The authors developed a method to estimate nozzle-wake exciting forces (NEF) using Fourier series development of angular momentum flux (AMF) at the blade inlet of radial turbines. The NEF is strongly affected by the nozzle profiles. Application of this method to the evaluation of the NEF and AMF resulted in fundamental standards for selection of the number of nozzle blades and the profiles. The values of each order of NEF are obtained from Fourier series development of AMF. There is an increasing region of NEF to the distance from a nozzle trailing edge. The maximum estimation error of the blade vibration stress, which is calculated using the values of the first order of NEF and the coefficients of effective exciting force, is 10%. The coefficient of effective exciting force is 1/3 in the first and second modes, and 1/2 in third mode. Those coefficients are evaluated as the ratio of NEF and equivalent exiting forces calculated using the measured data of vibration stresses at two different points on the blade.
|Number of pages||7|
|Journal||Nippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B|
|Publication status||Published - 1996|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering