• Title/Summary/Keyword: water circulation

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A Study on the Establishment of Water Circulation System for the Eastern Pangyo New Town (동판교 신도시의 물순환 체계 구축방안)

  • Choi, Hee-Sun;Kim, Kwi-Gon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.12 no.3
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    • pp.49-58
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    • 2009
  • This study was done to provide a case model with a concept of environmental integration based on the water circulation system. Area of interest (AOI) is the Eastern Pangyo New Town area, which has several advantages in adaptation of a water circulation system. The AOI has a potential of maintaining water resources, and has a good condition to construct the water circulation system. Research done for the purpose of the establishment of the water circulation system in the Eastern Pangyo New Town shows the following. The main sources of water supply in the water circulation system in the Eastern Pangyo New Town is from two subway stations and runoff water, along with the natural water flowing from the mountains, rain water, and stream water. It was determined that more than 35,000 tons of water would be needed for the creation of water circulation system at the Eastern Pangyo. If the creation of infrastructure for the use of runoff and rain water as well as the periodic management can be provided, it can serve as the new model for a new city with water circulation system. In addition, since the Eastern Pangyo New Town water circulation system can secure enough amount of water resources, natural drainage system (NDS) in which it can be in dry condition in non-rainy days, is applied and connected to the typical waterways. Such water circulation system has many positive aspects including the wise use of water resources, and providing wild Life animals corridors and habitats. Also, the water circulation system can lead to the environmental education to the residents and visitors on environmental awareness of the water circulation system and their environment.

Development of water circulation status estimation model by using multiple linear regression analysis of urban characteristic factors (도시특성 요인의 다중선형회귀 분석을 이용한 물순환상태추정모델 개발)

  • Kim, Youngran;Hwang, Seonghwan;Lee, Yunsun
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.6
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    • pp.503-512
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    • 2020
  • Identifying the water circulation status is one of the indispensable processes for watershed management in an urban area. Recently, various water circulation models have been developed to simulate the water circulation, but it takes a lot of time and cost to make a water circulation model that could adapt the characteristics of the watershed. This paper aims to develop a water circulation state estimation model that could easily calculate the status of water circulation in an urban watershed by using multiple linear regression analysis. The study watershed is a watershed in Seoul that applied the impermeable area ratio in 1962 and 2000. And, It was divided into 73 watersheds in order to consider changes in water circulation status according to the urban characteristic factors. The input data of the SHER(Similar Hydrologic Element Response) model, a water circulation model, were used as data for the urban characteristic factors of each watershed. A total of seven factors were considered as urban characteristic factors. Those factors included annual precipitation, watershed area, average land-surface slope, impervious surface ratio, coefficient of saturated permeability, hydraulic gradient of groundwater surface, and length of contact line with downstream block. With significance probabilities (or p-values) of 0.05 and below, all five models showed significant results in estimating the water circulation status such as the surface runoff rate and the evapotranspiration rate. The model that was applied all seven urban characteristics factors, can calculate the most similar results such as the existing water circulation model. The water circulation estimation model developed in this study is not only useful to simply estimate the water circulation status of ungauged watersheds but can also provide data for parameter calibration and validation.

Impact Assessment of Agricultural Reservoir and Landuse Changes on Water Circulation in Watershed (농업용 저수지와 토지이용변화가 유역 물순환에 미치는 영향 평가)

  • Kim, Seokhyeon;Song, Jung-Hun;Hwang, Soonho;Kang, Moon Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.63 no.2
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    • pp.1-10
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    • 2021
  • Agricultural reservoirs have a great influence on the water circulation in the watershed. It is necessary to evaluate the impact on water circulation by the agricultural reservoir. Therefore, in this study, we simulated the agricultural watershed through linkage of Hydrological Simulation Program Fortran (HSPF) and Module-based hydrologic Analysis for Agricultural watershed (MASA) and evaluated the contribution of the agricultural reservoir to water circulation by watershed water circulation index. As a result of simulating the Idong reservoir watershed through the HSPF-MASA linkage model, the model performance during the validation period was R2 0.74 upstream, 0.78 downstream, and 0.76 reservoir water level, respectively. To evaluate the contribution of agricultural reservoirs, three scenarios (baseline, present state, and present state without reservoir) were simulated, and the water balance differences for each scenario were analyzed. In the evaluation through the agricultural water circulation rate in the watershed, it was found that the water circulation rate increased by 1.1%, and the direct flow rate decreased by 13.6 mm due to the agricultural reservoir. In the evaluation through the Budyko curve, the evaporation index increased by 0.01. Agricultural reservoirs reduce direct runoff and increase evapotranspiration, which has a positive effect on the water circulation.

