Jet pump effect

MIcrofluldic Systems for Combinatorial Chemistry, Rgure 4 The valve from Fig. 3, the usual building block of the sampling unit, in the dosed state with the jet of sample fluid diverted into the vent The jet-pumping effect (entrainment Into the jet) causes a return flow through the main collector... 

Valve-Less RecfiflcaVeii Pumps, Hgure 14 Operation of the three-terminal Venturi rectifier. Ruid from the suction pipe of the pump enters the rectifier due to the jet-pumping effect of entrainment into the jet, which appears in both fiow haives of the operating cycie... 

When the mixing head is attached to the mold, it is important that the jet pump effect of the flowing mixture does not suck in air through a leaky joint. Furthermore, the reaction mixture should not be injected as a free jet into the mold cavity (Figure 1.125). The flow should at least keep contact to one cavity wall, preferred is the later visible part surface. 

Pumps where the pumping effect is based mainly on the diffusion of gases into a gas-free high speed vapor jet (vapor pumps)... 

This effect is caused by entrainment of the surrounding fluid into the jet, which carries this fluid away. It has to be replaced by the fluid pumped into the vicinity of the jet by jet pumping. The effect is much stronger in turbulent jets, existing at higher values of Reynolds... 

Valve-Less Rectification Pumps, Fig. 19 Jet-type rectifiers. (A) A classical jet-pump generates In the secondary inlet a suction by entrainment into the primary nozzle jet. Due to jet inertia, some effect is retained even during absence of inflow in the passive half-period. 

The ejector reactor conceptually is a bubble reactor into which a liquid jet entraining gas is injected (117) (Fig. 22). The ejector provides high liquid velocities (over 20 m/sec) which entrain gas by suction through a mixer device placed inside the reactor where there is intense gas-liquid contact. Also, gas and 1iqald ace circulated inside the reactor by a pumping effect in... 

There is considerable information available in the hterature on the design of ejectors (steam jet ejectors, water jet pumps, air injectors, etc.) supported by extensive experimental data. Most of this information deals with its use as an evacuator and the focus is on ejector optimization for maximizing the gas pumping efficiency. The major advantage of the venturi loop reactor is its relatively very high mass transfer coefficient due to the excellent gas-liquid contact achieved in the ejector section. Therefore, the ejector section needs careful consideration to achieve this aim. The major mass transfer parameter is the volumetric liquid side mass transfer coefficient, k a. The variables that decide k a are (i) the effective gas-hquid interfacial area, a, that is related to the gas holdup, e. The gas induction rate and the shear field generated in the ejector determine the vine of and, consequently, the value of a. (ii) the trae liquid side mass transfer coefficient, k. The mass ratio of the secondary to primary fluid in turn decides both k and a. For the venturi loop reactor the volumetric induction efficiency parameter is more relevant. This definition has a built in energy... 

Cangle filter n. A small filter interposed between the spinning pump and spinning jet to effect final filtration of the spinning solution prior to extrusion. 

Figure 5-14 shows a typical family tree for the dynamic pump family. Centrifugal pumps are often used in jet pump systems. A jet pump uses a unique design on the suction side of the pump to create a venturi effect as a portion of the discharge is pushed down the casing and back into the suction line. This process provides the lift needed to raise liquid levels that are lower than 40 feet. 

The tool design has jet nozzles that create a tighter stream of water that maintains its energy at the wall of large-diameter coke drums. The nozzle concentrates the power from the jet pump and provides a sharper hydraulic jet of water to more effectively cut the coke. 

Some jet pump components are subject to flow induced vibration. Fatigue is a potentially significant degradation mechanism for the jet pump and further evaluation of programmes to effectively manage age-related degradation is required. 

In September 1993, Grand Gulf Nuclear Power Station Unit 1 (GG-1) experienced an in-service failure of a jet pump beam due to IGSCC in the ear location at the end of the beam. As a result GE recommended replacement for beams of design similar to those used at GG-1. The recommended corrective actions have been effective. 

GE SIL 330S1 (2/1/81) BWR/4 Jet Pump Beam Cracks Discusses differences between failiue mechanisms of the BWR/3 and BWR/4 beam designs and corresponding effects on jet punq) performance monitoring and recommends that owner/operators with BWR/4 jet pump beam designs also implement surveillance procedures. f6.171... 

The BWR pilot plant life extension study [6.31, 6.32] recommended that at least one jet pump inlet mixer subassembly should be disassembled, dye penetrant tested, and examined for erosion effects following 30 to 40 years of operation. The stainless steel material of the jet pump together with favorable inspection results to date indicates that... 

Dresden-I showed that it was possible to operate with a steam quality high enough that external risers and an external steam drum were no longer necessary. Modern BWRs incorporate steam separators and driers mounted above the core inside the pressure vessel itself. A further advance is the adoption of internal jet pumps, mounted on the inside of the pressure vessel, for circulation of the coolant through the core. These are driven by external loop pumps, but the fraction of the core recirculation flow which is required to drive the jet pumps is only about one third of the whole, leading to a reduction in the number and size of the external loops, with a consequent reduction in the severity of the potential effects of breaches of the primary circuit. 

The increase in useful effect of the polymer slurry is also greatly dependent upon the polymer particle sizes and mixtures used. The results shown for the increase in useful effect are lower than expected, and probably too low for useful application. It is believed, however, that the short length of time between passes through the jet pump (<15 s) has very detrimental effects, and in non-laboratory applications, the effects would be much greater. 

The determination of equations (11) and (16) along with the determination of Figure 3 forms the basis for Figure 4 which is the end result of the analysis. Here the effect of the jet pump on efficiency ratio and suction specific speed ratio is shown. The effect of the specification parameter, P, is shown and the curves are related to Figure 3 by including lines of constant values of rj. The data from Figures 3 and 4 are used in the following manner ... 

A water-jet pump sucks up the used electrolyte through a flexible tube from the bottom of the pipe to reduce the corrosion effect. 

The code includes many generic component models from which general systems can be simulated. The component models include pumps, valves, pipes, heat releasing or absorbing structures, reactor point kinetics, electric heaters, jet pumps, turbines, separators, accumulators, and control system components. In addition, special process models are included for effects such as form loss, flow at an abrupt area change, branching, choked flow, boron tracking, and non-condensable gas transport. 

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