Volume flow

Having obtained the true velocity from a Pitot survey, multiplying that value by the free area of the duct will give the volume flow. 

The flow rate can be calculated in terms of volume flow. 

Ap = upstream static pressure minus the downsteam or throat static pressure, Pa Pi = density at the upstream tapping, kgm gv=measured at the upstream density pi, m s gm = constant right through the airway system, kg m a = flow coefficient as given in the appropriate standard E = expansibility factor as given in the appropriate standard 

For testing with atmospheric air, 8 may be taken as 1 provided Ap 1000 Pa. Also, a can be replaced by CE where C = coefficient of discharge 

the duct Reynold s number (based on the average velocity and air conditions in the approach duct /)) or 

Note that the mass flow is constant in the process, from spinning pump to winder. No mass is lost, in contrast to dry or wet spinning. For example, at the end of the spin-line the speed is 800 m min , flve times lower than after drawing, but the undrawn yarn still has a flve times higher titer. Also note that the volume flow is not completely constant, because the density increases (by about 20%) when the melt cools down, solidifies, and crystallizes. 

Eight yarn bundles make 8 x 668 = 5344 g min = 320.6 kg h , which would require a 120 mm, maybe 150 mm, extruder. The unit produces about 7.6 ton day, or about 2700 ton y.  

The density of a polyester melt is approximately 1.18 g cm. The volume flow per yam bundle and spinning pump thus is 668/1.18 = 566 cm min. This flow can be achieved with a 20 cm pump at 28.3 rpm. 

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Now integrate the equation (5) taking into account the formulae for pi and pN. As a result we arrive to the specific volume flow rate in a film, referred to the unit of length for cross section ... 

In the case, where all 3 phases are present, the detector measurements reveal the amounts of tracers in each phase and the position of the boundaries between the phases The cross section area of each phase is calculated fi-om the latter. From this the tracer concentrations and hence the volume flows of the 3 phases are calculated. 

The simple treatment of this and of other electrokinetic effects was greatly clarified by Smoluchowski [69] for electroosmosis it is as follows. The volume flow V (in cm /sec) for a tube of radius r is given by applying the linear velocity V to the body of liquid in the tube... 

A simple law, known as Darcy s law (1936), states that the volume flow rate per unit area is proportional to the pressure gradient if applied to the case of viscous flow through a porous medium treated as a bundle of capillaries,... 

Here z denotes distance measured along the tube from the injection point and f is the volume flow rate of carrier gas, per unit total cross-section. 

Torr (mm of mercury) Torr Volume flow rate ... 

This arrangement provides a thin film of liquid sample solution flowing down to a narrow orifice (0.007-cm diameter) through which argon flows at high linear velocity (volume flow is about 0.5-1 1/min). A fine aerosol is produced. This particular nebulizer is efficient for solutions having a high concentration of analyte constituents. 

Specialty Gases. The specialty gases are generally more reactive than the bulk gases and usually have low volume flow requirements in their appHcations. Historically, these have been deHvered almost exclusively in standard compressed gas cylinders. However, as the need for increased quantities has arisen, bulk specialty gas supply systems utilising larger ton-sized containers and tube trailers are being developed. 

Interfacial Mass-Transfer Coefficients. Whereas equiHbrium relationships are important in determining the ultimate degree of extraction attainable, in practice the rate of extraction is of equal importance. EquiHbrium is approached asymptotically with increasing contact time in a batch extraction. In continuous extractors the approach to equiHbrium is determined primarily by the residence time, defined as the volume of the phase contact region divided by the volume flow rate of the phases. 

Holdup and Flooding. The volume fraction of the dispersed phase, commonly known as the holdup can be adjusted in a batch extractor by means of the relative volumes of each Hquid phase added. In a continuously operated weU-mixed tank, the holdup is also in proportion to the volume flow rates because the phases become intimately dispersed as soon as they enter the tank. 

