Thermal protection of the nuclear rocket engine nozzle based on regenerative cooling method

In the design of the nuclear rocket engine nozzles, the heat in the throat area of nozzles is so intense that the temperature may exceed the endurance of existing materials. Regenerative cooling technology is a widely employed method for effectively cooling the nozzle. The influences of a strategy involving the arrangement of ribs in the regenerative cooling channel are investigated. The flow and heat transfer characteristics in the regenerative cooling channels with three different types of ribs are compared and analyzed. In accordance with the computational results, two composite structures are proposed. Moreover, the flow and heat transfer characteristics in the bending channel with these two composite structures are calculated and analyzed. The results show that the straight and streamlined ribs can reduce the maximum temperature only when the height is lower than 1 mm. The side rib can reduce the temperature near the rib. For the composite rib, when the distance between the side rib and bottom rib is ranging from 3 cm to 5 cm, the appearance of the high temperature zone, which is located near the bottom rib can be prevented. Moreover, in the bending channel, the straight composite rib can considerably reduce the maximum temperature in the throat area by 96 K. However, the streamlined composite rib can only reduce the wall temperature near the rib.