Chaotic mixing is generated in a lid driven cavity through a temporal forcing of the lid, which exploits repeated stretching and folding. The fluid flow features are simulated by solving mass and momentum conservation equations along with particle tracking, over a range of frequencies and amplitudes. By locating a passive circular plug inside the cavity, chaotic mixing is found to be dramatically altered. The mixing efficiency is assessed for the Reynolds number range of 50 to 5000. A new measure for the quantification of mixing efficiency called σ measure is introduced. Numerical particle tracking is performed by placing passive massless and inertialess particles along the vertical centerline of the cavity. The two parameters which influence mixing efficiency, viz. frequency and amplitude of the lid are varied. The advantage of the proposed σ measure is brought out vis-á-vis the existing techniques, such as stretching rate (SR) and mixing in weak sense ( ws  ).

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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 biodieseldiesel droplet in suspended mode ha\'e been studied for different blend compositions. Multiple modes of burning regimes are identified for the blended fuels.

This paper describes about the usage of Jatropha fuel in direct injection water-cooled diesel engine. In order to make use of Jatropha fuel in diesel engine, the properties of Jatropha oil has to be converted to diesel fuel, so for that methanol was added. There are three different blends are prepared by varying the ratio of Jatropha and methanol mixture, such as blend 1 (Jatropha 75%, methanol 25%), blend 2 (Jatropha 80%, methanol 20%), blend 3 (Jatropha 85%, methanol 15%). The prepared fuels are supplied to the conventional diesel engine, then the performance and emission characteristics were analysed. It is found that Jatropha methanol mixtures results are acceptable in half load and highly considerable in full load operation. Considerably torque developed is very low in low load than half and full load operations. Methanol addition has improved the performance and emission characteristics.

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