FUEL, cilt.343, sa.2, ss.1-15, 2023 (SCI-Expanded)
Since natural gas fuel boilers are environmentally friendly and efficient, they are widely used in heating systems
today. Improvements are continuing in the combustion efficiency and emissions of these boilers. Due to the high
costs and long manufacturing times, experimental studies are progressing slowly. For this reason, studies with
CFD simulations are also preferred. For realistic CFD results, it is important to correctly choose the turbulence
and combustion models. This study conducted an experimental study to obtain temperature and emission
measurements from a low-swirl natural gas boiler. Then, CFD simulations were made under the same conditions
using the 3D model prepared for the same boiler. In simulation studies, different turbulence and combustion
models were investigated. The turbulence models used in the simulations are Standard k-ε, Realizable k-ε, RNG kε, and Reynolds Stress Model (RSM), respectively. Combustion models are Eddy Dissipation (ED), Finite Rate/
Eddy Dissipation (FR/ED), Eddy Dissipation Concept (EDC), Non-Premix Combustion (NPC) and Partial-Premix
Combustion (PPC). When the results obtained by numerical simulations are compared with the experimental
data, it is understood that the Realizable k-ε turbulence model provides better convergence than other turbulence
models, while PPC and ED provide better convergence in combustion models. Since the two-step chemical
mechanism for natural gas used in EDC and FR/ED models neglects the formation of many intermediate products,
higher NOx values were obtained than the experimental for these combustion models. Different results were
obtained from the standard k − ε in terms of temperature and CO2, H2O, O2, CO, NOx results than other turbulence models.