• Title/Summary/Keyword: Water-hydraulic test

Search Result 536, Processing Time 0.032 seconds

Effect of Hydraulic Property and Mixing Intensity of Flocculation Basin on Flocculation Efficiency in Water Treatment Plant (정수장 플록형성지의 수리학적 특성과 교반강도가 플록형성 효율에 미치는 영향)

  • Jung, Yong-Jun;Min, Kyung-Sok
    • Journal of Korean Society on Water Environment
    • /
    • v.21 no.3
    • /
    • pp.230-235
    • /
    • 2005
  • The main purpose of the flocculation process is to make flocs bigger to be removed easily in the following processes. The flow pattern and mixing intensity have a great influence on flocculation. In this study, the flow pattern was examined by a hydraulic tracer-test, where 3 water treatment plants having $800,000m^3/d$, $44,000m^3/d$ and $40,000m^3/d$ were employed. Also, the settling test was conducted to find out the relationship between the mixing intensity and the settling ability of flocs. The hydraulic tracer-test was conducted for the various flocculation processes that have different structures of flocculation basins. In the result, the retention time distribution (RTD) curves for the flocculation processes were quite different. In case of the inappropriate structure of the flocculation basin, the flow is not even so that the floc does not grow enough. To find out the relationship between mixing intensity and settleability of flocs, G-values were calculated and the settling test was conducted for two flocculation basins which have the same conditions except the G-value. For the flocculation basin with uneven G-value, the floc settleability was revealed poor. On the other hand, the flocculation basin with even G-value, the settleability was better than the previous one. From these experimental results, it is confirmed that the flow pattern is closely related to the structure of the flocculation basin and the settleability is affected by mixing intensity. Therefore the flow pattern and the strength of the mixing intensity should be examined sufficiently to design and operate flocculation basin.

Experiments on Tension Characteristics of Perforated-type Floating Breakwaters (유공형 부방파제의 장력특성에 관한 실험)

  • Yoon, Jae Seon;Ha, Taemin
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2017.05a
    • /
    • pp.514-514
    • /
    • 2017
  • Floating breakwaters were treated as solid bodies without any perforation in previous studies. In this study, however, a floating breakwater is perforated to allow the partial absorption of the energy produced by incident waves and an air chamber is placed in the upper part to control the breakwater draft. A series of laboratory experiments for a floating breakwater installed with a mooring system are carried out. In general, a mooring system can be classified by the number of mooring points, the shape of the mooring lines, and the degree of line tension. In this study, a four-point mooring is employed since it is relatively easier to analyze the measured results. Furthermore, both the tension-leg and the catenary mooring systems have been adopted to compare the performance of the system. In laboratory experiments, the hydraulic characteristics of a floating breakwater were obtained and analyzed in detail. Also, a hydraulic model test was carried out on variable changes by changing the mooring angle and thickness of perforated wall. A hydraulic model was designed to produce wave energy by generating a vortex with the existing reflection method. Analysis on wave changes was conducted and the flow field around the floating breakwater and draft area, which have elastic behavior, was collected using the PIV system. From the test results the strong vortex was identified in the draft area of the perforated both-sides-type floating breakwater. Also, the wave control performance of the floating breakwater was improved due to the vortex produced as the tension in the mooring line decreased.

  • PDF

A Fundamental Study on the Waste Polyethylene Chips Mixed with Soil (폐비닐 골재 혼합토의 기본 성질에 관한 연구)

  • 김영진;김현민
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.03b
    • /
    • pp.548-555
    • /
    • 2000
  • It was investigated whether the waste polyethylene chips can be recycled as construction materials in geotechnical engineering field. The standard Proctor test, the hydraulic conductivity test, the large box direct shear test, the thermal conductivity test, the frost heaving test and the time domain reflectometry test were performed on weathered granite soil mixed with variable amount of the waste polyethylene chips. The experimental results showed that the hydraulic conductivity and the shear strength of weathered granite soil increase with increasing the amount of the waste polyethylene chips. On the other hand, the thermal conductivity, the amount of frost heaving and the unfrozen water contents of weathered granite soil decrease with increasing the amount of the waste polyethylene chips.

