Search

In this experimental study, efforts were undertaken to augment the overall efficiency of a dual-fuel engine. This present study was conducted in three steps. In the initial phase, Aluminium oxyhydroxide (AlO(OH)) was synthesized and analyzed using UV–visible spectroscopy, XRD (X-ray diffraction), Thermogravimetric (TG) analysis, and Differential Scanning Calorimeter (DSC). In the second part of the study, the impact of AlO(OH) NP dosage on the performance of a producer gas-powered diesel engine was investigated. To optimize adequate AlO(OH) NPs addition, three working fluids are prepared by dissolving NPs in dairy scum oil methyl ester (DiSOME) biodiesel ranging from 20 to 60 ppm and varied in steps of 20. In the next phase, the present study examined the effect of 60 ppm of various NPs, including multi-walled carbon nanotubes (MWCNT), Aluminum oxide (Al2O3), and AlO(OH) on the combustion and emission characteristics of a 1-cylinder 4-stroke direct injection diesel engine operating in dual fuel mode using a combination of DiSOME and producer gas. The study concluded that DiSOME-PG operation with 60 ppm AlO(OH) and without nano-addition resulted in decreased BTE by 2.9 % and 14.6 % respectively compared to diesel-supported dual fuel operation. To the extent that exhaust levels are concerned, AlO(OH) addition to the DiSOME-PG combination lowers hydrocarbon (HC) and carbon monoxide (CO) emissions than identical fuel amalgamation without AlO(OH) NP. It is noticed that the retarded combustion related to the DiSOME-producer gas mixture can be improved with NP addition. The DiSOME-producer gas functioning with NPs addition is the individuality of this current effort.

In the present research work, the influence of heat input rates on microstructures, hot tensile properties, and weld surface hardness number of Super Duplex Stainless Steel 2507 super duplex steels and austenitic steels 316L plates were investigated. Pulsed current and constant current modes were used in Tungsten Inert Gas (TIG) welding to join the dissimilar metals using ER2205 as filler. Microstructural studies were revealed at different zones of pulsed and constant current TIG weldments using optical microscopy. The tensile test was conducted at two different temperature conditions (i.e., 27 and 350°C) to investigate the strength of dissimilar weldments. Hardness measurements were made on the weld surface along the transverse direction using Vicker’s hardness tester. The microstructures revealed the formation of inter-granular austenite at the fusion zone with grain boundaries with austenite structures. Due to the constant heat input, a significant microstructural development with high austenite fractions was observed in constant current (CC)-TIG weldment. In comparison to CC-TIG weldments (UTS at 27°C = 600 MPa UTS at 350°C = 456 MPa), higher tensile characteristics were noted in Pulsed Current (PC)-TIG weldments (UTS at 27°C = 695 MPa UTS at 350°C = 475 MPa). The UTS of PC-TIG weldment is improved by 15.8% when compared to CC-TIG weldment due to the controlled heat input rates. PC-TIG weldments exhibited improved hardness numbers in various zones with smaller HAZ widths than CC-TIG weldments.

In this research, the effect of fillers wires on weldability, welding strength and structural changes of dissimilar welds of Inconel 718 and AISI 316L are studied. Pulse arc mode in TIG welding with multiple passes were used to join V-groove configuration with 1.6 mm filler diameter. Constant welding parameters were used for both the weldments to study the effect of alloying elements of filler wires. Tensile properties were evaluated by conducting tensile test on universal testing machine as per ASTM E/8 standards. To reveal the structural changes at various zones of weldment, optical microscope was utilized. The dissimilar metals were joined successfully using two-filler wires without any internal defects. The highest tensile strength of 553 MPa was observed in Hastelloy filler weldment when compared with ERNiCrMo-4 filler weldment (530 MPa). Also, the better yield strength properties were observed in Hastelloy filler weldment. Well defined with clear grain boundaries were observed in both the filler weldments. Due to the pulsed arc mode, segregation of alloying elements was reduced.

In this research, surface modification was carried out on aluminium alloy 6061 through friction stir processing by embedding surface with B4C particles. Three different samples namely, AA6061 with only stir processing (sample 1), friction stir processed by B4C with single pass (sample 2) and by B4C multi-pass (sample 3) were developed to study the wear, corrosion and microstructural properties. The modified surfaces were characterised by carrying out using optical and scanning electron microscopes. Pin-on disc method was employed to study the wear rate on these stir processed samples. Corrosion behaviour of three stir processed samples was characterised in a 3.5 wt.% NaCl solution at 10 mV/s scan rate. From microstructural analysis, the dark zones with onion rings were seen at the nugget zone in sample 2, whereas uniform distribution with clear grain boundaries were observed in sample 3. From wear test, the wear rate for sample 1 was higher when compared with other two samples. From corrosion test, corrosion rate of sample 2 was observed to be 1.469 mm/year which is lower than sample 1 (2.868 mm/year) and sample 3 (6.127 mm/year). Corrosion resistance of sample 2 was greatly improved due to proper mechanical mixing of B4C particles. [ABSTRACT FROM AUTHOR]

The paper presents the results of the laser beam welding of SS321, measurements of distortion, residual stress, weld bead shape, and metallurgy of weld joints. The laser CO2 laser beam welding uses an L4 orthogonal array. Weld distortion and residual stresses were assessed along the transverse axis using a vernier height gauge and X-ray diffraction technique, with the optimal desired value for a lower-the-better-quality feature zero. All combinations resulted in sound welds (porosity-free), and the joint microstructure, SEM/EDX, and mechanical analysis were carried out. All measured residual stresses are compressive, which is a desirable result. The stresses are within the yield limits and self-balances with the structure, and factor of safety of all the joints is 1.58. The results obtained from the tensile tests indicated that the welded specimens exhibited higher strength and ductile. [ABSTRACT FROM AUTHOR]