Numerical simulation of single-phase flow in a single square tube with blockage

摘要

CFETR was built to study and harness fusion energy, whose Coolant channel consists of square parallel tubes. Under certain operating conditions, such as foreign object entering, the coolant flow channel may be blocked. In this point, the flow of coolant through the blocked channel will decrease, and cause a rise in wall temperature, which will lead to local evaporation and eventually material damage and radioactive material leakage. In this paper, ANSYS FLUENT is used to calculate and study the case with 20%, 40%, 60% and 80% blockage of the cross-section area of the square tube in the middle of the flow channel, respectively. Different turbulence models and Reynolds numbers are considered. From the calculated results the following conclusions are drawn: (1) The increase of Reynolds number or the increase of area blockage share will lead to the increase of local pressure drop, up to about 17000 Pa. (2) With the increase of the blockage area share, the vortex radius of the downstream of the blockage becomes larger and larger, and the maximum value can reach about 40 mm. (3) The center of the vortex goes further and further away from the blockage object. (4) The SST k-omega model is recommended.