Fig. 1. Settings of model boundary condition

Fig. 2. Steam leakage development process

Fig. 3. Influence of leakage pressure, leakage amount and leakage direction on temperature distribution

Fig. 4. Influence of turbulence scale on temperature distribution

Fig. 5. Temperature distribution of leakage steam under different leakage pressure, leakage volume and leakage direction

Fig. 6. Schematic diagram of leakage steam

Fig. 7. (a) Temperature layer a; (b) Temperature layer b; (c) Temperature layer c; (d) Judgment result of intersection area of a and b; (e) Judgment result of intersection area of b and c

Fig. 8. (a) Temperature layer ; (b) Temperature layer ; (c) Temperature layer ; (d) Temperature layer ; (e) Temperature layer ; (f) Temperature layer ; (h) Difference area between temperature layer and ; (i) Difference area between temperature layer and ; (j) Difference area between temperature layer and (a) 温度层 ；(b) 温度层 ；(c)温度层 ；(d)温度层 ；(e)温度层 ；(f) 温度层 ；(h) 温度层 和 ；(i) 温度层 和 ；(j) 温度层 和

Fig. 9. (a) Skeleton; (b) Fitting line; (c) Direction of leakage source prediction

Fig. 10. (a) Infrared image of leakage steam collected by FOTCRIC 686; (b) Extracted suspected steam area

Fig. 11. (a) Original image; (b) Adaptive median filter (window size 5×5); (c) Adaptive median filter (window size 11×11); (d) Adaptive median filter (window size 25×25)

Fig. 12. Temperature layer extraction effect

Fig. 13. Variable scale extraction processing effect

Fig. 14. Frame diagram of Mask R-CNN

Fig. 15. (a) Binarization processing; (b) Dimensional adjustment; (c) Labeling

Fig. 16. (a) Judged as hammer-tail; (b) Judged as not a hammer-tail

Fig. 17. Flow chart of steam temperature field identification algorithm

Fig. 18. Steam experimental platform

Fig. 19. Original image and two consecutive infrared image

Fig. 20. Variable scale extraction processing

Fig. 21. Results of Mask R-CNN network model identification

Fig. 22. Judgment results of diffusion characteristic

Fig. 23. Judgment results of dynamic hammer tail characteristics

Fig. 24. Prediction results of steam leakage direction