Fig. 1. Structure diagram of the H-OTSG

Fig. 2. Nodalization scheme for RELAP5

Fig. 3. Variations of the mass flow heating section with time at inlet (a) and outlet (b)

Fig. 4. The oscillation pattern of working condition parameters with flow instability (color online)(a) Pressure drop, (b) Mass flow, (c) Temperature

Fig. 5. The phase shift of G-ΔP in each channel (color online) (a) Channel 1, (b) Channel 2~13, (c) Channel 14

Fig. 6. The limit cycles of G-ΔP in each channel (a) Channel 1, (b) Channel 2⁓13, (c) Channel 14

Fig. 7. The flow regime of channel in channel 1 (color online)

Fig. 8. Comparison of oscillation curves with different inlet throttling (color online)(a) R_in=1 100，(b) R_in=1 300，(c) R_in=1 500，(d) R_in=1 700

Fig. 9. Influence of inlet throttling on stability boundary

Fig. 10. Comparison of oscillation curves with different outlet throttling (color online)(a) R_out=50, (b) R_out=100, (c) R_out=150, (d) R_out=200

Fig. 11. Influence of outlet throttling on stability boundary

Fig. 12. Comparison of oscillation curves under different system pressure (a) P=3.7 MPa, (b) P=3.9 MPa, (c) P=4.2 MPa, (d) P=4.4 MPa

Fig. 13. Influence of system pressure on stability boundary