An experimental study on the combustion, performance and emission characteristics of a diesel engine fuelled with diesel-castor oil biodiesel blends

This review work focuses on biofuels with lower viscosity and cetane number and their mode of operation in a diesel engine. Though there were a number of review works describing the production, characterization and utilization of biodiesel, synthesized from vegetable oils, a comprehensive summary on other category of biofuels endowed with lower viscosity and cetane number has not come to light so far. In this backdrop, this review work would bring forth the existence of biofuels having lower viscosity and cetane number, classify them under one category and elucidate their operational feasibility in a diesel engine. Considerably, alcohol based fuels such as methanol, ethanol and butanol, and plant based light biofuels such as eucalyptus oil and pine oil have been chosen and classified as LVLC (less viscous and lower cetane) fuels in the current work. Besides describing the operation feasibility of these fuels, an extensive exploration of their physical, thermal and critical properties as well as their compositional attributes has been made. Despite their distinct properties, these fuels have found use in diesel engine by various strategies and apparently, they could be used in blends with diesel/biodiesel, dual fuel mode and as sole fuel. In this regard, herein, a detailed summary on operation of these fuels in the reported three different modes is clearly explained and their engine characteristics such as performance, combustion and emission are briefed.

Feasibility of using less viscous and lower cetane (LVLC) fuels in a diesel engine: A review

http://mae.eng.uci.edu/Faculty/WAS/theme/pdfs/18.pdf

Advances in droplet array combustion theory and modeling

Flame spray pyrolysis is an established technique for synthesizing nanoparticles in the gas phase through aerosol combustion of precursor/solvent droplets. The combustion characteristics of isolated micron-sized precursor/solvent droplets are investigated experimentally. Pure solvent droplets burn uniformly and classically quasisteady, whereas precursor/solvent droplets manifest disruptive combustion behavior. The fast onset of droplet disruption, which occurs only for solutions with dissolved metal precursors, is not due to solid-particle precipitation within the droplet. Instead, the mechanism of disruptive droplet burning is similar to that of slurry droplets, consisting of three main steps: (1) diffusion-controlled burning of the high-volatile solvent, (2) viscous-shell formation due to decomposition of the low-volatile metal precursor, and (3) subsequent disruption due to heterogeneous nucleation. The time sequence of the three steps depends on the concentration and decomposition characteristics of the metal precursor, shortening with increased concentration and higher incremental decomposition temperature. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4553–4566, 2013

Disruptive burning of precursor/solvent droplets in flame‐spray synthesis of nanoparticles

A comprehensive survey of the literature in the area of numerical heat transfer (NHT) published between 2000 and 2009 has been conducted Due to the immenseness of the literature volume, the survey

Literature Survey of Numerical Heat Transfer (2000–2009): Part II

Flame shapes and burning rates of spherical fuel particles in a mixed convective environment

The combustion of a fuel droplet in a mixed convective environment has been simulated both theoretically and experimentally. In the theoretical model, the flow and transport equations have been solved subject to the assumptions of constant properties (except for density) and infinite rate kinetics, using the finite element method. The gas density has been treated as a variable, only to determine the buoyancy force contribution, and it has been evaluated assuming an ideal gas mixture. A porous-sphere facility has been employed for simulating the burning characteristics of a fuel droplet experimentally. The effects of airflow rate and droplet size have been studied for both upward and downward airflow configurations. Theoretical predictions for the mass burning rate and flame shape are in excellent agreement with the experimental results of the present study and also those reported in the literature. For upward airflow configuration, the mass burning rate is under-predicted by 15 to 20 percent when...

Combustion of a Fuel Droplet in a Mixed Convective Environment

Numerical investigation of the interference effects between two burning fuel spheres

An experimental study of the flame zone around an n-hexane fuel droplet burning in air is presented here. The results are compared with the burning characteristics of a methanol droplet. The basic principle of Moire Deflectometry system which was employed to study the burning behavior of the droplet diffusion flame is explained. The temperature results are presented in the form of radial graphs and isotherms.

Structure of Burning n-hexane Droplet by Moiré Deflectometry

The interference effects during the burning of a binary tandem droplet array in a mixed convective environment have been studied both theoretically and experimentally for the upward airflow configuration. In the theoretical model, the flow and transport equations have been solved subject to the assumptions of constant properties (except for density) and infinite rate kinetics, by the use of the finite element method. The gas density has been treated as a variable, only for evaluating the buoyancy force contribution, and it has been determined through the ideal gas mixture assumption. A porous-sphere facility has been employed for simulating experimentally the burning characteristics of a fuel droplet array with fixed separation distance. The measured mass burning rates for both the spheres and the observed flame shapes are in excellent agreement with the corresponding theoretical predictions. The burning rate of the rear droplet is considerably less than that of the front droplet or an isolated droplet, for smaller separation distances. For larger separation distances, the burning rate of the rear droplet is of the same order as the front droplet, and it is sometimes even larger than that of the isolated droplet. The rate of burning of the front droplet mildly varies with separation distance, and it is approximately equal to that of an isolated droplet. The flame of a tandem binary droplet system is observed to be pushed away from the axis due to the presence of the second droplet.

R. Natarajan

Papers

Flame shapes and burning rates of spherical fuel particles in a mixed convective environment

Combustion of a Fuel Droplet in a Mixed Convective Environment

Numerical investigation of the interference effects between two burning fuel spheres

Structure of Burning n-hexane Droplet by Moiré Deflectometry

Interference Effects During Burning of Tandem Porous Spheres in Mixed Convective Environment