• Energy Research

Abstract The aim of the present study is to investigate the effect of higher alcohols with Calophyllum Inophyllum biodiesel on the diesel engine characteristics under various engine loads. Two higher alcohols have been identified for the present investigation namely 1-pentanol and 1-butanol and the six fuel samples have been prepared with Calophyllum Inophyllum biodiesel at 40%, 50% and 60% concentrations by volume. All the experiments are carried out in a single cylinder, four stroke and constant speed diesel engine and the experimental results are compared with conventional diesel and pure biodiesel fuels. The study revealed that the diesel engine operation with higher alcohol-biodiesel blends has shown lower brake thermal efficiency and higher brake specific fuel consumption. The reduction rate is higher with a higher concentration of alcohol in the fuel blends. On the other hand, the cooling effect of higher alcohol in the blend reduces the NOx emission due to their higher latent heat of vaporization. Moreover, the CO, HC and smoke emissions are decreased for all higher alcohol-biodiesel blends. The combustion characteristics are followed similar pattern for all tested fuels and peak pressure is comparatively lower for higher concentration of alcohol in the fuel blend. Finally, it is revealed that 1-pentanol and 1-butanol can be successfully used as partial substitute to diesel or biodiesel fuel.

Abstract Lemon peel oil (LPO: C10H16O0.082) shows very similar calorific value, stoichiometric air to fuel ratio as isooctane, an ideal reference fuel for a gasoline engine, and also possesses very good anti-knock tendency and octane number rating (RON = 80) making it possible alternative fuel for gasoline engines. The present study investigates the suitability of LPO for direct injection spark ignition application by contrasting the spray characteristics of LPO with reference fuel isooctane for simulated engine-like conditions. Experiments were performed in a constant volume spray chamber under various engine-like pressure and temperature conditions. A six-hole GDI injector was used to study the spray behavior of LPO and then compared to standard reference fuel, isooctane. The ambient conditions in the chamber were derived using the crank resolved pressure data of the GDI engine. The selected chamber conditions are a) 1.5 bar, 329 K; b) 2.5 bar, 371 K; c) 6.0 bar, 453 K simulating in-cylinder conditions for three different injection timings. Phase Doppler particle analyzer and Mie scatter imaging techniques were employed for spray characterization. Spray morphology along with joint probability distribution for droplet size and axial velocity, cumulative volume fraction and Weber and Reynolds number ranges were used to contrast the two sprays for LPO and isooctane. Results showed that ambient pressure and temperature have a significant effect on spray behavior and late injection in compression stroke is proposed to be ideal for LPO to match the engine performance with that of isooctane based on the spray quality comparison.

Proposed novel upgrading method for crude tire pyrolysis oil for utilization in diesel engines.

Lemon peel oil (LPO) is considered to be a viable alternative fuel for diesel engine applications due to its wider availability, renewable nature, easy extraction process, almost equivalent calorific value as neat diesel, and low viscosity. The present work aims to investigate the effect of novel emulsified LPO in a diesel engine in order to reduce the NOx emission without compromising the engine performance. A new ionic surfactant is introduced in the present study, namely methyl-dihydroxy propyl imidazolium chloride due to its higher hydrophilic-lipophilic balance value which helps to prepare stable water in oil emulsion. Also, Span 80 has been selected as another suitable surfactant for water in oil emulsion. Four emulsified fuel samples have been prepared using LPO, water, and different concentrations of surfactants. All the fuel samples are tested for their stability through gravitational technique for 7 days. Among the emulsified samples, 92% LPO + 5% water + 2% Span 80 + 1% methyl-dihydroxy propyl imidazolium chloride by volume (LPOE2) and 93.5% LPO + 5% water + 1.5% surfactant Span 80 by volume (LPOE4) have showed better stability when compared to other emulsion fuel samples. It is also revealed that the stability of LPO emulsion is improved by the addition of two emulsions. The experimental results showed that the brake thermal efficiency of LPO emulsion is reduced to 29.87 from 34.58% of pure LPO at full load condition. Oxides of nitrogen emission and smoke emission are reduced by 21-32 and 6-15% for the LPO emulsion samples compared to pure LPO. Moreover, the diesel engine operation with emulsified form of LPO increases the HC emission about 0.1 g/kWh for LPOE4 and 0.15 g/kWh for LPOE2 fuels from 0.053 g/kW for pure LPO at maximum power output condition. The reformulation of LPO into emulsified form increases the CO emission by 25-53% compared to pure LPO. Moreover, the reformulation of LPO into emulsions has resulted in lower cylinder pressure and heat release rate compared to pure LPO and diesel fuels.

