GFS model fidelity in capturing the transition of low pressure area to monsoon depression

2021 ◽  
Author(s):  
Sahadat Sarkar ◽  
P. Mukhopadhyay ◽  
Somenath Dutta ◽  
R. Phani Murali Krishna ◽  
Radhika Kanase ◽  
...  
Keyword(s):  
Low Pressure ◽  
Monsoon Depression ◽  
Model Fidelity ◽  
Pressure Area ◽  
Gfs Model

The Design of a Degassing Pump Based on Numerical and Experimental Research

2015 ◽  
Author(s):  
Dongjie Xie ◽  
Peng Wu ◽  
Dazhuan Wu
Keyword(s):  
Bubble Diameter ◽  
Low Pressure ◽  
High Energy ◽  
Balance Model ◽  
Multiphase Model ◽  
Dissolved Gas ◽  
Pump Design ◽  
Free Gas ◽  
Pressure Area ◽  
Productive Process

In the food industry, it is necessary to remove the gas in liquid, in order to prevent the juice from oxidation and prolong guarantee period. At present, vacuum tanks are widely used in beverage productive process to remove air. However, the vacuum tanks are usually bulky and of high energy consumption. In this study, the purposes of degassing pump design are: (1) effectively removing free gas and dissolved gas in liquid, (2) conveying the liquid, (3) more energy efficient than vacuum tank. In this process, numerical method is adopted to simulate the gas-liquid separation with eulerian multiphase model and population balance model (PBM) using the commercial code FLUENT. Structures of pulp pump and gas-liquid cylindrical cyclone separator are used for reference. The degassing pump mainly consists of inlet tube, centrifuge drum, exhaust tube, impeller, volute and outlet tube etc. The numerical simulation results show that there is a huge low pressure area in the center of the drum. Free gas and dissolved gas are separated into the low pressure region under the effect of centrifugal force and local low pressure. Bubble diameter has a great impact on the degassing effect. PBM which considers bubbles coalescence and breakup is adopted here to calculate the diameter of bubbles. The drum diameter has an extremely influence on the inlet pressure of degassing pump. The centrifuge drum is installed in front of impeller, so pre-swirl of the fluid inside impeller inlet is strong. The hydraulic performance of pump slightly declines when centrifuge drum is added in numerical calculation. The degassing pump is in manufacturing and will be tested in future.

Effects of Gas Nucleus on Cavitation Inception and Bubble Characteristics inside V-Throttling Groove

2014 ◽  
Vol 1006-1007 ◽  
pp. 147-151
Author(s):  
Xue Wen Du ◽  
Xin Fu ◽  
Hang Bin Tang
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Longitudinal Velocity ◽  
Low Pressure ◽  
Cavitation Inception ◽  
Forming Mechanism ◽  
Strong Shear ◽  
Pressure Area ◽  
Valve Opening ◽  
Bubble Characteristics

The paper combines CFD simulation and high-speed observation experiments to analyze the forming mechanism of high-speed cavitation flowing inside V-groove. It is found that the formation and development of cavitation are greatly affected by the cavitation nucleus, and subjected to two flow patterns, shear flow and vortex. When the groove is shallow or valve opening is small, cavitation inception occurs in the strong shear region near the throttling edge, which is related to the separation of boundary layer and the wall attachment effect. As the depth of the valve port increases, the reflux becomes stronger at the back of the throttling edge, which complements the low pressure area generated from the fluid separation. At the same time the pulsation is formed in the downstream due to the large longitudinal velocity gradient, resulting in vortex, and the area of ​​low pressure in the center of vortex also leads to the generation of cavitation.

scholarly journals Research and application of supramolecular gel plugging agent in abnormal pressure reservoir

2021 ◽  
Vol 2045 (1) ◽  
pp. 012006
Author(s):  
B Baletabieke ◽  
Y X Gu ◽  
T Zhou ◽  
D X Duan ◽  
J T Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Oil And Gas ◽  
Adhesion Force ◽  
Fiber Composite ◽  
Low Pressure ◽  
Effective Rate ◽  
Pressure Zone ◽  
Composite Gel ◽  
Pressure Area ◽  
Strong Adhesion

