Dynamics of a Large Scale Hydraulic Capsule Pipeline System

1999 ◽  
Vol 124 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Hongliu Du ◽  
Satish S. Nair
Keyword(s):  
Large Scale ◽  
Control Method ◽  
Experimental Studies ◽  
Small Scale ◽  
Pipeline System ◽  
Centrifugal Pumps ◽  
Long Distance ◽  
Column Separation ◽  
In Series ◽  
Hydraulic Capsule Pipeline

The dynamics of a booster station, which is critical for the control of a novel, long distance, hydraulic capsule pipeline, is simulated mathematically for design studies and control of the hydraulic transients caused by the valve actuators in the system. Several modifications to the pump bypass station configuration of the booster station have been studied. With the objective of eliminating column separation and reducing flow reversals, a configuration with several centrifugal pumps connected in series, and a carefully sized air chamber is found to be a viable design. A valve control method is designed to eliminate column separation and the design results in acceptable flow reversal levels in the main pipe. The simulation results match with trends in limited experimental studies performed on a small scale experimental capsule pipeline system.

scholarly journals Study of Flood Control Capability and Advanced Application of Multiple Dams Constructed in Series

2013 ◽  
Vol 8 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Hideo Oshikawa ◽  
◽  
Yuka Mito ◽  
Toshimitsu Komatsu ◽  
Keyword(s):  
Flood Control ◽  
Large Scale ◽  
Control Method ◽  
Upstream Region ◽  
Small Scale ◽  
Water Utilization ◽  
In Series ◽  
New Type ◽  
Cascade Method ◽  
Cascade Type

The new concept for flood control called ‘Cascade’ method which permits dams to overflow around an upstream region with a sequence of dams constructed in a river is proposed. Multiple small scale dry dams should be constructed in series instead of a large scale dam in order to prevent flood disaster and preserve the natural environment. Recently a flood control dam with a bottom outlet hole as its regular spillway, known as ‘dry dam’, has been reviewed, planned and built in some sites in Japan. Under a condition of a common reservoir capacity, the Cascade type flood control permitting upstream dams to overflow except for the most downstream dam in a river is compared with a conventional one not to overflow each dam in a numerical simulation. As a result, it is made clear that the Cascade method using multiple dry dams is much more effective than the conventional one. In this connection, the Cascade type flood control method permitting upstream dams to overflow from emergency spillways except for the most downstream dam can be applied to normal storage dams with slide gates operated conventionally. Therefore, it could become an effective adaptation method for the global warming problem since it is performed by only changing how to operate slide gates in existing storage dams constructed in series. In addition, we also propose a new type of dry dam that has a closable and openable gate for its regular spillway primarily to retain the water for the water utilization. The new type of dry dam, which should be constructed in the upper reach away from the existing downstream storage dam needing still more its capacity for water utilization, ensures the amount of water available for the use by closing the regular spillway after the new dry dam is at full capacity, and the flood control capacity of the dams including the new dry dam is stronger than that of the normal dams owing to the storage function with the new dry dam. The new dry dams may improve the water utilization, the flood control, and environmentfriendliness under the current condition in Thailand damaged by the severe flood in 2011.

scholarly journals Failure Mechanism of Rock Bridge Based on Acoustic Emission Technique

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Guoqing Chen ◽  
Yan Zhang ◽  
Runqiu Huang ◽  
Fan Guo ◽  
Guofeng Zhang
Keyword(s):  
Acoustic Emission ◽  
Failure Mechanism ◽  
High Speed ◽  
Large Scale ◽  
Small Scale ◽  
Failure Behavior ◽  
Long Distance ◽  
Rock Bridge ◽  
Rocky Slope ◽  
Landslide Model

Acoustic emission (AE) technique is widely used in various fields as a reliable nondestructive examination technology. Two experimental tests were carried out in a rock mechanics laboratory, which include (1) small scale direct shear tests of rock bridge with different lengths and (2) large scale landslide model with locked section. The relationship of AE event count and record time was analyzed during the tests. The AE source location technology and comparative analysis with its actual failure model were done. It can be found that whether it is small scale test or large scale landslide model test, AE technique accurately located the AE source point, which reflected the failure generation and expansion of internal cracks in rock samples. Large scale landslide model with locked section test showed that rock bridge in rocky slope has typical brittle failure behavior. The two tests based on AE technique well revealed the rock failure mechanism in rocky slope and clarified the cause of high speed and long distance sliding of rocky slope.

