Vapor, distribution velocity allowable

The present model takes into account how capillary, friction and gravity forces affect the flow development. The parameters which influence the flow mechanism are evaluated. In the frame of the quasi-one-dimensional model the theoretical description of the phenomena is based on the assumption of uniform parameter distribution over the cross-section of the liquid and vapor flows. With this approximation, the mass, thermal and momentum equations for the average parameters are used. These equations allow one to determine the velocity, pressure and temperature distributions along the capillary axis, the shape of the interface surface for various geometrical and regime parameters, as well as the influence of physical properties of the liquid and vapor, micro-channel size, initial temperature of the cooling liquid, wall heat flux and gravity on the flow and heat transfer characteristics. 

A numerical simulation tool has been developed that is capable of accounting for radial and axial variations in liquid-fuel distribution. In the absence of definite information on the chemistry of JP-10, a two-step global model analogous to that used in the gas-phase detonation simulations has been constructed. In this model, the residence time of the fuel vapor is tracked, and energy releaise is allowed to occur only after the elapse of a specified induction time. The amount of energy release is based on the lower heating value of the fuel and is calibrated to result in the CJ-detonation velocity for a fully vaporized fuel. 

Product losses in evaporator vapor may result from foaming, ing, or entrainment. Primary separation of liquid from vapor is accomplished in the vapor head by making the horizontal plan area large enough so that most of the entrained droplets can settle out against the rising flow of vapor. Allowable velocities are governed by the Souders-Brown equation V = kV(pi — p )/p , in which k depends on the size distribution of droplets and the decontamination factor F desired. For most evaporators and for F between 100 and 10,000, k =... 

Pressure drop is a critical factor in the design of adsorption systems, as it normally determines the allowable gas velocity and, therefore, the bed cross-sectional area. Although much work has been done on the subject, no completely satisfactory general correlation has been developed that takes into account the shapes of individual particles, size distribution, void fraction, and aging effects, as well as the more readily characterized gas properties and conditions. It is, therefore, common practice to use experimental and operating data and semi-empirical correlations aimed at specific adsorbent types and applications. Typical data and correlations are presented in subsequent sections covering dehydration with solid desiccants and organic vapor adsorption on activated carbon. 

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