Design optimization of several distribution flow pipeline levels in nozzle blade is important for uniformization of reaction
flow field and the cooling of primary nozzle blade by the secondary nozzle flow. Characteristics of the secondary nozzle
with three distribution flow pipeline level transport structure were studied based on three-dimensional fluid dynamics
method. Flow field uniformity of every distribution flow pipeline levels were calculated under the 1st level inlet pressure
of 3, 5, 8 atm. The existing designed area ratio of inlet and outlet of the 1st distribution flow pipeline level is rational, and
the flow uniformity of it meets the request of system. But the area ratio of the 2nd and 3rd levels needs to be optimized.