Thermal performance enhancement of non-premixed syngas combustion in a partial combustion unit by winged nozzle: Experimental and CFD study

This paper presents the effect of nozzle assembly design on the performance of a partial combustion unit (PCU) using the scale-adaptive simulation (SAS) and non-intrusive laser measurement techniques. Four different configurations were tested, namely, nozzle without wing and three nozzles with wing, i.e., flat surface wing, semi-sphere hollow wing and bent wingtip. The syngas-oxygen reaction chemistry was calculated using non-premixed flame model incorporated with GRI-MECH 3.0 mechanism. The radiative heat transfer was modelled using the discrete ordinates (DO) model. The simulation was compared with the particle image velocimetry (PIV) and a two-dimensional laser doppler anemometry (LDA) measurement on a scaled-down PCU model. A good agreement between the SAS prediction and experimental measurement was obtained. It was found that the modified nozzle assembly design with a semi-sphere hollow wing yielded the highest combustion temperature owing to the intense turbulence-induced recirculation mixing of oxy-fuel. The modified nozzle assembly design introduced in this work increased the peak outlet combustion temperature up to 18% higher compared to the original design. The finding in this work may useful for design retrofits of a combustion system. •Stereoscopic PIV provides a better agreement with CFD simulation.•Winged nozzle design induces flow recirculation that enhances combustion.•Winged nozzle design produces a bigger combustion flame.•Winged nozzle design increased the peak outlet temperature up to 18%.