JPH08312518A - Runner of reversible pump-turbine - Google Patents
Runner of reversible pump-turbineInfo
- Publication number
- JPH08312518A JPH08312518A JP7119594A JP11959495A JPH08312518A JP H08312518 A JPH08312518 A JP H08312518A JP 7119594 A JP7119594 A JP 7119594A JP 11959495 A JP11959495 A JP 11959495A JP H08312518 A JPH08312518 A JP H08312518A
- Authority
- JP
- Japan
- Prior art keywords
- blade
- runner
- vane
- turbine
- outlet end
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
Landscapes
- Hydraulic Turbines (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明はポンプ水車のランナに係
り、特にキャビテーションに対する性能を改善したラン
ナの羽根形状に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump turbine runner, and more particularly to a runner blade shape having improved performance against cavitation.
【0002】[0002]
【従来の技術】ポンプ水車のランナはその回転方向を変
えることにより発電及び揚水運転を行うことができる。2. Description of the Related Art A runner of a pump turbine can perform power generation and pumping operation by changing its rotating direction.
【0003】図8はポンプ水車の構造の概略を示してお
り、発電運転中ケーシング1に流入した水はランナ2に
流入し、これを回転駆動して吸出し管3から排出され
る。逆に揚水運転モード中は図示しない発電電動機によ
り発電運転時とは逆方向にランナ2が回転駆動され、吸
出し管3を通してランナ室内へ導かれた水はランナ2で
エネルギを与えられ、ケーシング1を介して上池(図示
せず)に揚水される。この種のポンプ水車のランナ2は
円周方向に等配された複数枚のランナ羽根4を有し、こ
れらのランナ羽根4は、主軸5の下端に結合されたラン
ナクラウン6とランナバンド7との間に固定されてい
る。FIG. 8 shows the outline of the structure of a pump turbine. During the power generation operation, the water that has flown into the casing 1 flows into the runner 2, which is rotationally driven and discharged from the suction pipe 3. On the contrary, in the pumping operation mode, the runner 2 is rotationally driven by a generator motor (not shown) in the opposite direction to that in the power generating operation, and the water guided into the runner chamber through the suction pipe 3 is given energy by the runner 2 and the casing 1 Water is pumped to the upper pond (not shown) via the water. The runner 2 of this type of pump turbine has a plurality of runner blades 4 which are evenly arranged in the circumferential direction. These runner blades 4 include a runner crown 6 and a runner band 7 connected to the lower end of a main shaft 5. Is fixed between.
【0004】図9はランナ2を水車出口側から見た図を
示しているが、ランナ羽根の水車流れ方向の出口側先端
(以下水車羽根出口端という)8はほぼ半径方向に放射
状に延在している。この水車羽根出口端8の羽根断面形
状は主に揚水運転条件から決定される。図10(a)
(b)は揚水運転時における図8のA−A断面の水車羽
根出口端における流れの速度三角形を示し、流れの絶対
速度Cはランナ周速U及び相対速度Wに分解される。図
10(a)は、小流量である高揚程運転時の状態を示し
ている。この状態では羽根角度β0 に対しランナ周速U
と相対速度Wとのなす相対流入角βが小さくなる。その
結果、羽根裏面4aで圧力が大きく低下し、そしてこの
圧力が蒸気圧以下になるとキャビテーション(一般にこ
の位置で発生するキャビテーションをK2という)が発
生するようになる。このキャビテーションが長時間発生
するとキャビテーション発生部付近で壊食が起こるよう
になる。FIG. 9 shows a view of the runner 2 as seen from the outlet side of the water turbine. The tip of the runner blade on the outlet side in the flow direction of the turbine (hereinafter referred to as the outlet end of the turbine blade) 8 extends radially substantially in the radial direction. are doing. The blade cross-sectional shape of the water turbine blade outlet end 8 is mainly determined by the pumping operation conditions. Figure 10 (a)
8B shows a velocity triangle of the flow at the exit end of the turbine blade in the AA cross section of FIG. 8 during the pumping operation, and the absolute velocity C of the flow is decomposed into the runner peripheral velocity U and the relative velocity W. FIG. 10 (a) shows a state during high head operation with a small flow rate. In this state, the runner peripheral speed U with respect to the blade angle β 0
The relative inflow angle β formed by the relative velocity W and the relative velocity W becomes smaller. As a result, the pressure is greatly reduced on the blade back surface 4a, and when this pressure becomes equal to or lower than the vapor pressure, cavitation (generally, cavitation generated at this position is referred to as K2) occurs. If this cavitation occurs for a long time, erosion will occur near the cavitation generation part.
