Effect velocity

These design fundamentals result in the requirement that space velocity, effective space—time, fraction of bubble gas exchanged with the emulsion gas, bubble residence time, bed expansion relative to settled bed height, and length-to-diameter ratio be held constant. Effective space—time, the product of bubble residence time and fraction of bubble gas exchanged, accounts for the reduction in gas residence time because of the rapid ascent of bubbles, and thereby for the lower conversions compared with a fixed bed with equal gas flow rates and catalyst weights. 

Good Good 3S-62 9.3-S.5 Higli-iron types excellent for resisting higli-velocity effects in condenser tubes... 

Piping to Burners - First and second stage piping and headers, as well as the burner lines themselves, are sized to minimize pressure drop and velocity effects. Thus, maldistribution of flow to the burners will be minimized. The burner lines are fabricated from standard 1(X) mm pipe, and are arranged in a split grid layout with distribution headers and split feed lines on opposite sides, for both first and second stage burners. First and second stage headers must be sloped so that any condensate will drain back to the seal drums. However, the burner lines must be accurately installed in a horizontal plane. 

Column diameter for a particular service is a function of the physical properties of the vapor and liquid at the tray conditions, efficiency and capacity characteristics of the contacting mechanism (bubble trays, sieve trays, etc.) as represented by velocity effects including entrainment, and the pressure of the operation. Unfortunately the interrelationship of these is not clearly understood. Therefore, diameters are determined by relations correlated by empirical factors. The factors influencing bubble cap and similar devices, sieve tray and perforated plate columns are somewhat different. 

Velocity effects can be achieved either by having the test-piece move through a presumably stationary liquid or by having a moving liquid come into contact with a stationary test-piece. Occasionally tests may involve both types of exposure. Details of test procedures are given in NACE TM 0270-70 Method of Conducting Controlled Velocity Laboratory Corrosion Tests. 

For a micro-channel connected to a 100 pm T-junction the Lockhart-Martinelli model correlated well with the data, however, different C-values were needed to correlate well with all the data for the conventional size channels. In contrast, when the 100 pm micro-channel was connected to a reducing inlet section, the data could be fit by a single value of C = 0.24, and no mass velocity effect could be observed. When the T-junction diameter was increased to 500 pm, the best-fit C-value for the 100 pm micro-channel again dropped to a value of 0.24. Thus, as in the void fraction data, the friction pressure drop data in micro-channels and conventional size channels are similar, but for micro-channels, significantly different data can be obtained depending on the inlet geometry. 

Here the CQ term represents the global effect due to nonuniform voids and velocity profiles. The VGU/(J) term represents the local relative velocity effect (Todreas and Kazimi, 1990). 

The model was fit to experimental planarization data with good success. Divergence from experimental results was explained by viscoelastic deformation of pad asperities. Incomplete elastic recovery reduces penetration of the trench and improves selectivity. This may be due to velocity effects (i.e., the interaction times are below the relaxation time for the material). 

Micellar catalysis is a broad field (Fendler and Fendler, 1975 Rathman, 1996 Rispens and Engberts, 2001), and caution is needed when using this term. In fact, whereas the broad term catalysis is justihed when referring to an increase of the velocity of reachon, this does not always mean that the velocity constant is increased (namely that there is a decrease of the specific activation energy). Rather, the velocity effect can be due to a concentration effect operated by the surface of the micelles. This is also the case for the autocatalytic self-reproduction of micelles discussed in the previous chapter, where the lipophilic precursor of the surfactant is concentrated on the hydrophobic surface of the fatty acid micelles (Bachmann et al., 1992), a feature that has given rise to some controversy (Mavelli and Luisi, 1996 Buhse etal, 1991 1998 Mavelli, 2004). 

McDow, S. R., and J. J. Huntzicker, Vapor Adsorption Artifact in the Sampling of Organic Aerosol—Face Velocity Effects, Atmos. Environ., 24A, 2563-2571 (1990). 

Detonotion Velocity, Effect of Replacement of Air in Explosive Chorges by Non-explosive Liquids. Accdg to Urbanski et al, (Refs 1 2), deton vels of expls, such as RDX or PETN are appreciably increased when the air contained in them is replaced by a non-expl liquid such as glycerin, acetone, etc... 

Detonation Velocity by Direct Visualization of the Explosive Flow (pp D66Q-R to D662-R) Detonation Velocity, Effect of Replacement of Air in Explosive Charges by Non-Explosive Liquids (p D663-L)... 

It should be noted that the importance of the continuity equation is in evaluating actual velocities within the reactor bed as influenced by the mole, temperature, and pressure changes. Because of the use of mass velocities (pgug), the importance of the actual velocities is really restricted to cases where pressure relationships such as the Blake-Kozeny equation or velocity effects on heat transfer parameters are considered. As will be shown later, very little increased computational effort is introduced by retaining the continuity equation, since it is solved as a set of algebraic equations. 

These devices showed EL enhancements to ammonia, methylamine, di-methylamine, trimethylamine, and sulfur dioxide that increased in magnitude with concentration until saturation was reached [14]. The LEDs with larger active layers produced the greatest change in EL intensity with exposure to sulfur dioxide and the amines. Intensity changes were attributed principally to surface recombination velocity effects, as the significant forward biases employed should eliminate the depletion width. 

Air Velocity. Effective Evapn. Constant, Increase in Evaporation Constant,... 

COMBUSTOR INLET-AIR VELOCITY. Inlet-air velocity effects on both smoke and coke deposition arc similar to inlet temperature effects—i.e., depending on operating and design variables, smoke and deposits may increase or decrease with increase in velocity. Velocity can increase coke deposition, for a given combustor design, by increasing recirculation of air currents that would cause more fuel impingement on walls... 

F.G. Hammitt, D.M. Ericson, J.F. Lafferty and M.J. Robinson, Gas content, size, temperature, and velocity effects on cavitation inception in a venturi, Amer. Soc. Mech. Engin. paper 67-WA/FE-22,1968. 

McDow, S.R. and J.J. Huntzicker. 1990. Vapor adsorption artifact in the sampling of organic aerosol face velocity effects. Atmos. Environ. 24A 2563-2571. 

Equation (9.45) assumes that there is no velocity effect on Hem. 

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