Pump dynamics

The most widely used pumps in the oil and gas industry are reciprocating displacement pumps (in particular piston plunger type), the rotary displacement pump, and the centrifugal dynamic pump. Only these pumps will be discussed in detail. 

In the dynamic pump, in particular, the centrifugal pump, the discharge rate Q is determined by the resistance pressure P in the flow system the pump discharges to (assuming some given speed of the pump). This is illustrated in Figure 3-49. 

The tear film leaves the surface of the globe and eyelids, enters the upper and the lower punctum at the medial aspect of the lid margin, and enters the lacrimal sac before drainage to the nasolacrimal duct and the nasal cavity. However, much of the tear film is eliminated by direct evaporation or by absorption at the level of the lacrimal sac. The lacrimal outflow system is based on an active and dynamic pumping mechanism. Blinking cycle leads to changes in the drainage canaliculi that activate a pump mechanism that drains tears even with the head held in an inverted position. When the palpebral blink mechanism is impaired, tears accumulation leads to spillover to the skin of the lids and cheek [4],... 

Richter A, Klenke C, Arndt KF (2004a) Adjustable low dynamic pumps based on hydrogels. Macromol Symp 210 377-384... 

Dynamic pumps infuse energy to the fluid in a manner that increases either its momentum (centrifugal pumps) or its pressure (electroosmotic and electrohydro-dynamic pumps) as shown in Table 4. They involve centrifugal or hydrodynamic actuations and, more specifically, are driven by electro-/magneto-hydrodynamic [257], electroosmotic [254-256], electrokinetic [251-253], electrowetting [258], and acoustic forces [259]. Centrifugal pumps are typically less effective for fluids with low Reynolds numbers and have limitation in miniaturization. 

Of the methods available to the computational chemist, dynamics is the only one capable of yielding a reliable quantum yield or excited-state lifetime. However, dynamics can also be used as a subtle mechanistic probe, especially to interpret time-resolved spectroscopy in the femtosecond regime. We will focus on the mechanistic use of dynamics. Pump-probe experiments can now follow the time evolution of a photochemical event at a very detailed level complementary trajectory calcidations can supply mechanistic information to interpret such experiments. We will use two examples to illustrate this idea. 

DYNAMIC PUMPS - Pumps in which energy is added to the water continuously and the water is not contained in a set volume. 

Nonmechanical pumps or dynamic pumps, which continuously add energy to the working fluid in a manner that increases either its momentum or its pressure directly [1,2]. Displacement micropumps generally operate... 

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. 

Although different fluid-handling procedures have been reported in the literature, hydro-dynamic pumping is the most used method to deliver fluids into microchannels. However, microfabrication of valves and pumps, besides being difficult and expensive to miniaturize, requires clean room facility technology. Associated to mycotoxin detection, both hydrodynamic and eletrokinetic flows have been addressed. 

Richter A, Bund A, Keller M, Arndt K-F (2004a) Characterization of a microgravimetric sensor based on pH sensitive hydrogels. Sens Actuators B Chem 99(2-3) 579-585 Richter A, Klenke C, Arndt K-F (2004b) Adjustable low dynamic pumps based on hydrogels. Macromol Symp 210(l) 377-384... 

Answer by Author Our data were taken while the samples were dynamically pumped with a diffusion pump and forepump. However, the results would be the same under static vacuum conditions if the pressure is below about 1 p Hg. 

Femto- and picosecond nonlinear transmission (z scan) measurements give the intrinsic TPA coefficient (3 4.7 cm/GW, whereas nanosecond studies show that P is intensity dependent, and ranges from 4.7 at low intensity to over 170 cm/GW at high intensity. The latter is attributed to excited-state contribution, which is confirmed in picosecond dynamical pump-probe studies. " " ... 

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