FH-1 Radiant Heat Transfer to Shock Tubes in a Cylindrical Firebox
A new method incorporated into FH 2.0 accounts for the direct radiant energy transfer between the firebox and the shock tubes in the convection section of a cylindrical heater by setting an equivalent roof sink emissivity. To obtain radiative properties of the arch volume between the roof of the firebox and the first row of shock tubes, FH treats the gas volume as a one clear gas/two gray gas model or as a three gray gas model. An example problem used to test implementation of the method shows that the radiation loss to the shock tubes is about 1 percent of the total radiant duty. Because the shock tubes recover much of this radiant energy, the overall effect on performance is limited.