scholarly journals Influence of the spark heat on the electrode behavior in Powder Mixed-EDM environment

2019 ◽  
Vol 13 (4) ◽  
pp. 6125-6143 ◽  
Author(s):  
M. A. Abbas ◽  
M. A. Lajis ◽  
A. D. Jawad ◽  
E. A. Rahim ◽  
S. Ahmed ◽  
...  
Keyword(s):  
Heat Flux ◽  
Pulse Duration ◽  
Removal Rate ◽  
Maximum Level ◽  
Correlation Factor ◽  
Copper Electrode ◽  
Experimental Results ◽  
Chromium Powder ◽  
Damage Sensing ◽  
Powder Mixed Edm

Most past studies did not attempt to improve the numerical model for the electrode removal rate which depends on the experimental results. Furthermore, these studies have not included the damage-sensing for the electrode in Powder Mixed-EDM (PMEDM) medium. Therefore, the current study aims to enhance this model for the copper electrode based on the heat flux for the spark channel. Besides, it focuses on sensing the copper electrode damage depending on the slope relation between eroding velocity and the pulse duration. In both studies, during machining D2 steel, Nano chromium powder in the dielectric liquid is applied. The correlation factor between the Numerical Heat Flux q(r) and the experimental results for the Tool Wear Rate (TWR) attained is 93.06%. The value of this factor improves the mathematical model for TWR instead of the traditional mechanism that adopts the crater volume. Also, the damage-sensing constant (STD) in the copper electrode is very efficient at the minimum value of the peak current (IP), powder concentration (PC) and the maximum level of the pulse duration (Ton). Thus, the statistical confirmation using Response Surface Methodology (RSM) produced a higher value of the composite desirability (96.76%) and error percent equals to (10.3%-1.55%) and (0.18%-2.40%) for TWR and q(r), respectively. On the other hand, the optimum operation values are IP = 10 Amps, Ton = 30 µs, and PC = 2 g/L. These confirmation values are similar to the trials No. (3) and No. (11). Therefore, these values confirm the main purpose in order to obtain the best performance for TWR at the minimum spark heat.

A Comparative Study for Machining of Ti–6Al–4V Alloy for Multi-Criteria Response

2018 ◽  
Vol 17 (04) ◽  
pp. 515-531 ◽  
Author(s):  
Manisha Priyadarshini ◽  
Kamal Pal
Keyword(s):  
Pulse Duration ◽  
Removal Rate ◽  
Pure Copper ◽  
Copper Electrode ◽  
Duty Factor ◽  
Taguchi Optimization ◽  
Peak Current ◽  
Utility Concept ◽  
Desirability Approach ◽  
Optimization Methodology

Nowadays, it has become very difficult for the manufacturer to satisfy all its customers with satisfactory products, as they have different demands considering the responses. However, hard-to-machine materials are difficult to manufacture. This study explores the application of electro-discharge machining (EDM) of Ti–6Al–4V alloy with pulse duration (Ton), duty factor ([Formula: see text], peak current (Ip) and gap voltage (Vg) as the control parameters using pure copper electrode. Machining effects are evaluated by performance characteristics including material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) by considering the multi-criteria preference of the customers that vary with the preference of responses. For the experiment, proper orthogonal arrays are found out using Taguchi methodology. The optimum parametric settings were obtained by utility-concept-based Taguchi method which were compared with desirability-approach-based Taguchi. It was found that utility-concept-based Taguchi optimization methodology results in more feasible parametric setting which has also been confirmed by the validation experiments. The optimum values of process variables obtained were pulse duration of 30[Formula: see text][Formula: see text]s, duty factor of 9%, peak current of 10[Formula: see text]A and gap voltage of 6[Formula: see text]V to achieve maximum MRR and lower TWR with better surface finish to satisfy multi-user criteria.

Experimental results from a high heat flux solar furnace with a molten metal-cooled receiver SOMMER

Solar Energy ◽  
2021 ◽  
Vol 221 ◽  
pp. 176-184
Author(s):  
F. Müller-Trefzer ◽  
K. Niedermeier ◽  
F. Fellmoser ◽  
J. Flesch ◽  
J. Pacio ◽  
...  
Keyword(s):  
Heat Flux ◽  
Molten Metal ◽  
High Heat ◽  
Experimental Results ◽  
Solar Furnace ◽  
High Heat Flux

scholarly journals A laser experiment for studying radiative shocks in astrophysics

2002 ◽  
Vol 20 (2) ◽  
pp. 263-268 ◽  
Author(s):  
X. FLEURY ◽  
S. BOUQUET ◽  
C. STEHLÉ ◽  
M. KOENIG ◽  
D. BATANI ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Experimental Results ◽  
Laboratory Astrophysics ◽  
Laser Pulse Duration ◽  
Radiative Shocks ◽  
Self Similar ◽  
Laser Experiment ◽  
Similar Solutions

In this article, we present a laboratory astrophysics experiment on radiative shocks and its interpretation using simple modelization. The experiment is performed with a 100-J laser (pulse duration of about 0.5 ns) which irradiates a 1-mm3 xenon gas-filled cell. Descriptions of both the experiment and the associated diagnostics are given. The apparition of a radiation precursor in the unshocked material is evidenced from interferometry diagrams. A model including self-similar solutions and numerical ones is derived and fairly good agreements are obtained between the theoretical and the experimental results.