Abstract The Aktobe project is the largest oil and gas producing area of PetroChina in Central Asia. However, after years of exploitation, the pressure of the reservoir has dropped, making it difficult to increase the production of a single well. Both the Kenkyak block and North Troyes block of the project have induced fractured leakage, and frequent leakage affects safe and efficient drilling and completion operations and production. Therefore, the research on leakage prevention and control technology is very necessary. This article focuses on the characteristics of the cracks in the high-pressure area of the Kenkyak block and the cracks in the low-pressure area of the North Troyes block. Aiming at the fracture characteristics of the high-pressure zone in the Kenkyak block and the low-pressure zone in North Troyes block, and taking advantage of the synergistic effect of supramolecules, a supramolecular plugging-while-drilling agent was developed based on the deformable fiber composite gel. It forms a strong adhesion plugging layer on the inner wall of the leakage channel through the strong adhesion force, and it achieves a good plugging effect. The 300-500mD sand disc bearing pressure could reach 700psi when adding 3% agent, and the bearing pressure of 3-5D permeability sand disc could reach above 450psi. A supramolecular static plugging agent was also developed based on the dilatant gel. It is rich in strong shear reversible gel with supramolecular structure, which guarantees its pumpability and plugging performance. The effective rate of one-time plugging is over 80%, and the viscosity is greatly reduced after the gel is broken for 72hr, which benefits the reservoir protection.

scholarly journals NUMERICAL SIMULATION OF COOLING JET FROM HYDROGEN AND DEUTERIUM AS APPLICABLE TO INSTALLATIONS ON RECEIVING CRYOGENIC MONODISPERSE TARGETS

2019 ◽  
Vol 46 (1) ◽  
pp. 8-18
Author(s):  
A. V. Bukharov ◽  
A. F. Ginevsky ◽  
E. V. Vishnevsky
Keyword(s):  
High Speed ◽  
Low Pressure ◽  
Numerical Calculations ◽  
Liquid Jets ◽  
Temperature Changes ◽  
Working Chamber ◽  
Pressure Area ◽  
Speed Up ◽  
Determination Of Parameters

Objectives. Development of a model and carrying out numerical calculations for the cooling of thin jets of Hydrogen and Deuterium as applicable to installations on receiving cryogenic monodisperse targets.Methods. To achieve this purpose, the model of cryogenic jet outflow into the low pressure area was created and using PHOENICS software the temperature change of the surface and the interior of a jet over time for various external parameters is investigated through the numerical method.Result. The dependences of temperature changes of liquid Hydrogen and Deuterium jets along the jet surface and along the radius depending on the jet diameter, speed, initial jet temperature and pressure in the working chamber of installations for receiving cryogenic monodisperse targets were carried out.Conclusion. The principal possibility of creating high-speed cryogenic monodisperse targets is shown. According to the calculations, at input of thin liquid jets of Hydrogen or Deuterium with a speed up to 100 m/s into the working chamber with low pressure, jets at a distance of up to 1 mm do not have time to freeze and can be broken into monodisperse drops. Drops are cooled due to evaporation and become granules. The developed model, the program for determination of parameters of steady monodisperse disintegration of liquid cryogenic streams and results of numerical calculations can be used during creation of units for receiving high-speed cryogenic monodisperse targets.

Politics and Economics in Southeast Asia

1959 ◽  
Vol 11 (2) ◽  
pp. 303-315
Author(s):  
Willis C. Armstrong
Keyword(s):  
Southeast Asia ◽  
Low Pressure ◽  
The North ◽  
Pressure Area ◽  
Great Pressure ◽  
Regional Basis

South of China, east of India, and above the Antipodes, Southeast Asia may be more of a “geographic expression” than a “region”; perhaps, however, it deserves analysis on a regional basis. Certain similarities unite these countries, even though a consciousness on the part of the peoples of the area that they are a “region” has been slow to develop; Dien Bienphu seemed nearer to Washington than to Singapore. One of the volumes reviewed here uses the term “low-pressure area” to explain the fact that historically the national states of Southeast Asia have not been strong, and that the area has been subjected to great pressure from more densely populated countries to the north and west.

scholarly journals Recent drumlins, flutes and lineations at Vestari-Hagafellsjökull, Iceland

1995 ◽  
Vol 41 (139) ◽  
pp. 596-606 ◽  
Author(s):  
Jane K. Hart
Keyword(s):  
Low Pressure ◽  
Glacial Retreat ◽  
The Core ◽  
Bed Forms ◽  
Pressure Area

AbstractIn the foreland of the Vestari-Hagafellsjökull glacier, Langajökull, central Iceland, three scales of subglacial bed forms are found: drumlins, flutes and lineations. The smaller bed forms are superimposed upon the larger. These three bed forms probably formed as a result of the presence of a rigid suhglacial core producing a lee-side low-pressure area into which sediment flowed and collected. The cores of the drumlins are tumuli (lava blisters), whilst the cores of the flutes and lineations were large clasts.Differences between the three scales of bed forms are that: (a) the flutes and lineations are far more mobile features as their cores could move within the deforming layer, whilst the drumlin bedrock cores were fixed; (b) the lineations formed in association with a clast pavement.The change in scale of the bed forms may he related to changes in thickness of the deforming layer and size of the core. At this site, smaller bed forms were superimposed upon larger bed forms and these may have formed as the deforming layer progressively thinned in association with glacial retreat.

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