A Flow Pump System for Assessing Clay Barrier-Permeant Compatibility

1997 ◽  
Vol 20 (2) ◽  
pp. 179 ◽  
Author(s):  
RC Chaney ◽  
K Demars ◽  
M Kashir ◽  
EK Yanful
Keyword(s):  
Pump System ◽  
Clay Barrier ◽  
Flow Pump

Foetal bypass: concepts and controversies

Perfusion ◽  
1998 ◽  
Vol 13 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Joseph J Sistino
Keyword(s):  
Heart Defects ◽  
Open Heart Surgery ◽  
Axial Flow ◽  
Right Atrial ◽  
Cyclooxygenase Inhibitors ◽  
Pump System ◽  
Maternal Risk ◽  
Valvular Stenosis ◽  
Axial Flow Pump ◽  
Flow Pump

One of the most controversial and challenging surgical undertakings of the next century promises to be foetal cardiac surgery. Animal studies have been underway for several years to gain an understanding of the physiological mechanisms required to achieve this undertaking. Not since the days of crosscirculation has there been a maternal risk associated with open-heart surgery. The diagnosis of congenital heart defects with foetal ultrasound can now be made as early as 12 weeks gestation. Simple cardiac abnormalities, such as valvular stenosis or atresia, alter intracardiac flow patterns and affect normal cardiac chamber development. Without early intervention, these complex lesions often require major surgical reconstruction, beginning in the neonatal period. Foetal cardiac bypass techniques have evolved from the use of roller pumps and bubble oxygenators primed with maternal blood to the use of an axial flow pump incorporated in a right atrial to pulmonary artery or aortic shunt. Because the blood entering the right atrium is oxygenated by the placenta, an oxygenator in the bypass circuit is probably not needed. The low prime axial flow pump system avoids the dilution of the foetus with the maternal adult haemoglobin and improves the outcome. A major focus of research has concentrated on maintenance of placental blood flow with the use of vasodilators and cyclooxygenase inhibitors. Investigation with primates will be necessary to confirm the placental physiology before human operations can be performed. As the foetal bypass challenges are overcome, there is the potential for a reduction in the number of complex cardiac lesions requiring early surgical intervention in the twenty-first century.

scholarly journals Suppression of Mixed-Flow Pump Instability and Surge by the Active Alteration of Impeller Secondary Flows

1993 ◽  
Author(s):  
Akira Goto
Keyword(s):  
Flow Characteristic ◽  
Secondary Flows ◽  
Wake Flow ◽  
Streamwise Vorticity ◽  
Jet Injection ◽  
Positive Slope ◽  
Suction Surface ◽  
Mixed Flow ◽  
Pump System ◽  
Flow Pump

An active method for enhancing pump stability, featuring water jet injection at impeller inlet, was applied to a mixed-flow pump. The stall margin, between the design point and the positive slope region of the head-flow characteristic, was most effectively enlarged by injecting the jet in the counter-rotating direction of the impeller. The counter-rotating streamwise vorticity along the casing, generated by the velocity discontinuity due to the jet injection, altered the secondary flow pattern in the impeller by opposing the passage vortex and assisting the tip leakage vortex motion. The location of the wake flow was displaced away from the casing-suction surface corner of the impeller, thus avoiding the onset of the extensive corner separation, the cause of positive slope region of the head-flow characteristic. This method was also confirmed to be effective for stabilizing a pump system already in a state of surge.

Laboratory Measurement of Low-Permeability Rocks With a New Flow Pump System

1997 ◽  
Vol 506 ◽  
Author(s):  
Ming Zhang ◽  
Manabu Takahashi ◽  
Tetsuro Esaki
Keyword(s):  
Pore Pressure ◽  
Fluid Pressure ◽  
Confining Pressure ◽  
Test System ◽  
Low Permeability ◽  
Specific Storage ◽  
Pump System ◽  
The Difference ◽  
Host Rocks ◽  
Flow Pump

ABSTRACTNearly impermeable host rocks have been recognized as favorable media for many kinds of underground utilization such as radioactive nuclear waste disposal, storage of oil and LP gas, and CAES. To properly evaluate the ability of a geologic medium to retard transmission of fluids, it is necessary to accurately measure its hydraulic properties, most notably the permeability and specific storage. This paper presents a new flow pump permeability test system capable of testing low-permeability rocks under high confining and high pore pressure conditions, which simulate ground pressures at large depths. The new system was used to test the Inada Granite from Japan. The results of present study show that: 1) both permeability and specific storage of the rock are dependent not only on the confining pressure but also on the pore pressure. They decrease with the increment of the effective confining pressure, i.e., the difference between confining and pore pressures; 2) the permeability and specific storage of Inada Granite range from 10−11 to 10−12 cm/s and 10−6 to 10−7 1/cm, respectively. The flow pump technique with its rigorous theoretical analysis can be used to effectively obtain such low permeabilities within several tens of hours; 3) the storage capacity of flow pump system itself decreases with the increment of fluid pressure within the permeating system.

Research on the Geometry Parameters of Diffuser Vane Influence on the Performance of Bulb Tubular Pumping System

2017 ◽  
Author(s):  
Yan Jin ◽  
Junxin Wu ◽  
Hongcheng Chen ◽  
Chao Liu
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Design Parameters ◽  
Hydraulic Loss ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Pumping System ◽  
Axial Flow Pump ◽  
Cfd Method ◽  
Flow Pump

Diffuser vane of tubular pump is different with that of the axial flow pump, since the diffusion angle after the impeller is larger than as usual, which is an important part of bulb tubular pump system. By calculating the hydraulic loss of each part of bulb tubular pump system, it is found that the hydraulic loss of diffuser vane is in large proportion of the whole hydraulic loss. For this situation, focuses on the design parameters of diffuser vane such as diffuser vane length, unilateral edge diffusion angle, equivalent diffusion angle are necessary. In this paper, CFD method is used to simulate the turbulent flow in a bulb tubular pumping system with two different diffuser vanes. The three dimensional flow fields in the whole passage of pumping system with different diffuser vanes are obtained. The results show that all the main geometry parameters of the diffuser vane design affect the performances of tubular pumping system, it should be chosen the parameters reasonably based on the actual situation.

Flow Characteristics of High-Efficient Axial Flow Pump System

2015 ◽  
Author(s):  
Chao Liu ◽  
Fan Yang ◽  
Yan Jin ◽  
Hua Yang
Keyword(s):  
Flow Characteristics ◽  
Axial Flow ◽  
Internal Flow ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Hydraulic Loss ◽  
Pump System ◽  
High Efficient ◽  
Axial Flow Pump ◽  
Flow Pump

Three-dimensional flow-fields in a high-efficient axial flow pump system were simulated by CFD to further study the internal flow characteristics. The internal flow patterns of the pump system were obtained at large, small and optimum operating conditions. The highest efficiency of pump system measured and calculated are 82.57% and 81% respectively at blade angle 0°. For the suction passage, the axial velocity distribution uniformity reach 97.51%, and the hydraulic loss is 0.039m, the pipe efficiency calculated is 98.5% at the optimum operating conditions. The maximum velocity is 1.429 m/s in the range of operating conditions, which meet the requirement of National standard. The performances predicted were compared with measurement results. It was found that the calculated results agree well with the measured results. The overall flow pattern of the pump system is uniform and smooth, and the hydraulic loss is very small which gives the excellent hydraulic performances of pump system.

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