• Title/Summary/Keyword: water pipe

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Integrated Expansion Analysis of Pipe-In-Pipe Systems

  • Choi, Han-Suk;Do Chang-Ho
    • Journal of Ocean Engineering and Technology
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    • v.20 no.5 s.72
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    • pp.9-14
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    • 2006
  • This paper presents an analytical method, application of expansion, mechanical design, and integrated expansion design of subsea insulated pipe-in-pipe (PIP) systems. PIP system consists of a flowline and a casing pipe for the transport of high temperature and high pressure product from the subsea wells. To prevent heat lass from the fiowline, insulation material is applied between the pipes. The fiawline pipe and the casing pipe have mechanical connections through steel ring plate (water stops) and bulkheads. Pipeline expansion is defined by temperature, internal pressure, soil resistance, and interaction force between the flowline and the casing pipe. The results of the expansion analysis, the mechanical design of connection system of the two pipes and tie-in spool design are integrated for the whole PIP system.

Three-dimensional modelling of water flow due to leakage from pressurized buried pipe

  • Zhu, Hong;Zhang, Limin;Chen, Chen;Chan, Kit
    • Geomechanics and Engineering
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    • v.16 no.4
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    • pp.423-433
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    • 2018
  • A three-dimensional model is constructed to simulate water infiltration in an unsaturated slope from a leaking pipe. Adaptive mesh refinement and time stepping are used, assisted by an automatic procedure for progressive steepening of the hydraulic property function for better convergence. The model is justified by comparing the simulated results with experimental data. Steady-state flow is investigated considering various pipe water pressures, locations and sizes of the opening, and soil layering. The opening size significantly affects the soaked zone around the pipe. Preferential flow dominates along the pipe longitudinal direction in the presence of a loose backfill around the pipe.

Influence of Pipe Materials and VBNC Cells on Culturable Bacteria in a Chlorinated Drinking Water Model System

  • Lee, Dong-Geun;Park, Seong-Joo;Kim, Sang-Jong
    • Journal of Microbiology and Biotechnology
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    • v.17 no.9
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    • pp.1558-1562
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    • 2007
  • To elucidate the influence of pipe materials on the VBNC (viable but nonculturable) state and bacterial numbers in drinking water, biofilm and effluent from stainless steel, galvanized iron, and polyvinyl chloride pipe wafers were analyzed. Although no HPC (heterotrophic plate count) was detected in the chlorinated influent of the model system, a DVC (direct viable count) still existed in the range between 3- and 4-log cells/ml. Significantly high numbers of HPC and DVC were found both in biofilm and in the effluent of the model system. The pipe material, exposure time, and the season were all relevant to the concentrations of VBNC and HPC bacteria detected. These findings indicate the importance of determining the number of VBNC cells and the type of pipe materials to estimate the HPC concentration in water distribution systems and thus the need of determining a DVC in evaluating disinfection efficiency.

Evaluation of Pressurized Water Diffusion in Water Treatment Process Using CFD (전산유체역학(CFD)를 활용한 정수공정에서 압력수 확산공정 진단)

  • Cho, Young-Man;Yoo, Soo-Jeon;Roh, Jae-Soon;Bin, Jae-Hoon;Choe, Kwang-Ju;Lee, Kwang-Ug;Lee, Gi-Bong;Lee, Jeong-Gyu
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.5
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    • pp.359-367
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    • 2011
  • The Process of Pressurized water diffusion is mixing process by pressurized water injection with coagulate and chlorine water in the water treatment system. The objectives of this research were to evaluate the mixing length and diameter of diffusion plate and distance from injection pipe for complete mixing by using computational fluid dynamics. From the results of CFD simulation, when diameter of injection pipe is 50 mm, 100 mm and injection pressure is $5kg/cm^2$ and the diameter of inlet pipe is 2,200 mm, the complete mixing length is 4D (D: Length as diameter of inlet pipe). When diameter of injection pipe is 50 mm, the diameter of the diffusion plate in o.1D and distance from injection pipe is 0.2D, the complete mixing length is 3D that is the most short mixing length. But when diameter of injection pipe is 100 mm and mutually related the diameter, distance of diffusion plate, the complete mixing length is 4D over. Therefore, as the diameter of inlet pipe is 2,200 mm, the injection pipe 50 mm is more efficient than 100 mm.

