JP4512428B2 - How to replace the pressure pulsation suppression valve - Google Patents
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- JP4512428B2 JP4512428B2 JP2004185021A JP2004185021A JP4512428B2 JP 4512428 B2 JP4512428 B2 JP 4512428B2 JP 2004185021 A JP2004185021 A JP 2004185021A JP 2004185021 A JP2004185021 A JP 2004185021A JP 4512428 B2 JP4512428 B2 JP 4512428B2
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- 230000010349 pulsation Effects 0.000 title claims description 103
- 230000001629 suppression Effects 0.000 title claims description 28
- 239000012530 fluid Substances 0.000 claims description 74
- 230000002441 reversible effect Effects 0.000 claims description 22
- 230000002093 peripheral effect Effects 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 10
- 238000011144 upstream manufacturing Methods 0.000 claims description 9
- 230000037237 body shape Effects 0.000 claims description 7
- 230000008602 contraction Effects 0.000 claims description 2
- 238000002474 experimental method Methods 0.000 description 18
- 230000003068 static effect Effects 0.000 description 12
- 230000000694 effects Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000009530 blood pressure measurement Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- -1 vapor Substances 0.000 description 1
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Description
本発明は、圧力脈動抑制弁の交換方法に関する。さらに詳しくは、本発明は、既存設備に既に設置されている弁であって、弁座に弁体を押し付けることで流体通路を閉じると共に、弁体のリフト量を変えることで流体の流量を変化させるタイプの圧力脈動抑制弁の交換方法に関するものである。 The present invention relates to a method for replacing a pressure pulsation suppression valve . More particularly, the present invention provides a valve that has already been installed in existing facilities, closes the fluid passage by pressing the valve body in the valve seat, the flow rate of fluid by changing the lift amount of the valve body The present invention relates to a method for replacing a pressure pulsation suppression valve of a changing type.
例えば、発電プラントの蒸気系の蒸気加減弁では、中間開度において振動が発生することが知られている。従来、このような振動を抑制するための蒸気加減弁として、例えば特公昭５８−４４９０９号公報に開示されたものがある。この蒸気加減弁を図２０に示す。蒸気加減弁１０１の弁体１０２の先端部分は、半球体の先端を流体通路１０３の軸線方向に対して垂直に切断した形状を成しており、その先端面に凹部１０８を形成することで全周にわたってエッジ部１０４を形成している。また、弁座１０５は、弁体１０２と当たる部分の付近では流体通路１０３を絞る形状を成しているが、その下流側は滑らかな曲線を有しながら徐々に広がる形状を成している。 For example, it is known that vibration occurs at an intermediate opening in a steam control valve of a steam system of a power plant. Conventionally, as a steam control valve for suppressing such vibration, there is one disclosed in, for example, Japanese Patent Publication No. 58-44909. This steam control valve is shown in FIG. The front end portion of the valve body 102 of the steam control valve 101 has a shape obtained by cutting the front end of the hemisphere perpendicularly to the axial direction of the fluid passage 103. An edge portion 104 is formed over the circumference. In addition, the valve seat 105 has a shape in which the fluid passage 103 is narrowed in the vicinity of the portion that contacts the valve body 102, but the downstream side has a shape that gradually spreads while having a smooth curve.
この蒸気加減弁１０１は、中間開度において、流体の流れが短周期で繰り返し変化することに起因した振動を防止することを目的としたものである。つまり、蒸気加減弁１０１の中間開度においては、弁体１０２に沿って流れていた流体がそのまま弁体１０２に沿って流れる場合と、途中で弁体１０２側から剥離して弁座１０５側に沿って流れる場合とがあり、両者の流れが交互に切り換えられて繰り返されることで振動が発生すると考えられており、このような振動の発生防止を蒸気加減弁１０１は目的としている。このため、弁体１０２のエッジ部１０４を、弁体１０２に沿う流れが弁体１０２から剥離する剥離点よりも上流側に形成し、流体が安定して流れるようにすることで、振動の発生防止を図っている。 The purpose of the steam control valve 101 is to prevent vibration caused by the fluid flow repeatedly changing in a short cycle at an intermediate opening. That is, at the intermediate opening degree of the steam control valve 101, when the fluid flowing along the valve body 102 flows along the valve body 102 as it is, it peels off from the valve body 102 side on the way to the valve seat 105 side. It is considered that vibrations are generated when the flows of the two are alternately switched and repeated, and the steam control valve 101 is intended to prevent such vibrations from occurring. Therefore, the edge 104 of the valve body 102 is formed upstream of the separation point where the flow along the valve body 102 peels from the valve body 102 so that the fluid flows stably, thereby generating vibration. I'm trying to prevent it.
