JP4405019B2

JP4405019B2 - Stator blade row of axial compressor

Info

Publication number: JP4405019B2
Application number: JP34857899A
Authority: JP
Inventors: 義博山口; 豊隆園田; 敏幸有馬
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1999-12-08
Filing date: 1999-12-08
Publication date: 2010-01-27
Anticipated expiration: 2019-12-08
Also published as: JP2001165096A

Description

【０００１】
【発明の属する技術分野】
本発明は、ガスタービン等の軸流型圧縮機の静翼列に関し、特に遷音速領域における抵抗を低減し得る軸流型圧縮機の静翼列に関する。
【０００２】
【従来の技術】
軸流型圧縮機の動翼列において、動翼の翼根元から５％の範囲内で、隣接する動翼の腹面および背面間の距離を規定することにより、翼間の衝撃波の発生を緩和するものが、特開平１１−１３６９２号公報により公知である。また圧縮性流体および非圧縮性流体の両方に適用できる翼型であって、腹面（負圧面）側および背面（正圧面）側の略中央位置にそれぞれ凹部を形成し、層流境界層領域を長く保って剥離を抑制することにより高迎角時の性能向上を図ったものが、米国特許第５３９５０７１号明細書により公知である。
【０００３】
【発明が解決しようとする課題】
ところで、軸流型圧縮機の静翼に流入する流れが臨界マッハ数に達すると、その静翼の背面側の流速が音速に達して衝撃波が発生するため、大きな造波抵抗が生じて性能を低下させる要因となる。従って、軸流型圧縮機の性能向上を図るには、静翼の背面側に発生する衝撃波を緩和して造波抵抗を低減することが必要である。
【０００４】
本発明は前述の事情に鑑みてなされたもので、遷音速領域において衝撃波の発生による造波抵抗を最小限に抑えることが可能な軸流型圧縮機の静翼列を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成するために、請求項１に記載された発明によれば、正圧を発生する腹面および負圧を発生する背面を有する多数の静翼を環状の流体通路に配置した軸流型圧縮機の静翼列において、隣接する２つの静翼の一方の腹面および他方の背面間の距離を一方の静翼の腹面から他方の静翼の背面に引いた垂線の長さとしたとき、前記距離の翼弦方向の分布が、前縁から後縁に向けて増加して極大値に達した後に減少し、極小値に達した後に再度増加することを特徴とする軸流型圧縮機の静翼列が提案される。
【０００６】
また請求項２に記載された発明によれば、請求項１の構成に加えて、前記距離が極大値となる位置が翼弦長の５０％〜７０％の範囲にあることを特徴とする軸流型圧縮機の静翼列が提案される。
【０００７】
また請求項３に記載された発明によれば、請求項１の構成に加えて、前記距離が極小値となる位置が翼弦長の８０％〜９３％の範囲にあることを特徴とする軸流型圧縮機の静翼列が提案される。
【０００８】
また請求項４に記載された発明によれば、請求項１の構成に加えて、隣接する静翼間の距離と静翼の翼弦長との比が１．５〜３．０であることを特徴とする軸流型圧縮機の静翼列が提案される。
【０００９】
上記構成によれば、静翼列の腹面および背面間の距離、つまり一方の静翼の腹面から他方の静翼の背面に引いた垂線の長さが極大値となる部分で腹面側の境界層を不安定化して積極的に剥離させることにより、不安定化した境界層に対向する背面側での衝撃波の発生を抑制して造波抵抗を低減することができる。腹面側の境界層の剥離によって若干の摩擦抵抗の増加が発生するが、それは衝撃波の発生の緩和による造波抵抗の低減に比べて遙に小さいため、全体として抵抗を大幅に低減することができる。また静翼列の腹面および背面間の距離が極大値に達した後に極小値まで減少するため、その極小値の部分で流れを絞って再加速することにより、境界層を安定化して剥離の促進を抑制し、腹面側の境界層の剥離による摩擦抵抗の増加を抑えることができる。
【００１０】
また隣接する静翼間の距離と静翼の翼弦長との比を１．５〜３．０に設定することにより、上記効果を特に良好に発揮させることができる。
【００１１】
【発明の実施の形態】