【0005】これに対して、図10(b)は、大流量で
ある低揚程運転時の状態を示している。この状態では、
水の相対流入角βは羽根角度β0 より大きくなって、羽
根表面4bで圧力が大きく低下し、高揚程運転時とは逆
に羽根表面4b側にキャビテーション(一般にこの位置
で発生するキャビテーションをK1 という)が発生する
ようになる。キャビテーション発生をある程度抑制する
ために、図11に示したように、水車羽根出口端部の羽
根形状を実線で示した流線形にすることが知られてい
る。このように羽根先端広がり角度αを大きめにし、か
つ滑らかな流線形曲面にすると、破線で示した形状に比
べ先端付近の圧力低下が小さく、キャビテーションが発
生しにくくなる。On the other hand, FIG. 10 (b) shows a state during low head operation with a large flow rate. In this state,
The relative inflow angle β of water becomes larger than the blade angle β 0 , the pressure greatly decreases on the blade surface 4b, and cavitation (generally, the cavitation generated at this position is K 1 ) will occur. In order to suppress the occurrence of cavitation to some extent, as shown in FIG. 11, it is known to make the blade shape at the outlet end of the water turbine blade a streamline shown by the solid line. When the blade tip divergence angle α is increased and the streamlined surface is smooth in this way, the pressure drop near the tip is smaller than that of the shape shown by the broken line, and cavitation is less likely to occur.
【0006】[0006]
【発明が解決しようとする課題】上述のようにポンプ水
車は発電水車運転及び揚水ポンプ運転を同一ランナを用
いて行うため、ランナ内を通過する水は運転モードによ
り流れの方向が可逆となることから、従来のランナ羽根
は両者の性能を考慮し、ランナ羽根の厚さは水車入口及
び出口側の両先端部を除き流れ方向に沿ってほぼ等厚
で、各先端部は先端に向かい羽根厚が単調に薄くなる形
状となっている。その上、ポンプ水車ランナの羽根の羽
根厚は比較的薄いので、上述の羽根先端広がり角度αを
大きくすることができないため、キャビテーション性能
を大きく改善することができないという問題を有してい
る。As described above, the pump turbine performs the generator turbine operation and the pumping pump operation using the same runner, so that the flow direction of water passing through the runner is reversible depending on the operation mode. Therefore, considering the performance of both, the conventional runner blades have almost the same thickness along the flow direction except the tips of the turbine turbine inlet and outlet, and each tip has a blade thickness toward the tip. Is monotonically thin. In addition, since the blade of the pump turbine runner has a relatively small blade thickness, it is impossible to increase the blade tip spreading angle α, and thus there is a problem that the cavitation performance cannot be significantly improved.
【0007】揚水発電所におけるポンプ水車の最高揚程
から最低揚程までの揚程変化幅(水車運転から見て落差
変化幅)はキャビテーションに対する性能から制限を受
けることになる。従って、従来のポンプ水車のランナで
は揚程もしくは落差の変化幅を大きくすることができな
い。このため、発電運転もしくは揚水運転での運転時間
が短くなり、運用効率が悪くなる。また、ダムの有効に
利用できない貯水量が多くなり、資源を有効に活用する
ことができないといった問題がある。そこで、本発明の
目的は、揚水運転時にポンプ水車のランナに発生するキ
ャビテーション性能を向上させ、運転可能な揚程、落差
変化幅を拡大することができるポンプ水車のランナを提
供することにある。[0007] The range of pump head change from the maximum pump head to the minimum pump head in pumped-storage power plants (the change width of the head as viewed from the turbine operation) is limited by the performance against cavitation. Therefore, the runner of the conventional pump turbine cannot increase the change range of the head or the head. Therefore, the operating time in the power generation operation or the pumping operation is shortened, and the operation efficiency is deteriorated. In addition, there is a problem that the amount of water that cannot be used effectively in the dam increases and resources cannot be used effectively. Therefore, an object of the present invention is to provide a pump turbine runner capable of improving the cavitation performance generated in the runner of the pump turbine during the pumping operation and expanding the operable head and the variation range of the head.