また、特公昭５８−４４９０９号公報において、従来技術として紹介されている蒸気加減弁１０６を図２１に示す。この蒸気加減弁１０６の弁座１０７は、図２０の蒸気加減弁１０１の弁座１０５とは異なった形状を成している。このため、既存の設備に図２１の蒸気加減弁１０６が既に設置されていた場合、この蒸気加減弁１０６を中間開度における振動を防止するために図２０の蒸気加減弁１０１に交換するには、弁体１０２のみならず弁座１０５をも交換する必要があり、このため、弁座１０５を設置する配管ごと交換する必要がある。 FIG. 21 shows a steam control valve 106 introduced as a prior art in Japanese Patent Publication No. 58-44909. The valve seat 107 of the steam control valve 106 has a different shape from the valve seat 105 of the steam control valve 101 of FIG. For this reason, when the steam control valve 106 of FIG. 21 is already installed in the existing equipment, this steam control valve 106 is replaced with the steam control valve 101 of FIG. 20 in order to prevent vibration at the intermediate opening. In addition, not only the valve body 102 but also the valve seat 105 needs to be replaced. For this reason, it is necessary to replace the piping in which the valve seat 105 is installed.
しかしながら、上述の蒸気加減弁１０１のようにエッジを有する弁体では、弁体と弁座の曲率比によっては流れの振動が発生する可能性がある。また、既存設備に設置されている蒸気加減弁１０６を交換するためには、弁座１０５ごとの交換が必要であるため、弁座１０５を設置する配管も交換する必要があり、交換作業が大掛かりなものとなって交換に要する費用が高かった。また、弁座１０５ごと交換することから、交換によって弁体１０２のリフト量と流体の流量との関係が変化し、交換前と同じ運転方法で発電プラントを運転することができなかった。 However, in a valve body having an edge like the above-described steam control valve 101, there is a possibility that flow vibration may occur depending on the curvature ratio of the valve body and the valve seat. Further, in order to replace the steam control valve 106 installed in the existing equipment, it is necessary to replace each valve seat 105. Therefore, it is also necessary to replace the piping on which the valve seat 105 is installed. The cost required for replacement was high. Further, since the entire valve seat 105 is replaced, the relationship between the lift amount of the valve body 102 and the fluid flow rate is changed by the replacement, and the power plant cannot be operated by the same operation method as before the replacement.
本発明は、新しい知見に基づき中間開度で発生する振動を効果的に抑制することができる圧力脈動抑制弁に関し、振動抑制を十分考慮していなかった既存設備の弁を新しいものと交換する際、弁体のリフト量と流体の流量の関係を変えることがない弁の交換方法を提供することを目的とする。 The present invention relates to a pressure pulsation suppression valve that can effectively suppress vibration generated at an intermediate opening based on new knowledge, and when replacing a valve of an existing facility that has not sufficiently considered vibration suppression with a new one. Another object of the present invention is to provide a valve replacement method that does not change the relationship between the lift amount of the valve body and the flow rate of the fluid.
本発明者らは、例えば蒸気加減弁等の中間開度における振動をより効果的に防止すべく鋭意研究を行った結果、振動の原因が２種類の流れが短周期で切り換わることによるものではなく、弁体に沿う流れが合流する際の衝突による圧力脈動によるものであることを突き止めた。即ち、流体の流れは弁体の全周にわたって発生し、弁体を通過して合流する。このとき、中間開度においては、弁体を通過する流れは弁体に沿う流れとなり、弁体に比較的近い位置で衝突し、局所的な高圧領域が発生する。この局所的な高圧領域は常に一定の位置にとどまるものではなく、弁体の周方向に移動し、しかもその移動方向は突然逆方向になるので、高圧領域が不規則に変化することになり、これによって圧力脈動が生じて振動を発生させることを見出した。そして、このような圧力脈動を抑えることについて鋭意研究を継続し、弁体の下流側部分の形状を延長すると共に、この延長部分を従来の形状とは逆方向の曲率を付けた形状にすることで、圧力脈動をより効果的に抑制できることを知見し、本発明に到達したものである。 As a result of intensive studies to prevent vibration at an intermediate opening such as a steam control valve more effectively, the inventors have found that the cause of vibration is not due to switching between two types of flows in a short cycle. However, it was determined that the flow along the valve body was caused by pressure pulsation caused by a collision at the time of merging. That is, the fluid flow is generated over the entire circumference of the valve body, and passes through the valve body to join. At this time, at the intermediate opening, the flow passing through the valve body is a flow along the valve body, and collides at a position relatively close to the valve body to generate a local high-pressure region. This local high-pressure region does not always stay at a fixed position, but moves in the circumferential direction of the valve body, and the direction of movement suddenly reverses, so the high-pressure region changes irregularly, It has been found that this causes pressure pulsation to generate vibration. And, continually researching to suppress such pressure pulsation, extend the shape of the downstream part of the valve body, and make this extended part a shape with a curvature opposite to the conventional shape. Thus, it has been found that pressure pulsation can be more effectively suppressed, and the present invention has been achieved.
