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Generally, microgas turbines are in the range of 30–200 kW. So, here it is proposed to develop a microgas turbine engine with a capacity of 3 kW which will have applications in unmanned aerial vehicle (UAV) and standalone power generation for domestic use. In this study, the behavior of non-reacting flow pattern inside a swirl stabilized can combustor is studied. Total pressure loss, which is an important performance parameter, is predicted numerically and compared with that from experiments. Good agreement is achieved between experimental and numerical results. The combustor total pressure drop was found to be negligible; in the range of 0.002–0.06% at an inlet velocity ranges from 1.7 to 10.19 m/s. Flow pattern indicates strong vortex formation due to secondary air entrainment inside the flame tube.

This study focuses on the thermal-diffusive oscillations of the full spectrum of co-flow laminar flames-from premixed to non-premixed through partially premixed flames for Lewis numbers sufficiently greater than unity. A premixedness parameter is identified using the analytical solution to the mixing field downstream of a splitter plate. Different premixedness levels ranging from zero (fully non-premixed) to unity (fully premixed) are then used as Dirichlet data for inlet concentrations of the reactants to the flame. The initial value problem is numerically solved by adopting a thermo-diffusive model and single-step finite rate chemical reaction and using higher-order compact schemes. A thumb-shaped region in the Damk�hler number - premixedness parameter space is identified as corresponding to limit cycle oscillations of the flame. This fills the gap between what is reported for the pulsating instability of non-premixed edge flames recently and fully premixed flames earlier. The thumb-shaped region enlarges with increase in the Lewis number in the range of 1.5-1.7, with marked increase in the oscillatory amplitude of the total heat release. A subcritical Hopf bifurcation is seen to occur at the boundary of this region in the above parametric space. The mechanism of oscillations is studied: hysteresis is found between the upstream and downstream propagation of the flame due to the thermal-diffusive imbalance. The oscillations are plotted in the phase space of the domain-integrated mass and heat diffusive fluxes of and to the reactants. The area of the limit cycle peaks at a particular Damk�hler number and premixedness parameter and drops to zero on both sides in this parametric space. � 2012 The Combustion Institute.