EXPERIMENTAL INVESTIGATION ON COOLING EFFECT OF SPHERICAL DIMPLED PROFILE ALUMINUM BLOCK BY THE TAGUCHI METHOD

Dimple profile plays a crucial role in enhancement of cooling process of various engineering application. This paper presents experimental investigation of convection heat transfer over spherical dimple on an aluminum block. In this study, an experimental investigation was carried out to observe the cooling effect under several conditions which are flow condition, dimple orientation, diameter of dimple, room temperature, air velocity, input of heat energy and condition of wind tunnel. A design of experiments technique was adopted in the form of orthogonal array L8 (23), Taguchi 2-Level approach. A total of 4 types dimpled surface are studied. The ANOVA results shows the room temperature is the major contributing factor towards rapid cooling process followed by wind tunnel condition, radius of dimple, air velocity, flow region and heat input. It was observed that the cooling time of 13 minutes can be achieved during laminar flow, 5 mm of dimple diameter, 60° angle of dimple orientation, 18 m/s of air velocity, 20 °C of room temperature

The Effects Of Dry And Chilled Air On Tool Wear Behavior During Face Milling Of Inconel 718

Tool wear is one of the important criteria during the cutting process. It is mostly caused by the machining parameters, namely; cutting speed, feed rate, depth of cut, cooling condition, etc. This paper presents the behavior of cutting tool during dry and chilled air condition of face mill with the cutting speed of 20 to 40 m/min, the feed rate of 0.1 to 0.2 mm/tooth and axial depth of 0.1 mm. The analysis of variance (ANOVA) is applied to identify the significance of these factors effect on tool performance, later the mathematical model for the tool life prediction was developed. The investigation revealed that the cutting speed, feed rate dominating wear rate whilst the chilled air found to be marginally significant. Finally, the optimum condition for machining parameter for greater tool life can be obtained by the combination cutting speed of 20 m/min, the feed rate of 0.1 mm/tooth under chilled air condition. Implementation of chilled air contributed 7% improvement with 45 min compared to a dry condition. The study exhibited the round type insert of dry face milling is more prone to rapid flank wear than chilled air with no BUE appearance on the tool cutting edge

CHEMICAL DESULPHURISATION OF SUB-BITUMINOUS HIGH SULPHUR INDONESIAN COAL VIA PEROXYACETIC ACID TREATMENT

The chemical desulphurisation from an Indonesian high sulphur sub-bituminous Banjarmasin Haji Ali-Aliansar coal was investigated using the peroxyacetic acid (PAA), a mild oxidising agent. A mixture of hydrogen peroxide:acetic acid (i.e. 30:70 by volume ratio with 6% of hydrogen peroxide concentration) at 50°C of reaction temperature is capable of reducing the total sulphur content in the coal from 3.46% to 1.29% by weight, corresponding to the removal of up to ca. 72% of the total sulphur; both the inorganic (mainly pyrite) and organic sulphur forms, and approximately 10 to 44% of ashes in the coal. The simultaneous removal of both inorganic and organic sulphur forms was measured with respect to reagent volume mixed ratio, reaction temperature and hydrogen peroxide concentrations. The success of desulphurisation was measured by the reduction of the total sulphur content of the desulphurised product, its S/ C atomic ratios and ash yields of the treated coal. In general, all inorganic and some of the organic sulphur could be removed from the coal using mild conditions without severely affecting the coal microstructure as observed via the Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX)  which supplied the coal sample