かかる目的を達成するために、請求項１記載の圧力脈動抑制弁の交換方法は、既存設備に設置されており、流体通路の壁面に設けられた弁座と、弁座に対して弁座の軸線方向上流側から当接して流体通路を閉じる弁体とを備える弁の交換方法において、弁座を交換することなく、弁体を、弁座に当接する部分を有し、周面の縦断面形状が弁体の内部に中心を有する曲率の曲線になっている縮流部と、縮流部から流体通路の下流側に向けて突出し、周面の縦断面形状が弁体の外部に中心を有する曲率の曲線になっている逆曲率部とを備え、縮流部と弁座との間の隙間によって流体の流量を決定し、且つ弁体のリフト量と流体の流量との関係が交換前のものと同じであり、交換前の弁体の形状とは異なる形状の弁体に交換するものである。したがって、既に設置されている弁の弁体と交換しても、弁体のリフト量と流体の流量との関係を維持することができる。
また、弁体に沿って流れる流体は、縮流部から逆曲率部へと流れて弁体を通過する。このとき、逆曲率部の周面はその縦断面形状が弁体の外部に中心を有する曲率の曲線になっているので、流れの方向を緩やかに変えて流体を流体通路の壁面に沿う方向、又は弁体から十分離れた位置で小さな角度で合流する方向に向けて流し、流体の流れが弁体に近い位置で大きな角度で衝突するのを防止する。また、逆曲率部が流体の流量に影響を与えることがなく、しかも縮流部の周面はその縦断面形状が弁体の内部に中心を有する曲率の曲線になっていることから既存設備に設置されている弁の弁体の形状と共通するため、既に設置されている弁の弁体と交換しても、弁体のリフト量（弁の開度）と流体の流量との関係を維持することができる。
In order to achieve this object, a pressure pulsation suppression valve replacement method according to claim 1 is installed in an existing facility, and a valve seat provided on a wall surface of a fluid passage, A valve exchanging method comprising a valve body that abuts from the upstream side in the axial direction and closes the fluid passage, and has a portion that abuts the valve seat without exchanging the valve seat, and a longitudinal section of the circumferential surface A contracted portion whose shape is a curve of curvature having a center inside the valve body, and projects from the contracted portion toward the downstream side of the fluid passage, and a longitudinal sectional shape of the peripheral surface is centered outside the valve body A reverse curvature portion having a curved curvature , and the flow rate of the fluid is determined by a gap between the contraction portion and the valve seat, and the relationship between the lift amount of the valve body and the flow rate of the fluid is before replacement. The valve body is replaced with a valve body having a shape different from the shape of the valve body before replacement. Therefore, the relationship between the lift amount of the valve body and the flow rate of the fluid can be maintained even when the valve body of the valve already installed is replaced.
Further, the fluid flowing along the valve body flows from the contracted flow portion to the reverse curvature portion and passes through the valve body. At this time, the circumferential surface of the reverse curvature portion has a curvature curve whose longitudinal cross-sectional shape has a center outside the valve body, so the direction of the fluid is gently changed along the wall surface of the fluid passage, Or it flows toward the direction where it joins at a small angle at a position sufficiently away from the valve body, and prevents the fluid flow from colliding at a large angle at a position close to the valve body. In addition, the reverse curvature part does not affect the flow rate of the fluid, and the peripheral surface of the contracted part is a curved curve with a longitudinal cross-section centered inside the valve body. Since the shape of the valve body of the installed valve is the same, even if the valve body of an already installed valve is replaced, the relationship between the lift amount of the valve body (valve opening) and the fluid flow rate is maintained. can do.
