Graphene and its derivatives have drawn interest across many disciplines due to their remarkable properties. We investigated the influence of graphite oxide (GO), aluminum oxide (Al2O3), and cerium oxide (CeO2) nanoparticles at 0.1% and 0.01% dosing concentrations on the combustion characteristics of diesel fuel by using the single droplet combustion experiment. Shortened ignition delay (ID) by up to 46.5%, increased burn-rate constant (up to 29.4%), reduced peak temperature (up to 13.8%), and shortened burnout time (up to 19.2%) are observed when a GO nanoparticle is dosed in diesel fuel. These remarkable features may substantially improve the combustion efficiency and reduce harmful emissions in diesel engine applications.

Summary Graphite oxide (GO) is an important member of the graphene family of carbon nanomaterials with remarkable physical, chemical, and thermal properties. We conducted an experimental investigation on the combustion characteristics of diesel and biodiesel droplets dosed with 0.1% GO. The fuels were tested by a single droplet combustion experiment in which the temporal variation in the burning behavior of a suspended droplet was captured using a high‐speed camera. Numerical analysis of the combustion data suggests that the addition of GO in both fuels resulted in shortened ignition delay (by up to 38.2%), increased burn‐rate constant (by up to 29.4%), lowered peak temperature (by up to 7.8%), and shortened burning period (by up to 11.6%). To illustrate, the burn‐rate constant increased from 0.68 to 0.88 mm2/second, and the burning period reduced from 2.7 to 2.2 seconds when GO was dosed in diesel. By contrast, the ignition delay and peak temperature both decreased from 1.6 to 1.4 seconds and 659 to 611 K, respectively, when GO was added in biodiesel. Our results suggest that the fuel additive–induced benefits could effectively reduce emissions and improve fuel consumption for diesel engine applications.

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Pollutant emission is becoming a serious environmental issue nowadays. Stringent legislations were introduced in several countries to limit the permissible levels of pollutant particle emission in major combustion systems such as burners and furnaces that have been widely used in industrial application. In this study, a numerical study of laminar coflow diffusion flame was performed in a model combustor using the commercial software ANSYS Fluent 19.1. The main focus of this study is to understand the effect of the variation of flow characteristics in the coflow diffusion flame on the prediction of NO x and soot emissions. A comparison study of the pollutant formation was performed with different hydrocarbon gaseous fuels (methane, ethylene, ethane, propane, and n-butane) with detailed high-temperature reaction mechanisms. In addition, the Moss−Brookes model was adopted to obtain the soot emission data. Variation of the flow characteristics on the pollutant formation was performed by examining the change in fuel inlet velocity, i.e., 0.5u ̅ 0 , u ̅ 0 , 1.5u ̅ 0 , 2u ̅ 0 with u ̅ 0 the mean fuel inlet velocity of baseline condition, and the effect of nozzle heating condition, i.e., 298 and 403 K. The results showed that ethylene flame produced higher NO x and soot compared to other hydrocarbon fuels. It was observed that the increase of the fuel inlet velocity promoted the formations of NO x and soot. Besides that, the nozzle heating condition increased the overall adiabatic temperature of the flame, where the relative effect was more pronounced on the alkane fuels, especially the lighter fuel compared to alkene fuel (ethylene).

Diesel−palm biodiesel blend could be an attractive fuel for diesel vehicles owing to its better physicochemical properties compared to those of fossil diesel. This study comprehensively investigates the combustion behavior of diesel droplet blended with palm biodiesel at 20% v/v, 40% v/v, and 60% v/v (i.e., B20, B40, and B60, respectively). Droplet combustion experimental results show that the B60 and palm biodiesel droplets exhibit a more prominent blue flame and less sooty flame compared to diesel droplet. Compared to those of diesel droplet, the ignition delay and burn-rate constant for B60 droplet increase by 27.0 and 56.3%, respectively, whereas, the burning duration of B60 droplet decreases significantly by 17.7%. Overall, this study suggests that B60 could be an effective fuel for improving the combustion and emission characteristics of diesel engines and has the potential to be utilized for other combustion-related applications.

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