Shape and Density Properties

Detonation Wave Shape and Density. Properties This is the title of Chapter 5 in Cook s book (Ref 52 pp 91-122). On p 91, under the title Theoretical Wave Profiles, Cook stated that the shape of the deton wave and the density- distance p(X) as well as the particle velocity-distance W(x) relations behind the wave front are of considerable importance. Langweiler (Ref 3a, quoted in Ref 52, p 91) assumed for the plane-wave case a simplified constant p(x) and W(x) contour followed by a sharp (presumable discontinuous ) rarefaction. He gave as the velocity of the rarefaction front the value (D + W)/2, where D = deton velocity and W = particle vel. He also stated that in an expl of infinite lateral extent, the compressional region or detonation head of wave should grow in thickness accdg to the equation  

In the Langweiler concept, no influence on velocity would be felt by any finite reaction zone of length less than 3Dt/8,since W1 (x) = W2 (particle vel at C-J plane) = constant, the C-J plane could arbitrarily be placed at the front of the rarefaction or at any other plane between this and the wave front without any influence on the velocity. Moreover, for any value of reaction zone length a s 3Dt/8 the velocity at the distance Dt from the point of initiation would be ideal (D = D ). Only for aQ V s would 

Cook considered the influence of finite charges on a simplified model by postulating the existence of lateral rarefaction waves (called release wave by E.M. Pugh) from the sides of the charge. He also assumed that they converged on the central axis with a sharp or discontinuous front of the same velocity as in Laipgweiler 

The deton head would develop thru stages of successive truncated cones of base to apex height ca 3Dt/8, reaching a fully developed cone of ca one chge diam height. 

In confined chges the steady-state deton head should, in this model, be somewhat larger because confinement would lower at least the initial velocity of the release Waves from the side. The detonation-head development and its steady-state fotm in confined and unconfined chges are illustrated in Fig 5.1 of Ref 52, p 92 (which is also reproduced here) taking into account the spherical shape of wave front 

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Heat pulse) 91-122 (Deton wave shape and density properties) 123-4 (Reaction rates in deton) 123 (Nozzle theory) 124 (Curved-front theory) 125-28 (Geometrical model) ... 

Equation for detn of vel vs density and Table LI) 47 49 (Curves giving relationships betw densities and deton velocities of some expls) and Chap 5, pp 91-122 entitled Detonation Wave Shape and Density Properties 7) Dunkle s Syllabus (1957-1958), 205 212-15 8) Baum,... 

Billiard Ball Me cbanism of Vj(t). See under Detonation Wave Shape and Density Properties... 

Detonation wave, shape and density properties 4D693... 

From the standpoint of collector design and performance, the most important size-related property of a dust particfe is its dynamic behavior. Particles larger than 100 [Lm are readily collectible by simple inertial or gravitational methods. For particles under 100 Im, the range of principal difficulty in dust collection, the resistance to motion in a gas is viscous (see Sec. 6, Thud and Particle Mechanics ), and for such particles, the most useful size specification is commonly the Stokes settling diameter, which is the diameter of the spherical particle of the same density that has the same terminal velocity in viscous flow as the particle in question. It is yet more convenient in many circumstances to use the aerodynamic diameter, which is the diameter of the particle of unit density (1 g/cm ) that has the same terminal settling velocity. Use of the aerodynamic diameter permits direct comparisons of the dynamic behavior of particles that are actually of different sizes, shapes, and densities [Raabe, J. Air Pollut. Control As.soc., 26, 856 (1976)]. 

The degree of bed expansion contributes to the efficiency of fluidised bed/expanded bed adsorption as a composite function of liquid distribution, liquid and particle properties (size, shape and density) and process conditions. Besides being an important design feature, the degree of bed expansion may be used as a quick and simple measure of bed stability.48... 

It is found that the major factor which determines the behaviour of the solid particles is their terminal falling velocity in the liquid. This property gives a convenient way of taking account of particle size, shape and density. 

Mixing together of particulate solids, sometimes referred to as blending, is a very complex process in that it is very dependent, not only on the character of the particles — density, size, size distribution, shape and surface properties — but also on the differences of these... 

The physical properties of solid fuels can be modified to a certain extent. It is the size, shape and density which are easy to change. Solid biofuels which are modified are here referred to as refined solid biofuels, see Figure 30. 

The effective viscosity depends on the solid hold-up, on particle size and distribution, on the surface properties, on the particle shape and density, on the properties of the liquid (p, p, d), on temperature, and the shear stress in the column. Depending on the solid concentration encountered in BSCR, we can classify the suspensions into "dilute" and "concentrated" groups. 

The final product in all cases is a-Fe203, but its hue can range from orange to pure red to violet through manipulation of particle size, shape, and surface properties. The four processes yield a range of physical properties. Density can vary from... 

Density When a powder is poured into a container, the volume that it occupies depends on a number of factors, such as particle size, particle shape, and surface properties. In normal circumstances, it will consist of solid particles and interparti-clulate air spaces (voids or pores). The particles themselves may also contain enclosed or intraparticulate pores. If the powder bed is subjected to vibration or pressure, the particles will move relative to one another to improve their packing arrangement. Ultimately, a condition is reached where further densilication is not possible without particle deformation. The density of a powder is therefore dependent on the handling conditions to which it has been subjected, and there are several definitions that can be applied either to the powder as a whole or to individual particles. 

Catalysts are formed by a variety of methods depending on the rheology of the materials. The products of different processes have been compared in general terms in Table 3.2. The choice of the method depends on the size, shape and density of the catalyst particle required, on the strength required and on the properties of the starting material. The three main processes used in catalyst manufacture to make conveniently sized particles from powders are pelletizing, extrusion and granulation. 

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