しかして、請求項１記載の圧力脈動抑制弁の交換方法では、弁座を交換することなく弁体を交換するので、交換作業が容易で、交換費用が安くすむにもかかわらず、圧力脈動の防止が十分考慮されていなかった既存設備の弁を、圧力脈動の防止が十分考慮された弁に交換することができる。つまり、簡単な作業、安いコストで、既存設備の弁を圧力脈動の抑制をより効果的に行うことができる弁に交換することができる。
また、交換した弁体によると、流体を流体通路の壁面に沿う方向、又は弁体から十分離れた位置で小さな角度で合流する方向に流すことができる。このため、流体が弁体に近い位置で大きな角度で衝突するのを防止でき、この衝突に起因した圧力脈動を抑制することができる。この結果、中間開度での流体の圧力脈動を抑制することができ、圧力脈動による圧力感知センサの誤動作や、騒音、振動をより効果的に抑制することができる。さらに、弁体を交換しても、弁体のリフト量と流体の流量との関係を交換前の既存設備に既に設置されていた弁のものと同じにすることができる。このため、既存の弁を設置した設備と同じ弁開度で同じ出力を得ることができ、同じ方法で設備、プラントを運転することができる。 Thus, the replacing of the pressure pulsation suppression valve according to claim 1, wherein, since the replace the valve without replacing the valve seat, easy replacement, despite the replacement cost is cheaper, pressure pulsation It is possible to replace the valve of the existing equipment that has not been sufficiently considered for prevention of pressure with a valve that is sufficiently considered for prevention of pressure pulsation. That is, the valve of the existing equipment can be replaced with a valve that can more effectively suppress the pressure pulsation with simple work and low cost.
Moreover, according to the exchanged valve body, the fluid can be made to flow in a direction along the wall surface of the fluid passage or in a direction where the fluid joins at a small angle at a position sufficiently away from the valve body. For this reason, it is possible to prevent the fluid from colliding at a large angle at a position close to the valve body, and it is possible to suppress pressure pulsation caused by the collision. As a result, the pressure pulsation of the fluid at the intermediate opening can be suppressed, and the malfunction, noise, and vibration of the pressure sensor due to the pressure pulsation can be more effectively suppressed. Furthermore, even if the valve body is replaced, the relationship between the lift amount of the valve body and the flow rate of the fluid can be made the same as that of the valve already installed in the existing equipment before replacement. For this reason, the same output can be obtained with the same valve opening degree as the equipment in which the existing valve is installed, and the equipment and the plant can be operated by the same method.
以下、本発明の構成を図面に示す最良の形態に基づいて詳細に説明する。 Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.
先ず最初に、圧力脈動抑制弁について説明する。図１に、本発明の圧力脈動抑制弁の実施形態の一例を示す。圧力脈動抑制弁１は、流体通路２の壁面３に設けられた弁座４と、弁座４に対して弁座４の軸線Ｌ３方向上流側から当接して流体通路２を閉じる弁体５とを備えている。弁体５は、弁座４に当接する部分（シート位置１０）を有し、周面の縦断面形状が弁体５の内部に中心を有する曲率の曲線になっている縮流部６と、縮流部６から流体通路２の下流側に向けて突出し、周面の縦断面形状が弁体５の外部に中心を有する曲率の曲線になっている逆曲率部７とを備えている。 First, the pressure pulsation suppression valve will be described. In FIG. 1, an example of embodiment of the pressure pulsation suppression valve of this invention is shown. The pressure pulsation suppression valve 1 includes a valve seat 4 provided on the wall surface 3 of the fluid passage 2, and a valve body 5 that contacts the valve seat 4 from the upstream side in the axis L 3 direction of the valve seat 4 to close the fluid passage 2. It has. The valve body 5 has a portion (seat position 10) that comes into contact with the valve seat 4, and the flow-reduced portion 6 in which the longitudinal cross-sectional shape of the peripheral surface is a curved curve having a center inside the valve body 5, A reverse curvature portion 7 that protrudes from the contracted flow portion 6 toward the downstream side of the fluid passage 2 and has a curved surface having a center in the longitudinal section of the peripheral surface outside the valve body 5 is provided.
