Kinematic parameter of flow

A1 and A2 intersection points on axes Kinematic parameter of flow... 

Figure 4.11 Influence of the kinematic parameter of flow A on the mixing quality [14]...

Figure 4.12 Influence of kinematic parameter of flow A and viscosity on the dispersion degree of Ti02 agglomerates in silicone oil (trials with a single screw extruder) [151...

An important dimensionless screw parameter is the kinematic parameter of flow. 

Figure 6.11 also includes the kinematic parameter of flow, defined in Eq. 6.1. The pressure characteristic also enables us to calculate the length for pressure generation. This is illustrated in Fig. 6.8, where the length for pressure generation is Lg c . 

Figure 7.9 Efficiency of a triple-flighted screw during pressure generation in relation to the kinematic parameter of flow A...

The rotational speed, which only appeared as a parameter in the linear Eqs. 7.1 and 7.4, forms now an independent dimensionless parameter in the form of the Deborah number n . While the dimensionless pressure generation and dimensionless energy only depend on the kinematic parameter of flow for Newtonian liquids, the dimensionless revolution speed appears as an additional influencing variable for shear thinning. This is plausible if we consider that the rotational speed is a measure of the shear stresses on the material, and thus influences the effective viscosity of the material. It is also to be expected that the interaction will assume a non-linear form since the flow curve is already non-linear. 

Figure 9.11 Degree of disaggregation as a function of the kinematic parameter of flow A and the viscosity of the fluid, measured with Ti02 in silicone oil in a single screw extruder [6, 7]...

Having established that these assumptions are reasonable, we need to consider the relationship between the parameters of the actual offset jet and the equivalent wall jet that will produce the same (or very similar) flow far downstream of the nozzle. It can be shown that the ratio of the initial kinematic momentum per unit length of nozzle of the wall jet to the offset jet,, and the ratio of the two nozzle heights,, depend on the ratio D/B, where D is the offset distance betw een the jet nozzle and the surface of the tank, and h, is the nozzle height of the offset jet. The relationship, which because of the assumptions made in the analysis is not valid at small values of D/hj, is shown in Fig 10.72. 

In addition, the effects of pulsatile flow cannot be ignored. One measure of the impact of oscillary flow is the Wcmersley parameter (a) a= h/2tt f/v where r is the tube radius, f the frequency of oscillation and v is the kinematic viscosity of the fluid (Wcmersley, 1955). The degree of departure from parabolic flow increases with and frequency effects may become important in straight tubes when a > 1 (Ultman, 1985). For conditions of these experiments, a exceeds one to beyond the third generation. 

In this representation, the throughput number Q is standardized by the intercept Ai. It is the numerical value of Q where the screw machine is conveying without pressure formation. With this kinematic flow parameter, h = QlAi, the state of flow of a screw machine can be outlined more distinctly. 

FIGURE 16 Generalized pressure drop correlation of Strigle21. Cs = flow parameter = Us[pg/(pL - Pg)]0 5, ft/s. Fp = packing factor, ft-1, v = kinematic viscosity of liquid, centipoises/specific gravity. 

Fig. 40 Subdivision of the typical working ranges of a screw machine by the flow-kinematic parameter A.

The Prandtl number via has been found to be the parameter which relates the relative thicknesses of the hydrodynamic and thermal boundary layers. The kinematic viscosity of a fluid conveys information about the rate at which momentum may diffuse through the fluid because of molecular motion. The thermal diffusivity tells us the same thing in regard to the diffusion of heat in the fluid. Thus the ratio of these two quantities should express the relative magnitudes of diffusion of momentum and heat in the fluid. But these diffusion rates are precisely the quantities that determine how thick the boundary layers will be for a given external flow field large diffusivities mean that the viscous or temperature influence is felt farther out in the flow field. The Prandtl number is thus the connecting link between the velocity field and the temperature field. 

Solution. For both capacity and pressure drop. Figure 12.53 will be used. For the mixture, the absolute viscosity is 0.38 cP, giving a kinematic viscosity of 0.45 cSt. From Table 12.8, the packing factor Fp for 50-mm metal PaU rings is 88 m or 26.8 ft. The abscissa for the figure (the flow parameter) is the same as before FP = 0.021. For Figure 12.53, the ordinate term is... 

The theoretical description of the turbulent mixing of reactants in tubular devices is based on the following model assumptions the medium is a Newtonian incompressible medium, and the flow is axis-symmetrical and nontwisted turbulent flow can be described by the standard model [16], with such parameters as specific kinetic energy of turbulence K and the velocity of its dissipation e and the coefficient of turbulent diffusion is equal to the kinematic coefficient of turbulent viscosity D, = Vj- =... 

---