Dynamic Propagation and Arrest of Buckles in Pipe-in-Pipe Systems

2002 ◽  
Author(s):  
Stelios Kyriakides ◽  
Theodoro A. Netto
Keyword(s):  
Collapse Pressure ◽  
Sea Floor ◽  
Pipe System ◽  
Recent Experimental Study ◽  
Dynamic Propagation ◽  
External Pressures ◽  
Buckle Propagation ◽  
Pipe Systems ◽  
Buckle Arrestors ◽  
Pressure Controlled

This paper deals with the problem of buckle propagation and arrest in pipe-in-pipe systems. A recent experimental study illustrated that if the geometric integrity of the carrier pipe is compromised, local collapse can result. In a pressure controlled environment such as that encountered in the sea, collapse will propagate dynamically usually collapsing both pipes. A new buckle arrestor consisting of a ring placed inside the annulus between the two pipes has been proposed. A methodology for designing such rings has been developed based on quasi-static buckle propagation and arrest experiments. Here we evaluate experimentally the adequacy of this design methodology under the more realistic case of dynamic buckle propagation. This is achieved by initiating collapse in a constant pressure environment similar to that encountered on the sea floor. The study involves first establishing the effect of the presence of the inner pipe on the velocity of buckles initiated at various external pressures ranging between the propagation pressure of the two-pipe system and the collapse pressure of the carrier pipe. Subsequently, the arresting efficiency of several internal ring buckle arrestors designed by the quasi-static criteria developed is established for buckles travelling at high velocities. Details of the experimental procedures used are presented along with the experimental results and discussion of their implications in practice.

scholarly journals Relining of pipe systems: conditions, benefits and application through case-study

2017 ◽  
Vol 19 (1) ◽  
pp. 7-14
Author(s):  
Victor Vladimirov ◽  
Thomas Simoner ◽  
Ioan Bica
Keyword(s):  
Urban Agglomerations ◽  
Pipe System ◽  
Diameter Pipe ◽  
Pipe Systems ◽  
The City

Abstract Relining is one of the best alternatives available today for pipe system rehabilitation. This trenchless solution is particularly interesting for urban agglomerations, as a smaller diameter pipe is pushed or pulled through the old pipeline. Relining creates a leak-tight “pipe within a pipe” system, which is as good as new in both structural and hydraulic terms. Relining can be performed with both circular and special, non-circular (NC) profiles. The latter is especially advantageous for the rehabilitation of old sewers, many of which were constructed in a variety of ovoid-like shapes. This paper presents the typical steps that are performed for pipeline rehabilitation with non-circular profiles, as well as an applied case study (a project implemented in the city of Würzburg in Germany).

scholarly journals Hydraulic simulation of perforated pipe systems feeding vertical flow constructed wetlands

2018 ◽  
Vol 77 (5) ◽  
pp. 1431-1440 ◽  
Author(s):  
Urte Paul ◽  
Christian Karpf ◽  
Thomas Schalk
Keyword(s):  
Constructed Wetlands ◽  
Goodness Of Fit ◽  
Hydraulic Modeling ◽  
Vertical Flow ◽  
Nsga Ii ◽  
Hydraulic Simulation ◽  
Pipe System ◽  
Vertical Flow Constructed Wetlands ◽  
Pipe Systems ◽  
Perforated Pipe

Abstract For successfully operating a vertical flow constructed wetland, the uniform distribution of wastewater on the surface of the soil filter is essential. In research, however, this aspect is often overlooked. This study presents a methodology for assessing discharge uniformity from perforated pipe systems via hydraulic modeling. First, the requirements and conditions for the simulation of perforated pipe systems are investigated and the model basics are explained. Then the whole process of model build-up, calibration, application and analysis is presented and discussed. The modeling is done by the software EPANET and supported by pressure measurements in the pipe system of a small wetland treating domestic sewage. A crucial factor in the modeling process is the choice of loss coefficients in dividing junctions. Different approaches for calculating such coefficients are compared. Model calibration is undertaken via the multicriterion optimization algorithm NSGA-II. By calibrating two parameters, a reasonable goodness of fit with the measured pressure values was achieved. Model results show that distribution uniformity of the pipe system in question is poor. An outlook on potential applications of hydraulic modeling of perforated pipe systems in vertical flow constructed wetlands is given.