本実施形態では、円筒部８の下流側に縮流部６が設けられ、縮流部６の周面の縦断面形状は、弁体５の内部のＯ点を中心とする半径Ｒの曲線となっている。一方、逆曲率部７の周面の縦断面形状は、弁体５の外部のＯ１点を中心とする半径Ｒ１の曲線となっている。また、逆曲率部７の下流側の部分７ａの周面は、流体通路２の壁面３の直線部分３ａと平行又は平行に近い角度に形成されている。さらに、逆曲率部７の先端は弁体５の軸線Ｌ１に対して垂直な平面である端面９となっている。即ち、逆曲率部７の下流側部分７ａの周面は端面９に対して垂直又は垂直に近い角度に形成されている。端面９の直径（幅）Ｗは、圧力脈動抑制弁１が全開状態（図１は中間開度の状態を示す）になった場合に、弁体５の下流側部分７ａが流体通路２の通路面積の最も狭い部分(スロート)になることが無いように設定されている。 In the present embodiment, the contracted portion 6 is provided on the downstream side of the cylindrical portion 8, and the longitudinal cross-sectional shape of the peripheral surface of the contracted portion 6 is a curve with a radius R centering on the point O inside the valve body 5. It has become. On the other hand, the vertical cross-sectional shape of the peripheral surface of the reverse curvature portion 7 is a curve having a radius R1 with the O1 point outside the valve body 5 as the center. Further, the peripheral surface of the downstream portion 7 a of the reverse curvature portion 7 is formed at an angle that is parallel or nearly parallel to the straight portion 3 a of the wall surface 3 of the fluid passage 2. Furthermore, the tip of the reverse curvature portion 7 is an end surface 9 which is a plane perpendicular to the axis L1 of the valve body 5. That is, the peripheral surface of the downstream portion 7 a of the reverse curvature portion 7 is formed perpendicular to the end face 9 or at an angle close to perpendicular. The diameter (width) W of the end face 9 is such that when the pressure pulsation suppression valve 1 is in a fully open state (FIG. 1 shows an intermediate opening state), the downstream portion 7a of the valve body 5 is a passage of the fluid passage 2. It is set so that it does not become the narrowest part (throat) of the area.
縮流部６と逆曲率部７との境界を、図１に符号Ｌ４で示す。また、境界Ｌ４の周面上の点を符号Ａで示す。弁体５の縦断面において、Ａ点はＯ点とＯ１点とを結ぶ線が弁体５の輪郭と交差する点である。境界Ｌ４より上流側の周面が半径Ｒの曲面、境界Ｌ４より下流側の周面が半径Ｒ１の曲面になっている。図中１点鎖線Ｌ２はＯを通りＬ１に垂直な線を示し、境界Ｌ２から角度θの位置にＡ点が設けられている。縮流部６の下流側端と逆曲率部７の上流側端の直径は同じであり、縮流部６と逆曲率部７との間にはほぼ段差はなく、両者の周面は連続している。このため、流体をスムーズに流しながらその方向を変えることができる。 The boundary between the contracted flow part 6 and the inverse curvature part 7 is indicated by a symbol L4 in FIG. A point on the peripheral surface of the boundary L4 is denoted by reference symbol A. In the longitudinal section of the valve body 5, point A is a point where a line connecting the point O and the point O <b> 1 intersects the contour of the valve body 5. The peripheral surface upstream of the boundary L4 is a curved surface with a radius R, and the peripheral surface downstream of the boundary L4 is a curved surface with a radius R1. In the figure, a one-dot chain line L2 indicates a line passing through O and perpendicular to L1, and a point A is provided at a position of an angle θ from the boundary L2. The diameters of the downstream end of the contracted flow part 6 and the upstream end of the reverse curvature part 7 are the same, there is almost no step between the contracted flow part 6 and the reverse curvature part 7, and the peripheral surfaces of both are continuous. ing. For this reason, the direction of the fluid can be changed while flowing smoothly.
シート位置１０即ち閉弁時に弁座４に当接する位置は、縮流部６に設けられている。本実施形態では、縮流部６のＡ点の近傍、好ましくは角度θよりも若干小さい角度θ１の位置に設けられている。例えば、角度θは４５度、角度θ１は４１度である。 The seat position 10, that is, the position that contacts the valve seat 4 when the valve is closed is provided in the contracted portion 6. In this embodiment, it is provided in the vicinity of the point A of the contracted flow portion 6, preferably at a position of an angle θ1 slightly smaller than the angle θ. For example, the angle θ is 45 degrees and the angle θ1 is 41 degrees.