Screening of Coagulant for Washing Wastewater Treatment

2015 ◽  
Vol 1092-1093 ◽  
pp. 972-975
Author(s):  
Jing Yang
Keyword(s):  
Wastewater Treatment ◽  
Removal Rate ◽  
Experimental Results ◽  
The Other ◽  
Aluminium Chloride ◽  
Coagulation Tests ◽  
Cyclic Utilization ◽  
Washing Wastewater ◽  
Better Than

According to the problems exist in cyclic utilization of washing wastewater, the coagulation tests utilizing ferric trichloride (FeCl3), alums, poly aluminium chloride (PAC) and polyacrylamide (PAM) are studied, respectively. Experimental results show that PAC was much better than the other coagulants in the removal of LAS and chroma as a single coagulant. Cast 2.5mL PAC(10%) into quantitative washing wastewater, the removal rate of LAS and chroma reach 82.5% and 87.8%, respectively. When mix the every two kinds of coagulants, maintaining the same total amount of coagulant to 2.5mL, cast1.0mL PAC(10%) and 1.5mL alum (10%) into washing wastewater ,the removal rate of LAS and chroma reach 84.1% and 90.0%, respectively.

scholarly journals Brush seal with thermo-regulating bimetal elements

2018 ◽  
Vol 8 (1) ◽  
pp. 307-313 ◽  
Author(s):  
Michał Stanclik
Keyword(s):  
Heat Flux ◽  
Contact Area ◽  
Heat Load ◽  
Experimental Results ◽  
Frictional Heat ◽  
Brush Seal ◽  
Thermoregulatory Function ◽  
Shaft Surface

Abstract This paper presents a new brush seal construction idea. It was shown that it is possible to use bimetallic elements for the construction of the brush seal, which have a thermoregulatory function by relieving a contact area between bristles and a shaft surface reducing frictional heat flux. This should improve the durability of the seal by diminishing the heat load and significantly decreases the temperature of the seal during the startup/ shutdown. This article shows a simplified construction of the concept brush seal as well as numerical and experimental results.

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1319-1326 ◽  
Author(s):  
I. E. Gönenç ◽  
D. Orhon ◽  
B. Beler Baykal
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Cod Removal ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Removal Mechanism ◽  
Term Operation ◽  
Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.

scholarly journals Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chih Ming Ma ◽  
Yung Shuen Shen ◽  
Po Hsiang Lin
Keyword(s):  
Aqueous Solutions ◽  
Reaction Rate ◽  
Removal Rate ◽  
Experimental Results ◽  
Order Kinetic ◽  
Solution Ph ◽  
Relationship Of ◽  
The Relationship ◽  
Photocatalytic Processes ◽  
Order Kinetic Equation

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.

scholarly journals Heat transfer enhancement during condensation of water steam on inclined pipe

2021 ◽  
Vol 2039 (1) ◽  
pp. 012031
Author(s):  
S Z Sapozhnikov ◽  
V Yu Mityakov ◽  
A V Mityakov ◽  
A Yu Babich ◽  
E R Zainullina
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Enhancement ◽  
Unit Area ◽  
Experimental Results ◽  
Transfer Enhancement ◽  
Water Steam ◽  
Saturated Water ◽  
Informative Content ◽  
Inclined Pipe

Abstract This paper presents experimental study of heat transfer during film condensation of saturated water steam on the outer surface of the inclined pipe by gradient heatmetry. Heat flux per unit area was measured by gradient heat flux sensors made of a single-crystal bismuth. The experimental results are presented in the graphs of heat flux per unit area dependence on time and azimuthal angle. The highest average heat transfer coefficient during condensation of α = 6.94 kW/(m2 • K) was observed when the pipe was inclined at the angle of ψ = 20 °. This value exceeds one obtained on a vertical pipe by 14.9 %. Heat transfer enhancement during condensation of saturated water steam on inclined pipe is associated with changes in condensate film flow. Another part of experiments was made by simultaneously using of gradient heatmetry and condensate flow visualization. Experimental results confirmed the applicability and high informative content of proposed comprehensive method. Comprehensive study of heat transfer during condensation confirmed that heat flux per unit area pulsations may be explained by the formation of individual drops, their coalescence, and drainage from the sensor surface.

Experimental Boiler Tube Burnout as a Function of Downcorner Resistance

1968 ◽  
Vol 12 (01) ◽  
pp. 46-56
Author(s):  
John B. Woodward
Keyword(s):  
Heat Flux ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Boiler Tube ◽  
Average Flow ◽  
Flow Reduction ◽  
Flow Oscillations ◽  
Independent Variable

Experiments to determine the burnout heat flux in a simulated boiler tube are described. The principal independent variable is downcorner resistance to flow, measured by the parameter fL/D, and varied by adjusting a plug cock in the downcorner. The experimental results show an increase in burnout heat flux with increasing downcorner resistance, up to the point at which average flow reduction reverses this trend. The results are explained by the effect of downcorner resistance on the magnitude of flow oscillations, which begin to occur at heat fluxes less than the burnout heat flux, and which tend to promote the onset of burnout.

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