以下、本発明の実施の形態を、添付図面に示した本発明の実施例に基づいて説明する。図１〜図１２は本発明の実施例を示すもので、図１は第１実施例の翼型と、その腹面および背面の曲率の変化とを示す図、図２は第１実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図、図３は第２実施例の翼型と、その腹面および背面の曲率の変化とを示す図、図４は第２実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図、図５は第３実施例の翼型と、その腹面および背面の曲率の変化とを示す図、図６は第３実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図、図７は隣接する静翼の腹面および背面間の距離の翼弦方向の分布を示す図、図８はマッハ数と圧力損失係数の関係を示す図、図９は第１実施例の静翼のまわりの流れの様子を可視化した図、図１０は比較例の静翼のまわりの流れの様子を可視化した図、図１１は比較例の翼型と、その腹面および背面の曲率の変化とを示す図、図１２は比較例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図である。
【００１２】
図１に示す第１実施例の静翼は軸流型圧縮機の環状の流体通路に設けられるもので、左端が前縁で右端が後縁であり、流体の流れに伴って正圧を発生する腹面（正圧面）と、流体の流れに伴って負圧を発生する背面（負圧面）とが、前縁および後縁の近傍の２点で腹面に接する翼弦線の上側に存在している。尚、翼弦線の定義は翼型の形状により種々存在するが、本発明では腹面および背面が共に背面側に湾曲している翼型に対して一般的に適用される、上記定義の翼弦線を採用している。また翼型を示す座標の横軸および縦軸は、翼弦長Ｃを１００％とした比率で表されている。
【００１３】
実線で示す背面の曲率は翼弦長Ｃの全域に亘って正値であり、従って背面の形状は翼弦長Ｃの全域に亘って上向きに凸に湾曲している。一方、破線で示す腹面の曲率は、翼弦長Ｃの１５％〜８０％の領域Ｒ２で正値であるが、翼弦長Ｃの０％〜１５％の領域Ｒ１と、翼弦長Ｃの８０％〜１００％の領域Ｒ３とで負値になっている。従って腹面の形状は中央の領域Ｒ２で上向きに凸に湾曲しているが、前縁側の領域Ｒ１および後縁側の領域Ｒ３で下向きに凸に湾曲している。
【００１４】
背面の曲率は前縁から後縁に向かって単調に増加し、翼弦長Ｃの４０％付近で極大値に達した後に単調に減少する。また腹面の曲率は前縁から後縁に向かって単調に増加し、翼弦長Ｃの５３％付近で極大値に達した後に単調に減少する。
【００１５】
静翼の腹面において、前縁側の領域Ｒ１の下向きに凸に湾曲している部分が本発明の第１膨出部を構成し、後縁側の領域Ｒ３の下向きに凸に湾曲している部分が本発明の第２膨出部を構成する。
【００１６】
図２は静翼列の隣接する２つの静翼の腹面および背面間の距離の前縁部（スロート部）から後縁部までの変化を示すもので、図２（ａ）に示すように上側の静翼の腹面から下側の静翼の背面に向かって垂線を下ろし、その垂線の長さの翼弦方向の変化を、下側の静翼の背面を直線に展開して示したものが図２（ｂ）に示される。図２（ｂ）を縦軸方向に拡大したものが図７に実線で示される。腹面および背面間の距離は前縁部から後縁部に向けて増加し、翼弦長Ｃの５５％付近のａ点で極大値に達した後に減少し、翼弦長Ｃの８２％付近のａ′点で極小値に達した後に再度増加している。
【００１７】
図３に示す第２実施例の静翼は、実線で示す背面の曲率は翼弦長Ｃの全域に亘って正値であり、従って背面の形状は翼弦長Ｃの全域に亘って上向きに凸に湾曲している。一方、破線で示す腹面の曲率は、翼弦長Ｃの２４％〜６６％の領域Ｒ２と、翼弦長Ｃの８６％〜１００％の領域Ｒ４とで正値であるが、翼弦長Ｃの０％〜２４％の領域Ｒ１と、翼弦長Ｃの６６％〜８６％の領域Ｒ３とで負値になっている。従って腹面の形状は２つの領域Ｒ２，Ｒ４で上向きに凸に湾曲しているが、他の２つの領域Ｒ１，Ｒ３で下向きに凸に湾曲している。
【００１８】
背面の曲率は前縁から後縁に向かって増加し、翼弦長Ｃの２２％付近で極大値に達した後に減少に転じ、翼弦長Ｃの４５％付近で極小値に達した後に増加に転じている。また腹面の曲率は前縁から後縁に向かって減少し、翼弦長Ｃの２２％付近で極小値に達した後に増加に転じ、翼弦長Ｃの４５％付近で極大値に達した後に減少に転じ、翼弦長Ｃの７３％付近で極小値に達した後に増加に転じている。
【００１９】
静翼の腹面において、前縁側の領域Ｒ１の下向きに凸に湾曲している部分が本発明の第１膨出部を構成し、後縁側の領域Ｒ３の下向きに凸に湾曲している部分が本発明の第２膨出部を構成する。
【００２０】
図４（ｂ）および図７（１点鎖線参照）に示すように、第２実施例の静翼は、腹面および背面間の距離が前縁部から後縁部に向けて増加し、翼弦長Ｃの５０％付近のｂ点で極大値に達した後に減少し、翼弦長Ｃの８０％付近のｂ′点で極小値に達した後に再度増加している。
【００２１】
