Subrata Kumar Ghosh

Experimental analysis for rheological properties of aluminium oxide (Al2O3)/gear oil (SAE EP-90) nanolubricant used in HEMM

Purpose – The purpose of this paper is to experimentally investigate the effect of aluminium oxide (Al2O3) nanoparticles on gear oil (SAE EP 90) as a lubricant in heavy earth moving machinery (HEMM). Design/methodology/approach – Particle size distribution, viscosity, density, stability and other rheological properties have been measured. The variations in rheological properties with varying nanoparticle volume fraction and temperature have been investigated at atmospheric pressure over a temperature range of 15-40°C. Classical as well as modified Krieger – Dougherty models have been used for finding out viscosity variation and a new empirical model has been presented. Findings – Dynamic light scattering data confirm the presence of large agglomeration of about 5.5 times of primary nanoparticles in nanofluid. Nanofluid starts behaving as a non-Newtonian fluid with increasing nanoparticle volume fraction. Viscosity of nanofluid is enhanced by 1.7 times of base fluid with 2 per cent volume fraction of Al2O3...

Analysis of wear generation in mine excavator bucket

Purpose – The purpose of this paper is to explore the wear phenomena on the bottom surface of an excavator bucket and optimize the design parameters to reduce wear rate by converting sliding motion to rolling motion of rock during the time of operation. Design/methodology/approach – A test rig has been developed to study the wear phenomena and type of wear on the excavator bucket. Three different bottom plates have been fabricated for experiments to observe the difference of severity of wear in terms of volume of material removal. Findings – It has been observed that the bottom plate having the mesh-type wear bar pattern was comparatively more resistive to wear than the other two models. Wear-affected zone on the bottom plate was also detected and represented with the help of colour contour. Practical implications – It is expected that these findings will contribute towards the development of the bottom plate of the excavator bucket with some new pattern of a wear bar, which will be efficient to reduce th...

Analysis of nanofluids as a means of thermal conductivity enhancement in heavy machineries

Purpose – Nanofluids exhibit enhanced heat transfer characteristics and are expected to be the future heat transfer fluids particularly the lubricants and transmission fluids used in heavy machinery. For studying the heat transfer behaviour of the nanofluids, precise values of their thermal conductivity are required. For predicting the correct value of thermal conductivity of a nanofluid, mathematical models are necessary. In this paper, the effective thermal conductivity of various nanofluids has been reported by using both experimental and mathematical modelling. The paper aims to discuss these issues. Design/methodology/approach – Hamilton and Crosser equation was used for predicting the thermal conductivities of nanofluids, and the obtained values were compared with the experimental findings. Nanofluid studied in this paper are Al2O3 in base fluid water, Al2O3 in base fluid ethylene glycol, CuO in base fluid water, CuO in base fluid ethylene glycol, TiO2 in base fluid ethylene glycol. In addition, stu...

Experimental and mathematical analysis of wear generation at bottom plate of mine excavator bucket

Mine excavator buckets are made of austenitic manganese steel and subjected to wear while excavating ore, minerals and hard soil etc. Wear bars are used to reduce the wear in original bucket plate. A mathematical model based on several processes and design parameters has been developed to analyze the mechanism of wear generation of the bottom plate in the excavator bucket. An experimental setup has also been developed to study the wear in the excavator bucket. Different angular orientations of wear bars have been used to find out the minimum volume of wear on the bottom plate. It has been found that the wear bar with 90° orientation causes least wear. It has also been observed that the mathematical model has a good agreement with the experimental results.