Orifice, jets

Tube collectors, 26 702 Tube-cooled converter, in methanol synthesis, 26 309 Tube furnaces, 12 739 Tube-in-orifice jet nozzle design,... 

The terms of Eq. (14-128) are in English units and are explained in the Nomenclature. The exponent n is calculated from Eq. (14-84). Equation (14-128) is based on transition data obtained from orifice jetting measurements for the air-water system and on entrainment minimum data for some hydrocarbon systems. 

The velocity of a fluid approaching an orifice or nozzle or similar device is called the velocity of approach. For example, consider a large tank, filled with liquid, with a small orifice on its wall, near the bottom. It is assumed that the area of the tank is so large relative to that of the orifice that the velocity at the surface of the liquid (point 1) is negligible. Let the Bernoulli theorem be written between point 1 at the surface and point 2 at the orifice jet discharge, assuming the pressure is the same at both points. Let h equal the height of the liquid, measured from the surface level to the center of the orifice. Then 0 + /i + 0 = 0 + 0 + Vj2/2g, from which... 

The flow rate through a Pelton-type hydro unit is controlled by the size of the orifice (jet) in the nozzle... 

Figure 2.22 Illustration of the collection processes in a two-stage cascade impactor. The orifice diameter in the upper plate (orifice jet 1) is larger than that in the lower...

The receiving flask should be placed in such a way that the oil stream from the orifice (jet) strikes the neck of the receiving flask and does not cause foaming. 

The St. Jude Medical valve has two semicircular leaflets, which divide the area available for forward flow into three regions two lateral orifices and one central orifice. The major part of the forward flow emerged from the two lateral orifices. The measurements at peak systole along the centerline plane, 8 mm downstream of the valve, showed a maximum velocity of 220 and 200 cm/s for the lateral and central orifice jets, respectively. The velocity of the jets remained about the same as the flow traveled from 8 to 13 mm downstream (Figure 77.5). The velocity profiles showed two defects, which corresponded to the location of the two leaflets. The velocity measurements indicated that the flow was more evenly distributed across the flow chamber during the deceleration, than during the acceleration phase. Regions of flow separation were observed around the jets adjacent to the flow channel wall as the flow separated... 

A jet emerging from a nonciicular orifice is mechanically unstable, not only with respect to the eventual breakup into droplets discussed in Section II-3, but, more immediately, also with respect to the initial cross section not being circular. Oscillations develop in the Jet since the momentum of the liquid carries it past the desired circular cross section. This is illustrated in Fig. 11-20. 

Fig. n-21. Surface tension as a function of age for 0.05 g/100 cm of sodium di(2-ethylhexyl)sulfosuccinate solution determined with various types of jet orifices [109]. 

Jet separator. An interface in which carrier gas is preferentially removed by diffusion out of a gas jet flowing from a nozzle. Jet separator, jet-orifice separator, jet enricher, and jet orifice are synonymous terms. 

This shroud length allows the jet issuiag from the orifice to expand and fill the shroud. The gas velocity leaving the shroud should not exceed 70 m/s, to minimize attrition. 

Fig. 6. Schematic of dry-jet wet spinning employing tube-in-orifice spinneret A, bore injection medium (liquid, gas, or suspended soHds) B, pump C, spinneret D, polymer spinning solution E, micrometer ( -lm) "dope" filter F, coagulation or cooling bath G, quench bath and H, collection spool.

Because the highest possible interfacial area is desired for the heterogeneous reaction mixture, advances have also been made in the techniques used for mixing the two reaction phases. Several jet impingement reactors have been developed that are especially suited for nitration reactions (14). The process boosts reaction rates and yields. It also reduces the formation of by-products such as mono-, di-, and trinitrophenol by 50%. First Chemical (Pascagoula, Mississippi) uses this process at its plant. Another technique is to atomize the reactant layers by pressure injection through an orifice nozzle into a reaction chamber (15). The technique uses pressures of typically 0.21—0.93 MPa (30—135 psi) and consistendy produces droplets less than 1 p.m in size. The process is economical to build and operate, is safe, and leads to a substantially pure product. 

There are two types of impulse printers (Eig. 19). A piezoelectric ink jet propels a drop by flexing one or more walls of the firing chamber to decrease rapidly the volume of the firing chamber. This causes a pressure pulse and forces out a drop of ink. The flexing wall is either a piezoelectric crystal or a diaphragm driven by a piezoelectric incorporated into the firing chamber (Eig. 19a). Thermal impulse ink jets also propel one drop at a time, but these use rapid bubble formation to force part of the ink in a firing chamber out the orifice (Eig. 19b). 

It has been postulated that jet breakup is the result of aerodynamic interaction between the Hquid and the ambient gas. Such theory considers a column of Hquid emerging from a circular orifice into a surrounding gas. The instabiHty on the Hquid surface is examined by using first-order linear theory. A small perturbation is imposed on the initially steady Hquid motion to simulate the growth of waves. The displacement of the surface waves can be obtained by the real component of a Fourier expression ... 

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