Predictions of formability parameters in tube hydroforming process

The objective of this study is to improve the bulging and minimize the thinning ratio to enhance manufacturing of components in Industries. Tube hydroforming is an advanced manufacturing technology used for making intricate and complex tubular parts which required less cycle time. This research focuses on hydroforming process, formability and process parameters design to replace the conventional tube bending, welding and cutting operations. The prediction of parameters is done by applying numerical and experimental approach. During experimentation the pressurized fluid is used to deform the tubes in a plastic deformation. In this study, two types of grade materials are used such as AISI304 and AISI409L of 57.15 mm external diameter with 1.5 mm thickness in the form of electric resistance welded tubes to measure stain path, thinning and bulge height. However, it is observed that the internal pressure and L/D ratio are effective parameters in both numerical analysis and experimentation. In axial feed condition, it is observed that 16.3% thinning in weld region and 44.6% thinning in base metal region, whereas, in fixed feed condition, it is observed that 7.7% thinning in weld region and 18.6%thinning in base metal region for L/D = 1 and L/D = 3 respectively. The numerical analysis with experimental results shows a very good match. It is seen that the axial feed leads to better formability with fixed feed condition because in axial feed condition material supplies towards the center of the bulge tube. The feasibility of the hydroforming process for manufacturing of AISI304 and AISI409L grade material as per the requirements of the industries is also checked. The maximum bulging is observed in L/D = 2 by comparing with the other ratios. This process can be effectively used for AISI304 grade material because the formability is better than AISI409L. Article highlights The strain path measured and predicted at necking point for ERW tube in both weld and base metal. Thinning is measured during bulging of tube under the axial and fixed feed condition. For L/D = 1 ratio observed strain distribution in unidirectional and L/D = 2, 3 observed in plane strain and bidirectional respectively.

Study on Separation Performance of Gas-Liquid Cyclone Separator with Pulsating Feeds

Background: In recent years, a kind of drilling method of Solid-Liquid separation combined with pulsating vacuum formed by vibrating screen and compressed air injection has emerged in oil drilling, which greatly improves the gas, solid and liquid separation ability of the drilling fluid vibration screen. Objective: Based on the above ideas, a kind of hydrocyclone used for gas-liquid separation with the pulsating feed boundary was proposed. The separation performance of gas-liquid hydrocyclone may change greatly due to the mixed pulsation of the gas-liquid fluid transported by the jet pump. Therefore, the flow characteristics of the pulsating feed hydrocyclone need to be analyzed and explored to provide basic data for further improvement of structure. Methods: The development status of cyclone separators are summarized through related literatures and patents investigation. The Computational Fluid Dynamics (CFD) software ANSYS Fluent 2019 R3 is used to analyze the flow field characteristics and optimize the parameters of the hydrocyclone with stable feed. Then, programming by the User-Define-Function (UDF) of Fluent is used to simulate the flow field of the separator under the condition of pulsating feed, meanwhile, the flow field analysis and parameter optimization are carried out accordingly. Results: The optimal parameters in stable state and pulsed state are obtained through the analysis of efficiency curve. The results show that the flow field can be stabilized in the pulsating feed state, and the sinusoidal pulsing with a frequency of 0.4Hz is used to achieve the highest separation efficiency, reaching 85.5%. Conclusion: The separators with pulsating feed and stable feed have similar flow field characteristics, and the optimal structural parameters under pulsating feed are obtained. Compared with the stable feed condition, the pulsating feed condition can connect multiple cyclone separators, which can separate more drilling fluid in unit time, and the work efficiency could be improved. It has a strong practicability, which provides an important basis for the structure optimization in future.

Simulation and Analysis of Abrasive Jet Machining with Wheel Restriction in Grinding

Abrasive jet precision finishing is a new machining method, which injects slurry of abrasive and liquid solvent to grinding zone under without feed condition. The machining is simulated by Finite Element Method (FEM) in the paper. Hydrodynamic pressure on modeling of wedge-like grinding zone between wheel and workpiece on abrasive jet finishing with wheel as restraint was established and simulation, based on Navier-Stokes and continuity equations. The liquid hydrodynamic pressure distributing principle and affecting factor were investigated. The relation hydronamic pressure with grinding wheel velocity was stimulated and verified experimentally. The experiment results show that the simulation results are agreement with experiment, so the simulation model can well forecast hydrodynamic pressure distribution at contact zone.