Imaging of diluted turbulent ethylene flames stabilized on a Jet in Hot Coflow (JHC) burner

3D DNS of MILD combustion: A detailed analysis of heat loss effects, preferential diffusion, and flame formation mechanisms

“…Since the H radical build up is due to dissociation of hydrogen and methane, it is verified that turbulence speeds up the ignition by better mixing the fuel with the hot regions of the coflow. Similar behaviors were observed in [11] and in [34], where the researchers increased the jet Reynolds number and obtained lower lift-off heights due to better entrainment of the fuel with the oxidizer.…”

“…that even though CH 2 O appears inside the jet core, the peak values occur at the boundaries of the jet, slightly inward to the peak locations of OH concentration. This agrees with the findings in [34] for all fuels except the C 2 H 4 /H 2 combination, but contradicts with [39] where the peak mean CH 2 O was measured at the jet centerline. The discrepancy with the latter study can be due to the higher jet Reynolds number in the experimental study compared to the current simulations, which leads to higher degrees of premixing and more CH 2 O production as shown in [39,40].…”

Modeling Lifted Jet Flames in a Heated Coflow Using an Optimized Eddy Dissipation Concept Model

“…The modified SKE and modified EDC model combination generally agreed well with the experimental data however, in most cases, the temperature distributions modelled downstream of the jet were in excess of those measured and the radial peaks in minor species distributions were not accurately predicted (Shabanian et al, 2013). These simulations also did not exhibit any lifted behaviour, in contrast to the C 2 H 4 -based flames measured by Medwell et al (2008). The particle density function (PDF) modelling approach of Shabanian et al (2013) was, however, in good agreement with this apparent lift-off phenomenon not captured by the computationally cheaper EDC model, especially in the C 2 H 4 /N 2 fuel case.…”

“…Subsequent findings of these studies have been extended by recent modelling efforts of the more complex C 2 H 4 -based fuel experiments (Shabanian et al, 2013). This work, trialling a number of different turbulence and combustion models, found best agreement with the experimental results of Medwell et al (2008) using the modified standard k -ε (SKE) turbulence model of Dally et al…”

“…The 4.6 mm diameter central jet of the JHC burner, issues into an 82 mm diameter concentric coflow of combustion products from an up-stream secondary burner. The JHC burner has been used to provide experimental data for numerous fuel and Reynolds number combinations (Dally et al, 2002;Medwell et al, 2007Medwell et al, , 2008Medwell & Dally, 2012;Oldenhof et al, 2010Oldenhof et al, , 2011Oldenhof et al, , 2012, as has the similarly configured Vitiated Coflow Burner (VCB) (Cabra et al, 2002(Cabra et al, , 2005Gordon et al, 2008).…”