【0008】[0008]
【課題を解決するための手段】この目的を達成するため
に本発明は、ランナクラウンとランナバンドとの間に複
数枚のランナ羽根を円周方向に等間隔をおいて固定保持
したポンプ水車のランナにおいて、前記ランナ羽根の水
車羽根出口端近くの羽根裏面およびまたは羽根表面に膨
出部を形成し、この膨出部の前後を滑らかな曲面で接続
したことを特徴とするものである。To achieve this object, the present invention relates to a pump turbine in which a plurality of runner blades are fixedly held at equal intervals in the circumferential direction between a runner crown and a runner band. In the runner, a bulging portion is formed on the blade back surface and / or the blade surface near the water turbine blade outlet end of the runner blade, and the front and rear of the bulging portion are connected by a smooth curved surface.
【0009】この構成にあっては、上記膨出部が水車流
れ方向に向かって羽根断面が膨らみ始める位置(以下、
羽根厚増加開始点という)と水車羽根出口端との間の円
周方向の角度をθs 、隣接する一対のランナ羽根の羽根
出口端の間の円周方向のピッチ角度をθ0 としたとき、
θs がθs ≦1.2θo の関係にあることが望ましい。In this structure, the bulging portion starts to bulge in the blade cross section in the flow direction of the water turbine (hereinafter,
(The blade thickness increase start point) and the turbine blade outlet end are defined as θ s , and the circumferential pitch angle between the blade outlet ends of a pair of adjacent runner blades is defined as θ 0. ,
It is desirable that θ s be in the relation of θ s ≦ 1.2 θ o .
【0010】また、上記ランナ羽根の羽根厚増加開始点
での羽根厚をB0 としたとき、水車羽根出口端を中心に
してB0 /2を半径として描いた仮想円と羽根表面及び
羽根裏面と交わってできる交点を通り、かつ羽根表面及
び裏面の羽根形状曲線に接する接線をそれぞれ引き、両
接線のなす角度をαとした時、αが、35°≦α≦60
°の関係にあることが望ましい。また、上記ランナ羽根
の水車羽根出口端における最大羽根厚がランナバンドと
ランナクラウン間の中央からランナバンドに向けて徐々
に増加するように設定することが望ましい。When the blade thickness at the blade thickness increase start point of the runner blade is B 0 , a virtual circle drawn with a radius of B 0/2 around the outlet end of the water turbine blade and the blade front surface and blade back surface. When a tangent line that passes through the intersection point formed by intersecting with and that is in contact with the blade shape curve on the front surface and the back surface of the blade is drawn and the angle formed by both tangent lines is α, α is 35 ° ≦ α ≦ 60
It is desirable to have a relationship of °. Further, it is desirable that the maximum blade thickness at the water turbine blade outlet end of the runner blade is set to gradually increase from the center between the runner bands to the runner band.
【0011】[0011]
【作用】本発明によるポンプ水車ランナでは、ランナ羽
根先端近傍の羽根厚が厚くなるのでランナ羽根先端広が
り角度を大きく、かつ滑らかな流線形状とすることがで
きるため、羽根先端部の圧力低下を抑制することがで
き、従って、揚水運転時のキャビテーションに対する性
能を向上させることができる。In the pump turbine runner according to the present invention, since the blade thickness near the tip of the runner blade becomes thicker, the runner blade tip spreading angle can be made large and the streamlined shape can be made smooth. Therefore, the performance against cavitation during the pumping operation can be improved.
【0012】[0012]
【実施例】以下本発明によるポンプ水車のランナの実施
例を図1を参照して説明する。図1は図8のA−A線に
沿って切断して示した隣り合った一対のランナ羽根の縦
断面形状を示している。図1において、ランナ羽根4の
水車羽根出口端8に近い羽根裏面4aには、膨出部10
が形成され、角度θs の範囲が滑らかな曲線で接続され
ている。言い換えれば、ランナ羽根4の中央部の羽根厚
B0 に対して、水車羽根出口端付近の羽根厚B1 の方が
厚く形成されており、ランナ羽根の先端広がり角度αは
大きく設定されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a runner for a pump turbine according to the present invention will be described below with reference to FIG. FIG. 1 shows a vertical cross-sectional shape of a pair of adjacent runner blades, which is cut along the line AA in FIG. In FIG. 1, the bulging portion 10 is provided on the blade back surface 4a near the water turbine blade outlet end 8 of the runner blade 4.
