scholarly journals Experimental study on pressure pulses in long-distance gas pipeline during the pigging process

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041988445
Author(s):  
Jun Zhou ◽  
Tao Deng ◽  
Jinghong Peng ◽  
Guangchuan Liang ◽  
Xuan Zhou ◽  
...  
Keyword(s):  
Drainage System ◽  
Injection Pressure ◽  
Liquid Level ◽  
Pipeline System ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Trapped Air ◽  
Air Pocket ◽  
Air Pockets ◽  
Hydraulic Pulse

Long-distance gas pipelines generally have complex, undulating sections. Trapped air pockets are often present at the high points or ends of pipelines. This article carries out an experimental research to figure out the transient changes. First of all, under the condition of using the pig with 231 g and the injection pressure of 0.3 MPa, the hydraulic pulse increases from 0.31 to 0.54 MPa as the liquid level rises from 1 to 8 m. And at the liquid level of 8 m, the injection pressure grows from 0.3 to 0.75 MPa and the hydraulic pulse from 0.54 to 0.95 MPa. When the interception air mass is located at the blind side of the pipeline’s end, the injection pressure is 0.75 MPa, and the hydraulic pulse decreases from 4.9 to 3.21 MPa with the increase in the void fraction. The maximum hydraulic pressure generates when the air pocket is located at the rear end of the drainage system (4.9 MPa) is far higher than that when the air pocket is located in front of the pig (1.0 MPa). Therefore, it is necessary to minimize the generation of trapped air pockets at the rear end of the pipeline system to ensure safety.

Compressor Issues for Hydrogen Production and Transmission Through a Long Distance Pipeline Network

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Fred Starr ◽  
Calin-Cristian Cormos ◽  
Evangelos Tzimas ◽  
Stathis Peteves
Keyword(s):  
Pressure Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Energy System ◽  
Pipeline System ◽  
Hydrogen Energy ◽  
Long Distance ◽  
System Pressure ◽  
Production Of Hydrogen ◽  
Plant Exit

A hydrogen energy system will require the production of hydrogen from coal-based gasification plants and its transmission through long distance pipelines at 70 � 100 bar. To overcome some problems of current gasifiers, which are limited in pressure capability, two options are explored, in-plant compression of the syngas and compression of the hydrogen at the plant exit. It is shown that whereas in-plant compression using centrifugal machines is practical, this is not a solution when compressing hydrogen at the plant exit. This is because of the low molecular weight of the hydrogen. It is also shown that if centrifugal compressors are to be used in a pipeline system, pressure drops will need to be restricted as even an advanced two-stage centrifugal compressor will be limited to a pressure ratio of 1.2. High strength steels are suitable for the in-plant compressor, but aluminium alloy will be required for a hydrogen pipeline compressor.

scholarly journals A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 372
Author(s):  
Ekaterina Sukhova ◽  
Elena Akinchits ◽  
Sergey V. Gudkov ◽  
Roman Y. Pishchalnikov ◽  
Vladimir Vodeneev ◽  
...  
Keyword(s):  
Higher Plants ◽  
Initial Point ◽  
Electrical Signal ◽  
Terminal Point ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Variation Potential ◽  
Damaged Zone ◽  
Pressure Dynamics ◽  
The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

scholarly journals Newly designed solid coupling medium for reducing trapped air pockets during extracorporeal shock wave lithotripsy_ a phantom study

BMC Urology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chien-Sheng Wang ◽  
Ching-Chia Li ◽  
Wen-Jeng Wu ◽  
Wen-Chin Liou ◽  
Yusen Eason Lin ◽  
...  
Keyword(s):  
Shock Wave ◽  
Phantom Study ◽  
Acoustic Energy ◽  
Disintegration Rate ◽  
Measuring Device ◽  
Trapped Air ◽  
Extracorporeal Shock Wave ◽  
Air Pockets ◽  
Coupling Medium ◽  
Level 2