図５に示す第３実施例の静翼は、実線で示す背面の曲率は大部分の領域で正値であるが、翼弦長Ｃの５８％〜６５％の領域Ｒ３のみ負値であり、従って背面の形状は前記領域Ｒ３において下向きに凸に湾曲している。一方、破線で示す腹面の曲率は、翼弦長Ｃの１１％〜８８の領域Ｒ２，Ｒ３，Ｒ４で正値であるが、翼弦長Ｃの０％〜１１％の領域Ｒ１と、翼弦長Ｃの８８％〜１００％の領域Ｒ５とで負値になっている。従って腹面の形状は中央の領域Ｒ２〜Ｒ４で上向きに凸に湾曲しているが、前縁側の領域Ｒ１および後縁側の領域Ｒ５で下向きに凸に湾曲している。
【００２２】
背面の曲率は前縁から後縁に向かって増加し、翼弦長Ｃの３２％付近で極大値に達した後に減少に転じ、翼弦長Ｃの６２％付近で極小値に達した後に増加に転じ、更に翼弦長Ｃの９０％付近で極大値に達した後に減少に転じている。また腹面の曲率は前縁から後縁に向かって増加し、翼弦長Ｃの２８％付近で極大値に達した後に減少に転じ、翼弦長Ｃの５６％付近で極小値に達した後に増加に転じ、翼弦長Ｃの７５％付近で極大値に達した後に減少に転じている。
【００２３】
静翼の腹面において、前縁側の領域Ｒ１の下向きに凸に湾曲している部分が本発明の第１膨出部を構成し、後縁側の領域Ｒ５の下向きに凸に湾曲している部分が本発明の第２膨出部を構成する。
【００２４】
図６（ｂ）および図７（２点鎖線参照）に示すように、第３実施例の静翼は、腹面および背面間の距離が前縁部から後縁部に向けて増加し、翼弦長Ｃの７０％付近のｃ点で極大値に達した後に減少し、翼弦長Ｃの９３％付近のｃ′点で極小値に達した後に再度増加している。
【００２５】
図１１は静翼の比較例を示すもので、その翼型の腹面の曲率は、前縁および後縁の極一部を除く翼弦長Ｃの実質的に全域で正値であり、かつ背面の曲率は翼弦長Ｃの全域で正値である。従って腹面は、第１〜第３実施例のものの第１膨出部および第２膨出部を備えていない。また図１２（ｂ）および図７（破線参照）に示すように、比較例の静翼列の腹面および背面間の距離は、前縁部から後縁部に向けて増加率を減少させながら単調に増加しており、極大値あるいは極小値を備えていない。
【００２６】
図８は第１〜第３実施例および比較例について、静翼列の入口におけるマッハ数と圧力損失係数との関係を示すものである。同図から明らかなように、設計ポイントである静翼列の入口におけるマッハ数＝０．８７において、第１〜第３実施例の圧力損失係数は、比較例の圧力損失係数に比べて０．０５程度小さくなっている。
【００２７】
第１〜第３実施例の上記効果は、主として静翼の腹面の前縁側に設けた第１膨出部と、後縁側に設けた第２膨出部とによって得られるものである。即ち、静翼の腹面の前縁側に設けた第１膨出部で該第１膨出部よりも後方の境界層を不安定化して積極的に剥離させることにより、静翼の背面における衝撃波の発生を抑制して造波抵抗を低減することができる。腹面の第１膨出部により境界層が剥離すると摩擦抵抗が増加するが、この摩擦抵抗の増加量は衝撃波の発生の抑制による造波抵抗の低減量に比べて遙に小さいため、全体として抵抗の低減に大きく寄与することができる。
【００２８】
しかも、腹面の前縁側に設けた第１膨出部により不安定化した境界層は、腹面の後縁側に設けた第２膨出部により再加速されて安定化され、境界層の剥離の促進が抑制される。これにより、腹面側の境界層の剥離による摩擦抵抗の増加を最小限に抑え、更なる抵抗の低減を可能にすることができる。
【００２９】
図９および図１０は、それぞれ第１実施例および比較例の静翼のまわりの流れの様子を可視化したものである。図９に示す第１実施例は、図１０に示す比較例に比べて、鎖線で囲って示す部分で衝撃波の後部の圧力勾配が緩やかになっており、造波抵抗の低減効果が確認される。
【００３０】
上記第１〜第３実施例の効果を静翼列の観点から説明すると、以下のようになる。
【００３１】
静翼列の腹面および背面間の距離が、前縁部から後縁部に向けて増加して極大値に達した後に減少し、極小値に達した後に再度増加しているので、前記距離が極大値となる部分で腹面側の境界層を不安定化して積極的に剥離させることにより、それに対向する背面側における衝撃波の発生を抑制して造波抵抗を低減することができる。腹面側の境界層の剥離により摩擦抵抗が増加するが、この摩擦抵抗の増加量は背面側での造波抵抗の低減量に比べて遙に小さいため、全体として抵抗が大きく低減する。
【００３２】
しかも、前記距離が極大値に達した後に極小値まで減少して再度増加するため、その極小値の部分で流れが絞られることにより腹面側の流れが再加速され、境界層が安定化されて剥離の促進が抑制される。その結果、腹面側の境界層の剥離による摩擦抵抗の増加が抑えられ、静翼全体の抵抗を更に低減することができる。
【００３３】
以上、本発明の実施例を説明したが、本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。
【００３４】
