Abstract:

Objective In daily operation, the outer wall of solar receiver tube is subjected to uneven heat flux between the inner and outer sides at cylindrical receiver, which leads to the uneven distribution of wall temperature and large temperature gradient. It is easy to generate high thermal stress, which causes the deformation and structural damage of receiver tube. Therefore, the thermal stress of the transversally corrugated tube in the cylindrical receiver is studied. Methods The three-dimensional model of the transversally corrugated tube is established by Design Modeler in Ansys, and the mesh is divided by Mesh. The thermal stress of the transversally corrugated tube under semi-circumference heating is numerically simulated by Fluent. Results The outer wall thermal stress at high heat flux side of the tube is the largest, and the wall thermal stress at the junction of the high and low heat flux surfaces is the lowest. The thermal stress value at the groove section of transversally corrugated tube is larger than that of the smooth section. For the same groove width, the groove depth is deeper, and the maximum equivalent thermal stress on the groove section is bigger. For the same groove depth, the groove width is wider, and the maximum equivalent thermal stress is smaller. The maximum equivalent thermal stress of the transversally corrugated tube increases with the rise of molten salt inlet temperature, and the maximum equivalent thermal stress reduces with the increase of molten salt inlet flow rate. Conclusion Through the thermal stress analysis, it can be seen that the influence law of the thermal stress on transversally corrugated tube changes with heat flux, groove depth and width, inlet temperature and inlet flow rate, which is of great significance to prolong the service life of the cylindrical receiver.

Key words: solar thermal power, solar receiver, cylindrical receiver, transversally corrugated tube, thermal stress, molten salt, numerical simulation