  • PDF

Integral effect tests for intermediate and small break loss-of-coolant accidents with passive emergency core cooling system

  • Byoung-Uhn Bae;Seok Cho;Jae Bong Lee;Yu-Sun Park;Jongrok Kim;Kyoung-Ho Kang
    • Nuclear Engineering and Technology
    • /
    • v.55 no.7
    • /
    • pp.2438-2446
    • /
    • 2023
  • To cool down a nuclear reactor core and prevent the fuel damage without a pump-driven active component during any anticipated accident, the passive emergency core cooling system (PECCS) was designed and adopted in an advanced light water reactor, i-POWER. In this study, for a validation of the cooling capability of PECCS, thermal-hydraulic integral effect tests were performed with the ATLAS facility by simulating intermediate and small break loss-of-coolant accidents (IBLOCA and SBLOCA). The test result showed that PECCS could effectively depressurize the reactor coolant system by supplying the safety injection water from the safety injection tanks (SITs). The result pointed out that the safety injection from IRWST should have been activated earlier to inhibit the excessive core heat-up. The sequence of the PECCS injection and the major thermal hydraulic transient during the SBLOCA transient was similar to the result of the IBLOCA test with the equivalent PECCS condition. The test data can be used to evaluate the capability of thermal hydraulic safety analysis codes in predicting IBLOCA and SBLOCA transients under an operation of passive safety system.

A Study on the Effect of the Inclined Structure on the Hydraulic Behavior Index within Sedimentation basin (경사 구조물이 침전지내 수리거동 Index에 미치는 영향)

  • Lim, Seong-Ho;Hwang, Jun-Sik;Park, No-Suk;Kim, Seong-Su;Lim, Kyung-Ho
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.23 no.5
    • /
    • pp.517-526
    • /
    • 2009
  • This research has been conducted to investigate the characteristics of hydraulic behavior within the PAC contactor, the rectangular shape sedimentation basin without inclined tube and the other one with inclined tube those are parts of demonstration plants(capacity : $2,000m^3/d$) in Korea Institute of Water and Environment. As results of tracer tests, the flow within PAC contactor was evaluated to divided into plug flow and dead space distinctly, and characteristics of dead space was close to that of CSTR(Complete/continuous Stirred Tank Reactor). Also, considering Reynolds number, Froude number, Morill, Modal, NCSTR Inex and plug flow/mixed flow fraction, in the case of the rectangular shape sedimentation basin without inclined tube, the characteristics of flow pattern was close to CSTR. On the other hand, in the case of the basin with inclined tube, the region of CSTR decreased precisely compared with the case of no-tube. Until now we have recognized that the inclined hydraulic structure just reduces the surface loading rate within a sedimentation basin. Actually besides, the inclined structure have an important effect on the hydraulic behavior within the basin.

해안매립지에서의 추적자시험 및 수위변화특성 연구

  • 이진용;황대규;이명재;최예권;김정우;이강근
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
    • /
    • 2002.04a
    • /
    • pp.221-224
    • /
    • 2002
  • To demonstrate prevention of the leachate leakage out of the landfill with creating inward hydraulic gradient, a tracer test and continuous waterlevel monitoring at the Inside and outside of the barrier wall of a costal landfill were peformed. When the tracers were injected into the well outside of the vertical wall system with high water level, then they were detected at the well inside of the system with low water level. Furthermore the lowered water level at the inside of the landfill than that at the outside prevented leachate leakage out of the landfill. This study reports results of the tracer test and waterlevel monitoring.

