High energy density entrainment-based catalytic micro-combustor for portable devices

Abstract

The increasing demand for low-cost, high energy density heat sources has motivated the development of compact and lightweight combustion-based devices. In this work, we developed an energy-dense (≈236 MW/m3) entrainment-based catalytic micro-combustor for heating portable systems. The multichannel micro-combustor (coated with Pt/Al2O3 catalyst) leverages a copper-nichrome wire to enable quick and localized ohmic preheating durations (2–3 mins). Furthermore, we demonstrated low ignition temperature (108–125 °C), which facilitates low energy consumption (∼1948 J). In addition, an optimal fuel flow rate (3.09 × 10-8 m3/s) was determined via FEM simulations and experiments to enable fuel savings (high fuel conversion) while achieving high heat fluxes by analyzing the reaction kinetics and species transport behavior in the microchannels. Through independent testing, we established the micro-combustor’s ability to maintain long-term autothermal combustion at a high saturation wall temperature (585 °C), which was attained at short timescales to enable fast heating/cooling cyclability. The successful cyclic heating demonstration of large thermal mass additions (at least 41 times the micro-combustor’s mass), coupled with the combustor’s high energy density, shows promise for device-level implementation for a range of commercial, defense, and energy conversion applications.