The effect of thermal conductivity and stably dispersed graphene nanoplatelets on Sterculia foetida biodiesel–diesel blends for the investigation of performance, emissions, and combustion characteristics on VCR engine

Abstract

The present study investigates the use of a Sterculia foetida biodiesel–diesel sample (B20) and graphene nanoplatelets (GNPs) at 60 ppm with different agents (non-ionic surfactant Span 80), surfactant cetyl trimethyl ammonium bromide (CTAB), and dispersant (QPAN 80) at various compression ratios (16:1, 17:1, and 18:1) in a diesel engine. The surface-modified GNPs (using an optimum ratio of 1:1 GNPs to agent) were added to the B20 blend using a bath and a probe sonicator. The prepared samples were analyzed for characterization using field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), fourier transform infrared (FTIR), X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and thermal conductivity. The highest stability was observed for the dispersant-added GNPs-B20 blend (B20 + GNPs 60 mg/L + QPAN 80 mg/L). In overall engine performance, brake thermal efficiency (BTE), cylinder pressure (CP), and net heat release rate (NHRR) were increased by 11.56, 18.61, and 15.88%, respectively, whereas brake-specific fuel consumption (BSFC), ignition delay (ID), and combustion duration (CD) were reduced by 27.5, 17.10, and 15.34%, respectively. Carbon monoxide (CO), unburnt hydrocarbon (UHC), nitrogen oxide (NO_x), and smoke opacity were reduced by 13.24, 23.04, 5.20, and 59.84%, respectively, for the B20 + GNPs 60 mg/L + QPAN 80 mg/L blend at a higher compression ratio and the maximum load condition. The results ultimately suggest that the blend B20 + GNPs 60 mg/L + QPAN 80 mg/L could be successfully used in diesel engines with no engine modifications.

Keywords:

• Sterculia foetida biodiesel
• surfactant
• dispersant
• graphene nanoplatelets
• compression ratio
• thermal conductivity

Future scope

Based on the findings of this study, the combination B20 + GNPs 60 mg/L + QPAN 80 mg/L is recommended at higher CRs. The performance, combustion, and emission characteristics of a diesel engine will be further investigated by adjusting engine input parameters such as injection pressure and injection timing using the same blend.

Acknowledgements

The authors sincerely thank the Department of Mechanical Engineering, GITAM School of Technology, GITAM Deemed to Be University, Visakhapatnam Campus, for providing laboratory facilities to conduct the research work. The authors also thank the Sophisticated Analytical Instrument Facility (SAIF), IIT Bombay, for the analysis of the sample.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data is available in the manuscript.