Nanofluids—a simple product of the emerging world of nanotechnology—are suspensions of nanoparticles (nominally 1–100 nm in size) in conventional base fluids such as water, oils, or glycols. Nanofluids have seen enormous growth in popularity since they were proposed by Choi in 1995. In the year 2011 alone, there were nearly 700 research articles where the term nanofluid was used in the title, showing rapid growth from 2006 (175) and 2001 (10). The first decade of nanofluid research was primarily focused on measuring and modeling fundamental thermophysical properties of nanofluids (thermal conductivity, density, viscosity, heat transfer coefficient). Recent research, however, explores the performance of nanofluids in a wide variety of other applications. Analyzing the available body of research to date, this article presents recent trends and future possibilities for nanofluids research and suggests which applications will see the most significant improvement from employing nanofluids.

Small particles, big impacts: A review of the diverse applications of nanofluids

Effect of metal based additive on performance emission and combustion characteristics of diesel engine fuelled with biodiesel

Increasing energy demand and environment concerns have prompted an evolution of alternative fuel sources. As an alternative fuel source, biodiesel is attractive because it reduces engine emissions. However, biodiesel produces higher NOx emissions compared to ordinary diesel fuel. Previous researches have established many factors that cause biodiesel to produce elevated NOx emissions. This study reviews the impacts of biodiesel combustion on NOx emissions and their reduction approaches in diesel engines. The first part of this study recaps the NOx formation mechanisms for understanding the kinetics behind the NOx forming reactions. The second part describes the factors affecting on NOx emissions. This paper established that higher NOx emissions are produced for biodiesel combustion which influenced by several factors such as physicochemical properties and molecular structure of biodiesel, adiabatic flame temperature, ignition delay time, injection timing and engine load conditions etc. The final section discusses on the reduction of NOx emissions from biodiesel fuelled engines for both pre and post combustion techniques. The results of reduction approaches of the NOx emissions implies, exhaust gas recirculation (EGR) and retarded injection timing are effective as well as low cost techniques than others. Between these two techniques, EGR reduces the NOx emissions at 5–25% EGR rate adequately in biofuelled engine by controlling oxygen content and combustion peak temperature with slightly decreasing HC and CO emissions. However this technique shows few penalties on smoke and PM emissions as well as brake specific fuel consumption if not perfectly optimized.

Impacts of biodiesel combustion on NOx emissions and their reduction approaches

Emission reduction in a Di diesel engine using exhaust gas recirculation (Egr) of palm biodiesel blended with TiO2 nano additives

The effect of nano-additives in diesel-biodiesel fuel blends: A comprehensive review on stability, engine performance and emission characteristics

In this present work, the investigations are carried out to study the performance, emission, and combustion characteristics of a single cylinder Compression Ignition (CI) engine using water–diesel emulsion fuel, and the alumina nanoparticles blended water–diesel emulsion fuels. The water–diesel emulsion fuel is prepared by the emulsification method in the proportion of 83% diesel, 15% water, and 2% surfactants by volume. The alumina nanoparticles are blended with the water–diesel emulsion fuel in the mass fractions of 25, 50, and 100 ppm systematically. The experiments are conducted at a constant speed of 1500 rpm and the results revealed a substantial enhancement in the performance and reduction in the harmful pollutants due to the incorporation of alumina nanoparticles in the water–diesel emulsion fuel. Furthermore, the hot-plate evaporation characteristics test asserted a considerable reduction in the evaporation time by adding the potential alumina nanoparticles to the water–diesel emulsion fuel.

An Experimental Study in a CI Engine Using Nanoadditive Blended Water–Diesel Emulsion Fuel

Due to the depleting amount of petroleum reserves and the increasing awareness on environmental concerns, biodiesel has become one of the most demanding and promising substitutes for the petroleum based fossil fuels. In this study, the biodiesel derived from waste cooking oil through the transesterification process was optimized using Response Surface Methodology. The biodiesel derived under optimum conditions was used for investigating the effect of injection pressure and timing on performance, emission and the combustion characteristics of single cylinder, four-stroke direct injection diesel engine at a constant speed of 1500 rpm. On varying the injection pressure and timing, it was found that the combined effect of higher injection pressure of 280 bar and an advanced injection timing of 25.5°bTDC had significant improvement in the brake thermal efficiency, cylinder gas pressure and heat release rate. Reduction in nitric oxide (NO) and smoke emission was also observed.

Effect of injection pressure and injection timing on DI diesel engine fuelled with biodiesel from waste cooking oil

The present study reports the results of Alumina and CNT (carbon nanotube) nanoparticles blended biodiesel fuel on the performance, emission, and combustion characteristics of a diesel engine. The biodiesel is produced from the raw jatropha oil by standard transesterification process, and subsequently, the nanoparticles such as Alumina, CNT, and Alumina–CNT are blended with the biodiesel fuel in the mass fractions of 25 and 50 ppm with the aid of an ultrasonicator. The characterization studies of the nanoparticles such as TEM and XRD are carried out to analyze their morphology. The whole investigation is carried out in a constant speed diesel engine in four phases using neat biodiesel fuel, Alumina blended biodiesel, CNT blended biodiesel, and Alumina–CNT blended biodiesel fuels. The results revealed a considerable enhancement in the brake thermal efficiency and marginal reduction in the harmful emissions for the nanoparticles blended biodiesel fuels compared to those of neat biodiesel fuel. Furthermore, the hot-plate evaporation test confirmed a shorten ignition delay effect, and improved heat transfer rate associated with the nanoparticles blended biodiesel fuels, owing to their enhanced surface area/volume ratio, and heat conduction properties.

The influence of nano additive blended biodiesel fuels on the working characteristics of a diesel engine

An experimental investigation is carried out to establish the performance, emission, and combustion characteristics of a diesel engine using carbon nanotubes (CNT) blended water–diesel emulsion fuels. The investigation is carried out in three phases using an experimental set-up consisting of a single-cylinder diesel engine coupled with an electrical loading device, an AVL Di-gas analyser, an AVL smoke meter, and a data-acquisition system comprising a Kistler piezoelectric pressure transducer and a crank angle encoder: using neat diesel in the first phase, water–diesel emulsion fuel in the second phase, and CNT blended water–diesel emulsion fuels in the third phase. The water–diesel emulsion fuel is prepared in the proportion of 5 per cent water, 93 per cent diesel, and 2 per cent surfactants (Span 80 and Tween 80) by volume with a hydrophilic–lipophilic balance of 8. The CNT are blended with the water–diesel emulsion fuel in the mass fractions of 25 and 50 ppm with the aid of a mechanical homogenizer and ...

R. Anand

Papers

Effect of metal based additive on performance emission and combustion characteristics of diesel engine fuelled with biodiesel

An Experimental Study in a CI Engine Using Nanoadditive Blended Water–Diesel Emulsion Fuel

Effect of injection pressure and injection timing on DI diesel engine fuelled with biodiesel from waste cooking oil

The influence of nano additive blended biodiesel fuels on the working characteristics of a diesel engine

An experimental investigation in a diesel engine using carbon nanotubes blended water–diesel emulsion fuel