• 연구논문집
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• s.30
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• pp.15-23
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• 2000

In this study, develop the thermal pump using water evaporation and condensation. Vapor from heating room moves up to pumping room and press the water of pumping room. Consequently water is pumped out to water tank. Then hot vapor direct contact with cold water in condensing room after pumping process. At this time, pressure of condensing room is down to-5kPa and suck in water of tank. This pump executes self ping and good durability because of no mechanical moving parts. Thermal pump is pumped cyclic so that, this pump is not used single. Therefore thermal pump of hot water boiler used to multi-stage for stable pumping rate. As the result of performance test, the developed thermal pump proves pumping action of water evaporation/condensation. And total volume flow rate is 500liter during one hour. If three thermal pump is installed parallel, this pump can use to the hot water boiler in the 300,000kcal/h class.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.503-508
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• 2004

Optimal remediation design using the pump and treat(P&T) method and natural attenuation was accomplished in consideration for degradation processes, such as sorption and first-order decay rate. Variation of both sorption and first-order decay rate has influence on design of optimal remediation application. When sorption effect increases, the more pumping rate and pumping wells are required. The location of operated wells is on the centerline of contaminant plume and wells near hot spot are mainly operated when sorption effect increases. The higher of first-order decay rate, the less pumping rate is required. These results show that the degradation processes have to be considered as one of the essential factors for optimal remediation design.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.75-85
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• 2016

Large scale constructions needs to estimate a possibility for pumping concrete. In this paper, the state of the art on prediction of concrete pumping including analytical and experimental works is presented. The existing methods to measure the rheological properties of slip layer (or called lubricating layer) are first introduced. Second, based on the rheological properties of slip layer and parent concrete, models to predict concrete pumping (flow rate, pumping pressure, and pumpable distance) are explained. Third, influencing factors on concrete pumping are discussed with the test results of various concrete mixes. Finally, future need for research on concrete pumping is suggested.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.41-49
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• 2010

Return flow rate of irrigation water was estimated by water balance method. Daepyeong pumping district to irrigate 75.8 ha of rice paddy in the Geum river basin was selected to install gauging instruments to collect data such as weather, water levels, infiltration rate and evapotranspiration during irrigation season (May 27 to Sept. 20) in 2003 and 2004. Irrigation and drainage discharge were calculated from the rating curve and evapotranspiration was estimated both by the modified Penman formula and by the lysimeter. The results were as followed : 1. Total amounts of pumping water during irrigation season were $1,076,000\;m^3$ in 2003 and $1,848,000\;m^3$ in 2004. Total amounts of rainfall were 1336.0mm and 1003.0mm respectively during the irrigation season in 2003 and 2004. 2. It was surveyed that the amount of infiltration was 196.5 mm (2.2 mm/day). The gauged evapotranspiration was 311.0 mm (3.5 mm/day) and the calculated evapotranspiration was 346.0 mm (3.9 mm/day) during irrigation period in 2003. It was surveyed that the amount of infiltration was 169.9 mm (2.4 mm/day). The amount of gauged evapotranspiration was 377.3 mm (5.3 mm/day) and the calculated evapotranspiration was 454.5 mm (6.6 mm/day) during irrigation period in 2004. 3. The rates of quick and delayed return flow were 52.4 % and 17.7 % respectively, and so return flow rate was 70.1 % in 2003. The rates of quick and delayed return flow were 45.4 % and 16.1 % respectively, and so return flow rate was 61.5 % in 2004. It means that average return flow rate in the Daepyeong pumping district was assumed to be 65 %.

• Progress in Superconductivity and Cryogenics
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• v.24 no.4
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• pp.65-70
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• 2022

A vacuum system is designed for thermal insulation of a 10 ton/day class air liquefaction cold box for liquid air energy storage. The vacuum system is composed of a turbomolecular pump, a backing pump and vacuum piping for the vacuum pumps. The turbomolecular pump is in combination with the backing pump for pumping capacity. The vacuum piping is designed with system installation conditions, such as distance from the cold box, connections to vacuum pumps and installation space. The capacity of the vacuum pump combination, namely pumping speed, is determined by analysis of the vacuum system, and pump-down time to 1×10^-5 mbar is estimated. Vacuum piping conductance, system pumping speed and outgassing rate are calculated for the pump-down time with the ultimate pumping speed range of the vacuum pump combination of 1400 - 2300 l/s. Although the pump-down time gets shorter by larger capacity vacuum pumps, it mainly depends on target vacuum degree and outgassing rate in the cold box. The pump-down time is estimated as 3 - 6 hours appropriate for cold box operation for the pumping speed range. Considering the outgassing rate has uncertainty, the vacuum pump combination with pumping speed of 1900 l/s is chosen for the vacuum system, which is middle value of the pumping speed range.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.450-450
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• 2022

