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Flow resistance evaluation based on three morphological patterns in step pool streams

Luo Ming, Yan Xufeng, Huang Er

Acta Geophysica

2023

Vol. 71, no. 1

359--372

Quantifying the flow resistance in step-pool streams is of importance for studying the restoration of benthic animals and bedload transport. The Darcy–Weisbach friction factor of the total flow resistance is partitioned into components associated with grains, spills, and loose-packed particles. By extending the two-dimensional hydraulic radius, a new proposed rough ness height is applied to evaluate resistance components induced by spills and loose-packed particles. Three morphological patterns induced by different-magnitude foods can be classified to form different flow resistance components, depending on the morphological variation. The three components varying with hydraulic and geometric parameters by considering the closest-1 NSEI and smallest RMSE and MRE have been examined. It is found that the grain resistance factor component, in comparison with other factors, has a slight impact on hydraulic parameters. Hydraulic and geometric parameters have a significant influence on the spill resistance component, accounting for the main proportion of the total resistance. The resistance associated with loose-packed particles correlates with parameters due to the initial random movement of particles and abundant sources.

Process parameter optimization and anisotropy sensitivity study for abrasive belt grinding of nickel-based single-crystal superalloy

Wang Chao, Yan Xufeng, Liao Hongzhong, Chai Linjiang, Zou Lai, Huang Yun

Archives of Civil and Mechanical Engineering

2021

Vol. 21, no. 4

584--602

Nickel-based single-crystal superalloys (SXs) are used as materials for aero- and industrial gas turbine blades due to their superior high-temperature strength. However, SXs have low thermal conductivity, high hardness, and high working hardening, which significantly increase the machining difficulty. Improving machining performance has been a critical aspect that influences functional performance, including the fatigue life of the blades. In this study, preliminary comparative tests were performed for abrasive belt grinding of SXs to obtain better performance in terms of surface roughness (Ra), material removal rate (MRR) and abrasive belt wear rate (Bw). Two empirical models of the process parameters of abrasive belt grinding were established using response surface methodology (RSM), and the influences of belt speed (Vs), feed speed (Vw), and normal grinding force (Fn) on Ra and MRR were analysed. The Ra and MRR were optimized with multiple responses to balance the grinding quality and efficiency based on the desirability function method. Both the percentage error of the experiments and model prediction error are within a reasonable range of 5%. In particular, three typical crystal planes ((001), (110), and (111)) were prepared and used to study the grinding performance from the perspective of anisotropy sensitivity.