この圧力脈動抑制弁１は、縮流部６と弁座４との間の隙間によって流体の流量を決定する。つまり、全閉状態から全開状態までの全開度において、流体通路２の流路面積が最も狭くなるのは縮流部６と弁座４との間であり、逆曲率部７と弁座４との間で流体通路２の流路面積が最も狭くならないようになっている。 The pressure pulsation suppression valve 1 determines the flow rate of the fluid by the gap between the contracted portion 6 and the valve seat 4. That is, at the full opening from the fully closed state to the fully open state, the flow path area of the fluid passage 2 is the smallest between the contracted portion 6 and the valve seat 4, and the reverse curvature portion 7 and the valve seat 4 The flow passage area of the fluid passage 2 is prevented from becoming the smallest between the two.
全閉状態では、弁体５は弁座４に当接しており、流体は流れない。この状態から弁体５がリフトすると、弁体５と弁座４の間から流体が流れ始める。弁体５に沿って流れる流体は、縮流部６から逆曲率部７へと流れて弁体５を通過する。このとき、逆曲率部７の周面はその縦断面形状が弁体５の外部に中心を有する曲率の曲線になっており、いわば逆曲率を付けた形状となっているので、流体を流体通路２の壁面３に沿う方向又は弁体５から十分離れた位置で小さな角度で合流する方向に向けて流し、流体の流れが弁体５に近い位置で大きな角度で衝突するのを防止する。 In the fully closed state, the valve body 5 is in contact with the valve seat 4 and no fluid flows. When the valve body 5 is lifted from this state, the fluid starts to flow between the valve body 5 and the valve seat 4. The fluid flowing along the valve body 5 flows from the contracted flow portion 6 to the reverse curvature portion 7 and passes through the valve body 5. At this time, the circumferential surface of the reverse curvature portion 7 has a curvature curve whose longitudinal cross-sectional shape has a center outside the valve body 5, that is, a shape with a reverse curvature. 2 in the direction along the wall surface 3 or in a direction sufficiently separated from the valve body 5 at a small angle to prevent the fluid flow from colliding at a large angle at a position close to the valve body 5.
ここで、逆曲率部７が無い弁（以下、通常弁という）を図２に示す。なお、図１に示す部材と同一の部材に同一の符号を付している。通常弁１１は、例えば発電プラントの蒸気加減弁等、既存設備に既に設置されている一般的な弁である。通常弁１１の弁体１２の先端部分１３は半径Ｒの半球形状を成しており、その一部分と圧力脈動抑制弁１の弁体５の縮流部６とは同形状である。また、通常弁１１の弁座４と圧力脈動抑制弁１の弁座４も同形状である。つまり、通常弁１１と圧力脈動抑制弁１とを比較すると、圧力脈動抑制弁１の弁体５に当該弁体５を下流側に延長するようにして逆曲率部７を設けた点で相違する。 Here, a valve having no reverse curvature portion 7 (hereinafter referred to as a normal valve) is shown in FIG. In addition, the same code | symbol is attached | subjected to the member same as the member shown in FIG. The normal valve 11 is a general valve that is already installed in existing equipment, such as a steam control valve of a power plant. The distal end portion 13 of the valve body 12 of the normal valve 11 has a hemispherical shape with a radius R, and the portion thereof and the contracted portion 6 of the valve body 5 of the pressure pulsation suppression valve 1 have the same shape. The valve seat 4 of the normal valve 11 and the valve seat 4 of the pressure pulsation suppression valve 1 have the same shape. That is, when the normal valve 11 and the pressure pulsation suppression valve 1 are compared, the difference is that the reverse curvature portion 7 is provided on the valve body 5 of the pressure pulsation suppression valve 1 so as to extend the valve body 5 downstream. .
中間開度、例えば弁から流出する流体の圧力と弁に流入する流体の圧力の比（以下、流出／流入圧力比という）が約０．５以下の超音速流が発生する条件状態では、通常弁１１については、図２に矢印で示すように、弁体１２に沿う流れが弁体１２に近い位置で大きな角度で衝突するように合流する。この位置での合流は、流れの向きが大きく異なるもの同士の合流であるため激しい衝突となり、圧力脈動を発生させる。これに対し、本発明の圧力脈動抑制弁１では逆曲率部７が逆曲率を付けた形状となっているので、弁体５に沿う流体の流れの向きを効果的に変化させ、衝突するような合流を防止することができるので、圧力脈動の発生を効果的に抑制することができる。このため、圧力脈動による圧力感知センサの誤動作や、騒音、振動をより効果的に抑制することができる。 In a condition where a supersonic flow with an intermediate opening, for example, a ratio of the pressure of the fluid flowing out from the valve to the pressure of the fluid flowing into the valve (hereinafter referred to as the outflow / inflow pressure ratio) is about 0.5 or less, As shown by the arrow in FIG. 2, the valve 11 merges so that the flow along the valve body 12 collides at a large angle at a position close to the valve body 12. The merging at this position is a merging between the flow directions that are significantly different from each other, resulting in a violent collision and generating pressure pulsations. On the other hand, in the pressure pulsation suppression valve 1 of the present invention, since the reverse curvature portion 7 has a shape with a reverse curvature, the direction of the fluid flow along the valve body 5 is effectively changed to collide. Therefore, the occurrence of pressure pulsation can be effectively suppressed. For this reason, malfunction, noise, and vibration of the pressure detection sensor due to pressure pulsation can be more effectively suppressed.
