microcombustion

Microcombustion refers to combustion processes that occur in structures with dimensions on the order of tens to hundreds of micrometers, such as microchannels, microreactors, and microburners used in MEMS-scale devices. The field aims to provide compact, high-energy-density power sources for portable electronics, sensors, and microelectromechanical systems, as well as propulsion components for small-scale platforms.

At micro scales, heat and mass transfer to surrounding walls become dominant. The large surface-to-volume ratio leads to significant heat losses, which can stabilize or extinguish flames and influence flame structure and stability. Flames in microchannels are typically laminar, and researchers explore premixed and non-premixed configurations, various channel geometries, and integration with on-chip sensors and actuators. Materials commonly used in microcombustors include silicon, glass, and ceramics, fabricated through MEMS-like processes. Integrated microheaters or catalytic surfaces are often employed to ignite and sustain combustion.

Common design approaches include straight or serpentine microchannels, heater-assisted burners, and catalytic microreactors to reduce ignition energy or enable different combustion modes. Some systems incorporate micro heat exchangers or fuel-processing steps to enable use of liquid fuels or reformates, enhancing practicality for portable power.

Challenges in microcombustion include managing heat losses, preventing flashback, ensuring flame stability over operating ranges, and meeting material and fabrication constraints. Efficiency is often limited by excessive heat transfer to walls and the demanding manufacturing requirements of micro-scale devices. Ongoing research focuses on flame stabilization, thermal management, catalysis, and system integration with energy storage, cooling, and microactuation.

Applications span micro-powered devices, MEMS energy sources, and micro propulsion for small-scale platforms, with continued work aimed at improving performance and reliability.