The Impact of Variable Inlet Mixture Stratification on Flame Topology and Emissions Performance of a Premixer/Swirl Burner Configuration

Table 1

Investigated premixer/burner conditions.

Case	𝑈Fuel	𝑈FBO	𝛿 (%)	Swirl	𝑇max (K)	𝐿𝑓/𝐷𝑏	𝐿𝑅/𝐷𝑏	Ka
1IS000	0	0	0	0	300	0	1.35	0
1IS065	0	0	0	0.65	300	0	1.236	0
2IS000	0	0	0	0	300	0	1.27	0
2IS065	0	0	0	0.65	300	0	1.15	0
3IS000	0	0	0	0	300	0	1.175	0
3IS065	0	0	0	0.65	300	0	1.125	0
1LS000	1.75	0.50	249	0	2181	6.4	1.98	12
1LS065	1.75	0.80	118	0.65	2122	5	1.78	28
2LS000	1.75	1.22	44	0	1995	5.35	1.57	10
2LS065	1.75	1.35	30	0.65	1975	3.85	1.37	26
3LS000	1.75	0.90	94	0	1981	5.10	1.58	10
3LS065	1.75	1.15	52	0.65	1925	3.75	1.45	25

(1) δ: (𝑚_Fuel−𝑚_FBO)/𝑚_FBO (%), (FBO: fuel flow at blow-off).
(2) 𝑇_max: maximum measured wake temperature.
(3) 𝐿_𝑓: visible flame length; 𝐿_𝑅: measured primary recirculation length.
(4) Central air velocity, 𝑈_𝑐 = 4.75 m/s, co-flow velocity, 𝑈_𝑠 = 10.5 m/s and Re_𝐷𝑏 = 7985 for all cases.
(5) Φ_Global = 0.18, global equivalence ratio, based on mass flow rates of fuel and central air supplies.
(6) MR = 0.14, momentum ratio between central fuel-air stream and swirl co-flow.
(7) Power, P = 6.73 kW for all flames.