Are formed, and the range of the angle θ s is connected by a smooth curve. In other words, the blade thickness B 1 in the vicinity of the water turbine blade outlet end is formed thicker than the blade thickness B 0 in the central portion of the runner blade 4, and the tip spread angle α of the runner blade is set to be large. .
【0013】このように、本発明によれば、水車羽根出
口端8付近の羽根厚B1 が羽根中央部の羽根厚B0 より
局部的に大きく設定したため、羽根の先端広がり角度α
を従来より更に大きく設定することが可能となり、キャ
ビテーションの発生を大幅に抑制することができる。As described above, according to the present invention, the blade thickness B 1 in the vicinity of the water turbine blade outlet end 8 is locally set to be larger than the blade thickness B 0 in the blade central portion, so that the blade tip spreading angle α
Can be set to a value larger than that of the conventional one, and the occurrence of cavitation can be significantly suppressed.
【0014】次に図2を参照して上述した本発明の実施
例による効果を従来例と対比して説明する。図2に示し
たグラフの横軸は設計点の揚水量Q0 に対する揚水量Q
の比を示し、縦軸はキャビテーションが発生し始める時
のキャビテーション係数(初生キャビテーション係数と
いう)σi を表している。実線は本発明の実施例を示
し、破線は従来例の場合を示しており、各々曲線より下
側の領域でキャビテーションが発生することを意味す
る。また、K1は羽根表面側に発生するキャビテーショ
ンを示し、K2は羽根裏面側に発生するキャビテーショ
ンを示している。このグラフからわかるように、例えば
キャビテーション係数0.14でのキャビテーションの
発生しない揚水量範囲ΔQi で比較すると、本発明の実
施例によれば従来例に比べキャビテーションの発生しな
い運転範囲を約2倍に拡大することができる。Next, the effect of the embodiment of the present invention described above will be described with reference to FIG. The horizontal axis of the graph shown in Fig. 2 is the pumped water quantity Q with respect to the pumped water quantity Q 0 at the design point.
And the vertical axis represents the cavitation coefficient (called the initial cavitation coefficient) σ i when cavitation starts to occur. The solid line shows the embodiment of the present invention, and the broken line shows the case of the conventional example, which means that cavitation occurs in the area below the curve. Further, K1 indicates cavitation generated on the blade front surface side, and K2 indicates cavitation generated on the blade back surface side. As can be seen from this graph, for example, when comparing the pumping amount range ΔQ i in which cavitation does not occur with a cavitation coefficient of 0.14, according to the embodiment of the present invention, the operating range in which cavitation does not occur is approximately doubled as compared with the conventional example. Can be expanded to.
【0015】次に図1および図3を参照して、ランナ羽
根4の肉厚を増大させる範囲とキャビテーション係数の
変化の態様について考察する。図1において、ランナ羽
根の肉厚が中央付近の羽根厚B0 から厚くなり始める位
置(以下、羽根厚増加開始点Sと呼ぶ)の羽根先端8か
ら円周方向への角度θs と、羽根間ピッチ角度θ0 との
関係は、好ましくは、θs が下記の範囲を満足するよう
に選定される。 θs ≦1.2θ0 Next, with reference to FIGS. 1 and 3, the range in which the wall thickness of the runner blade 4 is increased and the mode of variation of the cavitation coefficient will be considered. In FIG. 1, the angle θ s from the blade tip 8 to the circumferential direction at the position where the thickness of the runner blade starts to increase from the blade thickness B 0 near the center (hereinafter referred to as the blade thickness increase start point S), and the blade The relationship with the inter-pitch angle θ 0 is preferably selected so that θ s satisfies the following range. θ s ≦ 1.2 θ 0
【0016】図1に示すように、このθs を小さく設定
すると、羽根裏面4aの曲面形状は羽根先端側では凸形
状に、そして水車上流側では凹形状となるため、凸形状
から凹形状に変わる位置付近で圧力が低下し、キャビテ
ーション(以下K3という)が発生しやすくなる。しか
し、逆にθs を大きくすると、羽根間の流路幅aが狭く
なるため羽根間における水流の流速が速くなり、羽根表
面4bの羽根先端付近の圧力が低下し、キャビテーショ
ン(K1 )が発生しやすくなる。As shown in FIG. 1, when θ s is set small, the curved surface of the blade back surface 4a is convex on the blade tip side and concave on the turbine upstream side. The pressure decreases near the changing position, and cavitation (hereinafter referred to as K3) easily occurs. However, conversely, when θ s is increased, the flow passage width a between the blades is narrowed, the flow velocity of the water flow between the blades is increased, the pressure near the blade tips of the blade surface 4b is decreased, and the cavitation (K 1 ) is reduced. It tends to occur.
