Unsteady phenomena in HP turbines are caused by interaction of spatially non-uniform field of the gas flow parameters downstream of the NGV with the rotating blades of the rotor wheel.
This presentation details the use of the harmonic balance method in STAR-CCM+ to solve problems of unsteady interaction of the hot streams downstream of the combustion chamber with the rotating blades of the rotor wheel. The hot streams downstream of the combustion chamber are caused by discrete circumferentially located fuel nozzles and openings for air supply to the combustion chamber mixing zone. Unsteady interaction of the hot streams with the rotating blades of the rotor wheel leads to local redistribution of the time-averaged gas flow temperature which has effect on the blade – “temperature segregation”.
The article shows that the harmonic balance method included in STAR-CCM+ can simulate the unsteady phenomenon of the "temperature segregation" with significantly reduced CPU costs. The computational results are compared with the experimental results which show importance of the unsteady effects. All computations have been made in STAR-CCM+ v8.04.007.