Orbital-abrasion-assisted Electroforming of Non-rotating Parts

A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode.When cathode moves,hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing.Morphology,microstructure,surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods.Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules,disturb the crystal nucleation,and refine the grains of layer.The mechanical properties were significantly improved over traditional method.The micro-hardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV.It was confirmed that this technique had practical significance to non-rotating thin-walled parts.

Simulation on the Melt Flow in Laser Full Penetration Welding with a Model Including a Non-Rotational Symme-try Keyhole Based on Energy Balance

A three dimensional model including a non-rotational symmetry keyhole of which the geometry is calculated base on the energy balance at keyhole wall is created to simulate the heat transfer and fluid flow within the molten pool during laser full penetration welding of titanium alloy plate.In order to take into account the effects of multiple reflections within the keyhole,a ray tracing method is employed and the coordinate dependent heat flux obtained is exerted on keyhole wall during the simulation on the heat transfer and fluid flow within molten pool.Furthermore,the computed weld cross sectional profile is compared with the experimental result to verify the model and it is fond that the simulation result is consists with experimental result.

Comparative assessment and analysis of Rortex vortex in swirling jets

Recently, a new definition, called Rortex, was proposed to quantify the purely rotational motion of fluids. In this work, based on the DNS data, the Rortex is used to assess and visualize the rotational motion and structure of the vortex in swirling jets in comparison with other kinds of vortex criteria, including Q , λ2,vorticity and Ω criteria. The Rortex vector,Ω, Q and criteria are found to be better than the vorticity criterion for the vortex core identification. The vector triangle formed by the Rortex R , the nonrotational shear S , and the vorticity R is analyzed to give mechanical explanations, especially of the effect of the non-rotational shear on the rotation of fluids. In addition, the probability density distributions (PDF) of the Rortex R , the nonrotational shear S, and the vorticity R are computed. The peak value of the PDF of the vorticity could be used to explain the pure rigid rotation effect and the combination effects of the rigid rotation and the non?rotational shear.