Crown incident radiant heat flux measurements in an industrial, regenerative, gas-fired, flat-glass furnace

Crown incident radiant heat flux measurements performed during both firing and non-firing cycles are reported, for the first time, in the combustion s pace of a regenerative, side-port, 455 metric ton/day, gas-fired, flat-glas s furnace. Measurements were acquired through six crown access holes along the furnace axial centerline. Video and visual observations of the glass su rface were also made through access ports in the furnace. A three-dimension al numerical model of the turbulent mixing, reaction, and heat transfer pro cesses is also used to predict radiant heat flux to the crown. The measured crown incident radiant heat flux profile during firing cycles rises from 4 25 kW/m(2) close to the batch feeder to a peak of 710 kW/m(2) near the cent er of the combustion space, followed by a drop to approximately 575 kW/m(2) near the furnace working end. Numerical model results are in relatively go od agreement with measured results. During non-firing reversal cycles, meas ured flux levels at the crown rise from 320 kW/m(2) near the batch feeder, to a maximum of 565 kW/m(2) closest to the spring zone. Increases in crown incident radiant heat flux due to combustion are quantified, with nominal i ncreases of 105 kW/m(2) in regions closest to the batch feeder and approxim ately 155 kW/m(2) in the center of the combustion space. Lower increases fr om combustion (85 and 12 kW/m(2)) are exhibited in locations closest to the furnace working end, During the 20-25 s non-firing reversal period, the in cident heat flux to the crown typically decreased between 20 and 50 kW/m(2) at each measured location. Variation of heat flux to the crown during 15-m in firing cycles is typically 3-6% of the total incident heat flux, with a maximum typically occurring one-third of the way into the cycle (5-6 min) a nd declining during the remaining two-thirds of the period. (C) 2001 Elsevi er Science Inc. All rights reserved.