圧力脈動抑制弁１は、シート位置１０を縮流部６に設けており、また、全閉状態から全開状態までの全開度において、流体通路２の流路面積が最も狭くなるのは縮流部６と弁座４との間であり、逆曲率部７と弁座４との間で流体通路２の流路面積が最も狭くならない。これらのため、圧力脈動抑制弁１の弁体５のリフト量と流体の流量の関係は、通常弁１１の弁体１２のリフト量と流体の流量と関係と同じになり、同じ弁開度で同じ出力を得ることができる。したがって、同じ運転方法で設備やプラントの運転を行うことができる。 The pressure pulsation suppression valve 1 is provided with the seat position 10 in the contracted portion 6, and the flow path area of the fluid passage 2 is the smallest at the full opening from the fully closed state to the fully opened state. 6 and the valve seat 4, and the flow path area of the fluid passage 2 is not the smallest between the reverse curvature portion 7 and the valve seat 4. Therefore, the relationship between the lift amount of the valve body 5 of the pressure pulsation suppression valve 1 and the flow rate of the fluid is the same as the relationship between the lift amount of the valve body 12 of the normal valve 11 and the flow rate of the fluid, and the same valve opening degree. The same output can be obtained. Therefore, it is possible to operate the facility and the plant with the same operation method.
圧力脈動抑制弁１では、弁体５に沿う流れを弁体５の形状によって制御している。すなわち、弁座４の形状によらずに、逆曲率部７の形状によって弁体５に沿う流れを流体通路２の壁面３に沿う方向又は弁体５から十分離れた位置で小さな角度で合流する方向に向けている。このため、既存設備に設置されている弁を、本発明の圧力脈動抑制弁１に交換する場合、弁座４の交換を行う必要がなく、弁体５の交換を行えば足りる。このため、弁座４購入費用や、弁座４を交換するための配管工事費用が不要になり、また、交換作業自体も簡単なものとなるので、交換に要するコストが安く済む。 In the pressure pulsation suppression valve 1, the flow along the valve body 5 is controlled by the shape of the valve body 5. That is, regardless of the shape of the valve seat 4, the flow along the valve body 5 is merged at a small angle in the direction along the wall surface 3 of the fluid passage 2 or at a position sufficiently away from the valve body 5 by the shape of the reverse curvature portion 7. It is pointing in the direction. For this reason, when replacing the valve installed in the existing equipment with the pressure pulsation suppression valve 1 of the present invention, it is not necessary to replace the valve seat 4 and it is sufficient to replace the valve body 5. For this reason, the purchase cost of the valve seat 4 and the piping work cost for exchanging the valve seat 4 become unnecessary, and the replacement work itself becomes simple, so that the cost required for the replacement can be reduced.
即ち、弁体５を交換用の弁体とする。そして、既存設備に設置されており、流体通路２の壁面３に設けられた弁座４と、弁座４に対して弁座４の軸線Ｌ３方向上流側から当接して流体通路２を閉じる弁体８とを備える弁の交換方法において、弁座４を交換することなく弁体８を上述の弁体５に交換するものである。 That is, the valve body 5 is used as a replacement valve body . The existing facilities are installed, a valve seat 4 provided on the wall surface 3 of the fluid channel 2, closes the fluid passage 2 in contact with the axial line L3 upstream side of the valve seat 4 against the valve seat 4 a valve in replacing a valve and a body 8, it is intended to replace the valve body 8 without replacing the valve seat 4 in the valve body 5 as described above.
