scholarly journals An Investigation into Sub-Critical Choke Flow Performance in High Rate Gas Condensate Wells

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3992
Author(s):  
Nasriani ◽  
Khan ◽  
Graham ◽  
Ndlovu ◽  
Nasriani ◽  
...  
Keyword(s):  
Flow Rate ◽  
Parameter Variation ◽  
Gas Condensate ◽  
The Other ◽  
High Rate ◽  
Production Data ◽  
Empirical Correlations ◽  
New Correlation ◽  
Production Wells ◽  
Data Points

There have been some correlations in the literature to predict the gas and liquid flow rate through wellhead chokes under subcritical flow conditions. The majority of these empirical correlations have been developed based on limited production data sets that were collected from a small number of fields. Therefore, these correlations are valid within the parameter variation ranges of those fields. If such correlations are used elsewhere for the prediction of the subcritical choke flow performance of the other fields, significant errors will occur. Additionally, there are only a few empirical correlations for sub-critical choke flow performance in high rate gas condensate wells. These led the authors to develop a new empirical correlation based on a wider production data set from different gas condensate fields in the world; 234 production data points were collected from a large number of production wells in twenty different gas condensate fields with diverse reservoir conditions and different production histories. A non-linear regression analysis method was applied to their production. The new correlation was validated with a new set of data points from some other production wells to confirm the accuracy of the established correlation. The results show that the new correlation had minimal errors and predicted the gas flow rate more accurately than the other three existing models over a wider range of parameter variation ranges.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

scholarly journals First Report of blaNDM-1 Bearing IncX3 Plasmid in Clinically Isolated ST11 Klebsiella pneumoniae from Pakistan

2021 ◽  
Vol 9 (5) ◽  
pp. 951
Author(s):  
Hazrat Bilal ◽  
Gaojian Zhang ◽  
Tayyab Rehman ◽  
Jianxion Han ◽  
Sabir Khan ◽  
...  
Keyword(s):  
Sequence Type ◽  
The Other ◽  
High Rate ◽  
Antibiotics Resistance ◽  
New Delhi ◽  
Molecular Type ◽  
Plasmid Analysis ◽  
First Time ◽  
Encoding Genes ◽  
Sequence Types

The New Delhi Metallo-β-lactamase (NDM) is among the most threatening forms of carbapenemases produced by K. pneumoniae, well-known to cause severe worldwide infections. The molecular epidemiology of blaNDM-1-harboring K. pneumoniae is not well elucidated in Pakistan. Herein, we aim to determine the antibiotics-resistance profile, genes type, molecular type, and plasmid analysis of 125 clinically isolated K. pneumoniae strains from urine samples during July 2018 to January 2019 in Pakistan. A total of 34 (27.2%) K. pneumoniae isolates were carbapenemases producers, and 23 (18.4%) harbored the blaNDM-1 gene. The other carbapenemases encoding genes, i.e., blaIMP-1 (7.2%), blaVIM-1 (3.2%), and blaOXA-48 (2.4%) were also detected. The Multi Locus Sequence Typing (MLST) results revealed that all blaNDM-1-harboring isolates were ST11. The other sequence types detected were ST1, ST37, and ST105. The cluster analysis of Xbal Pulsed Field Gel Electrophoresis (PFGE) revealed variation amongst the clusters of the identical sequence type isolates. The blaNDM-1 gene in all of the isolates was located on a 45-kb IncX3 plasmid, successfully transconjugated. For the first time, blaNDM-1-bearing IncX3 plasmids were identified from Pakistan, and this might be a new primary vehicle for disseminating blaNDM-1 in Enterobacteriaceae as it has a high rate of transferability.

A Multiregion Model with Capital Accumulation and Endogenous Amenities

2007 ◽  
Vol 39 (9) ◽  
pp. 2248-2270 ◽  
Author(s):  
Wei-Bin Zhang
Keyword(s):  
Capital Accumulation ◽  
Comparative Statics ◽  
The Other ◽  
High Rate ◽  
Unique Equilibrium ◽  
Economic Activities ◽  
Technological Differences ◽  
National Output ◽  
Simulation Results ◽  
Wage Disparities

The author develops a multiregional growth model with endogenous amenity and capital accumulation for any number of regions. The simulation results demonstrate that the national dynamics have a unique equilibrium. Comparative statics analysis shows that, if environmental improvement occurs in the technologically advanced (less advanced) region, the national output rises (falls). As a region improves its technology, the other two regions' aggregated output levels fall—not only in relative, but also in absolute, terms. This implies that if any region has a high rate of technological change and the other regions remain technologically stationary, then economic activities will tend to be concentrated in the technologically advancing region. It is also shown that technological differences appear to play only a small role in accounting for spatial wage disparities and endowments.

