OCR Text |
Show l) Gas supply part In a cylindrical duct, a inner cylindrical duct with open ends is installed. In the center of the inner cylindrical duct, a gas supply pipe is installed. The gas supply pipe has 42- <t> 3 m m holes to enable the gas to blow out through them perpendicular to the air flow in the inner cylindrical duct. The m a x i m u m gas blowing out pressure is set to 20 kPa. The gas and the air, after being mixed in the inner cylindrical duct, are made to swirl by the swirling vanes in the inner cylindrical duct. The gas/air mixture, while being mixed with the outer air, is fed to the primary mixing part. 2) Primary mixing part This unit is so installed that it lets the gas/air mixture turn in 180 c angle and lets it evenly flow into the gas/air mixture supply duct via the rectifying plates. 3) Secondary mixing part The swirling vanes are installed in the gas/air mixing duct, which swirl the mixture and send them into the nozzle. 3. Test results 3-1. Flame shape and flame stability l) Flame shape Photographs.l and 2 show the flame shape observed through the peep hole in the rear part of the furnace at rated load with O 2=3.7% and 5.5%, respectively. Photographs.3 and 4 show the respective flame shapes at 3 0 % load with O 2 =2.4% and 6.2%. Unlike the conventional diffusion combustion, the flame length extends when the combustion condition becomes at high excess air. This is considered to be due to lowered combustion temperature. The flame flows along the furnace wall with thin film form. PHOTO 1. FLAME SHAPE AT RATED PHOTO 2. FLAME SHAPE AT RATED LOAD WITH 0:=3.7% LOAD WITH 0:=5.5% |