Simulation of Die-swell Flow for Wet Powder Mass Extrusion in Pharmaceutical Process

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Vimolrat Ngamaramvaranggul ◽  
Nawalax Thongjub
Keyword(s):  
Die Swell ◽  
Powder Mass

scholarly journals In situ measurement and closed-loop control for powder supply processes

2021 ◽  
Author(s):  
Philipp Peter Breese ◽  
Tobias Hauser ◽  
Daniel Regulin ◽  
Stefan Seebauer ◽  
Christian Rupprecht
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Closed Loop ◽  
In Situ Measurement ◽  
Closed Loop Control ◽  
Loop Control ◽  
Powder Feeder ◽  
Powder Mass

AbstractThe powder mass flow rate is one of the main parameters regarding the geometrical precision of built components in the additive manufacturing process of laser metal deposition. However, its accuracy, constancy, and repeatability over the course of the running process is not given. Reasons among others are the performance of the powder conveyors, the complex nature of the powder behavior, and the resulting issues with existing closed-loop control approaches. Additionally, a direct in situ measurement of the powder mass flow rate is only possible with intrusive methods. This publication introduces a novel approach to measure the current powder mass flow rate at a frequency of 125 Hz. The volumetric powder flow evaluation given by a simple optical sensor concept was transferred to a mass flow rate through mathematical dependencies. They were found experimentally for a nickel-based powder (Inconel 625) and are valid for a wide range of mass flow rates. With this, the dynamic behavior of a vibration powder feeder was investigated and a memory effect dependent on previous powder feeder speeds was discovered. Next, a closed-loop control with the received sensor signal was implemented. The concept as a whole gives a repeatable and accurate powder mass flow rate while being universally retrofittable and applicable. In a final step, the improved dynamic and steady performance of the powder mass flow rate with closed-loop control was validated. It showed a reduction of mean relative errors for step responses of up to 81% compared to the uncontrolled cases.

Influence of the Variation of Plasma Torch Parameters on Particle Melting and Solidification

1997 ◽  
Author(s):  
M. Vardelle ◽  
P. Fauchais ◽  
A. Vardelle ◽  
A.C. Léger
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Operating Conditions ◽  
Characteristic Parameters ◽  
Powder Mass ◽  
Arc Current ◽  
Plasma Sprayed ◽  
Carrier Gas Flow ◽  
Melting And Solidification

Abstract A study of the flattening and cooling of particles plasma-sprayed on a substrate is presented. The characteristic parameters of the splats are linked to the parameters of the impacting particles by using an experimental device consisting of a phase Doppler particle analyzer and a high-speed pyrometer. However, during the long experiments required to get reliable correlations, it was observed that variations in plasma spray operating conditions may alter the particles behavior in the plasma jet. Therefore, a simple and easy-to-use system was developed to control in real time the spray jet. In this paper, the effect of carrier gas flow rate, arc current and powder mass flow rate is investigated. The results on zirconia and alumina powders show the capability of the technique to sense the particle spray position and width.

Singular Finite Elements for the Die-Swell Simulation of Viscoelastic Fluids

2004 ◽  
Vol 37 (9) ◽  
pp. 1140-1149 ◽  
Author(s):  
Shuichi Iwata ◽  
Hideki Mori ◽  
Tsutomu Aragaki ◽  
Yusuke Takahashi ◽  
Masahito Hattori ◽  
...  
Keyword(s):  
Finite Elements ◽  
Viscoelastic Fluids ◽  
Die Swell

Application of a Singular/Decoupled Finite Element Method to the Viscoelastic Die-swell Flow Simulation

2002 ◽  
Vol 35 (7) ◽  
pp. 660-669 ◽  
Author(s):  
Shuichi Iwata ◽  
Tsutomu Aragaki ◽  
Hideki Mori ◽  
Masahito Hattori ◽  
Hikaru Waki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Flow Simulation ◽  
Die Swell ◽  
Element Method

Numerical Simulation of Die Swell of Second-Order Fluids Using Smoothed Particle Hydrodynamics

2010 ◽  
Author(s):  
Samir Hassan Sadek ◽  
Mehmet Yildiz
Keyword(s):  
Free Surface ◽  
Smoothed Particle Hydrodynamics ◽  
Second Order ◽  
Rheological Parameters ◽  
Die Swell ◽  
Two Dimensional ◽  
Polymeric Fluid ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Second Order Fluids