Optimization of Inlet Ring Groove Arrangement for Suppression of Unstable Flow in a Centrifugal Impeller

2005 ◽  
Author(s):  
Masahiro Ishida ◽  
Daisaku Sakaguchi ◽  
Hironobu Ueki
Keyword(s):  
Flow Rate ◽  
The Other ◽  
Centrifugal Impeller ◽  
Shape Parameters ◽  
Unstable Flow ◽  
Ring Groove ◽  
Flow Rates ◽  
Small Flow ◽  
Specific Speed ◽  
Large Flow

An optimization of the inlet ring groove arrangement has been pursued in the present study for obtaining better impeller characteristics and a wider operation range at both small and large flow rates in a high specific speed type centrifugal impeller with inducer. The effects of the shape parameters with respect to the inlet ring groove on the impeller characteristic and the flow incidence were analyzed mainly based on numerical simulations, but also compared to the experimental results. At small flow rates, a significant improvement in the impeller characteristic is achieved due to reduction in the excessive-positive flow incidence by optimizing both location and width of the rear groove near the inducer tip throat. On the other hand, the impeller characteristic is improved at large flow rates by implementing the corner radius at the rear groove edge and by placing another front ring groove in the suction pipe. As a result, by the optimized configuration of the front and rear ring grooves, the unstable flow range of the test impeller can be reduced by about 50% without deterioration of the impeller characteristic even at the 125% flow rate.

Voluntary intake, digestibility and rate of passage of a hay and a silage fed to horses and to cattle

1995 ◽  
Vol 1995 ◽  
pp. 164-164
Author(s):  
B. McLean ◽  
A. Afzalzadeh ◽  
L. Bates ◽  
R.W. Mayes ◽  
F.D.DeB. Hovell
Keyword(s):  
Sugar Beet ◽  
Microbial Degradation ◽  
Poor Quality ◽  
The Other ◽  
Alternative Strategy ◽  
High Rate ◽  
Beet Pulp ◽  
Voluntary Intake ◽  
Hind Gut ◽  
Adequate Nutrient

It is well established that the intake and digestibility of roughages by ruminants is positively correlated with rate of passage (ARC, 1980), presumably to enable as complete a microbial degradation of the poorer roughages as possible. On the other hand hind gut fermenters such as horses have been thought to have adopted the alternative strategy of using a high rate of passage to ‘cream’ off the rapidly degradable material of poor quality roughages so as to maintain adequate nutrient intakes. Surprisingly, there are remarkably few actual comparisons between ruminants and hindgut fermenters in the literature. Traditionally dried roughages (hay) and cereal and ‘by-product concentrates’ have been used as horse feeds (grains, brans sugar beet pulp). Recently there has been more interest in the use of silages with horses (eg Smoulders and Hobiers, 1988). However the information as to the utilisation of silages by horses is limited.

scholarly journals Correlations to Predict Elemental Compositions and Heating Value of Torrefied Biomass

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2443 ◽  
Author(s):  
Mahmudul Hasan ◽  
Yousef Haseli ◽  
Ernur Karadogan
Keyword(s):  
Carbon Content ◽  
Hydrogen Content ◽  
Woody Biomass ◽  
Coefficient Of Determination ◽  
Mass Yield ◽  
Solid Mass ◽  
Empirical Correlations ◽  
Heating Value ◽  
Torrefied Biomass ◽  
Data Points

Measurements reported in the literature on ultimate analysis of various types of torrefied woody biomass, comprising 152 data points, have been compiled and empirical correlations are developed to predict the carbon content, hydrogen content, and heating value of a torrefied wood as a function of solid mass yield. The range of torrefaction temperature, residence time and solid yield of the collected data is 200–300 °C, 5–60 min and 58–97%, respectively. Two correlations are proposed for carbon content with a coefficient of determination ( R 2 ) of 81.52% and 89.86%, two for hydrogen content with R 2 of 79.01% and 88.45%, and one for higher heating value with R 2 of 92.80%. The root mean square error (RMSE) values of the proposed correlations are 0.037, 0.028, 0.059, 0.043 and 0.023, respectively. The predictability of the proposed relations is examined with an additional set of experimental data and compared with the existing correlations in the literature. The new correlations can be used as a useful tool when designing torrefaction plants, furnaces, or gasifiers operating on torrefied wood.

Transverse dam-break waves

2014 ◽  
Vol 758 ◽  
Author(s):  
S. Karimpour Ghannadi ◽  
Vincent H. Chu
Keyword(s):  
Froude Number ◽  
Flow Rate ◽  
Main Flow ◽  
Dam Break ◽  
The Other ◽  
Water Diversion ◽  
The Family ◽  
The One ◽  
Limiting Case ◽  
The Waves

AbstractNumerical simulations of the transverse dam-break waves (TDWs) produced by the sudden removal of a gate on the side of a waterway are conducted based on the shallow-water equations to find solutions to a family of water-diversion problems. The Froude numbers in the main flow identify the members of the family. The depth and discharge profiles are analysed in terms of Ritter’s similarity variable. For subcritical main flow, the waves are comprised of a supercritical flow expansion followed by a subcritical outflow. For supercritical main flow, on the other hand, the waves are analogous to the Prandtl–Meyer expansion in gas dynamics. The diversion flow rate of two-dimensional TDWs on a flat bed is 55 % greater than the one-dimensional flow rate of Ritter in the limiting case of zero main flow, and approaches the rate of Ritter in the other limit when the value of the Froude number in the main flow approaches infinity. The diversion flow rate over a weir is generally higher than the rate over a flat bed depending on the Froude number of the main flow. These numerical simulation results are consistent with laboratory observations.

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