OCR Text |
Show 5 The measurement was conducted at two points, 10 mm upstream and 10 mm 0.5_-------------, downstream from the center of the noncombusting burner surfaces. To quantify the degree of the fluctuations, 0.4 the sensor outputs were converted into _0 -70.3 o - 02 0.1 L..-.'--'--'--'--'--'--'--'--'--'--"---' 0.7 1.0 1.3 1.6 1.9 Air Ratio air ratios. The air ratio fluctuations for a mean air ratio of 1.4, for perfect mixing and partial mixing, are shown in Figure 6. In the perfect mixing case, fluctuations were smaller than the strong fluctuations observed for the partial mixing case. A similar level of fluctuations to the small fluctuations of the perfect mixing case was observed in the air flow. Therefore, the small fluctuations of perfect mixing probably arise due to electrical noise and not due to air ratio fluctuations. Compar- Fig.5 Variation of normalized output from the light sensor with air ratio for various light pass lengths. 2.0 1.8 .g 1.6 ~ 1.4 ~ ~ 1.2 1.0 0.8 0.0 2.0 1.8 0 1.6 .;:; ~ 1.4 ~ ~ 1.2 1.0 0.8 0.0 (a) Upstream (b) Downstream 2.0 Perfect mixing 1.8 Perfect mixing 0 1.6 .;:; ~ 1.4 ~ ~ 1.2 1.0 I I I 0.8 I I 0.5 1.0 1.5 2.0 0.0 0.5 1.0 Time (sec) Time (sec) Partial mixing 0.5 2.0 1.8 Partial mixing .;0:; 1.6 ~ 1.4 ~ ~ 1.2 1.0 2.0 0.8 1.0 0.0 0.5 1.0 Time (sec) Time (sec) Fig.6 Light sensor outputs corresponding to air ratio fluctuations (a) Upstream (b) Downstream I 1.5 2.0 1.5 2.0 |