Vasudevan Raghavan

Bio: Vasudevan Raghavan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Combustion & Laminar flow. The author has an hindex of 17, co-authored 130 publications receiving 1051 citations. Previous affiliations of Vasudevan Raghavan include University of Nebraska–Lincoln & Indian Institutes of Technology.

Experimental Study of Effects of Coflow Air and Partial Premixing on Liquid Petroleum Gas Flames

Abstract: Investigation of the influence of coflow and partial air premixing on liquid petroleum gas (LPG) flames in a lab-scale co-flow burner is presented. Primary air is supplied along with LPG in the inner core, and secondary air is supplied through the annulus region of the burner. Digital images are analyzed to study the flame shape, color, height, radius, and qualitative laminar flame speed. Concentrations of product gases and emission species are measured using a digital gas analyzer. Results indicate that in a dual air stream configuration, the partial premixing is optimum at % primary air value of around 45%.

Enhanced Oil Spill Clean-Up Using Immersed Thermally Conductive Objects

Abstract: A method for rapid burning of hazardous oil spills on water is investigated with the ultimate goal of designing a burner for faster clean-up of hazardous spills in offshore and other remote environments. A thermally conductive object, which comprises of a 0.25 cm thick copper porous mesh, with or without conical copper coils, is used. The influence of this object on the burning rate of an Alaska North Slope crude oil slick (1 cm thick) on saline water is studied. For the mesh-alone case, heat from flame is transferred to the mesh, which rapidly gets heated up and transmits the heat to the oil slick. This heat transfer is much higher than that in the baseline case. In the case with conical coils, which are engulfed in the flame, the heated up coils transfer the heat to the copper mesh more effectively. Thus, the object enhances the mass burning rate. Experimental results reveal that the copper mesh reaches a temperature higher than the boiling point of the oil, such that onset of nucleate boiling is possible. The mesh-coil system is able to burn thin slick of oil resting on water achieving an efficiency of ~ 400% above baseline. A simple integral model is also proposed to predict the temperature profiles in mesh, oil, and water layers. The predicted temperature profiles show good agreement with the experimental results. A parametric study using the integral model is also reported. The model can be used as a guideline to optimize the mesh porosity and thickness for different hazardous spill scenarios.

Analysis of Multimode Burning Characteristics of Isolated Droplets of Biodiesel–Diesel Blends

Abstract: Blended fuels such as biodiesel–diesel blends are being extensively used in practical devises such as engines. The burning characteristics of blended fuels are quite different than that of the individual fuels and need to be understood. In this study, a semiempirical analysis concerning the mass burning rate characteristics of biodiesel–diesel blends is presented based on the data measured using porous sphere experiments. Finally, a correlation for evaluating instantaneous burning rate of biodiesel–diesel blended fuels has been proposed for practical applications. Further, using this correlation, transient burning characteristics of blended biodiesel–diesel droplet in suspended mode have been studied for different blend compositions. Multiple modes of burning regimes are identified for the blended fuels.

A User’s Guide

Abstract: OUTPU T 29 OUTPU T 30 OUTPU T 31 OUTPU T 32 OUTPU T 25 OUTPU T 26 OUTPU T 27 OUTPU T 28 OUTPU T 21 OUTPU T 22 OUTPU T 23 OUTPU T 24 OUTPU T 17 OUTPU T 18 OUTPU T 19 OUTPU T 20 OUTPU T 13 OUTPU T 14 OUTPU T 15 OUTPU T 16 OUTPU T 9 OUTPU T 10 OUTPU T 11 OUTPU T 12 OUTPU T 5 OUTPU T 6 OUTPU T 7 OUTPU T 8 OUTPU T 1 OUTPU T 2 OUTPU T 3 OUTPU T 4 29 30 31 32 25 26 27 28 21 22 23 24 17 18 19 20 13 14 15 16 9

A review of biodiesel production from Jatropha curcas L. oil

Abstract: The demand for petroleum has risen rapidly due to increasing industrialization and modernization of the world. This economic development has led to a huge demand for energy, where the major part of that energy is derived from fossil sources such as petroleum, coal and natural gas. However, the limited reserve of fossil fuel has drawn the attention of many researchers to look for alternative fuels which can be produced from renewable feedstock. Biodiesel has become more attractive because of its environmental benefits and it is obtained from renewable resources. There are four primary methods to make biodiesel: blending, microemulsion, pyrolysis and transesterification. The most commonly used method is the transesterification of triglycerides (vegetable oil and animal fats) with alcohol in the presence of a catalyst. There is a growing interest in using Jatropha curcas L. oil as the feedstock for biodiesel production because it is non-edible and thus does not compromise the edible oils, which are mainly used for food consumption. Non-edible oils are not suitable for human consumption because of the presence of toxic components. Further, J. curcas L. seed has a high content of oil and the biodiesel produced has similar properties to that of petroleum-based diesel. In this paper, an attempt has been made to review the different approaches and techniques used to generate biodiesel from Jatropha curcas oil. The main factors affecting the biodiesel yield, for example the molar ratio of alcohol to oil, catalyst concentration, reaction temperature and reaction time are discussed. Lastly, the environmental considerations and economic aspects of biodiesel are also addressed.

Wide range modeling study of dimethyl ether oxidation

Abstract: A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.