例えば、第２膨出部の前端の位置Ｘａは、第１実施例が翼弦長Ｃの８０％、第２実施例が翼弦長Ｃの６５％、第３実施例が翼弦長Ｃの８８％であるが、それを６０％〜９０％の範囲に設定すれば充分な効果を得ることができる。また第１膨出部の後端の位置Ｘｂは、第１実施例が翼弦長Ｃの１５％、第２実施例が翼弦長Ｃの２４％、第３実施例が翼弦長Ｃの１１％であるが、それを５％〜４０％の範囲に設定すれば充分な効果を得ることができる。
【００３５】
また第１〜第３実施例では、ソリディティ（隣接する静翼間の距離に対する翼弦長Ｃの比）が２．０であるが、それを１．５〜３．０の範囲に設定すれば充分な効果を得ることができる。
【００３６】
【発明の効果】
以上のように本発明によれば、静翼列の腹面および背面間の距離、つまり一方の静翼の腹面から他方の静翼の背面に引いた垂線の長さが極大値となる部分で腹面側の境界層を不安定化して積極的に剥離させることにより、不安定化した境界層に対向する背面側での衝撃波の発生を抑制して造波抵抗を低減することができる。腹面側の境界層の剥離によって若干の摩擦抵抗の増加が発生するが、それは衝撃波の発生の緩和による造波抵抗の低減に比べて遙に小さいため、全体として抵抗を大幅に低減することができる。また静翼列の腹面および背面間の距離が極大値に達した後に極小値まで減少するため、その極小値の部分で流れを絞って再加速することにより、境界層を安定化して剥離の促進を抑制し、腹面側の境界層の剥離による摩擦抵抗の増加を抑えることができる。
【００３７】
また隣接する静翼間の距離と静翼の翼弦長との比を１．５〜３．０に設定することにより、上記効果を特に良好に発揮させることができる。
【図面の簡単な説明】
【図１】第１実施例の翼型と、その腹面および背面の曲率の変化とを示す図
【図２】第１実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図
【図３】第２実施例の翼型と、その腹面および背面の曲率の変化とを示す図
【図４】第２実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図
【図５】第３実施例の翼型と、その腹面および背面の曲率の変化とを示す図
【図６】第３実施例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図
【図７】隣接する静翼の腹面および背面間の距離の翼弦方向の分布を示す図
【図８】マッハ数と圧力損失係数の関係を示す図
【図９】第１実施例の静翼のまわりの流れの様子を可視化した図
【図１０】比較例の静翼のまわりの流れの様子を可視化した図
【図１１】比較例の翼型と、その腹面および背面の曲率の変化とを示す図
【図１２】比較例の翼型の静翼列と、その腹面および背面間の距離の変化とを示す図[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stationary blade row of an axial flow compressor such as a gas turbine, and more particularly to a stationary blade row of an axial flow compressor that can reduce resistance in a transonic region.
[0002]
[Prior art]
In a moving blade row of an axial compressor, the generation of shock waves between blades is mitigated by defining the distance between the front and back surfaces of adjacent moving blades within a range of 5% from the blade root. This is known from JP-A-11-13692. It is an airfoil that can be applied to both compressible and incompressible fluids, with a recess formed at approximately the center position on the abdominal surface (negative pressure surface) side and back surface (positive pressure surface) side, and a laminar boundary layer region. U.S. Pat. No. 5,395,071 discloses an improvement in performance at a high angle of attack by keeping it long and suppressing peeling.
