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.

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.

The Theoretical and Experimental Evaluation of Gas-Particle Flow in Laser Cladding Repairing of Three Dimensions

Materials ◽  
2004 ◽  
Author(s):  
Hui-Shan Li ◽  
Xi-Chen Yang ◽  
Chun-Xian Wang
Keyword(s):  
Mass Flow Rate ◽  
Laser Cladding ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Flow ◽  
Ccd Camera ◽  
Longitudinal Axis ◽  
Three Dimensions ◽  
Theoretical Evaluation ◽  
Transportation Equipment

In this paper, the powders transportation in laser cladding repairing during the coaxial powder-feeding was evaluated. The theoretical evaluation is based on a two-fluid approach in which both the gas and particulate phase is treated each phase separately, and the only link between the phases is through the drag force in the momentum equations. The particles velocities are calculated with changes of the gas flow and mass flow rate. This is important for the coaxial nozzle and the carrier-gas powder transportation equipment characteristics determined. An experimentally of the influence of carrying gas on the powder stream was set up. The gas-particles flowing from the nozzle was illuminated by a 2D sheet of light. A typical image from the CCD camera is captured. The axial velocity and cross section were described. According to the results, it was found that: (1) Different mass flow rate Mp=0.5g/s, 0.67g/s, 0.83g/s, 1g/s, the powder stream luminance intensity and distribution will change. (2) The distribution of powder concentration at longitudinal axis from the nozzle exit is shown. The faster particulates stream has the less density per unit volume for a given mass flow rate. (3) The gas velocity for transportation is the most important parameter.

Novel Fabrication and Testing of a Bubble-Powered Micropump

2005 ◽  
Author(s):  
Jung-Yeul Jung ◽  
Ho-Young Kwak
Keyword(s):  
Mass Flow Rate ◽  
Silicon Wafer ◽  
Mass Flow ◽  
Flow Rate ◽  
Initial Period ◽  
Ccd Camera ◽  
Bubble Nucleation ◽  
Duty Ratio ◽  
Glass Wafer ◽  
Outlet Port

A bubble-powered micropump was fabricated and tested in this study. The micropump consists of a pair of nozzle-diffuser flow controller and a pumping chamber. The two-parallel micro line heaters were fabricated to be embedded in the silicon dioxide layer above a silicon wafer which serves as a base plate for the micropump. The pumping chamber, the pair of nozzle-diffuser unit and microchannels including the liquid inlet and outlet port were fabricated by etching through another silicon wafer. A glass wafer having two holes of inlet and outlet ports of liquid serve as upper plate of the pump. The sequential photographs of bubble nucleation, growth and collapse were visualized by CCD camera. Clearly liquid flow through the nozzle during the period of bubble growth and slight back flow of liquid at the initial period collapsing can be seen. The mass flow rate was found to be dependent on the duty ratio and the operation frequency. The mass flow rate decreases as the duty ratio increases in the micropump with either circular or square pumping chamber.

scholarly journals Influence of rubber powder mass flow rate on process of plasma pyrolysis

2019 ◽  
Author(s):  
Jarosław Szuszkiewicz
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Chemical Compounds ◽  
Plasma Generator ◽  
Arc Plasma ◽  
Rubber Powder ◽  
Gaseous Products ◽  
Powder Mass ◽  
Plasma Pyrolysis

The paper describes the experimental examination of thermal utilization of used rubber. The research was carried out to examine the influence of rubber powder mass flow rate on the process of plasma pyrolysis of rubber. An arc plasma generator has been applied. Ar and mixture of Ar and H2 were used as plasma gas. The analysis of composition of the gaseous products was done by the infrared absorption spectroscopy. All the rubber introduced to the plasma jet was decomposed. The outgoing gas did not contain any of toxic chemical compounds, like NOx or HCN.

Study on Factors Affecting CHF Based on Factorial Analysis in Narrow Rectangular Channel Under Natural Circulation

2018 ◽  
Author(s):  
Li Zichao ◽  
Zhou Tao ◽  
Shi Shun ◽  
Amir Haider ◽  
Li Bing ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Influencing Factors ◽  
Mass Flow ◽  
Flow Rate ◽  
Natural Circulation ◽  
Rectangular Channel ◽  
Factorial Analysis ◽  
Contribution Rate ◽  
Factors Affecting ◽  
System Pressure

Research on influencing factors of CHF in narrow rectangular channel under natural circulation is of great significance to the safety of reactors. Taking the narrow rectangular experimental device as the research object, influencing factors of CHF in narrow rectangular channel were experimentally studied under natural circulation. With factorial analysis, effects of different factors and their interactions on CHF were analyzed. It is found that the contribution rate of mass flow rate is the largest, followed by the effect of outlet dryness, followed by the effect of system pressure. Their interactions between different factors have little effects on CHF in narrow rectangular channel under natural circulation.

scholarly journals Digital Measurement of Powder Mass Flow Rate

1974 ◽  
Vol 11 (7) ◽  
pp. 413-417
Author(s):  
Yukio Nishimi ◽  
Tadaharu Onishi ◽  
Takeshi Katsura ◽  
Ikuo Enokiya
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Digital Measurement ◽  
Powder Mass

Investigation of Hastelloy C Laser Clad Melt Pool Size and its Effect on Clad Formation

2008 ◽  
Vol 384 ◽  
pp. 213-227 ◽  
Author(s):  
Shou Jin Sun ◽  
Milan Brandt
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Laser Power ◽  
Steel Substrate ◽  
Pool Size ◽  
Melt Pool ◽  
Scan Rate ◽  
Powder Mass ◽  
Melt Pool Size

The melt pool size of a single-track clad in the laser cladding of Hastelloy C, a Nickel based alloy, on mild steel substrate has been investigated. The effect of laser processing parameters, such as laser power density, scan rate and powder mass flow rate on the melt pool size has been examined. It was found that the melt pool size is strictly controlled by the melt pool temperature which increases with laser power but decreases with increasing scan rate and powder mass flow rate. The melt pool size is critical for the clad formation in terms of clad height and dilution with the substrate. The clad height increases linearly with the ratio of melt pool size to powder stream diameter while the dilution is an exponential function of the ratio of melt pool size to laser spot size.

scholarly journals Geothermal Power: Factors affecting the performance of Binary Plants

2015 ◽  
Vol 2 ◽  
pp. 32-49
Author(s):  
Izabela Domanski ◽  
Matthew Cappadona ◽  
Oliver Fuller ◽  
Zeb Krix
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Power Plants ◽  
Plant Performance ◽  
Factors Affecting ◽  
Binary Cycle ◽  
Well Depth ◽  
And Performance

A meta-study is conducted investigating the effect of plant parameters on the power output and efficiency of geothermal binary cycle power plants. Production well depth, geofluid temperature and mass flow rate are the parameters considered. An increase in mass flow rate is shown to increase both power output and efficiency. It is shown that a distinction can be made between two basic types of binary plants based off of mass flow and performance data. The well depth is shown to have no effect on plant performance. In addition, condenser parameters were investigated and the highest efficiency condenser system is determined.

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