Entropy generation during microcombustion

We use an entropy balance to formulate the entropy generation equation in a flame zone of a cylindrical microcombustor tube. In deriving this equation, we define a nondimensional radius as the ratio of the tube radius to the flame thickness, and we set up a thermal model of the flame zone by applying an energy balance for a steady flow system to the flame zone. Based on this model, we obtain a relationship between the flame temperature and the nondimensional radius. Given this relationship, the effects of the fuel, fuel-air ratio, unburned gas temperature, and tube radius on entropy generation are analyzed. The occurrence of minimum entropy generation is predicted. The efficient operating conditions of the microcombustor are suggested.