Calculate the length and diameter of the reaction zone of an afterburner that treats 2000 acfm of polluted air (measured at 250 F). The gases in the afterburner are at a temperature of 1400 F for a residence time of 0.50 sec. Assume the burner will bring in 10 acfm of methane and 350 acfm of outside air (both measured at 80 F and 1atm). The gas velocity in the afterburner is 20ft/sec.