Solar Load Ratio Parameters for a Passive Solar Heat Pipe System

2015 ◽  
Author(s):  
Logan S. Poteat ◽  
M. Keith Sharp
Keyword(s):  
Heat Pipe ◽  
Load Ratio ◽  
Building Design ◽  
Weather Data ◽  
Prediction Algorithm ◽  
Solar Heat ◽  
Pipe System ◽  
Thermal Network ◽  
Pipe Systems ◽  
Passive Solar

The Solar Load Ratio (SLR) method is a performance prediction algorithm for passive solar space heating systems developed at Los Alamos National Laboratory. Based on curve fits of detailed thermal simulations of buildings, the algorithm provides fast estimation of monthly solar savings fraction for direct gain, indirect gain (water wall and concrete wall) and sunspace systems of a range of designs. Parameters are not available for passive solar heat pipe systems, which are of the isolated gain type. While modern computers have increased the speed with which detailed simulations can be performed, the quick estimates generated by the SLR method are still useful for early building design comparisons and for educational purposes. With this in mind, the objective of this project was to develop SLR predictions for heat pipe systems, which use heat pipes for one-way transport of heat into the building. A previous thermal network was used to simulate the heat pipe system with Typical Meteorological Year (TMY3) weather data for 13 locations across the US, representing ranges of winter temperature and available sunshine. A range of (nonsolar) load-to-collector ratio LCR = 1–15 W/m2K was tested for each location. The thermal network, along with TMY3 data, provided monthly-average-daily absorbed solar radiation and building load to calculate SLR. Losses from the solar aperture in a heat pipe system are very low compared to conventional passive solar systems, thus the load-to-collector ratio of the solar aperture was neglected in these preliminary calculations. Likewise, nighttime insulation is unnecessary for a heat pipe system, and was not considered. An optimization routine was used to determine an exponential fit (the heart of the SLR method) to simulated monthly solar savings fraction (SSF) across all locations and LCR values. Accuracy of SSF predicted by SLR compared to the thermal network results was evaluated. The largest errors (up to 50%) occurred for months with small heating loads (< 80 K days), which inflated SSF. Limiting the optimization to the heating season (October to March), reduced the error in SSF to an average of 4.24% and a standard deviation of 5.87%. These results expand the applications of the SLR method to heat pipe systems, and allow building designers to use this method to estimate the thermal benefits of heat pipe systems along with conventional direct gain, indirect gain and sunspace systems.

Innovative Configurations of Large Scale Heat Pipes

2005 ◽  
Author(s):  
Jessica Sheehan ◽  
Donald Jordan ◽  
Douglas T. Queheillalt ◽  
Pamela M. Norris
Keyword(s):  
Heat Pipe ◽  
Large Scale ◽  
Heat Pipes ◽  
Heat Spreader ◽  
Pipe System ◽  
Pipe Systems

A large-scale heat pipe is one of many possible solutions to the modern day problem of quickly dissipating high amounts of concentrated heat. While heat pipes are a proven technology, little research has been directed at large-scale heat pipe systems. Two configurations of large-scale heat pipes are investigated in this study. The two configurations examined were a 2’ × 2’ heat spreader plate (a type of heat pipe) and an innovative heat pipe system that combines traditional heat pipes and heat spreader plates. The heat spreader plate, when tested, quickly becomes isothermal and works as a traditional heat pipe. This demonstrates the ability of this large-scale heat pipe configuration to work effectively to spread out high amounts of deposited heat. The experimentation on the innovative heat pipe system gave similar results, showing that the configuration works as a traditional heat pipe.

Limit States for Deepwater Flowlines and Risers: Review of the Research Activities at the Submarine Technology Laboratory/COPPE

2003 ◽  
Author(s):  
S. F. Estefen ◽  
T. A. Netto ◽  
I. P. Pasqualino
Keyword(s):  
Ultimate Strength ◽  
Large Scale ◽  
Failure Modes ◽  
Numerical Models ◽  
Experimental Tests ◽  
Limit States ◽  
Collapse Pressure ◽  
Research Activities ◽  
Structural Resistance ◽  
Buckle Arrestors

