 0 to 25%, respectively. During the experiment, it was found that the measured pressure drop and heat transfer rate increase with the mass flux and ice fraction; however the effect of ice fraction appears not to be significant at high mass flux region. At the region of low mass flux, a sharp increase in the pressure drop and heat transfer rate were observed depends on mass flux.