Development and scale effects of small Swiss-roll combustors

The configuration of Swiss-roll was adopted as a promising structure for the development of sub-millimetre scale combustors. In this study, the scaling effects are investigated both experimentally and analytically. Based on our first proto-type (64 mm in diameter), scaled-down combustors (45 mm) with different design parameters were fabricated; diameter of the combustor, top plate thickness, channel size and combustor material. A simple one-dimensional analytical model was constructed to interpret the combustion characteristics of the Swiss-roll combustors. Two energy equations for combustor body and mixture, along with species equations employing two-step global reaction model were solved. In spite of the simplicity of the present model, important characteristics of the combustors such as upper and lower flammability limits, effect of cap thickness on flammability limits were predicted well. Based on the analytical results, several smaller coin-size combustors (diameter 26 and 20 mm) were additionally developed and their characteristics were investigated. This study shows that the effects of design parameters are important in the practical development of smaller combustors.