Prediction of Static Pressure Drop, Velocity and Flow Rate of Higher Viscous Nature of Ester Oil in Power Transformers under Oil Directed Cooling Conditions

2020 ◽  
Author(s):  
Jeyabalan Velandy ◽  
Ankita Garg ◽  
C. S. Narasimhan
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Static Pressure ◽  
Power Transformers ◽  
Drop Velocity ◽  
Cooling Conditions

Numerical Investigation for Inner Flow Fields and Structure Improvements of Medium Speed Mill

2013 ◽  
Vol 732-733 ◽  
pp. 481-486
Author(s):  
Xian Ran Zhu ◽  
Cheng Yong Liu ◽  
Liang Cheng
Keyword(s):  
Numerical Model ◽  
Pressure Drop ◽  
Numerical Investigation ◽  
Flow Rate ◽  
Static Pressure ◽  
Flow Fields ◽  
Field Conditions ◽  
Pressure Drops ◽  
Medium Speed ◽  
Commercial Code

The numerical model for ZGM95 medium speed mill is built and the inner flow fields are simulated by employing the commercial code of FLUENT. The results show that the distributions of the static pressure and the flow rate are not uniform for 36 nozzle rings due to the primary air entering the mill only from one side. Two modified structures are assumed to improve the mills performances and the corresponding models are simulated further. The flow fields are still not good enough and the pressure drop increases sharply in the mill when blocking several nozzle rings, and this structure is not recommended if the amount of pulverizer rejects is not extremely huge. The structure with double-inlet can improve the distribution of the flow fields effectively in the mill and few pressure drops of the mill increase. However, the feasibility of the double-inlet structure is also depends on the field conditions. The pressure drop will be less and the flow fields will be better when adopting the horizontal inlet duct instead of the inclined one.

Numerical Optimization for Bottom Structure of ZGM Medium Speed Mill

2014 ◽  
Vol 672-674 ◽  
pp. 1656-1661
Author(s):  
Xian Ran Zhu ◽  
Cheng Yong Liu ◽  
Liang Cheng
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Numerical Optimization ◽  
Structural Modification ◽  
Static Pressure ◽  
Flow Fields ◽  
Numerical Investigations ◽  
Medium Speed ◽  
Commercial Code ◽  
Bottom Chamber

The inner flow fields in the ZGM95 medium speed mill are numerically simulated by employing the commercial code of FLUENT. The results show that the static pressure and the flow rate at each nozzle ring is different from those of others due to the primary air entering the mill only from one side. Some baffles are proposed to be added in the bottom chamber of the mill to optimize the performance of medium speed mill, and the modified models are also simulated. A couple of fan-shaped baffles, which are arranged symmetrically in the bottom chamber, can improve the distribution of the flow fields efficiently in the mill while few pressure drop of the mill will increase. The structure with fan-shaped baffles is recommended to be an important choice of the structural optimization of the medium speed mill. The numerical investigations also indicate that the structural modification of mill should be as simple as possible.

Two-Phase Pressure Drop Across Vertically Mounted Thick Plate Restrictions

1964 ◽  
Vol 86 (2) ◽  
pp. 227-238 ◽  
Author(s):  
J. O. Cermak ◽  
J. J. Jicha ◽  
R. G. Lightner
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Thick Plate ◽  
Static Pressure ◽  
Theoretical Models ◽  
Correlation Equation ◽  
Confidence Limits ◽  
Two Phase ◽  
Water Steam ◽  
Phase Pressure

The objective of this experimental study was to obtain two-phase (water-steam) flow pressure drop for thick-plate flow restrictions. Two-phase pressure drop data for uniformly heated tubular test sections were also obtained. A statistically designed program encompassing 536 runs was conducted employing 30-in. long test sections of six geometries. Two nozzle type, three thick-plate orifice type, and one straight expansion type flow restrictions were investigated. The ranges of parameters investigated were: Quality: 0–23 percent; Flow Rate: 500–1500 lb/hr; Pressure: 800–1600 psia; Tube Diameters: 0.416, 0.500 in. A complete factorial experimental design was employed which enabled an analysis of variance to be conducted to determine the significance of the flow rate, quality, and pressure on the response of the static pressure drop. Each of these factors was found to be highly significant. Inherent in the statistical methods employed was the establishment of the 95 percent confidence limits on the data for each test section studied. These limits ranged from 0.009 psi to 0.306 psi for the largest and smallest restriction diameters, respectively. The precision of the data was well within the limits for experimental two-phase flow technology. The results of an error analysis indicate that the accuracy with which flow rate, pressure, and geometry were determined gave rise to insignificant errors and the resulting maximum possible error in quality was less than the lower limit of the correlation equation confidence limits. The results of this study were compared with only moderate success to the theoretical models presented in the literature by Tippetts, Hoopes, and Mendler, et al. Several attempts at correlating the data resulted in a design equation to calculate the static pressure drop for the flow restrictions investigated. The form of the equation developed was: ΔPs=Zα′νG+1−α′νFgg0+K′νF2g0GR1−x1−α′2