This work presents the development of both weakly compressible and incompressible Smoothed Particle Hydrodynamics (SPH) models for simulating two-dimensional transient viscoelastic free surface flow which has extensive applications in polymer processing industries. As an illustration with industrial significance, we have chosen to model the extrudate swell of a second-order polymeric fluid. The extrudate or die swell is a phenomenon that takes place during the extrusion of polymeric fluids. When a polymeric fluid is forced through a die to give a polymer its desired shape, due to its viscoelastic non-Newtonian nature, it shows a tendency to swell or contract at the die exit depending on its rheological parameters. The die swell phenomenon is a typical example of a free surface problem where the free surface is formed at the die exit after the polymeric fluid has been extruded. The swelling process leads to an undesired increase in the dimensions of the extrudate. To be able to obtain a near-net shape product, the flow in the extrusion process should be well-understood to shed some light on the important process parameters behind the swelling phenomenon. To this end, a systematic study has been carried out to compare constitutive models proposed in literature for second-order fluids in terms of their ability to capture the physics behind the swelling phenomenon. The effect of various process and rheological parameters on the die swell such as the extrusion velocity, normal stress coefficients, and Reynolds and Deborah numbers have also been investigated. The models developed here can predict both swelling and contraction of the extrudate successfully. The die swell problem was solved for a wide range of Deborah numbers and for two different Re numbers. The numerical model was validated through the solution of fully developed Newtonian and Non-Newtonian viscoelastic flows in a two-dimensional channel, and the results of these two benchmark problems were compared with analytic solutions, and good agreements were obtained.

scholarly journals Effect of Gas Pressure and Temperature on Stereometric Properties of Al+Al2O3 Composite Coatings Deposited by LPCS Method

2014 ◽  
Vol 59 (3) ◽  
pp. 879-886 ◽  
Author(s):  
M. Winnicki ◽  
T. Piwowarczyk ◽  
A. Małachowska ◽  
A. Ambroziak
Keyword(s):  
Laval Nozzle ◽  
Composite Coatings ◽  
Gas Pressure ◽  
Feedstock Powder ◽  
Substrate Distance ◽  
Al2o3 Composite ◽  
Spray Method ◽  
Powder Mass ◽  
De Laval Nozzle ◽  
Temperature And Pressure

Abstract The paper deals with effect of working gas pressure and temperature on surface stereometry of coatings deposited by low-pressure cold spray method. Examinations were focused on aluminium coatings which are commonly used to protect substrate against corrosion. A commercial Al spherical feedstock powder with admixture of Al2O3 (Al + 60vol.-% Al2O3), granulation -50+10 µm, was used to coat steel, grade S235JR. Thedeposited coatings were studied to determine their stereometry, i.e. roughness, transverse and longitudinal waviness, topography of surface and thickness as the functions of gas pressure and temperature. A profilometer and focal microscope were used to evaluate the stereometric properties. In order to reduce the number of variables, the remaining process parameters, i.e. shape and size of de Laval nozzle, nozzle-to-substrate distance, powder mass flow rate, linear velocity of spraying gun, were kept unchanged. The investigation confirmed influence of temperature and pressure on coating thickness as well as on the surface seterometry.

Research on Powder Stream of Coaxial Powder Feeding in Laser Manufacturing Technology

2013 ◽  
Vol 423-426 ◽  
pp. 807-810
Author(s):  
Heng Quan ◽  
Yun Shan Wang ◽  
Li Feng Liu ◽  
Shao Jun Liu ◽  
Qing Ruo Meng
Keyword(s):  
Physical Model ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Concentration Field ◽  
Ccd Camera ◽  
Factors Affecting ◽  
Coaxial Nozzle ◽  
Powder Mass ◽  
Powder Feeding

Mathematical-physical model of powder stream in coaxial powder feeding was established. The concentration fields of powder stream of coaxial nozzle of different size and powder mass flow rate were analyzed. The concentration field and morphology of the powder stream were detected by CCD camera. The results show that the size of coaxial nozzle and powder mass flow rate are major factors affecting the powder stream. The mathematical-physical model and experimental data provide theoretical basis for laser cladding manufacturing.

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