  • PDF

Assessment of Hydraulic Conductivity of Modified Bentonite and Local Soil Mixture under Salt Water Condition (개량 벤토나이트와 현장토 혼합 차수층의 염수조건하에서의 투수성 평가)

  • Xu, Xin;Oh, Myounghak;Park, Junboum
    • Journal of the Korean Geotechnical Society
    • /
    • v.33 no.11
    • /
    • pp.97-104
    • /
    • 2017
  • A bentonite mixing with local soil widely used as liner layer for landfill should have low permeability less than $1{\times}10^{-7}cm/s$. But there are several limitations of bentonite used as liner layer, such as drying shrinkage cracking, ineffective waterproof ability under salt water condition like flocculation under sea water. The purpose of this research is the development of a salt resistance bentonite by mixing sepiolite and guar gum to overcome the weak points of bentonite to get high water resistance capacity and permeability coefficient below $1{\times}10^{-7}cm/s$ under salt water condition. After having performed drying shrinkage cracking test, swelling index test, compaction test, and hydraulic conductivity test we confirmed the optimal mixing ratio of materials and evaluated the performance of materials.

Chemical Compatibility of Solidified Liner Materials (매립장 고화차수재의 화학용액과의 반응특성)

  • 정하익;조진우;임재상;김상길
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2002.03a
    • /
    • pp.343-346
    • /
    • 2002
  • The chemical compatibility of leachate with the two natural materials was analyzed by performing the hydraulic conductivity test. The selected liner materials were natural marine clay and weathered soil sampled from Kimpo wastefill and Daehwa Dong, Kyonggi Do, respectively. PARAFIX, which is mainly composed of paraffin, cement, stearic acid, PVA etc., was used as solidifying agent. The chemical solutions used in the test were 10% acetic acid, 10% methanol, and real leachate from Kimpo wastefill and the results of tests were compared with that of distilled water. The results of tests show that hydraulic conductivity of solidified clay was increased slightly with permeation of acetic acid, methanol and the increase of hydraulic conductivity was not shown with permeation of leachate, distilled water and in case of weathered soil. Based on the tests, it is ascertained that the tested liner materials can be stable with the solution of low concentration.

  • PDF

A Comparative Study on the Impermeability-reinforcement Performance of Old Reservoir from Injection and Deep Mixing Method through Laboratory Model Test (실내모형시험을 통한 지반혼합 및 주입공법의 노후저수지 차수 보강성능 비교 연구)

  • Song, Sang-Huwon
    • Journal of the Korean Institute of Rural Architecture
    • /
    • v.24 no.2
    • /
    • pp.45-52
    • /
    • 2022
  • Of the 17,106 domestic reservoirs(as of December 2020), 14,611 are older than 50 years, and these old reservoirs will gradually increase over time. The injection grouting method is most applied to the reinforcement method of the aging reservoir. However, the injection grouting method is not accurate in uniformity and reinforced area. An laboratory model test was conducted to evaluate the applicability of the deep mixing method, which compensated for these shortcomings, as a reservoir reinforcement method. As a result of calculating the hydraulic conductiveity for each method through the model test results, the injection grouting method was calculated as a hydraulic conductiveity value that was about 7.5 times larger than that of the deep mixing method. As a result of measuring the water level change in the laboratory model test, it was found that the water level change decreased in the injection method and deep mixing method compared to the non-reinforcement method. In addition, deep mixing method showed a water level change of about 15% based on 40 hours compared to the injection method, indicating that the water-reducing effect was superior to that of the injection method.

Evaluation of Hydraulic Conductivity of Bentonite Filter Cake Using Modified Fluid Loss Test

  • Nguyen, The Bao;Lee, Chul-Ho;Yang, Jung-Hun;Choi, Hang-Seok
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2008.10a
    • /
    • pp.498-507
    • /
    • 2008
  • The mixture of bentonite powder and water is generally used to maintain the stability of excavation surface during the construction of vertical cutoff walls. The filter cake on the sidewall surface is the result of filtration of slurry into the adjacent soil formation. The filter cake is believed to have a very low hydraulic conductivity compared to that of the cutoff wall. This paper evaluates hydraulic conductivities of bentonite filter cakes set up with three types of bentonites under various pressure levels. A modified fluid loss test was employed in this experiment. Theory of filtration process was reviewed to explain the procedure in the present experiment. Hydraulic conductivity of the filter cakes with consideration of the filter medium resistance was evaluated. The results of the experiment with two calculation methods and discussion are presented to show the efficiency of the modified fluid loss test.

  • PDF