【0017】図3は羽根厚増加の開始点の位置と初生キ
ャビテーション係数の変化の態様を示したグラフであ
り、横軸は羽根間ピッチ角度θ0 で無次元化した羽根厚
増加開始点の角度θs を表し、縦軸は大流量の低揚程側
で揚水量一定の下で、θs =θ0 でのK1初生キャビテ
ーション係数を基準とした時のK1初生キャビテーショ
ン係数の変化ΔσiK1を表す。このグラフからわかる
ように、θs >1.2θ0 でK1初生キャビテーション
係数の変化Δσi K1が急激に大きくなっている。本実
施例によれば、K1初生キャビテーション性能の低下を
大幅に抑制することができる。FIG. 3 is a graph showing the position of the starting point of the blade thickness increase and the mode of change of the initial cavitation coefficient. The horizontal axis is the dimension of the blade thickness increasing start point made dimensionless by the blade pitch angle θ 0. θ s is represented, and the vertical axis represents a change ΔσiK1 of the K1 initial cavitation coefficient with reference to the K1 initial cavitation coefficient at θ s = θ 0 under a constant pumping amount on the low pump head side of a large flow rate. As can be seen from this graph, the change Δσ i K1 in the K1 initial cavitation coefficient rapidly increases when θ s > 1.2θ 0 . According to this embodiment, it is possible to significantly suppress the deterioration of the K1 initial cavitation performance.
【0018】次に図4を参照して本発明の他の実施例を
説明する。ランナ羽根4の水車羽根出口端8の近くの羽
根裏面4aと羽根表面4bとの両方の対称位置に膨出部
10、10を形成した例を示している。図4中、羽根先
端8を中心に羽根厚増加点Sでの羽根厚B0 の1/2倍
の長さを半径とする円を描き、ランナ羽根の羽根裏面4
a及び表面4bの羽根曲線と交わる交点を各々Xa及び
Xbとする。そして、Xa及びXb点から各羽根曲線に
接する接線を引き、両接線のなす角度を羽根先端広がり
角度αと定義する。Next, another embodiment of the present invention will be described with reference to FIG. An example is shown in which the bulged portions 10 and 10 are formed at symmetrical positions on both the blade back surface 4a and the blade surface 4b near the water turbine blade outlet end 8 of the runner blade 4. In FIG. 4, a circle having a radius of 1/2 times the blade thickness B 0 at the blade thickness increasing point S at the blade tip 8 is drawn to draw the blade back surface 4 of the runner blade.
Let Xa and Xb be the intersections of a and the surface 4b with the vane curves. Then, a tangent line tangent to each blade curve is drawn from the points Xa and Xb, and an angle formed by both tangent lines is defined as a blade tip spread angle α.
【0019】本実施例では、この羽根先端広がり角度α
は下記の範囲を満足するように選定される。In this embodiment, the blade tip spread angle α
Is selected to satisfy the following range.
【0020】35≦α≦60°35 ≦ α ≦ 60 °
【0021】このαが大きい方が、K1及びK2のキャ
ビテーションに対する性能が向上するが、一方でこのα
が大きくなると、羽根裏面4a側の凸形状の曲率が大き
くなり、凸部から凹部に変化する付近の圧力低下が更に
大きくなり、K3キャビテーションが発生しやすくな
る。The larger the value of α, the better the performance of K1 and K2 against cavitation.
Becomes larger, the curvature of the convex shape on the blade back surface 4a side becomes larger, the pressure drop in the vicinity of the change from the convex portion to the concave portion becomes larger, and K3 cavitation easily occurs.
【0022】図5は羽根先端広がり角度αとキャビテー
ション無発生幅との関係を示したグラフである。横軸は
羽根先端広がり角度αを表し、縦軸は図2で示すよう
に、キャビテーション係数一定の下で、設計点揚水量Q
0で無次元化したキャビテーションの発生しない揚水量
範囲ΔQi を表し、K1 〜K2 はK1 とK2 初生キャビ
テーション曲線間を、そしてK1 〜K3 はK1 とK3 初
生キャビテーション曲線間のキャビテーションの発生し
ない揚水量範囲を表す。FIG. 5 is a graph showing the relationship between the blade tip spread angle α and the cavitation-free width. The horizontal axis represents the blade tip spread angle α, and the vertical axis, as shown in FIG.