[0003]
[Problems to be solved by the invention]
By the way, when the flow flowing into the stationary blade of the axial compressor reaches the critical Mach number, the flow velocity on the back side of the stationary blade reaches the speed of sound and a shock wave is generated. It becomes a factor to reduce. Therefore, in order to improve the performance of the axial compressor, it is necessary to reduce the wave resistance by relaxing the shock wave generated on the back side of the stationary blade.
[0004]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a stationary blade row of an axial compressor that can minimize wave-making resistance due to generation of shock waves in a transonic region. To do.
[0005]
[Means for Solving the Problems]
To achieve the above object, according to the first aspect of the present invention, an axial flow type in which a number of stationary blades having a ventral surface for generating positive pressure and a back surface for generating negative pressure are arranged in an annular fluid passage. In the stationary blade row of the compressor, when the distance between one ventral surface and the other back surface of two adjacent stationary blades is the length of a perpendicular line drawn from the ventral surface of one stationary blade to the back surface of the other stationary blade, The axial flow compressor is characterized in that the chordal distribution of distance increases from the leading edge to the trailing edge, decreases after reaching the maximum value, and increases again after reaching the minimum value. A cascade is proposed .
[0006]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the position where the distance is a maximum value is in the range of 50% to 70% of the chord length. A stationary blade row of a flow compressor is proposed.
[0007]
According to the invention described in claim 3, in addition to the configuration of claim 1, the position where the distance becomes the minimum value is in the range of 80% to 93% of the chord length. A stationary blade row of a flow compressor is proposed.
[0008]
According to the invention described in claim 4 , in addition to the configuration of claim 1, the ratio between the distance between adjacent stator blades and the chord length of the stator blades is 1.5 to 3.0. A stationary blade row of an axial compressor characterized by the above is proposed.
[0009]
According to the above configuration, the distance between the abdominal surface and the back surface of the stationary blade row , that is , the boundary layer on the abdominal surface side in the portion where the length of the perpendicular drawn from the abdominal surface of one stationary blade to the back surface of the other stationary blade becomes the maximum value. By destabilizing and positively peeling, the generation of shock waves on the back side facing the destabilized boundary layer can be suppressed to reduce wave resistance. A slight increase in frictional resistance occurs due to peeling of the boundary layer on the ventral side, but this is much smaller than the reduction in wave resistance due to the relaxation of shock wave generation, so the overall resistance can be greatly reduced. . In addition, since the distance between the abdominal surface and back surface of the stationary blade row reaches the maximum value, it decreases to the minimum value, and the boundary layer is stabilized and accelerated separation by reducing the flow at the minimum value and re-acceleration. , And an increase in frictional resistance due to separation of the boundary layer on the ventral surface side can be suppressed.
[0010]
The distance and the ratio of the chord length of the vane between or next to adjacent vanes by setting 1.5 to 3.0 can be particularly well demonstrated the effects.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings. FIGS. 1 to 12 show an embodiment of the present invention. FIG. 1 is a view showing the airfoil of the first embodiment and changes in the curvature of its abdominal and back surfaces. FIG. 2 is the wing of the first embodiment. FIG. 3 is a diagram showing a stationary blade row of a mold and a change in the distance between its abdominal surface and back surface, FIG. 3 is a diagram showing a blade shape of the second embodiment and a change in the curvature of its abdominal surface and back surface, and FIG. The figure which shows the change of the distance between the airfoil stator blade row of 2nd Example, and the abdominal surface and back surface, FIG. 5 is the figure which shows the airfoil of 3rd Example, and the change of the curvature of the abdominal surface and back surface. FIG. 6 is a diagram showing the airfoil stationary blade row of the third embodiment and a change in the distance between the abdominal surface and the back surface thereof, and FIG. 7 is a chord direction of the distance between the abdominal surface and the back surface of the adjacent stationary blades. FIG. 8 is a diagram showing the relationship between the Mach number and the pressure loss coefficient, FIG. 9 is a diagram visualizing the flow around the stationary blade of the first embodiment, and FIG. 10 is a comparative example. FIG. 11 is a diagram visualizing the flow around the wing, FIG. 11 is a diagram showing the airfoil of the comparative example, and changes in the curvature of the abdominal surface and the back surface, and FIG. 12 is a stationary blade row of the airfoil of the comparative example, It is a figure which shows the change of the distance between an abdominal surface and a back surface.
