報告書番号

T99053

タイトル（和文）

3次元有限要素解析に基づくガスタービン起動・定格・停止運転下における初段動翼の損傷評価

タイトル（英文）

Damage Evaluation based on Three-dimensional Finite Element Analysis for First Row Blades under Starting/Steady-state/Stopping Operation of Gas Turbine

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究では，DSS運用を模擬した条件下でのGT初段動翼の応力／ひずみ分布および履歴を明らかにするため，3次元有限要素解析を実施した。その結果，例えば，運転中，最も温度の高い前縁翼高さ中央部では，起動過程で翼高さ方向の単軸の圧縮応力が発生し，定格過程で緩和され，停止過程において単軸の引張応力が生じる。一方，内部冷却孔近傍では，起動過程において多軸の引張応力が発生し，定格過程においてわずかに緩和し，停止過程では逆に多軸の圧縮応力が発生する。次に，当所の提案する熱疲労寿命評価法を適用し，代表的な部位におけるき裂発生寿命を評価した。その結果，前縁翼高さ中央部で寿命が最も短く，背側，腹側，および内部冷却孔近傍よりも3～5倍短いことが分かった。最後に，クリープ構成式や熱疲労寿命評価法などに関する一連の研究を通し，1100℃級GTを対象とする解析的き裂発生寿命評価法を開発した。

概要 （英文）

In this study, 3-dimensional finite element analyses for a first row blade of a gas turbine (GT) were carried out to clarify its stress/strain distribution and history in conditions simulating daily-start-stop (DSS) operation. As a result, for example, uniaxial compressive stress along blade axis direction occurred in startup process at middle height of the leading edge where the temperature was the highest, and it relaxed during steady-state operation, and uniaxial tensile stress yielded in stop process. On the other hand, biaxial tensile stress appeared near internal cooling holes and slight stress relaxation occurred during steady-state operation, and biaxial compressive stress oppositely appeared in stop process. Then, thermo-mechanical fatigue life prediction method proposed by CRIEPI was applied based on these results and crack initiation life for representative portions of the blade was evaluated. Consequently, prediction results indicated that the life is the shortest at the middle height of the leading edge and lives in suction and pressure side and near cooling holes were 3~5 times longer than that in the leading edge. Finally, analytical crack occurrence life prediction method for 1100ｰC class GT was developed based on a series of studies on proposal of creep constitutive equation and thermo-mechanical life evaluation method.

報告者

キーワード