Solid-Fuel Rocket Motor Efficiency Improvement Scheme - Novel Combustion Concepts for Sustainable Energy Development - page 540

1 st Frame

8 th Frame

Fig. 12 Frames taken at 1,000 fps for exit velocity; mean air velocity 40 m/s (Amano et al. 2014a , b )

The increase in the breakup ratio with increased air velocity is displayed in
Fig. 13 . The breakup ratio of 3.0 % for air velocity of 10 m/s is not likely due to
actual water breakup, but rather to error in calculation of boundary height and mean
exit velocity. Figure 14 displays a distribution of experimental breakup and surface
interface. The breakup phenomenon is again noticed in the simulation distributions
of Fig. 16 a, b, respectively.
In Fig. 14 b d liquid breakup is seen around the wedge location. Figure 14 is the

distribution concentration displaying the concentration level of liquid water parti-
cles from the liquid and two-phase interface. This is graphically demonstrated in
Fig. 15 with water droplet concentration range highest at the boundary interface
depicted by the point along the arrow. The concentration drops with increase of
distance from the interface. This is also seen in the concentration distribution slope
where higher breakup is seen with a shallower slope from the two-phase boundary.
Figure 16 presents the time distributions of simulation for

-

fl flow simulations with

air velocities of 30 and 40 m/s.

Migration of water to air stream

40.0

32.5

28.6

26.9

30.0

23.7

20.0

10.0

3.0

0.0

10 15 20 30 40

Air velocity (m/s)

Fig. 13 Migration of liquid water leaving chamber in two-phase flow relative to the water inlet
rate (Amano et al. 2014a , b )