TY - JOUR
T1 - Evaluation of flamelet-based combustion models for the use in a flameless burner under different operating conditions
AU - Mayrhofer, Markus
AU - Koller, Michael
AU - Seemann, Peter
AU - Prieler, René Josef
AU - Hochenauer, Christoph
PY - 2021/1/25
Y1 - 2021/1/25
N2 - The thermal input of a flameless burner is commonly realized by its switch on-time at a unique, optimized design point. This typical on–off regulation approach may provide temporal-inhomogeneous temperature distributions in continuous operating furnaces. An alternative way of regulation is a modulated controlled flameless burner, which deals with off-design points and reaches so a more temporal-homogeneous temperature distribution. Influences on the temperature field of the flameless reaction zone, caused by the off-design operation are investigated in this paper. This is done by experimental investigations with an aspirated thermocouple and with numerical simulations, using several flamelet-based combustion models. Additionally, Nitrogen oxide emissions were measured for each design point, which starts from 165 kW at nominal power to lower limit of 60 kW. The results suggest, that the non-premixed flamelet model is suitable for the application of flameless combustion in design and off-design. Furthermore, local temperature peaks in the flameless reactions zone increase (from about 1450 to 1530 °C) and the NOx emissions increase (from about 32 to 88 ppm) by decreasing the thermal input of the flameless burner at constant furnace temperatures
AB - The thermal input of a flameless burner is commonly realized by its switch on-time at a unique, optimized design point. This typical on–off regulation approach may provide temporal-inhomogeneous temperature distributions in continuous operating furnaces. An alternative way of regulation is a modulated controlled flameless burner, which deals with off-design points and reaches so a more temporal-homogeneous temperature distribution. Influences on the temperature field of the flameless reaction zone, caused by the off-design operation are investigated in this paper. This is done by experimental investigations with an aspirated thermocouple and with numerical simulations, using several flamelet-based combustion models. Additionally, Nitrogen oxide emissions were measured for each design point, which starts from 165 kW at nominal power to lower limit of 60 kW. The results suggest, that the non-premixed flamelet model is suitable for the application of flameless combustion in design and off-design. Furthermore, local temperature peaks in the flameless reactions zone increase (from about 1450 to 1530 °C) and the NOx emissions increase (from about 32 to 88 ppm) by decreasing the thermal input of the flameless burner at constant furnace temperatures
KW - Computational fluid dynamics
KW - Flameless combustion
KW - Off-design
UR - http://www.scopus.com/inward/record.url?scp=85092731081&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.applthermaleng.2020.116190
DO - https://doi.org/10.1016/j.applthermaleng.2020.116190
M3 - Article
SN - 1359-4311
VL - 183
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
IS - 1
M1 - 116190
ER -