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We have studied the stability of location of various equilibrium points of a passive micron size particle in the field of radiating binary stellar system within the framework of circular restricted three body problem. Influence of radial radiation pressure and Poynting-Robertson drag (PRdrag) on the equilibrium points and their stability in the binary stellar systems RW-Monocerotis and Krüger-60 has been studied. It is shown that both collinear and off axis equilibrium points are linearly unstable for increasing value of β 1 (ratio of radiation to gravitational force of the massive component) in presence of PR-drag for the binary systems. Further we find that out of plane equilibrium points (L i , i = 6, 7) may exists for range of values of β 1 > 1 for these binary systems in the presence of PR-drag. Our linear stability analysis shows that the motion near the equilibrium points L 6,7 of the binary systems is unstable both in the absence and presence of PR-drag.

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We have investigated the out of plane equilibrium points of a passive micron size particle and their stability in the field of radiating binary stellar systems Krüger-60, RW -Monocerotis within the framework of photo-gravitational circular restricted three-body problem. We find that the out of plane equilibrium points (L i , i = 6, 7, 8, 9) may exist for range of β 1 (ratio of radiation to gravitational force of the massive component) values for these binary systems in the presence of Poynting-Robertson drag (hereafter PR-drag). In the absence of PR-drag, we find that the motion of a particle near the equilibrium points L 6,7 is stable in both the binary systems for a specific range of β 1 values. The PR-drag is shown to cause instability of the various out of plane equilibrium points in these binary systems.

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Liquefied Petroleum Gas (LPG) is widely used as a cooking fuel as it has higher energy content and produces lower emissions compared to other traditional fuels. Due to massive demand for LPG, aside from its limited reserve, performance improvement of the LPG cook stoves is essential. In the present work, the thermal efficiency of a traditional cook stove has been studied both experimentally and numerically for LPG fuel. Based on the knowledge from the computational model concerning flow field and species transport parameters, the conventional cook stove design has been modified for improving the efficiency. In the modified design of the stove, attachment of an annular metal plate insert and introduction of an extended spill-tray to close the gap around the burner are considered. The modifications result in favourable guidance of the flow of secondary air and hot product gases of combustion to ensure better heat transfer rate to the loading vessel. The thermal efficiency of the modified cook stove is around 73.6%, which is about 4.7 percentage point improvement from that of an identical stove without the insert and extended spill-try.

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Disintegration of annular liquid sheets is an important field of study that plays a crucial role in engine combustion. The focus of this study is to analyze different modes of sheets experimentally in an advanced hybrid injector, which uses both pressure swirl and air momentum to impart instability into the sheet. Apart from measurement of certain macroscopic spray physical parameters like breakup length and sheet width, the images for different sheet profiles were processed to obtain fractal dimensions, temporal frequency, and different orthogonal modes using proper orthogonal decomposition. A moderate airflow is seen to create a stable liquid sheet with increased breakup length, whereas higher airflows at low liquid flows create an air-blast type of spray with disintegration very close to the nozzle. The latter shows dominance of multiple smaller temporal frequencies with relatively lower power spectral densities. A spray with high liquid flow and relatively low airflows shows a longer and wider sheet with a single dominant frequency.