Solid-Fuel Rocket Motor Efficiency Improvement Scheme - Novel Combustion Concepts for Sustainable Energy Development - page 537

Superposition of 3 time step in Figure 6

(a)

(b) Superposition of 260 time steps

Fig. 9 VF figures after superposition of a 3 time step and b 260 time steps of RSM 40 m/s

color for boundaries that change position over three time frames. The probability
distribution of the two-phase boundary movement by the superposition over three
pictures, and if 260 pictures are superposed, the resulting image becomes smoother
as shown in Fig. 9 b. Thus giving a convenient comparison of the distribution of the
average position of two-phase boundary. The time-averaged two-phase boundary
probability is a visualization indicator of different fl flow characteristics.

7 Results and Discussion

7.1 Experiment Result

Table 4 presents experimental calculations for two-phase mean viscosity and
density, and Speci c Reynolds ' and Weber numbers for varied air velocity. As seen

in Eqs. ( 3 ) ( 5 ) and Table 4 , both mean viscosity and density vary with mean air

velocity. This air velocity dependence is due to de

-

ning the mass fraction in terms

of mass flow rate of water was held constant, the mean

viscosity and density are solely functions of mean air velocity.

fl flow rates. Since the mass fl

Table 4 Speci c Reynolds and Weber numbers at 0.676 m/s mean water velocity, surface tension
of water and air taken at 70 ° C (Amano et al. 2014a , b )
Mean air
velocity (m/s)

Viscosity
(N s/m 2 )

Mean density
(kg/m 3 )

Reynolds
number (

Weber
number ( ) )

- -

5 2.47E − 04 21.00 86 277

10 1.47E 04 11.20 165 686

−

15 1.08E 04 7.89 243 1,141

−

20 8.73E − 05 6.23 320 1,639

25 7.42E 05 5.23 398 2,180

−

30 6.53E 05 4.56 476 2,764

−

35 5.89E − 05 4.08 553 3,390

40 5.40E 05 3.72 631 4,058

−