INVESTIGATION INTO THE INFLUENCE OF IMPREGNATION ON PINE TIMBER COMBUSTION USING A CONE CALORIMETER AND LARGE SCALE TESTS

2011 ◽  
Vol 3 (3) ◽  
pp. 91-104 ◽  
Author(s):  
Jerzy Gałaj ◽  
Zbignev Karpovič ◽  
Waldemar Jaskółowski
Keyword(s):  
Cone Calorimeter ◽  
Large Scale ◽  
Experimental Studies ◽  
Fire Retardant ◽  
Full Scale ◽  
Lower Amount ◽  
Small Scale ◽  
Fire Retardants ◽  
Co Concentration ◽  
Piloted Ignition

Fire safety is one of the main requirements with respect to the regulations on the buildings involved into the category of human hazards. Human safety measures are applied equally to inhabitants, users, customers, spectators, etc., as well as to fire brigades taking part in the activities connected with rescue actions. Methods for emission research were applied to estimate thermo-kinetic parameters related to smoke and toxic gases. The methods fall into two types: full scale methods reflect fire conditions and small laboratory scale methods having a significantly lower degree of reflection. This paper presents the results of studies on the influence of BAK-1 and Flamasepas-2 fire retardants produced in Lithuania and applied for timber on the selected parameters of the fire environment. Experimental studies were conducted using a cone calorimeter (small scale) in the closed compartment equipped with measuring devices (full scale). The undertaken studies have demonstrated that considering some parameters, such as heat release rate (HRR), a positive effect of the lower amount of the released heat can be obtained. Unfortunately, in case of the major part of the studied parameters, including time to ignition, CO concentration and extinction parameter reflecting smokiness, worse results (shorter time, higher CO values and higher extinction coefficient) have been observed for the treated timber rather than for the non-impregnated one. The obtained results have showed combustion with piloted ignition. In case of no piloted ignition, the results were slightly different. For all studied specimens treated with fire retardants, no ignition was observed and tests were terminated following 15 minutes. CO concentration and extinction parameter (smokiness) were higher for non-impregnated timber. Full scale experiments have confirmed the above provided information; moreover, it has been found that the application of fire retardant has no significant impact on temperatures in the compartment.

Reliability Calculation Method for Natural Gas Pipelines with Girth Weld Defects Identified through In-Line Inspection

2019 ◽  
Vol 795 ◽  
pp. 225-232 ◽  
Author(s):  
Ming Fei Li ◽  
Jian Chen ◽  
Zheng Qiang Lei ◽  
Hong Long Zheng ◽  
Zai Rong Li
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Plastic Material ◽  
Pipeline System ◽  
Long Distance ◽  
Weld Defects ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
The Monte Carlo Method ◽  
Reliability Assessments

To introduce a method for reliability analysis of China's large-scale natural gas pipeline system, one should first have a method to calculate the reliability of pipe segments, compressors, valves, and other factors. This article models the rules prescribed in BS7910-2013, a guide to methods for assessing the acceptability of flaws in metallic structures, and combines pipeline reliability assessments from CSA Z662-2015 to present a method (based on the Monte Carlo method) to calculate the failure probability/reliability of long-distance pipelines containing a large number of girth weld defects. The method involves the destruction of plastic material, brittle fracture failure analysis, consideration of the division of units by using pipeline area classes for calculation, and reliability index analysis. The results of a magnetic flux leakage (MFL) in-line inspection (ILI) of a defective girth weld from a section of a pipeline in China are used to demonstrate how to determine the reliability of the entire pipeline.

scholarly journals Fairness Time-Slot Allocation and Scheduling with QoS Guarantees in Multihop WiMAX Mesh Networks

