Wire Electrode Diameter Research Articles

FeSO4·7H2O optimisation of earthed atomising corona discharge (Fe-EACD) a process for the pharmaceutical wastewater treatment

ABSTRACT Pharmaceutical residues can cause serious water pollution problems, harm human health and destroy the ecological balance. FeSO4·7H2O optimisation of the earthed atomising corona discharge (Fe-EACD) process was used to dispose of pharmaceutical wastewater in this research. Experiments were analyzed by VI characteristic curves to optimise the electrode distance (20–50 mm) and wire electrode diameter (0.3–0.5 mm). The effects of discharging voltage (7–12 kV), time (0–54 min) and FeSO4 dosage (0.2–1.2 g/L) were investigated using the response surface methodology (RSM). According to the RSM results, the best removal efficiency of COD (89.6%) was detected at the optimal discharging voltage of 12 kV, time of 42 min and Fe2+ concentration of 0.4 g/L. The Fe-EACD process could work efficiently with BOD5/COD ratio moving to 0.49 in an acid environment. The kinetic analysis and mechanism study suggested that the Fe-EACD process was demonstrated well by the pseudo-first-order based on the correlation coefficient (R 2). Active •OH producing in the EACD process is responsible for the COD removal and the FeSO4·7H2O as a catalyst can promote the formation of active hydroxyl. In other words, EACD with Fe2+ optimisation was an economic and feasible process for pharmaceutical wastewater treatment.

Research on Machining Gap Distribution in Wire Electrochemical Micromachining

Wire electrochemical micromachining (WECMM) has become a research hotspot in recent years due to its advantages in machining metallic microstructures. Profiles of metallic microstructures fabricated by WECMM are determined by the machining gap distribution. This paper focuses on equilibrium machining gap distribution in WECMM. A two-dimensional electric field model of WECMM was established and the evolution process of slit profile was investigated. It was found that in machining equilibrium status, the machining gap gets the minimum value at the wire electrode feeding direction and exponentially increases with the increase of the induced angle between the wire electrode normal direction and its feeding direction. Furthermore, the effects of wire electrode diameter, machining voltage, and wire electrode feed rate on the equilibrium machining gap distribution were studied through machining simulation. The quantitative relationship among the machining gap at any wire electrode normal direction, the machining voltage, and the wire electrode feed rate was determined through function fitting. Finally, machining experiments were carried out to verify the regularity of the machining gap distribution. Experimental results are basically consistent with the simulation and function fitting results, with the ratio of the calculation error to the experimental value less than 12.78%.

Estimation of Contact Tip to Work Distance (CTWD) using Artificial Neural Network (ANN) in GMAW

A method for optimizing monitoring by using Artificial Neural Network (ANN) technique was proposed based on instability of arc voltage signal and welding current signal of solid wire electrode (GMAW). This technique is not only for effective process modeling, but also to illustrate the correlation between the input and output parameters responses. The algorithms of monitoring were developed in time domain by carrying out the Moving Average (M.A) and Root Mean Square (RMS) based on the welding experiment parameters such as travel speed, thickness of specimen, feeding speed, and wire electrode diameter to detect and estimate with a satisfactory sample size. Experiment data was divided into three subsets: train (70%), validation (15%), and test (15%). Error back-propagation of Levenberg-Marquardt algorithm was used to train for this algorithm. The proposed algorithms on this paper were used to estimate the variety the Contact Tip to Work Distance (CTWD) through Mean Square Error (MSE). Based on the results, the algorithms have shown that be able to detect changes in CTWD automatically and real time with takes 0.147 seconds (MSE 0.0087).

Wire electrode diameter effect on cutting speed, in WEDM of varying height Inconel-718

Wire electrode diameter effect on cutting speed, in WEDM of varying height Inconel-718

Wire electropolishing of microgroove structures on a cobalt-based alloy

The surface quality of microstructures greatly affects their performance. Electropolishing has many advantages as a technique for eliminating surface defects of microstructures and components. This paper presents a new electropolishing method to improve the surface quality of microgrooves. A wire with a diameter in the micrometer range is employed as the cathode. The whole of the microgroove is polished by moving this wire electrode along the outline of the microgroove. The anodic dissolution behaviors of a cobalt-based alloy in phosphoric acid solutions with various concentrations are investigated using polarization curves. The effects of the wire electropolishing parameters, namely, the wire electrode diameter, feed rate, polishing gap, applied voltage, pulse period, and duty cycle are also studied both theoretically and experimentally. Using optimized values of these parameters, the surface roughness of the microgroove is reduced from Ra = 0.3 to 0.036 μm. A mirror-like surface is obtained after polishing.

