New Validated Methodology for the Required Force to Operate Balanced Disk Globe Valves

Author(s):  
Zachary Leutwyler ◽  
Kenneth Beasley ◽  
Emil Leutwyler ◽  
Mital Mistry

Electric Power Research Institute (EPRI) contracted Kalsi Engineering, Inc (KEI) to perform flow loop testing, computational fluid dynamic (CFD) analyses, and methodology development to more accurately predict flow-induced forces in balanced globe valves. The flow loop test conditions included single-phase and two-phase water flow, straight pipe and upstream-flow-disturbance pipe configurations, and two 4-inch balanced disk globe valves test specimens with a combination of quick opening and linear trim. CFD predictions were performed with a commercial grade dedicated version of ANSYS CFX 16.0 software. The methodology was developed to utilize key dimensional characteristics of the disk and cage to determine the effective area through the stroke. The methodology accounts for trim characteristics, flow orientation, disk style, maximum valve DP and maximum flow rate. The model is validated for fluid temperatures between 70 °F and 160 °F, flow velocities up to 45 ft/sec. The methodology was validated against flow loop test data over a range of flow conditions, disk styles, and trim characteristics. Paper published with permission.

Author(s):  
Ji-Gu Lee ◽  
Ji-Yun Kang ◽  
Youn-Jea Kim

Induced Gas Flotation (IGF) vessel is used for water treatment of plant industries such as oil sand and chemical plants. An understanding of the interaction between the stator and rotor is essential for the design of IGF with consideration of geometric blade configuration is essential for the design of IGF. In this study, the effect of the number of stator blades on flotation performance was numerically investigated using the commercial code, ANSYS CFX ver. 16.1. The two-phase (water and air) flow characteristics in the forced-air mechanically stirred Dorr-Oliver flotation cell were considered. The flotation performance was evaluated on the basis of the correlations among the number of stator blades (8, 12, 16, 20, 24), power number and void fraction. By comparing the result of each case, the newly designed model with 12 stator blades which had the highest flotation performance was derived.


2019 ◽  
Vol 27 (01) ◽  
pp. 1950005 ◽  
Author(s):  
Raid Ahmed Mahmood ◽  
David Buttsworth ◽  
Ray Malpress

The flash tank separator is one of the most important components that can be used to improve the performance of a refrigeration cycle by separating the liquid from the gas–liquid two-phase flow and providing the evaporator with only liquid refrigerant. This technique increases the effective area and enhances the heat transfer coefficient in the evaporator. To optimize the size of the vertical flash tank separator for obtaining high separation efficiency, the effect of the size of the vertical flash tank separator needs to be considered. This paper investigates the effect of the size on the liquid separation efficiency of the vertical flash tank separator. This paper also assesses the usefulness of Computational Fluid Dynamic (CFD) in flash tank design, and this is achieved through experiments and simulations on a range of relevant configurations using water as the working fluid. The results revealed that the size has a significant effect on the liquid separation efficiency, as the highest value was achieved by the largest size (VFT-V5). The CFD simulations give a good agreement with the experiments; all the simulations underestimated the liquid separation efficiency by approximately 0.02 over the range of conditions tested.


2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Ihab H. Alsurakji ◽  
A. Al-Sarkhi ◽  
M. Habib ◽  
Hassan M. Badr

This paper presents experimental investigations conducted to understand the influence of water-soluble drag-reducing polymers (DRPs) in single- and two-phase (stratified wavy) flow on flow-field characteristics. These experiments have been presented for water and air–water flowing in a horizontal polyvinyl chloride 22.5-mm ID, 8.33-m long pipe. The effects of liquid flow rates and DRP concentrations on streamlines and the instantaneous velocity were investigated by using particle image velocimetry (PIV) technique. A comparison of the PIV results was performed by comparing them with the computational results obtained by fluent software. One of the comparisons has been done between the PIV results, where a turbulent flow with DRP was examined, and the laminar–computational fluid dynamic (CFD) prediction. An agreement was found in the region near the pipe wall in some cases. The results showed the powerfulness of using the PIV techniques in understanding the mechanism of DRP in single- and two-phase flow especially at the regions near the pipe wall and near the phases interface. The results of this study indicate that an increase in DRP concentrations results in an increase in drag reduction up to 45% in single-phase water flow and up to 42% in air–water stratified flow.


2021 ◽  
Vol 655 (1) ◽  
pp. 012024
Author(s):  
O.H. Ajesi ◽  
M.B. Latif ◽  
S.T. Gbenu ◽  
C. A. Onumejor ◽  
M. K. Fasasi ◽  
...  

2021 ◽  
Author(s):  
Filipe Smith Buarque ◽  
Cleide Mara Faria Soares ◽  
Ranyere Lucena de Souza ◽  
Matheus Mendonça Pereira ◽  
Álvaro Silva Lima

Two-phase water-free systems containing high ethanol content in the coexisting phases can selectively partition hydrophobic molecules from natural biomass.


1965 ◽  
Vol 87 (1) ◽  
pp. 134-141 ◽  
Author(s):  
F. J. Moody

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.


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