Tangential nozzles

Induced swirl, as shown in Fig. 27, which imparts to the solids-gas flow a swirling action and also controls the rate and direction of rotation of swirl via tangential nozzles. However, the residual swirl that would occur in the downstream pipe branches may cause problems if several swirl inducers follow one another (Selves et al., 1995). This problem could be eliminated by introducing the dropout box splitter shown in Fig. 28. 

York, Stubbs, and Tek (27C) have developed a theory for the breakup of thin liquid sheets as produced by tangential nozzles. A force balance between the inter-facial tension and aerodynamic forces is the basic concept, and the criteria for stability and instability are determined from it. Wave formation at the interface is of major importance in the subsequent breakup. 

Alternatively, multivane triangular diffusers (Fig. 14-7lb. c) such as the Schoepentoeter have been successful for high-velocity vapor-rich feeds. These are used with radial (as distinct from tangential) nozzles. The vanes knock out the liquid and direct it downward while the vapor expands to the tower diameter. 

The pressurized process stream is guided radially into the rotor by the primary nozzles, which are a series of vanes forming nozzles jetting the gas tangentially and inwardly into the rotor (see Fig. 29-47). These... 

In order to handle higher loads, the liquid baffle is placed at the top to collect liquid and cause it to drop back down through the gas body. If the baffle is omitted, the liquid will run dowm the oudet pipe and be sw ept into the outlet nozzle by the outgoing gas as shown in Figure 4-50B. Figure 4-50 and 4-51 show several alternate entrance and exit details. The unit with a tangential entry is 30%-60% more efficient than one with only a turned-down 90° elbow in the center. 

A flame edge can be defined as the boundary between the burning and the nonbuming states along the tangential direction on a flame surface, which could exist in both premixed and nonpremixed flames [1,2]. The base of a nozzle-attached flame, either premixed or nonpremixed systems, is a typical example. 

In internal mixing atomization (for example centrifugal-pneumatic atomization), 159] the liquid metal and gas enter the swirl jet atomizer tangentially under pressure (Fig. 2.13)J159] The two fluids rotate, form a mixture, and accelerate in the confuser. Due to the strong centrifugal force, the liquid metal forms a film at the nozzle exit even without the presence of the gas. With the applied gas, the liquid film is atomized into a fine dispersion of droplets outside the nozzle. 

Axial and swirling air streams in the combustor issued from a circular chamber through a conical nozzle. The chamber was utilized both as an acoustic resonator and a settling chamber. It contained a honeycomb to straighten the how and two acoustic drivers to apply acoustic excitation to the jet. The nozzle exit diameter was 3.8 cm and the maximum Reynolds number based on this diameter and the exit velocity with and without air forcing was 4800 and 1400, respectively. The tests were performed with total air how rate of 85 1/min, and fuel how rate of 0.063 1/min. The swirl was applied with tangential air injection and the maximum swirl number tested was Ns = 0.30. 

The working principle of hollow cone nozzles is that the liquid throughput is subjected to rotation by a tangential inlet and is then further accelerated in the conical housing toward the orifice (see the sketch in Figure 19). A liquid film with a thickness d is thereby produced, which spreads to a hollow cone sheet and disintegrates into droplets at the discharge from the orifice. 

Although these examples are more specific to the Wurster process, similar guidelines can be applied to the top-spray process, in which case the definition for working capacity will be different. When dealing with the tangential-spray process, the quantity of product that is sufficient to ensure that the spray nozzles are completely immersed when the product is in motion will define the minimum starting batch weight. 

---