Abstract Introduction Air pockets between the lithotripter head and body surface are almost inevitably generated when applying a handful of gel onto the contact portion of the treatment head and that on the patient’s skin during coupling procedure. These air pockets can compromise the transmission of acoustic energy of shock wave and may significantly affect efficacy of stone disintegration. Comparing to conventional gel, this study aims to investigate efficacy of stone disintegration by using a proprietary isolation-coupling pad (“icPad”) as the coupling medium to reduce trapped air pockets during ESWL procedure. Method In this phantom study, Dornier lithotripter (Delta-2 RC, Dornier MedTech Europe GmbH Co., Germany) was used with a proprietary gel pads (icPad, Diameter = 150 mm, Thickness = 4 mm and 8 mm). The lithotripter was equipped with inline camera to observe the trapped air pockets between the contact surface of the lithotripter head. A testing and measuring device were used to observe experimental stone disintegration using icPad and semi-liquid gel. The conventional semi-liquid gel was used as control for result comparison. Results The stone disintegration rate of icPad 4 mm and 8 mm after 200 shocks of energy at level 2 were significantly higher than that of the semi-liquid gel (disintegration rate 92.3%, 85.0% vs. 45.5%, respectively, p < 0.001). The number of shocks for complete stone disintegration by icPad of 4 mm and 8 mm at the same energy level 2 were significantly lower than that of the semi-liquid gel (the number of shocks 242.0 ± 13.8, 248.7 ± 6.3 vs. 351.0 ± 54.6, respectively, p = 0.011). Furthermore, quantitative comparison of observed air pockets under Optical Coupling Control (OCC) system showed that the area of air pockets in semi-liquid group was significantly larger than that of the group using icPad (8 mm) and that of the group using icPad (8 mm) after sliding (332.7 ± 91.2 vs. 50.3 ± 31.9, 120.3 ± 21.5, respectively, p < 0.05). Conclusion The advantages of icPad includes: (1) reduced the numbers of shock wave and increased stone disintegration rate due to icPad’s superior efficacy; (2) significantly reduce trapped air pockets in ESWL coupling. Due to the study limitation, more data are needed to confirm our observations before human trials.

scholarly journals Investigation of Puffing and Micro-Explosion of Water-in-Diesel Emulsion Spray Using Shadow Imaging

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2281 ◽  
Author(s):  
Mhadi A. Ismael ◽  
Morgan Heikal ◽  
A. A. Aziz ◽  
Cyril Crua ◽  
Mohmmed El-Adawy ◽  
...  
Keyword(s):  
Droplet Size ◽  
High Speed ◽  
Elevated Temperatures ◽  
Injection Pressure ◽  
Image Processing Algorithm ◽  
Long Distance ◽  
Secondary Atomization ◽  
High Injection ◽  
Digital Microscope ◽  
Injection Pressures

Water-in-diesel emulsions potentially favor the occurrence of micro-explosions when exposed to elevated temperatures, thereby improving the mixing of fuels with the ambient gas. The distributions and sizes of both spray and dispersed water droplets have a significant effect on puffing and micro-explosion behavior. Although the injection pressure is likely to alter the properties of emulsions, this effect on the spray flow puffing and micro-explosion has not been reported. To investigate this, we injected a fuel spray using a microsyringe needle into a high-temperature environment to investigate the droplets’ behavior. Injection pressures were varied at 10% v/v water content, the samples were imaged using a digital microscope, and the dispersed droplet size distributions were extracted using a purpose-built image processing algorithm. A high-speed camera coupled with a long-distance microscope objective was then used to capture the emulsion spray droplets. Our measurements indicated that the secondary atomization was significantly affected by the injection pressure which reduced the dispersed droplet size and hence caused a delay in puffing. At high injection pressure (500, 1000, and 1500 bar), the water was evaporated during the spray and although there was not enough droplet residence time, puffing and micro-explosion were clearly observed. This study suggests that high injection pressures have a detrimental effect on the secondary atomization of water-in-diesel emulsions.

Experimental Validation of Existing Numerical Models for the Interaction of Fluid Transients With In-Line Air Pockets

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Jane Alexander ◽  
Pedro J. Lee ◽  
Mark Davidson ◽  
Huan-Feng Duan ◽  
Zhao Li ◽  
...  
Keyword(s):  
Time Delay ◽  
Wave Speed ◽  
Numerical Models ◽  
Diagnostic Process ◽  
Air Pocket ◽  
Fluid Transients ◽  
Entrapped Air ◽  
Air Pockets ◽  
The Given ◽  
Potential Tool

Entrapped air in pipeline systems can compromise the operation of the system by blocking flow and raising pumping costs. Fluid transients are a potential tool for characterizing entrapped air pockets, and a numerical model which is able to accurately predict transient pressures for a given air volume represents an asset to the diagnostic process. This paper presents a detailed study on our current capability for modeling and predicting the dynamics of an inline air pocket, and is one of a series of articles within a broader context on air pocket dynamics. This paper presents an assessment of the accuracy of the variable wave speed and accumulator models for modeling air pockets. The variable wave speed model was found to be unstable for the given conditions, while the accumulator model is affected by amplitude and time-delay errors. The time-delay error could be partially overcome by combining the two models.

