Fig. 1. Irradiation diagram of window reflected stray light

Fig. 2. Simplified model of round pipe

Fig. 3. Numerical simulation of discretization model

Fig. 4. Temperature contour of pipe wall(a), and section(b), temperature cloud chart(c)

Fig. 5. OPD (a) and Zernike coefficients (b) of pipe outlet

Fig. 6. Temperature changing curve of different aluminum pipes

Fig. 7. Comparison of influence of different structures on temperature rise of pipe wall

Fig. 8. ΔT (a) and RMS of OPD (b) change curves with aluminum pipe thicknesses at t=30 s

Fig. 9. Temperature rise changing curves of three materials with equal thickness

Fig. 10. Temperature rise changing curves of three materials with equal mass

Fig. 11. ΔT changing curves of three materials with equal mass

Fig. 12. Ray tracing results of 8 mm (a) and 16 mm (b) thickness pipe

Fig. 13. Zernike coefficient of OPD in the outlet of 8 mm/16 mm pipe