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Chien-Yu Wu ◽  
Hann-Jang Ho ◽  
Sing-Ling Lee ◽  
Liang Lung Chen
Keyword(s):  
Large Scale ◽  
Heuristic Algorithms ◽  
Mesh Networks ◽  
Time Slot ◽  
Optimal Solution ◽  
Small Scale ◽  
Scheduling Problem ◽  
Slot Allocation ◽  
Long Distance ◽  
Time Slot Allocation

The WiMAX technology has been defined to provide high throughput over long distance communications and support the quality of service (QoS) control applied on different applications. This paper studies the fairness time-slot allocation and scheduling problem for enhancing throughput and guaranteeing QoS in multihop WiMAX mesh networks. For allocating time slots to multiple subscribe stations (SSs), fairness is a key concern. The notion of max-min fairness is applied as our metric to define the QoS-based max-min fair scheduling problem for maximizing the minimum satisfaction ratio of each SS. We formulate an integer linear programming (ILP) model to provide an optimal solution on small-scale networks. For large-scale networks, several heuristic algorithms are proposed for better running time and scalability. The performance of heuristic algorithms is compared with previous methods in the literatures. Experimental results show that the proposed algorithms are better in terms of QoS satisfaction ratio and throughput.

scholarly journals TEST CHARACTERISTICS OF CENTRIFUGAL PUMPS ON COOLING HYDRONIC SYSTEM USING ENVIRONMENTAL FRIENDLY REFRIGERATION

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Yudhy Kurniawan ◽  
Kusnandar Kusnandar
Keyword(s):  
Air Conditioning ◽  
Large Scale ◽  
Cold Water ◽  
Cooling Capacity ◽  
Water Tank ◽  
Centrifugal Pumps ◽  
Practice Test ◽  
Compression System ◽  
In Series ◽  
Vapour Compression

In generally cooling hydronic system applied to large-scale commercial or industrial use, where water cooling is processed through heat transfer mechanism in the evaporator pipe using a vapour compression system such as a chiller with refrigerant. The research idea is based on not available practice test of cooling hydronic system at the Department of Refrigeration and Air Conditioning Engineering at State Polytechnic of Indramayu which is the main competency in the course of Air Conditioning Applied. As teh utilization practice made cooling hydronic system by utilizing a vapour compression system that is split AC using refrijeran R32 is environmentally friendly. The split AC system modifies its evaporator coil into a heat exchange medium to cool water in the water tank. The cold water is then distributed in the piping installation system with the two pumps that are varied in series and parallel. From this process, it is necessary to know the working capability of the pumps in terms of its characteristics (head and capacity) or its performance, including energy losses and cooling capacity system. The results obtained are analyzed and the calculation is in accordance with theoretically known study.

scholarly journals DIMPLE GENERATOR OF VORTEX STRUCTURES

2021 ◽  
pp. 95-102
Author(s):  
A. V. Voskobijnyk ◽  
V. M. Turick ◽  
O. A. Voskoboinyk ◽  
V. A. Voskoboinick
Keyword(s):  
Large Scale ◽  
Vortex Flow ◽  
Flat Surface ◽  
Pressure Fluctuations ◽  
Experimental Studies ◽  
Vortex Structures ◽  
Small Scale ◽  
Wall Pressure Fluctuations ◽  
Large Scale Vortex ◽  
Streamlined Surface

The paper presents the results of experimental studies of the space-time characteristics of the velocity and pressure field inside a hemispherical dimple on a flat surface. The features of the formation and development of vortex structures generated inside the dimple, as well as their interaction with the streamlined surface of the dimple and the boundary layer were established. Integral, spectral and correlation characteristics of the field of velocity, dynamic and wall pressure fluctuations were obtained. The velocities and directions of transfer of large-scale vortex structures and small-scale vortices inside the dimple were determined. The frequencies of rotations and ejections of large-scale vortices, the frequencies of oscillations of the vortex flow inside the dimple and self-oscillations of the vortex structures of the shear layer, their subharmonics and harmonics of higher orders were established.