Axial fans are classified as propeller, tube-axial, and vane-axial (Fig. 9). The choice of fan requited is determined by the resistance (static pressure) the fan must work against as well as the volume flow requited. PtopeUet fans usually discharge iato a plenum or directly iato the atmosphere. Tube-axial fans are usually mounted ia ducts as ia an air conditioning system. Vane-axial fans are also mounted ia ducts but feature a stationary guide vane on the discharge side that straightens the air flow to improve efficiency. Tube-axial fans can work at static pressures up to 623 Pa (2.5 ia. H2O) vane-axial fans can work up to 2000 Pa (8 ia. H2O). 

Spunbonded fabrics are effective filters in that they are layered stmctures of relatively fine fibers, the three-dimensional stmcture of which creates a torturous path. Even relatively thin spunbonded fabrics (eg, 0.2—0.25 mm) present a significant challenge to the passage of soil fines and are suitable for use in some filtration appHcations. The porosity of geotextile fabrics is classified by means of several procedures such as flux (volume flow/area per time) and equivalent opening size (EOS), which is a measure of the apparent pore size of the openings in the fabric. The flux measures the porosity to Hquid water, and the EOS measures the porosity to soHd particles of a known diameter. Literature is available on limitations of particular styles of fabrics within an apphcation (63). 

Molecules arrive at the surfaces of traps and baffles by volume flow and surface creep. Molecules are trapped in vacuum systems by binding with energies much greater than kT of the surface, where k is Boltzmann s constant and Tthe absolute temperature, or by lowering the temperature of the surface in such a way that kT is less than the heat of physisorption of a molecular species on a surface. 

Electrically assisted transdermal dmg deflvery, ie, electrotransport or iontophoresis, involves the three key transport processes of passive diffusion, electromigration, and electro osmosis. In passive diffusion, which plays a relatively small role in the transport of ionic compounds, the permeation rate of a compound is deterrnined by its diffusion coefficient and the concentration gradient. Electromigration is the transport of electrically charged ions in an electrical field, that is, the movement of anions and cations toward the anode and cathode, respectively. Electro osmosis is the volume flow of solvent through an electrically charged membrane or tissue in the presence of an appHed electrical field. As the solvent moves, it carries dissolved solutes. 

Both catalyst space velocity and bed geometry play a role. The gas hourly space velocity (GHSV) is used to relate the volumetric flow rate to the catalyst volume. GHSV has units of inverse hour and is defined as the volume flow rate per catalyst volume. 

G Mass velocity kg/(s-m") lb/(s-fP) q Volume flow rate mVs ftVs... 

General Principles There are two main types of mass flowmeters (1) the so-called true mass flowmeter, which responds directly to mass flow rate, and (2) the inferential mass flowmeter, which commonly measures volume flow rate aud flmd density separately. A variety of types of true mass flowmeters have been developed, including the following (a) the Maguus-effect mass flowmeter, (b) the axial-flow, transverse-momentum mass flowmeter, (c) the radial-flow, transverse-momentum mass flowmeter, (d) the gyroscopic transverse-momentum mass flowmeter, aud (e) the thermal mass flowmeter. Type b is the basis for several commercial mass flowmeters, one version of which is briefly described here. 

Gos velocity Velocity distribution Collection oreo Volume flow... 

The results of a specific case study are shown in Fig. 26-49. This depicts the change in inbreathing volume flow rate as a function of time. The middle curve describes the case when the tank is filled with dry air that is, no condensation occurs. When the air is saturated with water vapor at 55°C (131°F) and condensation occurs, the top curve is obtainea. The bottom line represents the volume flow rate brought about by thermal contraction alone, not including the amount condensed. Because of the heat of condensation released, this fraction is less than the volume flow rate without condensation, but this effect is more than compensated for by the additional volume flow rate due to condensation. 

Variables sueh as eoneentration of reaetants, reaetion eoil length, injeetion volume, flow rate. ete. are studied and optimized. Reprodueibility, linearity, deteetion limit and statistieal evaluation are shown. The methods results are in good agreement to other standard methods. 

There are many types of sen.sors used to feed-back the process operating conditions to the switching logistics of an inverter unit. They can be in terms of temperature, pressure, volume, flow, time or any activity on which depends the accuracy and quality of the process. Direct sensing devices used commonly for the control of a drive and used frequently in the following text are speed. sensors, as noted below. 

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