Effectiveness of Ultraviolet Light For Mitigating Risk of Microbiologically Influenced Corrosion in Steel Pipeline

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
M. K. F. M. Ali ◽  
N. Md. Noor ◽  
N. Yahaya ◽  
A. A. Bakar ◽  
M. Ismail
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Microbiologically Influenced Corrosion ◽  
Metal Loss ◽  
Desulfovibrio Vulgaris ◽  
Pipeline System ◽  
Long Distance ◽  
Gas Industry ◽  
Internal Corrosion ◽  
Steel Pipeline

Pipelines play an extremely important role in the transportation of gases and liquids over long distance throughout the world. Internal corrosion due to microbiologically influenced corrosion (MIC) is one of the major integrity problems in oil and gas industry and is responsible for most of the internal corrosion in transportation pipelines. The presence of microorganisms such as sulfate reducing bacteria (SRB) in pipeline system has raised deep concern within the oil and gas industry. Biocide treatment and cathodic protection are commonly used to control MIC. However, the solution is too expensive and may create environmental problems by being too corrosive. Recently, Ultraviolet (UV) as one of the benign techniques to enhance mitigation of MIC risk in pipeline system has gained interest among researchers. An amount of 100 ml of modified Baar’s medium and 5 ml of Desulfovibrio vulgaris (strain 7577) seeds was grown in 125 ml anaerobic vials with carbon steel grade API 5L-X70 coupons at the optimum temperature of 37°C and pH 9.5 for fifteen days. This was then followed by exposing the medium to UV for one hour. Results from present study showed that UV radiation has the ability to disinfect bacteria, hence minimizing the risk of metal loss due to corrosion in steel pipeline. 

scholarly journals Development of Pant-Type Harness with Fabric Air-Pocket for Pain Relief

2019 ◽  
Vol 9 (9) ◽  
pp. 1921
Author(s):  
Dongwoo Nam ◽  
Miyeon Kwon ◽  
Juhea Kim ◽  
Bummo Ahn
Keyword(s):  
Contact Area ◽  
Peak Pressure ◽  
Applied Pressure ◽  
The Body ◽  
Area Measurement ◽  
Medical Applications ◽  
Air Pocket ◽  
Long Time ◽  
Developed Pressure ◽  
Air Pockets

Harnesses can be used in various applications, such as entertainment, rescue operations, and medical applications. Because users are supported on the harness for a long time, they should feel comfortable wearing the harnesses. However, existing commercial harnesses are uncomfortable to wear and cause continuous serious pain. Therefore, in this study, a new pant-type harness with a fabric air pocket to reduce the applied pressure on the body, especially in the groin, is proposed. Keeping this in mind, we have designed and developed the pant-type harness. In addition, we performed pressure and contact area measurement experiments using the harness developed, pressure sensor, and a human mannequin. Peak and mean pressures and contact areas near the groin and waist were measured in the experiments. From the results, when air is injected in the air pockets, the peak pressure and contact area near the waist increased, and the peak pressure near the groin decreased. This means that the pressure applied on the human mannequin near the groin reduces because of the increased contact area near the waist, which is achieved by multi-layered air pockets. In this study, we proposed the optimal design of a novel pant-type harness that can address the limitations of existing harnesses. The proposed harness can be used for a prolonged time in applications, such as virtual reality entertainment, rescue operations, and rehabilitation.

scholarly journals Structure and evolution of the drainage system of a Himalayan debris-covered glacier, and its relationship with patterns of mass loss

2017 ◽  
Vol 11 (5) ◽  
pp. 2247-2264 ◽  
Author(s):  
Douglas I. Benn ◽  
Sarah Thompson ◽  
Jason Gulley ◽  
Jordan Mertes ◽  
Adrian Luckman ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Satellite Image ◽  
Drainage System ◽  
Ablation Zone ◽  
Negative Mass ◽  
Long Distance ◽  
Glacier Surface ◽  
Base Level ◽  
Englacial Drainage

Abstract. We provide the first synoptic view of the drainage system of a Himalayan debris-covered glacier and its evolution through time, based on speleological exploration and satellite image analysis of Ngozumpa Glacier, Nepal. The drainage system has several linked components: (1) a seasonal subglacial drainage system below the upper ablation zone; (2) supraglacial channels, allowing efficient meltwater transport across parts of the upper ablation zone; (3) sub-marginal channels, allowing long-distance transport of meltwater; (4) perched ponds, which intermittently store meltwater prior to evacuation via the englacial drainage system; (5) englacial cut-and-closure conduits, which may undergo repeated cycles of abandonment and reactivation; and (6) a "base-level" lake system (Spillway Lake) dammed behind the terminal moraine. The distribution and relative importance of these elements has evolved through time, in response to sustained negative mass balance. The area occupied by perched ponds has expanded upglacier at the expense of supraglacial channels, and Spillway Lake has grown as more of the glacier surface ablates to base level. Subsurface processes play a governing role in creating, maintaining, and shutting down exposures of ice at the glacier surface, with a major impact on spatial patterns and rates of surface mass loss. Comparison of our results with observations on other glaciers indicate that englacial drainage systems play a key role in the response of debris-covered glaciers to sustained periods of negative mass balance.

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