2015 Volume 57 Issue 179 Pages 60-70
The effects of elevated-pressure on rotating counterflow twin flame were numerically investigated. The range of pressure is from 1 to 8 atm. We performed numerical simulations with and without radiative heat loss. The loss was evaluated by using an optically thin model, which does not consider reabsorption of radiative energy. Without radiation, the leanest extinction limits reached ultralean conditions; the higher the pressure is, the leaner the extinction limits are. On the other hand, with radiative heat loss, the leanest extinction limits are shifted to richer condition as the pressure becomes higher; above 2 atm, the leanest extinction limits cannot reach ultralean condition. The response curves of the flame temperature to the equivalence ratio are distorted when radiative heat loss is considered. Under high pressure, the flame thickness is thinner and the heat release rate is enhanced mainly because of the increase of gaseous density in the both cases of with and without radiation heat loss. However, the temperature behind the flame zone much decreases due to the radiative heat loss in the high pressure case. This is because of increments of partial pressures of the radiative species and the length of the residence time of fluid in the backflow region of burned gas.
