Void distribution and bubble motion in bubbly flows in a 4×4 rod bundle. Part II: numerical simulation

Figures & data

Figure 1. Shape factor.

Figure 2. Restriction of bubble lateral motion in n-based method. (a) channel box and (b) inner and side subchannels.

Figure 3. Computational domain.

Table 1. Turbulent dispersion coefficient C_T.

	CT in n-based	CT in α-based
d (mm)	method	method
1.4	0.50	1.0
2.2	0.40	0.50
3.2	0.02	0.50
4.2	0.01	0.50

Figure 4. Streamwise liquid velocity in single-phase flows (x = 27 mm).

Figure 5. Void fraction and liquid and gas velocities in Case T1 (x = 27 mm). (a) Void fraction and (b) Liquid and bubble-relative velocities.

Table 2. Root mean square errors e_rms in predicted α, V_L and V_R.

			erms in VL	erms in VR
Case	Scheme	erms in α	(m/s)	(m/s)
T1	n-based	0.037	0.137	0.035
	α-based	0.053	0.104	0.11
T2	n-based	0.016	0.191	0.17
	α-based	0.022	0.181	0.20

Figure 6. Void fraction and liquid and gas velocities in Case T2 (x = 27 mm). (a) Void fraction and (b) Liquid and bubble-relative velocities.

Figure 7. Effects of C_D model on V_R (n-based) (x = 27 mm). (a) Case T1 and (b) Case T2.

Figure A1. Simulation of single-phase flow in two by two rod bundle. (a) two by two rod bundle (flow is symmetric with respect to dotted-lines), (b) boundary-fitted cells and (c) predicted streamwise liquid velocities at x = 25 mm.