[0012]
The stationary blade of the first embodiment shown in FIG. 1 is provided in an annular fluid passage of an axial compressor, the left end is the leading edge and the right end is the trailing edge, and positive pressure is generated with the fluid flow. The upper surface of the chord line that touches the abdominal surface at two points in the vicinity of the leading edge and the trailing edge is located on the abdominal surface (positive pressure surface) and the back surface (negative pressure surface) that generates negative pressure with the flow of fluid. Yes. Although there are various definitions of the chord line depending on the shape of the wing shape, in the present invention, the chord line defined above is generally applied to an wing shape in which both the abdominal surface and the back surface are curved to the back side. The line is adopted. Further, the horizontal axis and the vertical axis of the coordinates indicating the airfoil are represented by a ratio with the chord length C being 100%.
[0013]
The curvature of the back surface indicated by the solid line is a positive value over the entire region of the chord length C. Therefore, the shape of the back surface is curved upward and convex over the entire region of the chord length C. On the other hand, the curvature of the abdominal surface shown by the broken line is positive in the region R2 of 15% to 80% of the chord length C, but the region R1 of 0% to 15% of the chord length C and the chord length C It is negative in the region R3 of 80% to 100%. Therefore, the shape of the abdominal surface is curved upward and convex in the central region R2, but curved downward and convex in the region R1 on the front edge side and the region R3 on the rear edge side.
[0014]
The curvature of the back surface increases monotonously from the leading edge toward the trailing edge, and decreases monotonically after reaching a maximum value in the vicinity of 40% of the chord length C. The curvature of the abdominal surface monotonously increases from the leading edge toward the trailing edge, and decreases monotonically after reaching a maximum value in the vicinity of 53% of the chord length C.
[0015]
On the abdominal surface of the stationary blade, a portion that is convexly curved downward in the region R1 on the front edge side constitutes the first bulge portion of the present invention, and a portion that is convexly curved downward in the region R3 on the rear edge side. The 2nd bulging part of this invention is comprised.
[0016]
FIG. 2 shows the change in distance between the front and back surfaces of the two adjacent stationary blades in the stationary blade row from the front edge (throat portion) to the rear edge, as shown in FIG. 2 (a). A vertical line is drawn from the abdominal surface of the lower stator blade toward the back surface of the lower stator blade, and the change in chord direction of the length of the perpendicular is shown by developing the back surface of the lower stator blade in a straight line. It is shown in FIG. An enlarged view of FIG. 2B in the vertical axis direction is shown by a solid line in FIG. The distance between the abdominal surface and the back surface increases from the leading edge to the trailing edge, decreases after reaching a maximum at point a near 55% of the chord length C, and decreases to near 82% of the chord length C. After reaching the minimum value at point a ', it increases again.
[0017]
In the stationary blade of the second embodiment shown in FIG. 3, the curvature of the back surface indicated by a solid line is a positive value over the entire region of the chord length C. Therefore, the shape of the back surface is upward over the entire region of the chord length C. It is convexly curved. On the other hand, the curvature of the abdominal surface shown by the broken line is positive in the region R2 of 24% to 66% of the chord length C and the region R4 of 86% to 100% of the chord length C. 0% to 24% of region R1 and 66% to 86% of region R3 of chord length C are negative values. Accordingly, the shape of the abdominal surface is convexly convex upward in the two regions R2 and R4, but is convexly convex downward in the other two regions R1 and R3.
[0018]
The curvature of the back surface increases from the leading edge toward the trailing edge, starts to decrease after reaching a maximum near 22% of the chord length C, and increases after reaching a minimum near 45% of the chord length C It has turned to. Also, the curvature of the abdominal surface decreases from the leading edge to the trailing edge, starts to increase after reaching a minimum value near 22% of the chord length C, and reaches a maximum value near 45% of the chord length C. It started to decrease, and after reaching a minimum value in the vicinity of 73% of the chord length C, it started to increase.
[0019]
On the abdominal surface of the stationary blade, a portion that is convexly curved downward in the region R1 on the front edge side constitutes the first bulge portion of the present invention, and a portion that is convexly curved downward in the region R3 on the rear edge side. The 2nd bulging part of this invention is comprised.
[0020]
As shown in FIG. 4B and FIG. 7 (see the one-dot chain line), in the stationary blade of the second embodiment, the distance between the abdominal surface and the back surface increases from the front edge portion to the rear edge portion, It decreases after reaching the maximum value at the point b near 50% of the length C, and increases again after reaching the minimum value at the point b 'near 80% of the chord length C.