A zero-dimensionalized cavitation-free pumping range ΔQ i is represented, where K 1 to K 2 are between K 1 and K 2 primary cavitation curves, and K 1 to K 3 are K 1 and K 3 primary cavitation curves. Represents the range of pumping volume where cavitation does not occur.
【0023】このグラフからわかるように、α=35°
付近からキャビテーションの発生しない範囲が大幅に拡
大するが、α=60°付近からK3 キャビテーション性
能が悪くなり、キャビテーションの発生しない揚水量範
囲は大きくは拡大しなくなる。このように本発明によれ
ば、運転可能範囲の拡大に寄与する羽根先端広がり角度
αを与えることができる。As can be seen from this graph, α = 35 °
The range where cavitation does not occur greatly expands from the vicinity, but the K 3 cavitation performance deteriorates from around α = 60 °, and the pumped-up range where cavitation does not occur does not expand significantly. As described above, according to the present invention, it is possible to provide the blade tip spread angle α that contributes to the expansion of the operable range.
【0024】次に、ランナ水車羽根出口端8近傍の最大
羽根厚変化を示した図6を参照して説明する。横軸は、
ランナクラウンからランナバンド間の水車羽根出口端8
に沿った距離l0 で無次元化したランナクラウンからの
距離lを表し、縦軸はランナバンド上の最大羽根厚B1B
で無次元化した最大羽根厚B1 を表す。本実施例では、
ランナクラウンから出口端中央付近までは最大羽根厚は
ほぼ同一であるが、中央付近からランナバンドにかけて
最大羽根厚が徐々に増大している。この作用を図7を参
照して説明する。一般に、羽根入口付近の圧力低下は次
式で表される。Next, description will be made with reference to FIG. 6 showing the maximum blade thickness change in the vicinity of the runner turbine blade outlet end 8. The horizontal axis is
Water turbine blade outlet end 8 between the runner crown and the runner band
Represents the distance l from the dimensionless runner crown along the distance l 0 along the vertical axis, and the vertical axis represents the maximum blade thickness B 1B on the runner band.
Represents the maximum blade thickness B 1 made dimensionless. In this embodiment,
The maximum blade thickness is almost the same from the runner crown to the center of the outlet end, but the maximum blade thickness gradually increases from the center to the runner band. This action will be described with reference to FIG. Generally, the pressure drop near the blade inlet is represented by the following equation.
【0025】 Δp=λ1・C2 /2g+λ2・W2 /2gΔp = λ1 · C 2 / 2g + λ2 · W 2 / 2g
【0026】ここで、λ1及びλ2は係数で、およそλ
1〜1.2、λ2〜0.3の値をとる。図7(a)はラ
ンナバンド側の速度三角形を示すが、ランナバンド側は
半径が大きいので周速UB が速くなるため、相対速度W
B も速くなる。従って、ランナバンド側では相対的に圧
力低下Δpは大きくなり、キャビテーションが発生しや
すくなる。逆に図7(b)はランナクラウン側の速度三
角形を示すが、絶対速度Cはランナバンド側とほぼ同一
であるが、半径が小さくなるためた周速Ucが遅くな
り、かつ相対速度Wcも遅くなる。従って、ランナクラ
ウン側では相対的に圧力低下Δpは小さくなり、キャビ
テーションは比較的発生しにくい。従って、本実施例に
よれば、キャビテーションの発生しやすいバンド側で羽
根先端付近の最大羽根厚を増大することにより、ランナ
クラウンからランナバンドまでのキャビテーション性能
をバランス良くすることができる。Here, λ1 and λ2 are coefficients, and approximately λ
The values are 1 to 1.2 and λ2 to 0.3. FIG. 7A shows a velocity triangle on the runner band side, but since the radius is large on the runner band side, the peripheral velocity U B becomes faster, so the relative velocity W
B also becomes faster. Therefore, the pressure drop Δp becomes relatively large on the runner band side, and cavitation easily occurs. On the contrary, FIG. 7B shows a velocity triangle on the runner crown side. Although the absolute velocity C is almost the same as that on the runner band side, the peripheral velocity Uc due to the smaller radius becomes slower and the relative velocity Wc also becomes Become slow. Therefore, the pressure drop Δp is relatively small on the runner crown side, and cavitation is relatively unlikely to occur. Therefore, according to the present embodiment, by increasing the maximum blade thickness near the blade tip on the side of the band where cavitation is likely to occur, the cavitation performance from the runner crown to the runner band can be balanced.
