Design and Flow Analysis of Special-Shaped Cross-Section Flow Channel Based on Selective Laser Melting

Selective laser melting has the potential to be applied into hydraulic pipelines manufacturing because it can realize the forming of flow channels with arbitrary direction and curvature. Due to the stacking of layers, selective laser melting still has many limitations while processing complex flow channels. In particular, the manufacturing of overhanging structures with circular cross sections needs to use internal supports to prevent surface collapse, which is challenging to be removed. Therefore, it is necessary to optimize the flow channel with a self-supporting ability, then systematically discussing its forming quality with the influence on fluid dynamics to compromise. In this paper, a simplified multi-channel structure with 1 inlet and 4 outlets is extracted from a hydraulic valve block of an aero-engine system, and the cross-section of its branch channel is re-designed to guarantee its self-supporting ability based on additive manufacturing optimization strategy. Numerical simulation was used to analyze the influence of different shape sections on the pressure loss and mass flow rate of multi-channel structure. The results show that the pressure loss and outlet flow of the 45° rhombus + ellipse section are the closest to the circular area. According to the maximum internal deformation of the three outlets, the 65° rhombus section has the better forming quality and the non-circular section is not the worst.