Research activities related to the limit states of flowlines and risers conducted at the Submarine Technology Laboratory / COPPE in cooperation with PETROBRAS are presented. The motivation for most of the research programs is associated with deepwater challenges arising from the rigid pipe installations at Campos Basin. Initially ultimate strength of intact pipes are investigated together with aspects related to residual strength, buckling propagation and buckle arrestors. Based on the experimental results numerical models have been correlated in order to be used to generate results for full scale steel pipes. Ultimate strength curves have been then produced as well as the analytical equation representative of these curves. Experimental tests of buckling propagation for small and large scale pipes have also been performed to obtain the bias factor for different equations proposed in the literature. Based on this study an equation for propagation pressure has been recommended. In addition, ring and cylinder buckle arrestors have been tested in order to propose an expression relating crossing over pressure with the arrestor geometries. An overview of the studies aiming at establishing the influence of the reeling method of installation on the failure modes of flowlines and steel catenary risers is presented. It is emphasized the influence of cross-section ovality and weld defect amplification due to plastic bending on collapse pressure and fatigue life, respectively. Finally, the development of a new concept of sandwich pipe for ultra deepwater, combining structural resistance and thermal insulation is discussed.

An Efficient Quasi-2D Simulation of Waterhammer in Complex Pipe Systems

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Huan-Feng Duan ◽  
Mohamed S. Ghidaoui ◽  
Yeou-Koung Tung
Keyword(s):  
Von Neumann ◽  
Pipe System ◽  
2D Simulation ◽  
The Family ◽  
In Series ◽  
Efficient Scheme ◽  
Pipe Systems ◽  
External Flows ◽  
Single Pipe ◽  
Basic Boundary

An efficient quasi-2D numerical waterhammer model for turbulent waterhammer flows has been previously developed for a single pipe system (reservoir-pipe-valve system). Basic boundary conditions, such as valves, reservoirs, and external flows, were also implemented. This paper extends this previously developed efficient scheme to a general model for a multipipe system. More specifically, an approach for matching the family of characteristic equations in each pipe at a junction of two or more pipes is proposed. In addition, the numerical stability conditions of the efficient scheme are investigated using the Von Neumann method. The resulting model is verified against experimental data and then applied to different complex systems involving pipes in series, branching, and network. Using this model, the effects of unsteady friction in complex pipe systems are examined and analyzed in this paper. From the case studies, it is found that the quasi-2D model is highly efficient, robust, and suitable for application to waterhammer problems in real complex pipe system.

Application of Transfer Matrix Method to Dynamic Analysis of Pipes With FSI

2014 ◽  
Author(s):  
Shuaijun Li ◽  
Bryan W. Karney ◽  
Gongmin Liu
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Structural Equations ◽  
Analytical Models ◽  
Pipe System ◽  
Various Boundary Conditions ◽  
Pipe Systems

Analytical models of three dimensional pipe systems with fluid structure interaction (FSI) are described and discussed, in which the longitudinal vibration, transverse vibration and torsional vibration were included. The transfer matrix method (TMM) is used for the numerical modeling of both fluidic and structural equations and then applied to the problem of predicting the natural frequencies, modal shapes and frequency responses of pipe systems with various boundary conditions. The main advantage of the present approach is that each pipe section of pipe system can be independently analyzed by a unified matrix expression. Thus the modification of any parameter such as pipe shapes and branch numbers does not involve any change to the solution procedures. This makes a parameterized analysis and further mechanism investigation much easier to perform compared to most existing procedures.

Solar Light-Vent Pipe Systems: Create Good Building Luminous Environment and Indoor Air Quality

2011 ◽  
Vol 374-377 ◽  
pp. 639-642
Author(s):  
Yan Peng Wu ◽  
Zhi You Yue
Keyword(s):  
Air Quality ◽  
Research And Development ◽  
Energy Saving ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Solar Light ◽  
Future Prospects ◽  
Pipe System ◽  
Pipe Systems

Solar light-vent pipe system, which is a new kind of green, ecological, energy-saving construction equipment, combining natural ventilation with solar light pipe, can not only improve the architecture luminous environment, but also optimize indoor air quality. This study introduces solar light-vent pipe systems theories and the related technical key point to combine natural ventilation with solar light pipes, gives an overview of the research and development of solar light-vent pipe systems and discusses the current situation and future prospects.

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