Arun Kumar Tiwari

Progress of Nanofluid Application in Machining: A Review

A colloidal mixture of nanometer-sized (<100 nm) metallic and non-metallic particles in conventional cutting fluid is called nanofluid. Nanofluids are considered to be potential heat transfer fluids because of their superior thermal and tribological properties. Therefore, nano-enhanced cutting fluids have recently attracted the attention of researchers. This paper presents a summary of some important published research works on the application of nanofluid in different machining processes: milling, drilling, grinding, and turning. Further, this review article not only discusses the influence of different types of nanofluids on machining performance in various machining processes but also unfolds other factors affecting machining performance. These other factors include nanoparticle size, its concentration in base fluid, lubrication mode (minimum quantity lubrication and flood), fluid spraying nozzle orientation, spray distance, and air pressure. From literature review, it has been found that in nanofluid machining, higher nanoparticle concentration yields better surface finish and more lubrication due to direct effect (rolling/sliding/filming) and surface enhancement effect (mending and polishing) of nanoparticles compared to dry machining and conventional cutting fluid machining. Furthermore, nanofluid also reduces the cutting force, power consumption, tool wear, nodal temperature, and friction coefficient. Authors have also identified the research gaps for further research.

Combined energy and exergy analysis of a corrugated plate heat exchanger and experimental investigation

This paper presents an experimental investigation on combined energetic and exergetic performance characteristics of a corrugated plate heat exchanger using water. On the basis of experimental data considering heat exchange with ambient, various energetic and exergetic performance parameters have been evaluated and discussed their interrelationship. General relationship between energy effectiveness and exergy efficiency has been established as well. The result shows that the exergetic efficiency increases with the Reynolds number, hot and cold water inlet temperatures. The exergy loss increases with increase in hot side Reynolds number and inlet temperature, and decreases with increase in cold side Reynolds number and inlet temperature. The dimensionless exergy loss increases with increase of friction factor and number of transfer units. Study reveals that the heat loss has significant contribution on irreversibility and both heat capacity ratio and effectiveness affect the exergetic efficiency. Some energy–exergy relationship correlations have been also obtained based on experimental data.

An Investigation on Tool Flank Wear Using Alumina/MoS2 Hybrid Nanofluid in Turning Operation

The present work is focused on the development of a hybrid nano-lubricant with improved tribological properties by mixing molybdenum-disulphide (MoS2) nanoparticles with alumina nanoparticles in oil-water emulsion base fluid in a fixed volumetric proportion (10:90). The tribological testing and contact angle measurement of prepared lubricants have been performed on pin-on-disc tribometer and goniometer, respectively. The hybrid lubricant has shown better results compare to base fluid (oil-water emulsion) and alumina-based monotype lubricant. Furthermore, the test results confirm the reduction in wear and coefficient of friction with increase of nanoparticle concentration. Moreover, the performance of hybrid nanofluid has been evaluated in terms of machining response using minimum quantity lubrication (MQL) technique on turning of AISI 304 steel. The addition of hybrid nanoparticles significantly reduces the tool flank wear as compared to monotype nano-lubricant and base fluid.

Influence of graphene and multi-walled carbon nanotube additives on tribological behaviour of lubricants

In the present study, the tribological performance of water-based emulsion (lubricant) was investigated by blending carbon fillers such as graphene nanoplatelets and multiwall carbon nanotubes using pin-on-disc tribometer. It was noticed that addition of GnP and MWCNT in water-based emulsion (conventional lubricant) increases the thermal conductivity and viscosity as compared to conventional lubricants. The nanolubricants were supplied with minimum quantity lubrication (MQL) technique at a constant flow rate and pressure in the sliding zone. The addition of 0.8 wt.% concentration of GnP showed 58.39% reduction in coefficient of friction and 61.80% reduction in wear depth compared to the conventional lubricant. Similarly, for 0.8 wt.% concentration of MWCNT showed 26.27% reduction in coefficient of friction and 47.35% reduction in wear depth compared to the conventional lubricant. The sliding surface micrographs were also investigated to explain the synergistic effect of nanoparticles.