Study on the possible application of Vibrated and Rolled reinforced concrete pipe to vertical.crossing water distribution system (진동 및 전압 철근 콘크리트관의 종.횡단배수관 적용성 검토에 관한 연구)

  • Park Do-Kyong;Lee Myung-Kue;Yang Keek-Young
    • Journal of the Korea Institute of Building Construction
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    • v.6 no.2 s.20
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    • pp.111-117
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    • 2006
  • In case of carrying out vortical crossing water distribution system in expressways or general roads construction, VR(Vibrated and Rolled reinforced concrete) pipes are restricted because of their specification of reinforced spun concrete pipe or on-site made pipe. Therefore, in order to apply VR pipes to those constructions, through the structural behavior experiments of the pipes, VR pipes are compared and verified with reinforced spun concrete pipe and the results are obtained as the following. From the experiments and analyses of Pipe Stiffness(PS) of the pipes, cracking loading is approved to satisfy the KS regulations. Through a direct load test, the cracking loading strength and the maximum load test of VR pipe is larger compared with reinforced spun concrete pipe. Particularly, even if side weld is thin, there is no little change in the cracking strength of VR pipe. The results of the direct load test analysis show that the structural behavior of VR pipe is equivalent or higher compared with reinforced spun concrete pipe in performance and VR pipe could be used as the water distribution pipe for roads. In this study, through pipe stiffness, direct load test and load teat on earth, reinforced spun concrete pipe and VR pipe are compared. And as a result, the structural behavior of VR pipe is comprehensively excellent. From the structural behavior tests, VR pipe's section shows more thickness and has uniform characteristics so that VR pipe is considered more favorable than reinforced spun concrete pipe.

INVESTIGATION ON EFFECTS OF ENLARGED PIPE RUPTURE SIZE AND AIR PENETRATION TIMING IN REAL-SCALE EXPERIMENT OF SIPHON BREAKER

  • Kang, Soon Ho;Lee, Kwon-Yeong;Lee, Gi Cheol;Kim, Seong Hoon;Chi, Dae Young;Seo, Kyoungwoo;Yoon, Juhyeon;Kim, Moo Hwan;Park, Hyun Sun
    • Nuclear Engineering and Technology
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    • v.46 no.6
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    • pp.817-824
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    • 2014
  • To ensure the safety of research reactors, the water level must be maintained above the required height. When a pipe ruptures, the siphon phenomenon causes continuous loss of coolant until the hydraulic head is removed. To protect the reactor core from this kind of accident, a siphon breaker has been suggested as a passive safety device. This study mainly focused on two variables: the size of the pipe rupture and the timing of air entrainment. In this study, the size of the pipe rupture was increased to the guillotine break case. There was a region in which a larger pipe rupture did not need a larger siphon breaker, and the water flow rate was related to the size of the pipe rupture and affected the residual water quantity. The timing of air entrainment was predicted to influence residual water level. However, the residual water level was not affected by the timing of air entrainment. The experimental cases, which showed the characteristic of partical sweep-out mode in the separation of siphon breaking phenomenon [2], showed almost same trend of physical properties.

The Replacement Plans for Aged Public Water Supply Pipes in Apartment Buildings : Especially Apartment Buildings in Bucheon (공동주택의 노후 급수관 개선방안에 관한 연구 : 부천시 공동주택을 중심으로)

  • Lee, Yong-Hwa;Heo, Yong-Chul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.4
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    • pp.228-232
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    • 2015
  • The water supply galvanized steel pipes of apartment buildings in Bucheon city constructed with building permission before 1994 have many problems such as leaks, the water containing rust, and low water pressure due to corrosion. Therefore, this study aims to find a way to renew the water supply pipes under investigation through a survey. As a result, when replacing the galvanized steel pipe with the corrosion-resistant pipe, the water supply system should also be changed from the gravity tank system to the booster pump system and the hygienic water storage tank. It is necessary to redraft the long-term repair plan including the replacement of the water supply system. Also, it is necessary to save the allowance reserve according to the modified long-term repair plan.