【0027】[0027]
【発明の効果】以上の説明から明らかなように、本発明
によると、ポンプ水車のランナ羽根の羽根先端近傍の羽
根断面が膨らみをもち、かつ滑らかな流線形状とするた
め、揚水運転時、羽根先端部の裏面及び表面での大きな
圧力低下を抑制することができる。これによって、キャ
ビテーション性能を向上でき、最高揚程と最低揚程間の
運転可能範囲を大幅に拡大することができる。As is apparent from the above description, according to the present invention, since the blade cross section near the blade tip of the runner blade of the pump turbine has a swollen and smooth streamline shape, during pumping operation, A large pressure drop on the back surface and the front surface of the blade tip can be suppressed. As a result, the cavitation performance can be improved, and the operable range between the maximum head and the minimum head can be greatly expanded.
【図1】本発明によるポンプ水車のランナの一実施例を
概略的に示したランナ羽根断面図。FIG. 1 is a cross-sectional view of a runner blade schematically showing an embodiment of a runner of a pump turbine according to the present invention.
【図2】本発明の効果を実証するために揚水量比と初生
キャビテーション係数との関係を従来例と対比して示し
たグラフ。FIG. 2 is a graph showing the relationship between the pumping rate and the primary cavitation coefficient in comparison with the conventional example in order to demonstrate the effect of the present invention.
【図3】羽根厚増加開始点位置比と初生キャビテーショ
ン係数変化との関係を示したグラフ。FIG. 3 is a graph showing the relationship between the blade thickness increase start point position ratio and the change in initial cavitation coefficient.
【図4】本発明によるポンプ水車のランナの他の実施例
を概略的に示したランナ羽根断面図。FIG. 4 is a sectional view of a runner blade schematically showing another embodiment of the runner of the pump turbine according to the present invention.
【図5】ランナ羽根先端広がり角度とキャビテーション
無発生幅との関係について示したグラフ。FIG. 5 is a graph showing the relationship between the runner blade tip spreading angle and the cavitation-free width.
【図6】クラウンから水車羽根出口端に沿った距離と羽
根出口端最大厚みとの関係を示したグラフ。FIG. 6 is a graph showing the relationship between the distance from the crown along the outlet end of the turbine blade and the maximum thickness of the outlet end of the blade.
【図7】(a) ランナバンド側の速度三角形を示した
概略図。 (b) ランナクラウン側の速度三角形を示した概略
図。FIG. 7 (a) is a schematic view showing a velocity triangle on the runner band side. (B) Schematic diagram showing a velocity triangle on the runner crown side.
【図8】従来のポンプ水車の構造を概略的に示した断面
図。FIG. 8 is a sectional view schematically showing the structure of a conventional pump turbine.
【図9】従来のランナを水車出口側から見た羽根構成
図。FIG. 9 is a blade configuration diagram of a conventional runner as seen from the water turbine outlet side.
【図10】(a) 高揚程運転時のランナ羽根流入状態
を速度三角形で模式的に示した概略図。 (b) 低揚程運転時のランナ羽根流入状態を速度三角
形で模式的に示した概略図。FIG. 10 (a) is a schematic view schematically showing a runner blade inflow state during high head operation with a speed triangle. (B) A schematic view schematically showing a runner blade inflow state during low head operation with a speed triangle.
【図11】(a) 従来のランナ羽根の先端形状を示し
た断面図。 (b) 羽根面圧力分布の状態を模式的に示した概略
図。FIG. 11A is a sectional view showing a tip shape of a conventional runner blade. (B) The schematic diagram which showed typically the state of vane surface pressure distribution.
