Optimization of Electro Discharge Machining Parameters on Mg / SiC P-Metal Matrix Composites by Response Surface Methodology
Metal Matrix Composites (MMCs) are present engineer ing materials which have more advantages when compare to conventional materials. Magnesium based MMCs among the MMCs have become an important resear ch subject because of their low density and high stren gth/weight ratio in recent years. The aim of this s tudy is to find out the most influence factors of the electro-disch arge machining (EDM) process parameters. The specim ens were used as Mg/SiCp metal matrix composites. The specim ens were prepared by the powder metallurgy techniqu es. Brass tool with diameter of 10mm was used to machin e the specimens. Experiments were conducted under d iff rent conditions of pulse on time (Ton), pulse off time ( Toff), current (I). The output responses measured w re material removal rate (MRR) and Tool wear rate (TWR). Mathem atical models are proposed for the above responses using response surface methodology (RSM). The analysis of variance (ANOVA) was carried out to study the effe ct of process parameters on process performance.
ESTABLISHING EMPIRICAL RELATION TO PREDICT TEMPERATURE DIFFERENCE OF VORTEX TUBE USING RESPONSE SURFACE METHODOLOGY
Vortex tube is a device that produces cold and hot air simultaneously from the source of compressed air. In this work an attempt has been made to investigate the effect of three controllable input variables namely diameter of the orifices, diameter of the nozzles and inlet pressure over the temperature difference in the cold side as output using Response Surface Methodology (RSM). Experiments are conducted using central composite design with three factors at three levels. The influence of vital parameters and interaction among these are investigated using analysis of variance (ANOVA). The proposed mathematical model in this study has proven to fit and in line with experimental values with a 95% confidence interval. It is found that the inlet pressure and diameter of nozzle are significant factors that affect the performance of vortex tube.
Evaluation of CuAl2O4 as an Oxygen Carrier in Chemical-Looping Combustion
The chemical-looping combustion (CLC) process is a novel solution for efficient combustion with intrinsic separation of carbon dioxide. The process uses a metal oxide as an oxygen carrier to transfer oxygen from an air to a fuel reactor where the fuel, or gasification products of the fuel, reacts with the solid oxygen carrier. In this work, copper(II) aluminate (CuAl2O4) was assessed as a potential oxygen carrier using methane as fuel. The carrier particles were produced by freeze–granulation and calcined at 1050 °C for a duration of 6 h. The chemical-looping characteristics were evaluated in a laboratory-scale fluidized-bed reactor in the temperature range of 900–950 °C during 45 alternating redox cycles. The oxygen carrier exhibited reproducible and stable reactivity behavior in this temperature range. Neither agglomeration nor defluidization was noticed in any of the cycles carried out at 900–925 °C. However, after reactivity tests at 950 °C, soft agglomeration and particle fragmentation were observed. Systematic phase analysis of the Cu–Al–O system during the redox cycle was carried out as a function of duration of reduction and oxygen concentration during the oxidation period. It was found that the CuAl2O4 is reduced to copper(I) aluminate (CuAlO2; delafossite), Cu2O, and elemental Cu. The CuAlO2 phase is characterized by slow kinetics for oxidation into CuO and CuAl2O4. Despite this kinetic limitation, complete conversion of methane with reproducible reactivity of the oxygen carrier is achieved. Thus, CuAl2O4 could be a potential oxygen carrier for chemical-looping combustion.