Discussion: “Correlations for Prediction of Pressure Gradient of Liquid–Liquid Flow Through a Circular Horizontal Pipe” [Dasari, A., Desamala, A. B., Ghosh, U. K., Dasmahapatra, A. K., and Mandal, T. K., 2014, ASME J. Fluids Eng., 136(7), p. 071302]

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
M. M. Awad
2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Anjali Dasari ◽  
Anand B. Desamala ◽  
Ujjal K. Ghosh ◽  
Ashok K. Dasmahapatra ◽  
Tapas K. Mandal

We report a detailed investigation on the measurement and prediction of pressure gradient characteristics of moderately viscous lubricating oil-water flow through a horizontal pipe of 0.025 m internal diameter. Experiments are carried out over a wide range of phase velocities of both oil (USO = 0.015–1.25 m/s) and water (USW  =  0.1–1.1 m/s). Experimental pressure gradients yield significant errors when fitted to the existing correlations, which are largely used for gas-liquid flow. To predict pressure gradient characteristics for liquid-liquid flow, the existing correlations need to be modified. We propose two correlations, based on the Lockhart–Martinelli's approach (by modifying the correlation between the Lockhart–Martinelli parameter and a two-phase multiplier suitable for the present system) and dimensionless analysis, following the Buckingham's Pi-theorem. We observe significant improvement in the prediction of pressure gradient. The correlation based on the dimensionless analysis predicts better with an average absolute error of 17.9%, in comparison with the modified Lockhart–Martinelli correlation, which yields an average error of 22%, covering all the flow patterns. The present analysis shows better prediction as compared to two-fluid model Zhang et al. (2012, “Modeling High-Viscosity Oil/Water Concurrent Flow in Horizontal and Vertical Pipes,” SPE J., 17(1), pp. 243–250) and Al-Wahaibi (2012, “Pressure Gradient Correlation for Oil-Water Separated Flow in Horizontal Pipes,” Exp. Therm. Fluid Sci., 42, pp. 196–203) work.


Author(s):  
Suman Debnath ◽  
Anirban Banik ◽  
Tarun Kanti Bandyopadhyay ◽  
Mrinmoy Majumder ◽  
Apu Kumar Saha

2007 ◽  
Author(s):  
Wenhong Liu ◽  
Liejin Guo ◽  
Ximin Zhang ◽  
Kai Lin ◽  
Long Yang ◽  
...  

2021 ◽  
Vol 11 (4) ◽  
pp. 1936
Author(s):  
Abdel-Hakim Bouzid

The accurate prediction of liquid leak rates in packing seals is an important step in the design of stuffing boxes, in order to comply with environmental protection laws and health and safety regulations regarding the release of toxic substances or fugitive emissions, such as those implemented by the Environmental Protection Agency (EPA) and the Technische Anleitung zur Reinhaltung der Luft (TA Luft). Most recent studies conducted on seals have concentrated on the prediction of gas flow, with little to no effort put toward predicting liquid flow. As a result, there is a need to simulate liquid flow through sealing materials in order to predict leakage into the outer boundary. Modelling of liquid flow through porous packing materials was addressed in this work. Characterization of their porous structure was determined to be a key parameter in the prediction of liquid flow through packing materials; the relationship between gland stress and leak rate was also acknowledged. The proposed methodology started by conducting experimental leak measurements with helium gas to characterize the number and size of capillaries. Liquid leak tests with water and kerosene were then conducted in order to validate the predictions. This study showed that liquid leak rates in packed stuffing boxes could be predicted with reasonable accuracy for low gland stresses. It was found that internal pressure and compression stress had an effect on leakage, as did the thickness change and the type of fluid. The measured leak rates were in the range of 0.062 to 5.7 mg/s for gases and 0.0013 and 5.5 mg/s for liquids.


1996 ◽  
Vol 21 (5) ◽  
pp. 347-356 ◽  
Author(s):  
V. Velidandla ◽  
S. Putta ◽  
R. P. Roy

Neurosurgery ◽  
1987 ◽  
Vol 20 (2) ◽  
pp. 249-253 ◽  
Author(s):  
Jack Chang ◽  
Margot R. Roach

Abstract In some cases, basilar artery aneurysms cannot be repaired surgically and the basilar artery is occluded near the neck of the aneurysm to stop flow into the aneurysm. After the operation, the aneurysm can fill only by flow through the posterior communicating arteries (PCoAs). Hemodynamically, if the flow were the same in both PCoAs and there were no phase lag in the pressures, there would be no pressure gradient for flow to go across the neck of the aneurysm and therefore the aneurysm would thrombose. We have assumed that the diameter of the artery is roughly proportional to the flow that goes through it chronically. We measured the diameters of the PCoAs in 25 patients who had hunterian ligation of the basilar artery. We also measured the maximal width, height, and depth of the aneurysms on angiograms obtained before and after operation. Eleven aneurysms thrombosed completely and had a diameter ratio of > 0.6; 10 aneurysms thrombosed partially and had a diameter ratio of 0.46 ˜ 1.0; 4 aneurysms did not change and had a diameter ratio of <0.45. The ratio of the sizes of the PCoAs pre- and postoperatively was comparable in most cases, so we believe that it is possible to predict reasonably accurately from this simple measurement whether the aneurysm is likely to thrombose if the basilar artery is ligated.


Ultrasonics ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 195-196 ◽  
Author(s):  
H.V. Fairbanks ◽  
W.I. Chen

Sign in / Sign up

Export Citation Format

Share Document