Effect of upper end wall boundary layer suction on high-load helium compressor performance in thorium molten salt reactors

The performance of the helium compressor is a crucial factor in determining the efficiency of thermal-to-work conversion in thorium molten salt reactors. The high-load design approach can efficiently increase the pressure ratio while minimizing the number of compressor stages. However, due to this design technique, compressor flow passages become narrower with short blades. Consequently, the impact of the end wall boundary layer on the compressor's performance becomes a point of concern. The end wall boundary layer can be effectively controlled and regulated through the suction technique. This paper investigates the effect of suction holes at various positions and angles impacting the performance characteristic of multi-stage high-load helium compressors. This research concluded that the optimum suction axial position is at 0.3 of the suction-side arc length, the optimum circumferential position is 2.0 mm, and an angle of 120° can decrease the total-pressure loss coefficient by 10.47%. Moreover, due to the suction effect, the efficiency and total pressure ratio at the design point can be improved up to 0.29% and 0.129%, respectively.