Open pipe

Heat transfer in static mixers is intensified by turbulence causing inserts. For the Kenics mixer, the heat-transfer coefficient b is two to three times greater, whereas for Sulzer mixers it is five times greater, and for polymer appHcations it is 15 times greater than the coefficient for low viscosity flow in an open pipe. The heat-transfer coefficient is expressed in the form of Nusselt number Nu = hD /k as a function of system properties and flow conditions. 

Separate forced ventilation is required for some apphcations (for example, adjustable-speed drives which operate at low speed) these must depend on an external ventilation. This classification includes open externally ventilated machines, open pipe-ventilated machines. 

At the Lipari Landfill site in New Jersey, the gas venting system installed in 1983 consisted of two underground 4-inch (10-cm) perforated PVC pipes and five vent risers. Two parallel PVC pipes were installed 200 feet apart prior to cap emplacement during the period of wall construction and were placed about 3 feet beneath the finished grade. The vent risers were connected to the buried manifold pipes and consisted of open pipe installed perpendicular to the underground pipes and the ground surface. Filters were not attached to the riser exit points (U.S. EPA, 1987). 

The equation of Brooke [36] is useful in estimating water or similar fluids flow from the end of open pipes ... 

APq for open pipe, and f = Re vs f chart (Fluid Flow, Chapter... 

An open pipe-ventilated machine is an open machine except that openings for the admission of the ventilating air are so arranged that inlet ducts or pipes can be connected to them. Open pipe-ventilated machines shall be self-ventilated (air circulated by means integral with the machine (ICll) or forced-ventilated (air circulated by means external to and not a part of the machine) (IC17). Enclosures shall be as defined in 1.25.1a to 1.25.5a, inclusive. 

P0 = Np = Power number, dimensionless, Equation 5-19 Ppew = Plate coil width, one plate, ft Ap = Pressure drop, psi AP0 = Pressure drop for open pipe, psi AP, = Static mixer pressure drop in turbulent flow, psi Q = Flow rate or pumping capacity from impeller, cu l t/sec, or Ls/1... 

El), Oldshue (Ol), and Johnson et al. (J4)] have been concerned with the determination of the volume transfer coefficient KtAb (liter/hr), where Kx is the mass-transfer coefficient and Ab is the total gas-liquid interfacial area. The results obtained using a turbine impeller and an open pipe sparger can be correlated in terms of the nominal gas velocity wg(ft/hr) and the horsepower input to the impeller HP by an expression of the following form ... 

In 1962 Jottrand and Grunchard (J7) reported on mass transfer to a small rectangular nickel plate immersed in a liquid fluidized bed of sand particles. Mass-transfer rates were five to ten times higher than those measured in an open pipe flow a maximum rate was measured at a bed porosity of 0.58. Le Goff et al. (Lie) later showed that this maximum is directly related to a maximum in the average kinetic energy of the fluidized particles per unit bed volume. 

Open Pipe The end of a pipe is fully opened exposing the cross sectional area of the pipe (e.g., drilling blowouts). 

If burning is proceeding under constant pressure, such as in a Bunsen burner or in an open pipe, the rate of burning is constant. 

Many early experiments were carried out with the Meker type of burner. A perforated metal plate is placed on top of an open pipe (the thicker the plate, the more stable is the flame). On ignition, a number of small cones... 

Axial dispersion Low Z/D and low Reynolds number flow conditions Vessel with baffles or internals obstructing flows High ZID and high Reynolds flow in open pipes... 

Concentric-orifice devices can be easily installed in high-pressure lenses. The high-end- and the low-end connection of such devices could be coupled with differential pressure transmitters, for example, with the before-mentioned devices of [54]. The devices are mounted in different ways. Mostly, the open pipe technique is used. Furthermore, both connected sides of the transmitter are fed with an inert gas, for example, nitrogen. For cases where the systems must separated, membrane devices can be arranged between them. All the mentioned orifice devices are technically proved and are applied in the high-pressure area. 

Although for a closed vessel the boundary conditions are different from the case of an open pipe (see Section 2.3.5 below), we will assume that the above methods of data treatment apply because, as will subsequently be verified, the dispersion number in this Example is small. 

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