CFD-based study of the abrasive flow characteristics within constrained flow passage in polishing of complex titanium alloy surfaces

Abstract

Study on the constrained abrasive flow polishing of complex titanium alloy surfaces is discussed both numerically and experimentally. The numerical simulation using Computational Fluid Dynamics method and Discrete Phase Model is first conducted to model the particle-laden fluid through the constrained flow passage by considering four types of constrained plate, including chevron-type, golf ball-type, fork-type and triangle-type. The triangle-type constrained plate is found to be the most optimized design than the other types of pattern for the polishing purpose because of increasing the dynamic pressure of water flow and resulting in a relatively uniform distribution of water flow velocity near the bottom surface of the constrained flow passage, as well as increasing the number of collisions between particles and the target surface. A set of experiments, including the rough and precision polishing procedures, is then conducted to evaluate the polishing performance by using the original and triangle-type constrained plates, respectively. It is found that the average material removal rate obtained from the triangle-type constrained abrasive polishing process is larger than the corresponding data taken from the original passage, and the surface roughness is found to be reduced after the triangle-type constrained abrasive polishing process. These experimental results are in a good agreement with the corresponding simulated results. Thus, both the polishing efficiency and quality have been improved by using the abrasive flow polishing of complex titanium alloy surfaces with the triangle-type constrained plate.