A Study of Design factors for Increasing Energy Production in Small Hydro power with Using Long Pipe (장대관로를 이용한 소수력 발전량 향상을 위한 설계요소에 관한 연구)

  • Kim, Hyun-Han;Kim, Kwang-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.8
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    • pp.1134-1139
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    • 2014
  • Recently the need for renewable energy development is expanding due to the global climate change, the environmental issues and the limited fossil energy resources. Dependence of energy on overseas is high in Korea. To resolve the environmental problems and to improve the energy independence rate, the development of renewable energy is more required. The small hydro power, one of the renewable energy resources, has been developing and operating from a long time ago. If we are new developing a small hydro power with the use existing dams and reservoirs, we will design the length of inlet pipe and the diameter suitable for it. However, in case of using the existing water supply pipe which had been designed suitable for water service, the designer has to review and check that the pipe is suitable for operating a generator. In this paper, the design of small hydro power using the existing long pipe of water supply, we suggest the optimum way to reduce the water hammer in pipe which causes the unsteady flow during the load-shutdown of generator, the generator operation plan for the stable supply of water and the design factor of determining the generator capacity through the analysis between discharge and head-loss.

Development of the Computational Model to Evaluate Integrated Reliability in Water Distribution Network (상수관망의 통합신뢰도 산정을 위한 해석모형의 개발)

  • Park, Jae-Hong;Han, Kun-Yeon
    • Journal of Korea Water Resources Association
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    • v.36 no.1
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    • pp.105-115
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    • 2003
  • The computation model which evaluates combined hydraulic and mechanical reliability, is developed to analyze the integrated reliability in water distribution system. The hydraulic reliability is calculated by considering uncertain variables like water demand, hydraulic pressure, pipe roughness as random variables according to proper distribution type. The mechanical reliability is evaluated by analyzing the effect of pipe network with sequential failure of network components. The result of this study model applied to the real pipe network shows that this model can be used to simulate the uncertain factors effectively in real pipe network. Therefore, The pipe-line engineers can design and manage the network system with more quantitative reliability, through applying this model to reliable pipe network design and diagnosis of existing systems.

Non-invasive acceleration-based methodology for damage detection and assessment of water distribution system

  • Shinozuka, Masanobu;Chou, Pai H.;Kim, Sehwan;Kim, Hong Rok;Karmakar, Debasis;Fei, Lu
    • Smart Structures and Systems
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    • v.6 no.5_6
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    • pp.545-559
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    • 2010
  • This paper presents the results of a pilot study and verification of a concept of a novel methodology for damage detection and assessment of water distribution system. The unique feature of the proposed noninvasive methodology is the use of accelerometers installed on the pipe surface, instead of pressure sensors that are traditionally installed invasively. Experimental observations show that a sharp change in pressure is always accompanied by a sharp change of pipe surface acceleration at the corresponding locations along the pipe length. Therefore, water pressure-monitoring can be transformed into acceleration-monitoring of the pipe surface. The latter is a significantly more economical alternative due to the use of less expensive sensors such as MEMS (Micro-Electro-Mechanical Systems) or other acceleration sensors. In this scenario, monitoring is made for Maximum Pipe Acceleration Gradient (MPAG) rather than Maximum Water Head Gradient (MWHG). This paper presents the results of a small-scale laboratory experiment that serves as the proof of concept of the proposed technology. The ultimate goal of this study is to improve upon the existing SCADA (Supervisory Control And Data Acquisition) by integrating the proposed non-invasive monitoring techniques to ultimately develop the next generation SCADA system for water distribution systems.