Numerical simulation and design optimization of an electrohydrodynamic pump for dielectric liquids

With an ever increasing demand for more effective heat sinks, liquid based electronic cooling has become a new prospect in the field. The present study introduces an electrohydrodynamic (EHD) pump with a simple design for dielectric liquids which have potential applications for electronic cooling. The pump consists of an eccentrically sandwiched wire electrode placed at the horizontal centerline between two parallel flat-plate electrodes. The EHD flow of dielectric liquid induced by the space charge generated due to the Onsager effect was obtained by the numerical solution of the Poisson–Nernst–Planck equations for ion transport and the Navier–Stokes equations for fluid flow. Good agreement obtained in the comparison of the numerical and the experimental results of velocity for the centrally sandwiched wire electrode case confirmed the validity of the numerical results. For a fixed voltage, the pump flow rate depends on the eccentricity of the wire electrode with respect to the plate electrodes and also with the electrode dimensions. By using the Taguchi method an optimum design for the EHD pump is obtained considering the wire electrode diameter, the flat plate electrode length and the eccentricity (the horizontal distance between the centers of wire and flat-plate electrodes) as the design parameters for fixed channel dimensions.

Free surface electrospun fibers: The combined effect of processing parameters

In this study, a free surface electrospinning experimental setup was developed based on rotating spiral copper wire electrode and used as the spinneret. The scheme was investigated by varying processing parameters including polymer solution concentration, distance between the electrode and the collector, applied voltage between the electrode, and the collector and wire electrode diameter. An average of fiber diameter ranged between 202 and 543 nm and a relative standard deviation ranged between 11.0 and 26.9% were obtained. The combined effects of processing parameters on the resulting fiber morphology were investigated. The analysis shows that in a multiple variable process like electrospinning, the interaction between the different processing parameters played an important role, rather than one parameter separately in obtaining desired nanofibers. Knowing the relative combined effects of processing parameters on fiber morphology should be useful for process control and prediction of electrospun fiber quality as it has been demonstrated in this study. POLYM. ENG. SCI., 54:189–197, 2014. © 2013 Society of Plastics Engineers

Enhancement of submicron particle electrostatic precipitation using dielectric barrier discharge in wire-to-square tube configuration

The aim of the present parametric study is to enhance the performances of a wire-to-square tube electrostatic precipitator (ESP) for the collection of submicrometer particles using dielectric barrier discharge (DBD). The input parameters under study are: the high voltage waveform, the wire electrode diameter, the collection electrode dimensions (width, discretization and number of collection sides) and the tube cross-section. The electrical measurements show that the discharge mode of the ESP is rather homogeneous. The particle collection efficiency as determined from aerosol spectroscopy measurements is higher at high applied voltage and within a certain frequency range. The parametric study of the ESP points out that using thicker wire electrodes as well as collection electrodes with different number of sides does not deteriorate the ESP performance. However, the penetration decreases with larger or discretized collection electrodes and larger tube cross-sections. ► We optimize the collection of submicrometer particles using DBD-ESP. ► The input parameters are geometrical parameters. ► Using bigger wire diameter and different collecting sides has no effect on the performance. ► Penetration decreases with larger or discretized ground electrode and bigger sections.

Sub-nanosecond monitoring of micro-hole electrical discharge machining pulses and modeling of discharge ringing

Monitoring the gap voltage and current in micro-hole electrical discharge machining (EDM) using high-speed data acquisition with 0.5 ns sampling period is conducted. The spark and arc pulses at three stages, namely electrode dressing, drilling, and penetration, of the micro-hole EDM are recorded. The EDM process parameters are setup to use negative polarity to blunt the electrode tip and positive polarity for micro-hole drilling and penetration. A new phenomenon of pre-discharging current is discovered. In the first 20–30 ns of spark and arc pulses, the current starts to rise while the voltage remains the same. Effects of EDM process parameters, including the open voltage, electrode diameter, and polarity, on the rate of spark and arc pulses and electrode feed rate are investigated. A model based on the RLC circuit is developed to study the ringing effect at the end of a discharge. The intrinsic parasitic capacitance and resistance of a RLC circuit are calculated from the decaying voltage signal and compared under two sets of experiments with varying wire electrode diameter and gap voltage to validate the ringing model. The calculation and experimental results validate the proposed RLC model for ringing phenomenon. The model shows the electrode diameter has negligible effect on ringing and high open voltage increases the parasitic resistance and damping in ringing. The monitoring technique and ringing model developed in this research can assist in the selection and optimization of micro-hole EDM process parameters.

Electric discharge removal of SO 2 and NO x from combustion flue gas by pulsed corona discharge

Based upon the reported studies on removal of SO 2 and NO x from combustion flue gas by pulsed corona discharge, experimental studies on simulated combustion gas have been conducted changing parameters such as pulse width, polarity, wire electrode diameter, discharge gap, gas composition, gas temperature, etc. that are believed to be fundamental in the deSO x and deNO x process. Corona wind, which is expected to promote mixing of oxidizing radicals with SO 2 and NO x in pulsed corona discharge, has been tried to be visualized. Future works concerning about measurements of oxidizing radical OH concentration and about simulation of electric discharge chemical process, which are now in progress, have been put in order to explain more details of deSO x and deNO x processes.