Effect of Velocity

Solution Velocity The effect of velocity is not usually determined in laboratory tests, although specific tests have been designed for this purpose. However, for the sake of reproducibility some velocity control is desirable. 

Figure 9-9. Effect of velocity and air angle on utilization factor.

Most designers ignore the effects of velocity head, but the above brief examples emphasize that the effect varies depending on the situation and the degree of accuracy desired for the head determinations. 

Nelson presents data in Figure 10-40A on some fluids showing the effects of velocity and temperature. Also see Figure 10-40B. 

Figure 10-57. Effect of velocity on heat transfer rates and pressure drop shell-side and tube-side. (Used by permission Shroff, P. D. Chemical Processing, No.4, 1960. Putnam Publishing Co., Itasca, III. All rights reserved.)...

Figure 4-457. Effect of velocity of flow on the initial rate of corrosion of steel pipe. (From Ref. [197].)...

Figure 26.4 illustrates the effect of velocity for water at 16°C on heat transfer coefficients. This graph also plots pressure drop against velocity under the same conditions. The film coefficients are very high and can be obtained for a moderate pressure drop. 

Fig. 1.31 Shape of cathodic polarisation curve when transport overpotential is rate controlling, (a) Effect of velocity on ( l and corrosion rate, (b) effect of concentration on tY and corrosion rate and (c) effect of position and slope of anodic curve (after Stern...

Fig. 3.40 Effect of velocity upon cast iron in sea-water Rotor test at a water temperature of...

Velocity The precise control of velocity and the study of effects of velocity on corrosion are extremely difficult, especially when high velocities are involved. A major problem is to prevent, or to take into account properly, the tendency of a liquid to follow the motion of a specimen moved through it, e.g. by rotation at high velocity. This can be controlled to some extent by proper baffling, but uncertainties as to the true velocity remain —as they do also when the test liquid is made to pass at some calculated velocity over a stationary test-piece or through a test-piece in the form of a tube or pipe ... 

That the flow may be considered essentially as unidirectional (2f-direction) and that the effects of velocity components perpendicular to the surface within the boundary layer may be neglected (that is, uy Reynolds numbers where the boundary layer thickens rapidly. 

M. K. Kim, S. H. Won, and S. H. Chung, Effect of velocity gradient on propagation speed of tribrachial flames in laminar coflow jets, Proc. Combust. Inst. 31 901-908,2007. 

Rosenow WM, Webber JH and Ling AT (1956) Effect of Velocity on Laminar and Turbulent Film Condensation, Trans ASME, 78 1645. 

Effect of velocity and subcooling The relative motion of a heating surface to the Leidenfrost drop was studied by Baumeister and Schoessow (1968), who related the vaporization time of a moving drop to that for a stationary drop through an empirical correlation. 

Logan, D., C. T. Baroczy, J. A. Landoni, and H. A. Morewitz, 1970, Effects of Velocity, Oxide Level, and Flow Transients on Boiling Initiation in Sodium, AI-AEC-12939 Rockwell Int., Canoga... 

The process parameters influencing droplet sizes may include liquid pressure, flow rate, velocity ratio of air to liquid (mass flow rate ratio of air to liquid), and atomizer geometry and configuration. It has been clearly established that increasing the velocity ratio of air to liquid is the most important practical method of improving atomization)211] In industrial applications, however, the use of mass flow rate ratio of air to liquid has been preferred. As indicated by Chigier)2111 it is difficult to accept that vast quantities of air, that do not come into any direct contact with the liquid surface, have any influence on atomization although mass flow rates of fluids include the effects of velocities. 

Velocity inversion is a special case of velocity rotation of every particle, which corresponds to acceleration. Thus one can expect that velocity rotations and acceleration will also produce a change of the 7Y-function or a change of entropy. The effects of velocity rotations on the 7f-function have been considered in Ref. 22. 

To separate effects of a mean velocity from the effects of velocity fluctuations, we expand paq )-p as a sum... 

An explosion or detonation produces both an air blast and a shock wave in the air. The air blast consists of the air in violent motion in a general direction away from the site of the expln and in a condition of extreme turbulence. This degree of turbulence may be imagined by estimating a "Reynolds Number of it, devised by Engl scientist Osborne Reynolds (1842-1912), to describe the effect of velocity phenomena in connection with flow of liquids. If k is Reynolds Number, d=diameter of moving stream, u = its linear velocity, p = its density and = its viscosity,... 

Effects of velocity on homogeneous-heterogeneous ignition and extinction (with RJ. Olsen and L.D. Schmidt). Combust. Sci. Tech., 99 (1995). 

Figure 7. Effect of velocity on lithium carbonate deposition...

Sodium Sulfate. With this system, 49 runs of up to 6 hours duration were made, showing the usual behavior with no appreciable effect of velocity over a 4.5-fold range. Here the wall temperature was from 145° to 265° F. at the point of scale formation. 

For a polemic against the conventional way of viewing of the effect of velocity on mass see Okum L (1989) Physics Today, June 30... 

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