Development of Agricultural Water Circulation Rate Considering Agricultural Reservoir and Irrigation District (농업용 저수지 및 관개지구를 고려한 농업유역 물순환율 개발)

  • Kim, Seokhyeon;Song, Jung-Hun;Hwang, Soonho;Kim, Hak-Gwan;Kang, Moon Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.62 no.2
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    • pp.83-95
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    • 2020
  • The water circulation in agricultural watersheds changes with the operation of agricultural reservoirs, it is necessary to classify and evaluate them into upstream, agricultural reservoirs, irrigation districts, and downstream. Therefore, in this study, we developed the agricultural water circulation rate (AWCR) considering an agricultural reservoir and irrigation district by improving the water circulation rate of the Water environmental conservation Act. we applied it to Jinwi watershed using the module-based hydrologic analysis system to simulate the water circulation for agricultural reservoirs and irrigation areas. The model performance during the validation period was NSE of 0.762 for the downstream stream and 0.682 for the reservoir level. And the hydrograph separation model was applied to separate the direct and baseflow. As a result of this study, The AWCR of Jinwi watershed was 71.8% on average, which was higher than the water circulation rate estimated by the downstream hydrograph separation.

The Effect of Flow Induction Machine in Water Circulation System of Cheongna Canal Way (청라지구 물순환체계내 주운수로의 흐름유발시설 설치효과)

  • Kim, Dong-Eon;Choi, Gye-Woon;Park, Young-Sik;Yoon, Geun-Ho
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.77-81
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    • 2010
  • This study carried out hydraulic model test for water circulation system in Cheongna district as part of Incheon Free Economic Zone. Canal way project of Cheongna was planned to establish for environment-friendly water circulation system, improve quality of life and diversification of traffic through using boat as a water-friendly international business city. The navigation canal, There are two intake facility in central park and it can purify water 15,000$m^3$ per day. After purify, water move to 8 facility of water culture area which supplies water in canal way. This process called water circulation system in cheongna. Also, there are several flow induction machine in canal way except south-north way. Therefore, this study will verify about validity of water circulation system's safety through hydraulic model test.

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A Study on Anti-Icing Technique for Ballast Water of Icebreaking Vessels Operating in Ice-Covered Water (극지운항용 빙해선박의 밸러스트 수 결빙방지 기법 연구)

  • Jeong, Seong-Yeob;Lee, Chun-Ju;Cho, Seong-Rak
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.1
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    • pp.93-97
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    • 2011
  • When freezing is present on ballast water, it can impose additional loads on the hull and effect on stabilization of ship. The anti-icing techniques of ballast water, therefore, are key criteria for ship safety. The existing anti-icing techniques of ballast tank are hull heating, water circulation and air bubble system etc. In this research, anti-icing performance tests for the ballast water using micro-bubble system and sea water circulation system have been carried out at two temperature conditions($-10^{\circ}C$ and $-25^{\circ}C$). Ambient temperature, sea water temperature and temperature of the inner parts of the ballast tank are measured and also ballast water conditions are checked during the model test. The applied anti-icing techniques of ballast water, such as micro-bubble system and sea water circulation system show good performance in the low temperature conditions.

