Research on gas turbine using pressure gain combustion for improving thermal efficiency

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04481
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 24010:Aerospace engineering-related
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Sakurai Takashi 東京都立大学, システムデザイン研究科, 准教授 (10433179)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 圧力増大燃焼 / パルス燃焼 / ガスタービン / 熱効率

Outline of Final Research Achievements

In this study, pulse combustion, a type of pressure-gain combustion, was applied to a gas turbine to demonstrate the improvement of thermal efficiency. First, the conditions for pulse combustion were investigated. The acceleration of the flame forming the compression wave was found to be important for increasing the pressure gain, and a maximum pressure gain of 6.7% was achieved by adjusting the fuel filling and purge fractions. Next, the performance of a gas turbine equipped with a pulse combustor was investigated through operational tests. It was confirmed that pulse combustion increased the turbine inlet pressure, resulting in an increase in power output compared to constant-pressure combustion. However, the pulsation of the combustion gas also caused the increase of fluctuations of power output and reduced the efficiency of the turbine and compressor, creating a new challenge in terms of improving thermal efficiency.

Free Research Field

推進工学

Academic Significance and Societal Importance of the Research Achievements

本研究で取り組んだパルス燃焼は，燃焼器の入口や出口が解放状態であるため定積燃焼ではない．しかし，燃焼圧力のピークは燃焼前の2倍程度まで達しており，どのような物理機構で圧力が上昇しているのか明らかではなかった．本研究の結果，圧力上昇は火炎の加速によって生じる圧縮波によることを明らかにした．
パルス燃焼は燃焼ガスの大きな脈動を生じる．この脈動がタービンだけでなく，圧縮機の作動状態にも影響し，両者の断熱効率を大きく損なっていることを明らかにした．これは圧力増大燃焼をガスタービンに適用する場合に共通する課題であり，燃焼器で生じる脈動の緩和がガスタービン熱効率の向上において必要である．