Vertical impinging streams

BEHAVIOR OF A SINGLE PARTICLE IN CO-AXIAL VERTICAL IMPINGING STREAMS... 

In vertical impinging streams the two streams are flowing vertically. In this case the effect of gravity cannot be neglected. The trajectories of a single particle in the impinging streams are shown in Fig. 2.7. 

Figure 2.7 Movement of a single particle in vertical impinging streams.

For vertical impinging streams and under the assumptions of neglecting buoyancy force and the particle being spherical in form, the equation for the particle motion, Eq. (3.1), can be rewritten in the generalized form, applicable for various cases, as... 

Left Figure 6.3 Vertical impinging stream dryer 191]. 

Right Figure 6.4 Vertical impinging stream dryer with an impingement cave. 

Tamir, A. and Kitron, Y. (1989). Vertical impinging-stream and spouted-bed dryers. Drying Technology, 7 183-204. 

Tamir, A. 1989. Vertical impinging streams and spouted bed dryers Comparison and performance. Drying TechnoL, 7(2) 183-204. 

Figure 2 Impinging stream contactors of various configurations [51. (a) Coaxial-horizontal two impinging streams (b) Horizontal three impinging streams (c) Coaxial-vertical two impinging streams (d) Curvilinear two impinging streams (e) Curvilinear four impinging streams (f) Four impinging streams. A—air P-—particles W water.

Kostiuk et al. [40] measured experimentally the flow field of the vertical co-axial turbulent impinging streams with a two-component Laser Doppler velocity meter. The opposing gas streams were ejected from two burner nozzles, which were designed to produce a uniform axial velocity profile at their exits. The turbulence in the flow was generated by a perforated plate located at the end of the contraction section in each nozzle. The air velocity at the exit of the nozzle was varied from 4.1 to 11.4 m s and... 

The main significance of the terminal velocity lies in the fact that it defines the minimum gas velocity requested. The particle enters the system at Point 1 at zero velocity. If a gas velocity is employed so that u, < uh the particle cannot get into but drops out of the system if the gas velocity makes the relative velocity equal the terminal velocity, i.e., u, = it, the particle will move with a constant velocity of zero with respect to the ground, and so will remain at Point 1 while if the gas velocity makes the relative velocity greater than the terminal velocity, i.e., u,> it, the particle will be accelerated by the gas flow to the terminal velocity and will then move towards Point 2 at that velocity. Therefore, the terminal velocity is necessary for the determination of the operational range of the gas flow velocity for a specific vertical gas-solid impinging stream system. 

The structure of the circulative impinging stream dryer developed is sketched in Fig. 6.13, in which the flow configuration of vertical two impinging streams is employed. The equipment consists of three basic parts mounted co-axially the body, the upper and the lower accelerating tubes. The body is of a conical/cylindrical shape with different diameters. The lower-middle part of the body is a cylinder with a relatively... 

Figure 7.22 Vertical view of the combined multifunctional impinging stream gas-liquid reactor. 1-tower 3-gas outlet tube 5-gas conduit, 7-liquid feeding tube.

In order to overcome these disadvantages and extend the application area, the vertical circulative impinging stream reactor (VCISR) was designed and patented [232] its structure is shown in Fig. 17.1. 

Figure 17.1 The vertical circulative impinging stream reactor.

The major difference between the VCISR and the SCISR is the former s vertical structure, while the SCISR has a horizontal structure. This changes the flow configuration from horizontal impinging streams in the SCISR to vertical in the VCISR, and also the container form of the VCISR is changed to a cylinder. 

Figure 17.2 Vertical circulative impinging stream reactor of Type II.

Wu, Yuan, Xu, Jianmin, and Zhou, Yuxin, Wuhan Institute of Chemical Technology (2003). The vertical circulative impinging stream reactor. CNP, ZL03235518.1. 

The principle of operation, basic design, and process characteristics for most common types of dryers with inert carriers are well described in easily accessible literature. These are the vibrated fluid bed dryer and the fluid bed dryer in its conventional and two-chamber configurations (Kudra and Mujumdar, 1995 Erdesz and Ormos, 1986), spouted bed dryer (Re and Freire, 1989), jet-spouted bed dryer (Markowski, 1992), pneumatic dryer (Blasco et al., 1996), rotary dryer (Limaverde et al., 2000), impinging stream dryer (Kudra and Mujumdar, 1989), dryer with a vertical inner conveyor screw (Pallai et al., 1995), etc. Therefore, here we present less common configurations that are interesting from research and applications points of view. 

Juai XL, Liu DY, Li CZ, Meng Q. The investigation of combined impinging stream dryer of vertical and sloped semi-circle. Proc. 12 Inti. Drying Symposium (IDS 2000). Coumans WJ, Kerkhof PJAM, eds. Noordwijkerhout, The Netherlands, Paper No 104, 2000. 

PM Control - An impingement-plate scrubber is a vertical chamber with plates mounted horizontally inside a hollow shell. Impingement-plate scrubbers operate as eountercurrent PM collection devices. The scrubbing liquid flows down the tower while the gas stream flows upward. Contact between the liquid and the particle-laden gas occurs on the plates. The plates are equipped with openings that allow the gas to pass through. Some plates are perforated or slotted, while more complex plates have valve-like openings. 

Wall-jet electrode — An electrochemical cell design wherein a streaming electrolyte solution impinges vertically onto an electrode embedded into the cell wall ... 

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