The study aims to develop scenarios for efficient groundwater use using existing wells in order to prepare for an eventual drought. In the recent decades, droughts are not only intensifying, but they are also spreading into territories where droughts used to be less intense and relatively infrequent. With the increasing disaster, efficient groundwater use is urgently needed not only to prevent the problem of groundwater depletion but also drought risk reduction. Thus, the research addressed the problem of efficient aquifer use as source of water during drought and emergencies. The research focused on well network system applied to Yanggok-ri in Korea using simulation models in visual MODFLOW. The approach consists to variate groundwater pumping rate in the most important wells used for irrigation across the study area and evaluate the pumping effect on water level fluctuation. From the evaluation, the pumping period, appropriate pumping rate of each well and the most vulnerable wells are determined for a better groundwater management. The project results divide the study area into two different regions (A and B), where the wells in the region A (western part of the region) show a crucial drop in water level from May to early July and in august as consequence of water pumping. While wells in region B are also showing a drawdown in groundwater level but relatively less compare to region A. The project suggests a scenarios of wells which should operate considering water demand, groundwater level depletion and daily pumping rate. Well Network System in relevant project, by pumping in another well where water is more abundant and keep the fixed storage in region A, is a measure to improve preparedness to reduce eventual disaster. The improving preparedness measure from the project, indicates its implication to better groundwater management.

• Journal of the Korea Institute of Building Construction
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• v.15 no.3
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• pp.291-297
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• 2015

In this study, the evaluation and the analysis of the correlation between rheological properties and pumpability of high performance concrete, C80A which was applied to the height of from 200 m to 350 m in a super tall building, was carried out by measuring pumping pressure and flow rate, testing concrete properties at before and after pumping. As the results, C80A had satisfactory properties of fresh and hardened concrete to the requirements even after pumping and the maximum pumping pressure showed increase of 10~15% at every 50m higher pumping and the average flow rate showed the above $25m^3$ per hour which means proper productivity. Additionally it was verified that pumping pressure and friction factor in pipeline are inversely proportional to slump flow and showed a tendency to increase according to the higher T-500 value.

• Journal of Korea Water Resources Association
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• v.32 no.3
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• pp.301-310
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• 1999

In this paper a numerical model and two analytical models in the hydraulically connected stream-aquifer system were analyzed to compare the induced infiltration rate curves derived from each model. And we also examined the effects of anisotropy of hydraulic conductivity and the direction of the ambient ground water flow on the quantification of the induced infiltration rate. The induced infiltration rate curve determined by models is very simple and useful for estimating the induced infiltration rate since it contains only four physical variables such as the induced infiltration rate, the pumping rate, the distance between the pumping well and the stream, and the ambient ground water flow rate. Under the conditions tested in this paper the induced infiltration rate curves resulted from the Wilson's analytical model and FEWA numerical model were in good agreement, and the anisotropic ratio of hydraulic conductivity was evaluated as a physical factor which influences the behaviour of the induced infiltration rate curve. The methods and results of the paper might Icad to improve the understanding of the induced infiltration phenomenon and can be applied to the planning and disign of pumping well and the optimal determination of the induced infiltration rate and pumping rate for water quality management of the water supply wells.

• Journal of Korea Water Resources Association
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• v.48 no.7
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• pp.545-552
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• 2015

The objective of this study is to spatially assess the streamflow depletion due to groundwater pumping near the main stream of Juksanchoen watershed. The surface water and groundwater integrated model, SWAT-MODFLOW, in this study, was used to simulate streamflow responses to each groundwater pumping from wells located within 500m from the stream. The simulated results showed that the streamflow depletion rate divided by the pumping rate for each well location ranges from 20% to 96%. In particular, the streamflow depletion exceeds 60% of pumping rate if the distance between stream and well is lower than 100 m, hydraulic diffusivity is higher than $500m^2/d$, and streambed hydraulic conductance is above 25m/d. The simulated results were also presented in the form of spatial distribution maps that indicate the fraction of the well pumping rate in order to show the effect of a single well more comprehensively and easily. From the developed areal distribution of stream depletion, higher and more rapid responses to pumping occur near middle-downstream reach, and the spatially averaged percent depletion is about 66.7% for five years of pumping. The streamflow depletion map can provide objective information for the near-stream groundwater permission and management.

• Journal of Soil and Groundwater Environment
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• v.19 no.3
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• pp.111-122
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• 2014

Partitioning interwell tracer test (PITT) is a method to quantify and qualify a site contaminated with NAPLs (Non-Aqueous Phase Liquids). Analytical description of PITT assumes that the injection-pumping well pair is on the line of the ambient groundwater flow direction, but the test-well pair could frequently be off the line in a real field site, which could be an erroneous factor in analyzing PITT data. The purpose of this work is to study the influence of the angle of the test-well pair on the ambient groundwater flow direction based on the result from PITT. From the experiments, it was found that the obliqueness of the test-well pair to the ambient groundwater flow direction could affect the tracer test resulting in a decreased NAPL estimation efficiency. In case of an oblique arrangement of the test-well pair to the ambient flow direction, it was found that the injection of a chase fluid could enhance the estimation efficiency. An increase of the pumping rate could enhance the recovery rate but it cannot be said that a high pumping rate can increase the test efficiency because a high pumping rate cannot give partitioning tracers enough time to partition into NAPLs. The results have a implication that because the arrangement of the test-well pair is a controlling factor in performing and interpreting PITT in the field in addition to the known factors such as heterogeneity and the source zone architecture, flow direction should be seriously considered in arranging test-well pair.