Thermal Performances in Ribbed Rectangular Convergent and Divergent Channels

2013 ◽  
Vol 479-480 ◽  
pp. 249-253
Author(s):  
M.S. Lee ◽  
S.S. Jeong ◽  
Soo Whan Ahn
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Static Pressure ◽  
Pumping Power ◽  
Inclination Angles ◽  
Divergent Channel

The rectangular convergent/divergent channels with one sided ribbed surface only have the inclination angles of 0.72oand1.43o at which the ribbed wall is manufactured with a fixed rib height ( e) =10 mm and the ratio of rib spacing (p) to height ( e) =10. The comparison shows that among the four channels (Dho/Dhi =0.67, 0.86, 1.16, and1.49) the divergent channel of Dho/Dhi =1.49 has the highest thermal performance at the identical mass flow rate, and the divergent channel of Dho/Dhii =1.16 has the highest at the identical pumping power and static pressure drop.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

scholarly journals Effect of the Gas Volume Fraction on the Pressure Load of the Multiphase Pump Blade

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 650
Author(s):  
Guangtai Shi ◽  
Dandan Yan ◽  
Xiaobing Liu ◽  
Yexiang Xiao ◽  
Zekui Shu
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Volume Fraction ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Multiphase Pump ◽  
Pressure Load ◽  
Gas Volume Fraction ◽  
Power Capability ◽  
Gas Volume

The gas volume fraction (GVF) often changes from time to time in a multiphase pump, causing the power capability of the pump to be increasingly affected. In the purpose of revealing the pressure load characteristics of the multiphase pump impeller blade with the gas-liquid two-phase case, firstly, a numerical simulation which uses the SST k-ω turbulence model is verified with an experiment. Then, the computational fluid dynamics (CFD) software is employed to investigate the variation characteristics of static pressure and pressure load of the multiphase pump impeller blade under the diverse inlet gas volume fractions (IGVFs) and flow rates. The results show that the effect of IGVF on the head and hydraulic efficiency at a small flow rate is obviously less than that at design and large flow rates. The static pressure on the blade pressure side (PS) is scarcely affected by the IGVF. However, the IGVF has an evident effect on the static pressure on the impeller blade suction side (SS). Moreover, the pump power capability is descended by degrees as the IGVF increases, and it is also descended with the increase of the flow rate at the impeller inlet. Simultaneously, under the same IGVF, with the increase of the flow rate, the peak value of the pressure load begins to gradually move toward the outlet and its value from hub to shroud is increased. The research results have important theoretical significance for improving the power capability of the multiphase pump impeller.

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.

Experimental and Computational Analyses of Pressure Differentials in Flexible Ducts With Different Bent Angles

2007 ◽  
Author(s):  
Ray R. Taghavi ◽  
Wonjin Jin ◽  
Mario A. Medina
Keyword(s):  
Pressure Drop ◽  
Static Pressure ◽  
Complex Geometry ◽  
Analysis Data ◽  
Secondary Flows ◽  
Low Flow ◽  
Pressure Drops ◽  
Pressure Distributions ◽  
Geometrical Effects ◽  
Cfd Analyses

A set of experimental analyses was conducted to determine static pressure drops inside non-metallic flexible, spiral wire helix core ducts, with different bent angles. In addition, Computational Fluid Dynamics (CFD) solutions were performed and verified by comparing them to the experimental data. The CFD computations were carried out to produce more systematic pressure drop information through these complex-geometry ducts. The experimental setup was constructed according to ASHRAE Standard 120-1999. Five different bent angles (0, 30, 45, 60, and 90 degrees) were tested at relatively low flow rates (11 to 89 CFM). Also, two different bent radii and duct lengths were tested to study flexible duct geometrical effects on static pressure drops. FLUENT 6.2, using RANS based two equations - RNG k-ε model, was used for the CFD analyses. The experimental and CFD results showed that larger bent angles produced larger static pressure drops in the flexible ducts. CFD analysis data were found to be in relatively good agreement with the experimental results for all bent angle cases. However, the deviations became slightly larger at higher velocity regimes and at the longer test sections. Overall, static pressure drop for longer length cases were approximately 0.01in.H2O higher when compared to shorter cases because of the increase in resistance to the flow. Also, the CFD simulations captured more pronounced static pressure drops that were produced along the sharper turns. The stronger secondary flows, which resulted from higher and lower static pressure distributions in the outer and inner surfaces, respectively, contributed to these higher pressure drops.

scholarly journals Maximum Flow Rate of a Single Component, Two-Phase Mixture

1965 ◽  
Vol 87 (1) ◽  
pp. 134-141 ◽  
Author(s):  
F. J. Moody
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Maximum Flow ◽  
Single Component ◽  
Maximum Flow Rate ◽  
Vapor Flow ◽  
Two Phase ◽  
Slip Ratio ◽  
Phase Mixture ◽  
Local Slip

A theoretical model is developed for predicting the maximum flow rate of a single component, two-phase mixture. It is based upon annular flow, uniform linear velocities of each phase, and equilibrium between liquid and vapor. Flow rate is maximized with respect to local slip ratio and static pressure for known stagnation conditions. Graphs are presented giving maximum steam/water flow rates for: local static pressures between 25 and 3,000 psia, with local qualities from 0.01 to 1.00; local stagnation pressures and enthalpies which cover the range of saturation states.

Sign in / Sign up

Export Citation Format

Share Document