[0021]
In the stationary blade of the third embodiment shown in FIG. 5, the curvature of the back surface indicated by the solid line is positive in most regions, but only the region R3 of 58% to 65% of the chord length C is negative, Therefore, the shape of the back surface is convexly curved downward in the region R3. On the other hand, the curvature of the abdominal surface shown by the broken line is positive in the regions R2, R3, R4 of 11% to 88% of the chord length C, but the region R1 of 0% to 11% of the chord length C and the chord. It is negative in the region R5 of 88% to 100% of the length C. Accordingly, the shape of the abdominal surface is convexly curved upward in the central regions R2 to R4, but is curved convexly downward in the region R1 on the front edge side and the region R5 on the rear edge side.
[0022]
The curvature of the back surface increases from the leading edge toward the trailing edge, starts to decrease after reaching a maximum near 32% of the chord length C, and increases after reaching a minimum near 62% of the chord length C Then, after reaching the maximum value in the vicinity of 90% of the chord length C, it starts to decrease. Also, the curvature of the abdominal surface increases from the leading edge to the trailing edge, and after reaching a maximum near 28% of the chord length C, it begins to decrease, and after reaching a minimum near 56% of the chord length C. It started to increase, and after reaching a local maximum in the vicinity of 75% of the chord length C, it started to decrease.
[0023]
On the abdominal surface of the stationary blade, a downwardly convex portion of the front edge side region R1 constitutes the first bulging portion of the present invention, and a downwardly convex portion of the rear edge side region R5 is convexly curved. The 2nd bulging part of this invention is comprised.
[0024]
As shown in FIG. 6B and FIG. 7 (see the two-dot chain line), in the stationary blade of the third embodiment, the distance between the abdominal surface and the back surface increases from the front edge portion to the rear edge portion, It decreases after reaching a maximum at point c near 70% of length C, and increases again after reaching a minimum at point c 'near 93% of chord length C.
[0025]
FIG. 11 shows a comparative example of a stationary blade, and the curvature of the airfoil surface of the airfoil is a positive value in substantially the entire region of the chord length C except for the extreme part of the leading edge and the trailing edge, and the back surface. Is a positive value over the entire chord length C. Therefore, the abdominal surface does not include the first bulging portion and the second bulging portion of the first to third embodiments. Further, as shown in FIG. 12B and FIG. 7 (see broken line), the distance between the abdominal surface and the back surface of the stationary blade row of the comparative example is monotonous while decreasing the increase rate from the front edge portion toward the rear edge portion. It does not have a maximum or minimum value.
[0026]
FIG. 8 shows the relationship between the Mach number at the inlet of the stationary blade row and the pressure loss coefficient for the first to third embodiments and the comparative example. As can be seen from the figure, when the Mach number at the inlet of the stationary blade row, which is the design point = 0.87, the pressure loss coefficient of the first to third examples is 0. It is about 05 smaller.
[0027]
The above-described effects of the first to third embodiments are mainly obtained by the first bulging portion provided on the front edge side of the abdominal surface of the stationary blade and the second bulging portion provided on the rear edge side. That is, by destabilizing and actively separating the boundary layer behind the first bulging portion at the first bulging portion provided on the front edge side of the abdominal surface of the stationary blade, Generation | occurrence | production can be suppressed and wave-making resistance can be reduced. When the boundary layer is peeled off by the first bulging portion of the abdominal surface, the frictional resistance increases. However, since the increase in the frictional resistance is much smaller than the reduction in the wavemaking resistance due to the suppression of the generation of shock waves, the resistance as a whole is increased. It is possible to greatly contribute to the reduction.
[0028]
Moreover, the boundary layer destabilized by the first bulging portion provided on the front edge side of the abdominal surface is re-accelerated and stabilized by the second bulging portion provided on the rear edge side of the abdominal surface, and the separation of the boundary layer is promoted. Is suppressed. As a result, an increase in frictional resistance due to separation of the boundary layer on the abdominal surface side can be minimized, and further resistance reduction can be achieved.
[0029]
9 and 10 visualize the flow around the stationary blades of the first example and the comparative example, respectively. Compared with the comparative example shown in FIG. 10, the first embodiment shown in FIG. 9 has a gentle pressure gradient at the rear of the shock wave in the portion surrounded by the chain line, and the effect of reducing the wave resistance is confirmed. .
[0030]
The effects of the first to third embodiments will be described as follows from the viewpoint of the stationary blade row.
[0031]
The distance between the abdominal surface and the back surface of the stationary blade row increases from the front edge to the rear edge and decreases after reaching the maximum value, and increases again after reaching the minimum value. By destabilizing and actively separating the boundary layer on the abdominal surface side at the portion where the maximum value is reached, the generation of shock waves on the back side facing it can be suppressed and the wave-making resistance can be reduced. Although the frictional resistance increases due to the separation of the boundary layer on the ventral surface side, the amount of increase in the frictional resistance is much smaller than the reduction amount of the wave-making resistance on the backside, so that the resistance is greatly reduced as a whole.
