Session: FSI-02-06 Selected Topics in FSI

Paper Number: 105560

105560 - Estimation of Oscillating Frequency Due to Combustion Oscillation Generated in a Hydrogen Co-Firing Gas Turbine Combustor 

To reduce carbon dioxide emissions from the combustion of fossil fuels, the development of hydrogen co-firing combustion technology, in which a portion of the fossil fuel is replaced by hydrogen, is underway. In particular, natural gas and hydrogen co-firing are being considered for gas turbine combustors. Gas turbines generate thermoacoustic vibrations called combustion oscillations, which can cause equipment failures and malfunctions. However, hydrogen has different combustion characteristics from conventional fuels, and its effect on combustion oscillation has yet to be thoroughly investigated. Therefore, prediction techniques must be improved to avoid combustion oscillations, which can cause serious accidents. The authors previously conducted combustion oscillation experiments under natural gas and hydrogen co-firing conditions in which hydrogen was mixed with natural gas at a ratio of 10 to 40% by volume. The oscillating frequency of 350 Hz was observed under the natural gas-only condition. 200 Hz and 400 Hz were observed under the co-firing condition. The frequency of 350 Hz oscillated under natural gas-only combustion conditions was a value that could be estimated from the combustor column oscillations. However, the 200 Hz frequency obtained in the case of hydrogen co-firing was considered a first-order mode, which could only be obtained by considering the piping upstream of the combustor. To clarify the shift in oscillating frequency, an acoustic network model, including the combustor and piping upstream of the combustor, was constructed, and the resonance frequencies were calculated. Several resonance frequencies were obtained and considered as candidates for the oscillating frequency. In this study, the oscillating frequencies were estimated by calculating the damping and amplification components of the vibration energy. The damping component was assumed to be introduced by the pressure drop and was obtained using general-purpose CFD analysis software. The amplification component was calculated using the n-tau model, and the oscillating frequency was estimated from the sum of these components.

Presenting Author: Akane Uemichi Waseda University

Presenting Author Biography: Dr. Uemichi studied mechanical engineering at University of Tsukuba (2005-13). She received her doctoral degree from University of Tsukuba (2013). Her doctoral thesis dealt with ultra-lean flame stabilization mechanisms. After that, she spent almost five years as Assistant Professor at the University of Tokyo, working on the application aspect of combustion fundamentals and starting fluid-induced vibration research. She then spent nearly one year as Assistant Professor at Tokyo University of Agriculture and Technology, working on energy system research. In 2020, Dr. Uemichi became Tenure Truck Associate Professor at Waseda University.

Authors:

Akane Uemichi Waseda University
Ryota Imai Waseda University