LES of a CH4/air Mesocombustor at 3 atm: EDC and Laminar-rate models

Abstract

3 volume; diameter and height are 0.006m and 0.009m, respectively. The combustion chamber pressure assumed is 3 atm, in order to produce mechanical work when connected to an internal combustion engine, f.i., a gas turbine. Two simulations are carried out by means of the LES� WALE approach, with finite rate chemistry taken from the GRIMech 1.2 kinetic mechanism (32 species and 177 reactions). The Kolmogorov scale analysis suggested to adopt both the laminarrate and the EDC combustion models. Gas temperature at the exhaust section and combustion efficiency are also predicted. Results show that the methane duct diameter should be of appropriate size to prevent air reflux and that, its small dimensions notwithstanding, relatively high combustion efficiency is possible with such chamber, making it suitable to power devices or recharge batteries. The two combustion models predict combustion efficiency difference of just few percentage points (demonstrating the complex fluid dynamics inside the chamber) and different products maps. This work advances previous simulations at ambient pressure, where results were also compared to experimental measurements. These are taken at 3 atm, are still underway and will be reported later.