Abstract This paper presents flow field measurements for the turbulent stratified burner introduced in two previous publications in which high resolution scalar measurements were made by Sweeney et al. [1] , [2] for model validation. The flow fields of the series of premixed and stratified methane/air flames are investigated under turbulent, globally lean conditions (ϕg = 0.75). Velocity data acquired with laser Doppler anemometry (LDA) and particle image velocimetry (PIV) are presented and discussed. Pairwise 2-component LDA measurements provide profiles of axial velocity, radial velocity, tangential velocity and corresponding fluctuating velocities. The LDA measurements of axial and tangential velocities enable the swirl number to be evaluated and the degree of swirl characterized. Power spectral density and autocorrelation functions derived from the LDA data acquired at 10 kHz are optimized to calculate the integral time scales. Flow patterns are obtained using a 2-component PIV system operated at 7 Hz. Velocity profiles and spatial correlations derived from the PIV and LDA measurements are shown to be in very good agreement, thus offering 3D mapping of the velocities. A strong correlation was observed between the shape of the recirculation zones above the central bluff body and the effects of heat release, stoichiometry and swirl. Detailed analyses of the LDA data further demonstrate that the flow behavior changes significantly with the levels of swirl and stratification, which combines the contributions of dilatation, recirculation and swirl. Key turbulence parameters are derived from the total velocity components, combining axial, radial and tangential velocities.

One of the key elements in the prediction of thermoacoustic oscillations is the determination of the acoustic response of flames as an element in an acoustic network, in the form of a flame describing function (FDF). In order to obtain a response, flames often have to be confined into a system with its own acoustic response. Separating the pure flame response and that of the system can be complicated by the non-linear effects that the flame can have on the overall system response. In this paper, we investigate whether it is possible to obtain a flame response via the usual methods of dynamic chemiluminescence and pressure measurements, starting from an unforced system with incipient self-excitations at a given frequency fs, in the form of a stabilized flame at atmospheric pressure with a 700 mm tube as a combustor. The flame is forced at discrete frequencies from 20 to 400 Hz, away from the self-excitation, and the response of the flame is measured using OH* chemiluminescence. This response was compared to a flame response measured in a short tube with no other excitations. The results show that both the gain and phase can be entirely dominated by the behavior of the self-excitation, so that in general it is not possible to extract reliable gain and phase information as if the forced and self-excited modes acted independently and linearly. Although the gain in this particular case was not significantly affected, the phase information of the original flame became dominated by the triggered self-excitation. Boundary conditions and systems used for flame acoustic forcing therefore need to be carefully controlled whenever there is a possibility of self-excitation.

Abstract The depletion of natural resources coupled with the alarming increase of pollution level is the driving force to use diesel in an environmentally benevolent manner. Research done till now is mainly focused upon the utilization of lower alcohols and information on higher alcohol blend is limited. The present study aims to investigate the effect of using a ternary blend of diesel, biodiesel, and decanol on a diesel engine. Tests were performed using decanol blended with biodiesel and diesel. The concentration of ternary blends were 10%, 15%, 20%, 30%, and 40% of decanol by volume while the diesel concentration was maintained to be 50% throughout. The study revealed that among the ternary blend, brake thermal efficiency increases with increase in the concentration of decanol. The brake specific fuel, and energy consumption decrease with an increase in alcohol content. Thus 40% decanol blend shows the least brake specific fuel consumption. NOx emission increased with the increase of alcohol concentration, whereas the emission levels of CO, HC, and smoke opacity decreased. Peak pressure is also found to be highest for 40% decanol blend and least for 10% decanol blend. With the addition of decanol content in the ternary blend, heat release rate is found to be increased whereas the cumulative heat release rate is observed to be reduced during the end phase of combustion. The study concluded that 40% blend of decanol, biodiesel and diesel can optimize engine performance and emission without performing any modifications in the CI engine.

The local equivalence ratio distribution in a flame affects its shape and response under velocity perturbations. The forced heat release response of stratified lean-premixed flames to acoustic velocity fluctuations are investigated via chemiluminescence measurements and spatial Fourier transfer analysis. A laboratory scale burner and its boundary conditions were designed to generate high-amplitude acoustic velocity fluctuations in flames. These flames are subject to inlet radial equivalence ratio distributions created via a split annular fuel delivery system outfitted with a swirling stabilizer. Simultaneous measurements on the oscillations of inlet velocity and heat release rate were carried out via a two-microphone technique, and OH* chemiluminescence. The measurements show that, for a given mean total power and equivalence ratio (ϕg = 0.60), the flame responses vary significantly depending on forcing frequency, equivalence ratio split and velocity fluctuation amplitude, showing significant non-linearities with respect to forcing amplitude and stratification ratio. Furthermore, the spatial Fourier transfer analysis shows the underlying changes in the rate of heat release, including the direction and speed of the perturbation within the flame.