Disc turbine

Radial-flow impellers include the flat-blade disc turbine, Fig. 18-4, which is labeled an RlOO. This generates a radial flow pattern at all Reynolds numbers. Figure 18-17 is the diagram of Reynolds num-ber/power number curve, which allows one to calculate the power knowing the speed and diameter of the impeller. The impeller shown in Fig. 18-4 typically gives high shear rates and relatively low pumping capacity. 

Flat-blade disc turbine (ftushton turbine)... 

The flow patterns for single phase, Newtonian and non-Newtonian liquids in tanks agitated by various types of impeller have been repotted in the literature.1 3 27 38 39) The experimental techniques which have been employed include the introduction of tracer liquids, neutrally buoyant particles or hydrogen bubbles, and measurement of local velocities by means of Pitot tubes, laser-doppler anemometers, and so on. The salient features of the flow patterns encountered with propellers and disc turbines are shown in Figures 7.9 and 7.10. 

Figure 7.10. Radial flow pattern from disc turbine...

Figure 7,20. Commonly used impellers (a) Three-bladed propeller ( >) Six-bladed disc turbine (Rushton turbine) (c) Simple paddle (d) Anchor impeller (e) Helical ribbon (/) Helical screw with draft tubs...

Elat blade disc turbine unbaffled, or baffled vessel. Re < 400 0.54 0.67... 

This research used mechanically agitated tank reactor system shown in Fig. 1. The reactor, 102 mm in diameter and 165 mm in height, was made of transparant pyrex glass and was equipped with four baffles, 120 mm in length and 8 mm in width, and six blades disc turbine impeller 45 mm in diameter and 12 mm in width. The impeller was rotated by electric motor with digital impeller rotation speed indicator. Waterbath thermostatic, equipped with temperature controller was used to stabilize reactor temperature. Gas-liquid mass transfer coefficient kia was determined using dynamic oxygenation method as has been used by Suprapto et al. [11]. 

Flat blade disc turbine, baffled or unbaffled vessel, transfer to vessel wall, Re < 400 ... 

The reactor described in Example 12.12 is fitted with a flat blade disc turbine agitator 0.6 m diameter, running at 120 rpm. The vessel is baffled and is constructed of stainless steel plate 10 mm thick. 

Disc-type turbines In this type of turbines, blades can be straight or curved. In the related literature, the term straight is some times replaced by the term flat. The most popular turbine of this type is the straight-blade disc turbine, which is better known as the Rushton turbine (Figure 3.18). The same turbine is also called flat-blade turbine, vaned disc or simply flat-blade turbine. ... 

Vertical blade disc turbines can have curved blades, and in this case they are called Smith turbines. 

For Rushton turbines (flat-blade disc turbines), the following equation can be used (Nouri and Hockey, 1998) ... 

Flat blade disc turbine with six blades 0.99 1.4 2.18... 

Recently, in contrast to the traditional small impellers, a large impeller has been manufactured in Japan. In general, it has been said that the disc turbine-type, turbine-type, and pitched-type impellers mainly produce radial, tangential,... 

FIGURE 1 Three typical impellers for low and medium viscosity (a) Axial flow, 45° blade (A200), (b) radial flow, disc turbine (R100), and (c) fluidfoil axial flow impeller (A300). 

Chapman et al. [17] proposed an extremely simple relationship from which the increase in stirrer speed required to suspend all particles under aerated conditions over unacrated conditions is given for disc turbines of diameter dc/2 and clearance of height dc/4 ... 

Ranade, V. V, and Joshi, J. B., Flow generated by a disc turbine Part I. Experimental. Treats. /. Chem. E. 68(Part A), 19 (1990a). 

Problem A recently built reactor, equipped with a flat-blade disc turbine, does not satisfy the process requirements. By examining the hquid surface, the operator suspects that the gas is rising straight through the impeller to the hquid surface. In other words, the impeller is flooded. The mass-transfer rate is usually lower when the impeller is flooded than when it is able to completely disperse the gas. Pertinent information about the reactor is T = 2m D = 0.8m N = 1.13rps Qg = 0.12m /s /i = 1 cP p = 1,000 kg/m Na = 0.21 Npr = 0.1. 

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