One-Dimensional Analysis of Air-Water Two Phase Natural Circulation Flow (공기와 물의 이상 자연순환 유동의 1 차원 해석)

  • Park, Rae-Joon;Ha, Kwang-Soon;Kim, Jae-Cheol;Hong, Seong-Wan;Kim, Sang-Baik
    • Proceedings of the KSME Conference
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    • pp.2626-2631
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    • 2007
  • Air-water two phase natural circulation flow in the T-HERMES (Thermo-Hydraulic Evaluation of Reactor cooling Mechanism by External Self-induced flow)-1D experiment has been evaluated to verify and evaluate the experimental results by using the RELAP5/MOD3 computer code. The RELAP5 results have shown that an increase in the coolant inlet area leads to an increase in the water circulation mass flow rate. However, the water outlet area does not effective on the water circulation mass flow rate. As the coolant outlet moves to a lower position, the water circulation mass flow rate decreases. The water level is not effective on the water circulation mass flow rate. As the height increases in the air injection part, the void fraction increases. However, the void fraction in the upper part of the air injector maintains a constant value. An increase in the air injection mass flow rate leads to an increase in the local void fraction, but it is not effective on the local pressure.

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Performance Evaluation of Water Circulation Facilities with Infiltration and Retention Functions (침투 및 저류 기능을 가진 물 순환 시설의 효과 평가)

  • Hong, Jung Sun;Maniquiz-Redillas, Marla C.;Kim, Ree Ho;Lee, Seon Ha;Kim, Lee-Hyung
    • Ecology and Resilient Infrastructure
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    • v.2 no.4
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    • pp.305-310
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    • 2015
  • In 2014, the city of Seoul revised the ordinance regarding water-cycle restoration in the Seoul Metropolitan areas by incorporating the 'Low Impact Development (LID)' policy. The new ordinance plan will utilize 630 mm or almost 45 to 50% of annual rainfall until 2050 by means of providing a rainwater management system consisting of infiltration, retention and vegetation. The LID is believed to be the key to achieving the target requirements, specifically in development projects. This research was performed to evaluate the stormwater runoff and pollutant reduction performance of three different LID facilities (water circulation facilities) including an infiltration inlet, bioretention swale, and permeable pavement constructed in Seoul City. Results show that among the water circulation facilities, the permeable pavement achieved the highest runoff reduction as it was able to entirely capture and infiltrate the runoff to the ground. However, in order to attain a long-term performance it is necessary to manage the accumulated sediment and trapped pollutants in the landscape areas through other water circulation techniques such as through soil erosion control. In terms of pollutant reduction capability, the infiltration inlet performed well since it was applied in highly polluted areas. The bioretention facility integrating the physico-chemical and biological mechanisms of soil, microorganisms and plants were able to also achieve a high runoff and pollutant reduction. The water circulation facilities provided not only benefits for water circulation but also various other benefits such as pollutant reduction, ecological restoration, and aesthetic functions.

An Experimental Study on Variable-Speed Control of an Ground-Water Circulation Pump for a Ground Source Multi-Heat Pump System (주거용 건물 지열원 멀티 히트펌프시스템의 지열순환펌프 가변유량제어에 관한 실증연구)

  • Song, Suwon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.8
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    • pp.443-449
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    • 2013
  • The purpose of this study is to propose an enhanced variable-speed control method of ground-water circulation pumps using inlet and outlet ground-water temperature difference and analyze its effect for the ground source multi-heat pump system installed in a single-family house. As a result, it has shown to significantly reduce the electricity use of ground-water circulation pump and improve overall system Coefficient of Performance (COP) due to the proposed variable-speed control under partial load conditions after oversized and inefficient single-speed pump retrofit.

A Study on Substrate Stage Temperature (기판스테이지 온도에 관한 연구)

  • Kim, Sun-Ki;Lee, Woo-Young;Kang, Heung-Suk
    • Journal of the Semiconductor & Display Technology
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    • v.5 no.4
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    • pp.35-40
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    • 2006
  • This paper shows that the effect of exposing on the top area and a solution which using a water circulation system. Semiconductor substrate stage is made from Aluminum and is repeated the sequence of exposing (150), turning OFF shutter, taking 30 sec. interval at the top area of stage. So the temperature of substrate temperature rises continuously. On this, we made a waterway at the inner part of the substrate stage and operated a water circulation system. We measured the temperature of a substrate stage surface with a thermocouple attached to the substrate stage. To analyze the top area's temperature, we used Analysis Program ANSYS for analysis and 3D CAD program Solid-Works for modeling.

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