Spinning Disc Reactor for Green Processing and Synthesis - Process Intensification for Green Chemistry - page 69

Flowrate 30 cc/s

16

Smooth

14

Metal sprayed

12

Normal grooved

10

Reentry
grooved

8

6

4

2

0

300 410 500 650 770 890

Rotational speed (rpm)

Figure 3.10 Heat-transfer characteristics on various rotating surface configurations applicable
to process heating operation. Reprinted from [ref 20] # 1994, with permission from Elsevier.

less efficiently, so that the top film surface remains colder across a larger proportion of the
disc area than it does with the water film.
The thermograms also provide a useful insight into the wavy nature of the water film
surface and the trajectory of the film path on the disc. In Figure 3.11a, the relatively large-
amplitude waves formed on the water film result in overlapping boundaries between
annular sections of the film close to the inner region, which is indicative of radial mixing.
As the film moves towards the disc edges, these large-amplitude waves appear to either
decay completely or give way to waves of such greatly reduced amplitudes that they
become less involved in promoting radial mixing. A faint spiral profile is also apparent in

Figure 3.11 Thermograms for Q ¼ 10ml/ s, working fluid: water; (a) N ¼ 500 rpm;
(b) N ¼ 2000 rpm. Reprinted from [ref 17] # 2012, with permission from Elsevier.