Session: 24-04 Forced response

Paper Number: 82368

82368 - Study on Blade Vibration Alleviation in a Nozzleless Radial Turbine via Casing Treatment 

High cycle fatigue (HCF) is the most common form of blade failure in nozzleless radial turbines and blade excitation force mainly originates from circumferential flow distortion caused by volute tongue. Current studies related to blade vibration alleviation focus on modification of volute geometry to suppress flow distortion. However, these methods have the disadvantages of high cost and performance sacrifice. This paper investigates the flow control method based on casing treatment for blade vibration alleviation in a nozzleless radial turbine through experimentally validated fluid-structure interaction (FSI) numerical method. Axial grooves evenly distributed in the circumferential direction are designed on the casing in the vicinity of blade trailing edge. Flow field analysis indicates that small disturbances are introduced to pressure fluctuations on the blade surface when the blade sweeps by each groove, and the strength of disturbance is not sensitive to the circumferential position of the groove. In combination with generalized force analysis, it can be inferred that the excitation force caused by volute is going to be offset by casing treatment via adjusting the relative circumferential position between volute and grooves. FSI results prove that blade vibration amplitude is significantly reduced by reasonable design of casing treatment. Furthermore, casing treatment can alleviate blade vibration in different operating conditions and the negative influence on turbine performance can be neglected, which proves the broad applicability of this novel flow control method.

Presenting Author: Lei Pan Shanghai Jiao Tong University

Presenting Author Biography: PhD student focusing on blade excitation in nozzleless radial turbine

Authors:

Lei Pan Shanghai Jiao Tong University
Mingyang Yang Shanghai Jiao Tong University
Shota Murae IHI Corporation
Wataru Sato IHI Corporation
Naoto Shimohara IHI Corporation
Akihiro Yamagata IHI Corporation