S. Prabhakar ¹, V. N. Banugopan ¹, K. Annamalai ¹, S. Jayaraj ¹

Affiliations
1 Department of Automobile Engineering, MIT Campus, Anna University, Chennai, IN

Abstract

The methyl and ethyl esters of vegetable oils, known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternative fuel for diesel engine. In the present work, methyl and ethyl esters of nerium oil were prepared by transesterification using both methanol and ethanol. However, viscosity of ethyl esters of nerium oil (EEON) was slightly higher than that of methyl esters of nerium oil (MEON). A single cylinder stationary kirloskar engine is used to compare the Performance and Emission and Combustion characteristics between pure diesel and nerium blends. The nerium oil blends are in percentage of 20%, 40%, 60%, 80%, and 100% of nerium oil to 80%, 60%, 40%, 20% and 0% of diesel. Results show that methyl esters of nerium oil (MEON) produced slightly higher efficiency than ethyl esters of nerium oil (EEON). Exhaust emissions and Combustion characteristics of methyl esters of nerium oil (MEON) were also higher than ethyl esters of nerium oil (EEON). Hence methyl and ethyl esters of nerium blend can be used in existing diesel engines without compromising the engine performance.

Keywords

Transesterification, Methyl Esters, Ethyl Esters, Nerium Oil

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Arun K. Raj ¹, K. Dileep ², S. Jayaraj ¹

Affiliations
1 Department of Mechanical Engineering, NIT Calicut – 673601, Kerala, IN
2 Department of Mechanical Engineering, VAST, Mumbai – 400059, Maharashtra, IN

Abstract

Objectives: A comparative numerical analysis is conducted, to emphasize the capability of an open source CFD package (OpenFOAM) over the commercial CFD package of ANSYS. Methods/Analysis: Buoyancy driven flows occurring within the vacuum tubes of gravity-assisted solar water heaters are analyzed. A scaled model of the ETC type solar water heater has been chosen for computation. The geometry and meshing of the model was done by using the 'Design Modeler' and 'ICEM-CFD' packages available in ANSYS. The same configuration was also modeled in OpenFOAM to account for 3-D, transient, incompressible, laminar fluid flow analyses analogous to the available models in FLUENT. Findings: Boussinesq approximation is considered to be valid. Governing equations were discretized based on Finite Volume Method (FVM). The significance of the inlet velocity and varying incident solar radiation on the nature of flow and performance of the collector is examined. Mass flow rates have been varied from 0.0002 to 0.03 kg/s while the solar insolation considered was in the range of 300 to 1000 W/m². For a uniform heat flux, with decrease in velocity of the fluid entering the storage tank, temperature of the water obtained at the outlet was found to be higher. This is due to the prolonged interaction of the fluid with the tube walls, which facilitates a higher heat gain from the tube surface to the fluid. Similarly, as the heat flux increases, the magnitude of the tube surface temperature increases which results into a higher outlet temperature. The performance of ETC type solar water heaters is said to be more efficient at lower flow rates and the same is true at higher incident solar radiations. Applications/Improvements: Comparison of the results between OpenFOAM and FLUENT shows the wide reliability and urges the use of open source software like OpenFOAM for more complicated CFD modeling and computational studies.

Keywords

Finite Volume, Flow Rate, Heat Flux, OpenFOAM, Solar Water Heater.

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