Progress in small-scale combustion

Abstract

This article briefly reviews the recent works related to small-scale combustion and its potential impact into combustion science and engineering is presented. Followed by a simple description of the scale effect on combustion to highlight its "unique" feature, past related works are then summarized. The impact of heat recirculation appearing in combustion systems, which is the most prominent feature of a micro-or small-scale combustion system, is focused upon and is understood that exactly the same strategy promising better combustion performance is confirmed irrespective of flame type (either premixed or non-premixed). With respect to this, paying attention to the entire combustor design, to optimize within the target working range is a crucial matter when micro-scale combustion is adopted. Potential subjects to be covered to further promote these aspects in this field are then presented.

Performance of cylindrical and planar meso­scale combustor with double narrow slit flame holder for micropower generator

“…The high energy density of hydrocarbon combustion has attracted many researchers to explore micro/mesoscale combustion devices as a source of energy in micro rotary engines or gas turbines, thermophotovoltaic, or thermoelectric systems or better known as micropower plants [7]. To be able to produce high energy, the micro/mesoscale combustor must be able to produce a stable flame.…”

Numerical Investigations of Micro-Scale Diffusion Combustion: A Brief Review

“…where λ is the mixture thermal conductivity, q rad is the radiative heat transfer. However, in some studies the radiative heat transfer is neglected, due to the lower impact at micro scale [2]. The radiative heat transfer can be modeled by assuming the optically thin radiation hypothesis, in which the self-absorption of radiation is neglected.…”

“…However, combustion-related power generation in micro scales has its own challenges as it is not trivial to obtain a stable flame. This is essentially attributed to (a) the low residence time inside of the micro combustor to complete the combustion process and (b) the higher heat losses from the combustion chamber walls due to the larger surface to volume ratios [1,2].…”

Combustion Characteristics of Premixed Hydrogen/Air in an Undulate Microchannel

“…This type of system needs external power supply and, given the typical battery limitations, efforts have been made to develop alternatives based on microcombustion in order to take advantage of the high-density energy of the hydrocarbon and hydrogen fuels. Nevertheless, early experimental studies involving microcombustion presented some difficulties to obtain a stable flame caused mainly by two phenomena: the low residence time inside of the microcombustor to complete combustion and the higher heat losses from the combustion chamber walls [2,3].…”