[0032]
Moreover, since the distance decreases to the minimum value and increases again after reaching the maximum value, the flow is throttled at the portion of the minimum value, the flow on the ventral side is re-accelerated, and the boundary layer is stabilized. The promotion of peeling is suppressed. As a result, an increase in frictional resistance due to separation of the abdominal surface side boundary layer is suppressed, and the resistance of the entire stationary blade can be further reduced.
[0033]
Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.
[0034]
For example, the position Xa of the front end of the second bulging portion is 80% of the chord length C in the first embodiment, 65% of the chord length C in the second embodiment, and the chord length C in the third embodiment. Although it is 88%, if it is set in the range of 60% to 90%, a sufficient effect can be obtained. The position Xb of the rear end of the first bulging portion is 15% of the chord length C in the first embodiment, 24% of the chord length C in the second embodiment, and the chord length C in the third embodiment. Although it is 11%, if it is set in the range of 5% to 40%, a sufficient effect can be obtained.
[0035]
In the first to third embodiments, the solidity (the ratio of the chord length C to the distance between adjacent stationary blades) is 2.0, but if it is set in the range of 1.5 to 3.0, A sufficient effect can be obtained.
[0036]
【The invention's effect】
As described above, according to the present invention, the distance between the abdominal surface and the back surface of the stationary blade row , that is, the length of the perpendicular drawn from the abdominal surface of one stationary blade to the back surface of the other stationary blade becomes the maximum value. By destabilizing and actively separating the boundary layer on the side, generation of shock waves on the back side facing the destabilized boundary layer can be suppressed, and the wave-making resistance can be reduced. A slight increase in frictional resistance occurs due to peeling of the boundary layer on the ventral side, but this is much smaller than the reduction in wave resistance due to the relaxation of shock wave generation, so the overall resistance can be greatly reduced. . In addition, since the distance between the abdominal surface and back surface of the stationary blade row reaches the maximum value, it decreases to the minimum value, and the boundary layer is stabilized and accelerated separation by reducing the flow at the minimum value and re-acceleration. , And an increase in frictional resistance due to separation of the boundary layer on the ventral surface side can be suppressed.
[0037]
The distance and the ratio of the chord length of the vane between or next to adjacent vanes by setting 1.5 to 3.0 can be particularly well demonstrated the effects.
[Brief description of the drawings]
FIG. 1 is a diagram showing the airfoil of the first embodiment and the change in curvature of the abdominal surface and the back surface thereof. FIG. FIG. 3 is a diagram showing the airfoil of the second embodiment and changes in the curvature of its abdominal surface and back surface. FIG. 4 is a diagram showing the airfoil stationary blade row of the second embodiment, its abdominal surface and FIG. 5 is a diagram showing a change in the distance between the rear surfaces. FIG. 5 is a diagram showing the airfoil of the third embodiment and changes in the curvature of the abdominal surface and the rear surface. Fig. 7 shows the change in the distance between the ventral surface and the back surface of the ventral surface and the back surface. Fig. 7 shows the distribution in the chord direction of the distance between the ventral surface and the back surface of the adjacent stationary blade. Diagram showing the relationship [FIG. 9] Visualizing the flow around the stationary blade of the first embodiment [FIG. 10] Visualizing the flow around the stationary blade of the comparative example FIG. 11 is a view showing the airfoil of the comparative example and changes in the curvature of the ventral surface and the back surface thereof. FIG. 12 Figure showing

Claims

In a stationary blade row of an axial-flow compressor in which a large number of stationary blades having a ventral surface generating positive pressure and a back surface generating negative pressure are arranged in an annular fluid passage,
When the distance between one abdominal surface and the other back surface of two adjacent stationary blades is the length of a perpendicular drawn from the abdominal surface of one stationary blade to the back surface of the other stationary blade, the distribution in the chord direction of the distance is A stationary blade row of an axial-flow compressor, which increases from the leading edge toward the trailing edge, decreases after reaching the maximum value, and increases again after reaching the minimum value .

The stationary blade row of the axial-flow compressor according to claim 1, wherein a position where the distance becomes a maximum value is in a range of 50% to 70% of a chord length .

The stationary blade row of the axial-flow compressor according to claim 1, wherein a position where the distance is a minimum value is in a range of 80% to 93% of a chord length .

The stator blade row of the axial-flow compressor according to claim 1, wherein a ratio between a distance between adjacent stator blades and a chord length of the stator blade is 1.5 to 3.0.