1 ケーシング 2 ランナ 3 吸出し管 4 ランナ羽根 4a ランナ羽根裏面 4b ランナ羽根表面 6 ランナクラウン 7 ランナバンド 8 水車羽根出口端 10 膨出部 1 casing 2 runner 3 suction pipe 4 runner blade 4a runner blade back surface 4b runner blade surface 6 runner crown 7 runner band 8 turbine blade outlet end 10 bulging portion
───────────────────────────────────────────────────── フロントページの続き (72)発明者 吉 森 隆 彦 大阪府大阪市北区中之島三丁目3番22号 関西電力株式会社内 (72)発明者 鈴 木 敏 暁 神奈川県横浜市鶴見区末広町2丁目4番地 株式会社東芝京浜事業所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiko Yoshi Mori 3-22-3 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Kansai Electric Power Co., Inc. 2-4, Machi Within the Keihin office of Toshiba Corporation
Claims (4)
数枚のランナ羽根を円周方向に等間隔をおいて固定保持
したポンプ水車のランナにおいて、前記ランナ羽根の水
車羽根出口端近くの羽根裏面および羽根表面の少なくと
も一方に膨出部を形成し、この膨出部の前後を滑らかな
曲面で接続したことを特徴とするポンプ水車のランナ。1. A runner of a pump turbine in which a plurality of runner blades are fixedly held at equal intervals in the circumferential direction between a runner crown and a runner band, and a blade back surface near the outlet end of the turbine blade of the runner blade. A runner for a pump turbine, wherein a bulging portion is formed on at least one of the blade surfaces, and the front and rear of the bulging portion are connected with a smooth curved surface.
断面が膨らみ始める位置(以下、羽根厚増加開始点とい
う)と水車羽根出口端との間の円周方向の角度をθs 、
隣接する一対のランナ羽根の羽根出口端の間の円周方向
のピッチ角度をθ0 としたとき、θs がθs ≦1.2θ
0 の関係にあることを特徴とする請求項1に記載のポン
プ水車のランナ。2. The angle in the circumferential direction between the position where the bulging portion begins to swell in the blade cross section in the turbine flow direction (hereinafter referred to as the blade thickness increase start point) and the outlet end of the turbine blade, θ s ,
When the pitch angle in the circumferential direction between the blade outlet ends of a pair of adjacent runner blades is θ 0 , θ s is θ s ≦ 1.2 θ
The runner for a pump turbine according to claim 1, wherein the runner has a relationship of 0 .
根厚をB0 としたとき、水車羽根出口端を中心にしてB
0 /2を半径として描いた仮想円と羽根表面及び羽根裏
面と交わってできる交点を通り、かつ羽根表面及び裏面
の羽根形状曲線に接する接線をそれぞれ引き、両接線の
なす角度をαとした時、αが、35°≦α≦60°の関
係にあることを特徴とする請求項1に記載のポンプ水車
のランナ。3. When the blade thickness at the start point of increasing the blade thickness of the runner blade is B 0 , B is centered at the outlet end of the turbine blade.
When a tangent line that passes through the intersection point formed by the virtual circle drawn with the radius of 0/2 and the blade surface and the blade back surface and that is in contact with the blade shape curve of the blade front surface and the blade back surface is defined as α , Α is in the relationship of 35 ° ≦ α ≦ 60 °. The runner for a pump turbine according to claim 1, wherein
最大羽根厚がランナバンドとランナクラウン間の中央か
らランナバンドに向けて徐々に増加するように設定した
ことを特徴とする請求項1ないし請求項3のいずれかに
記載のポンプ水車のランナ。4. The maximum blade thickness at the outlet end of the water turbine blade of the runner blade is set so as to gradually increase from the center between the runner band and the runner crown toward the runner band. A runner for a pump turbine according to any one of Items 3.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11959495A JP3762453B2 (en) | 1995-05-18 | 1995-05-18 | Pump turbine runner |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11959495A JP3762453B2 (en) | 1995-05-18 | 1995-05-18 | Pump turbine runner |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08312518A true JPH08312518A (en) | 1996-11-26 |
JP3762453B2 JP3762453B2 (en) | 2006-04-05 |
Family
ID=14765255
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11959495A Expired - Lifetime JP3762453B2 (en) | 1995-05-18 | 1995-05-18 | Pump turbine runner |
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Country | Link |
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JP (1) | JP3762453B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006029229A (en) * | 2004-07-16 | 2006-02-02 | Toshiba Corp | Hydraulic machine runner |
-
1995
- 1995-05-18 JP JP11959495A patent/JP3762453B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006029229A (en) * | 2004-07-16 | 2006-02-02 | Toshiba Corp | Hydraulic machine runner |
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Publication number | Publication date |
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JP3762453B2 (en) | 2006-04-05 |
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