タービン翼列の非定常損失に関する研究 : 直線翼列を用いた実験的研究  [in Japanese] Studies on Unsteady Aerodynamic Loss of Turbine Rotors : Experimental Works by Use of a Linear Cascade  [in Japanese]

Despite a number of research activities, less information on aerodynamic loss generation in turbine rotors under the influence of unsteady flows encountered in actual turbomachines is available. This paper describes our newly started research project which aims to gain an insight into the physics of the aerodynamic interaction between turbine rotors and incoming periodic wakes, and to establish a method for evaluation of unsteady aerodynamic losses of turbine rotors generated by the wakes. In this study, using a linear turbine cascade and wake generator, the wake-affected flow field upstream and downstream of the cascade is measured in detail with a five-hole pneumatic pressure tube and a hot-wire probe in order to obtain time-averaged as well as time-resolved characteristics of the flow field. It is accordingly found that the wake passing considerably affects the cascade loss. It is also revealed that a so-called negative jet effect associated with the wakes plays an important role in unsteady loss generation of the turbine cascade.