Compressive Behavior of Large-Scale Hybrid FRP-Concrete-Steel Double-Skin Tubular Columns

2011 ◽  
Vol 243-249 ◽  
pp. 1138-1144 ◽  
Author(s):  
Pan Xie ◽  
T Yu ◽  
Y.L. Wong ◽  
J.G. Teng
Keyword(s):  
Large Scale ◽  
Experimental Studies ◽  
Steel Tube ◽  
Small Scale ◽  
Structural Members ◽  
Compression Tests ◽  
Tubular Columns ◽  
Compressive Response ◽  
Double Skin ◽  
Frp Tube

Hybrid FRP-concrete-steel double-skin tubular columns (DSTCs) are a new form of hybrid structural members. A hybrid DTSC consists of an inner steel tube, an outer FRP tube and a concrete infill between them. Hybrid DSTCs possess many important advantages over conventional structural members, including their excellent corrosion resistance as well as excellent ductility and seismic resistance. A large amount of research has been conducted on hybrid DSTCs, but the existing experimental studies have been limited to the testing of small-scale columns. This paper presents preliminary results from the first series of large-scale axial compression tests on hybrid DSTCs, which forms part of a larger experimental study currently under way at The Hong Kong Polytechnic University. These test results confirm the excellent axial compressive response of hybrid DSTCs as initially expected.

scholarly journals HYDRODYNAMICS UNDER LARGE-SCALE REGULAR AND BICHROMATIC BREAKING WAVES

2018 ◽  
pp. 90
Author(s):  
Dominic Van der A ◽  
Joep Van der Zanden ◽  
Ming Li ◽  
James Cooper ◽  
Simon Clark ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Surf Zone ◽  
Experimental Studies ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Small Scale ◽  
Breaking Wave ◽  
Wave Flume ◽  
Cfd Models

Multiphase CFD models recently have proved promising in modelling cross‐shore sediment transport and morphodynamics (Jacobsen et al 2014). However, modelling breaking wave turbulence remains a major challenge for these models, because it occurs at very different spatial and temporal length scales and involves the interaction between surface generated turbulence and turbulence generated in the bottom boundary layer. To an extent these challenges arise from a lack of appropriate experimental data, since most previous experimental studies involved breaking waves at small-scale, and have not permitted investigation of the turbulent boundary layer processes. Moreover, most existing studies have concentrated on regular waves, thereby excluding the flow and turbulence dynamics occurring at wave group time-scales under irregular waves within the surf zone. These limitations motivated a new experiment in the large-scale CIEM wave flume in Barcelona involving regular and irregular waves. The experiment was conducted in May-July 2017 within the HYDRALAB+ Transnational Access project HYBRID.

scholarly journals An Innovative Method for Placement of Gangue Backfilling Material in Steep Underground Coal Mines

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 107 ◽  
Author(s):  
Yanchun Yin ◽  
Tongbin Zhao ◽  
Yubao Zhang ◽  
Yunliang Tan ◽  
Yue Qiu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Large Scale ◽  
Small Scale ◽  
Underground Coal Mining ◽  
Long Distance ◽  
Subsidence Area ◽  
Working Face ◽  
Underground Coal Mines ◽  
Gob Area ◽  
Gangue Backfilling

Using gangue backfilling in underground coal mining not only controls the roof deformation in the gob area but also reduces the amount of mining waste rock. However, due to the limitations of the complicated engineering conditions, backfilling mining in the steep coal seam is not widely applied. In this study, a long-distance backfilling technology with a scraper winch for a steep coal seam was proposed and applied in a flexible shield supporting working face in Datai Mine, Beijing. Aiming at the problem of the decreasing backfilling ratio in field practice, numerical simulation was carried out to research the moving law of gangue in the goaf. The gangue mainly experienced four stages: gangue landslide stage, small-scale subsidence stage, funnel-shaped subsidence stage, and large-scale subsidence stage. The moving area of the gangue could be divided into five areas including a motionless area, a landslide area, a subsidence area, a funnel-shaped subsidence area, and a to-be-backfilled area. With the increase of the inclined length of the working face, the moving time of the gangue increased gradually. Based on the simulation results, the scheme of backfilling and mining in Datai Mine was optimized, for which the inclined length of the working face was shortened, and a higher backfilling ratio was obtained.

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