本発明の圧力脈動抑制弁１は、例えば発電プラントの蒸気系に設けられている蒸気加減弁として使用することができる。ただし、蒸気加減弁に限るものではなく、流体通路２の壁面３に設けられた弁座４と、弁座４に対して弁座４の軸線Ｌ３方向上流側から当接して流体通路２を閉じる弁体５を有する弁に適用可能である。 The pressure pulsation suppression valve 1 of the present invention can be used, for example, as a steam control valve provided in a steam system of a power plant. However, it is not limited to the steam control valve, and the valve seat 4 provided on the wall surface 3 of the fluid passage 2 is brought into contact with the valve seat 4 from the upstream side in the direction of the axis L3 of the valve seat 4 to close the fluid passage 2. The present invention can be applied to a valve having the valve body 5.
また、流体の種類は特に制限されるものではなく、蒸気、ガス、空気など、気体、液体のいずれの流体でも適用可能である。 In addition, the type of fluid is not particularly limited, and any fluid such as vapor, gas, air, and the like can be applied.
なお、上述の形態は本発明の好適な形態の一例ではあるがこれに限定されるものではなく本発明の要旨を逸脱しない範囲において種々変形実施可能である。例えば上述の説明では、中間開度で発生する圧力脈動を例にしていたが、中間開度で発生する圧力脈動に限るものではない。つまり、蒸気加減弁とは違う弁において中間開度以外の開度で同じ原理の圧力脈動が発生する場合にも適用できる。 The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above description, the pressure pulsation generated at the intermediate opening is taken as an example, but the pressure pulsation generated at the intermediate opening is not limited. That is, the present invention can also be applied to a case where pressure pulsation of the same principle occurs at an opening other than the intermediate opening in a valve different from the steam control valve.
また、上述の説明では、縮流部６の周面の縦断面形状を半径が一定（半径Ｒ）の曲線としたが、半径が変化する曲線としても良い。また、上述の説明では、縮流部６の周面の縦断面形状を中心位置が一定（Ｏ点）の曲線としていたが、中心位置が変化する曲線としても良い。 In the above description, the longitudinal cross-sectional shape of the peripheral surface of the contracted portion 6 is a curve with a constant radius (radius R), but may be a curve with a changing radius. In the above description, the longitudinal cross-sectional shape of the peripheral surface of the contracted portion 6 is a curve with a constant center position (point O), but may be a curve with the center position changing.
また、上述の説明では、逆曲率部７の周面の縦断面形状を半径が一定（半径Ｒ１）の曲線としたが、半径が変化する曲線としても良い。また、上述の説明では、逆曲率部７の周面の縦断面形状を中心位置が一定（Ｏ１点）の曲線としていたが、中心位置が変化する曲線としても良い。 In the above description, the longitudinal cross-sectional shape of the peripheral surface of the inverse curvature portion 7 is a curve with a constant radius (radius R1), but may be a curve with a changing radius. In the above description, the longitudinal cross-sectional shape of the peripheral surface of the inverse curvature portion 7 is a curve having a constant center position (O1 point), but may be a curve in which the center position changes.
また、本発明は、弁座に対して該弁座の軸線方向上流側から当接して流体通路を閉じる弁体を備える全ての弁の弁体に対して適用可能であり、例えば図２０や図２１に示す弁のように、弁体と弁棒とを別々に形成して連結したタイプの弁についても適用可能である。 Further, the present invention can be applied to the valve bodies of all valves including a valve body that contacts the valve seat from the upstream side in the axial direction of the valve seat and closes the fluid passage. Like the valve shown in FIG. 21, it is applicable also to the type of valve which formed and connected the valve body and the valve stem separately.
（１）発電プラント等の蒸気系の蒸気加減弁（図３）の中間開度での流体振動現象に関して、弁体周りの流れ場を高精度かつ安定に計算することができるＣＦＤコードＭＡＴＩＳ（Multi-Dimensional Accurately Time Integration Simulation）を使用して計算を行い、流体として空気を用いた弁体模擬実験を実施した。弁体の振動を考慮しない条件では、弁が中間開度の時に、弁体に流れが付着（弁体付着流、図４）し、それによって局所的なスパイク状の圧力脈動が発生して（図５）、それが配管の周方向に回転して弁に大きな変動力を与えることが新たに判明し、これが弁体の中間開度時に弁体・配管に生じる振動の原因の１つである事が分かった。 (1) CFD code MATIS (Multi) which can calculate the flow field around the valve body with high accuracy and stability with respect to the fluid vibration phenomenon at the intermediate opening of the steam control valve (Fig. 3) of the steam system of a power plant, etc. -Dimensional Accurately Time Integration Simulation) was used to perform valve body simulation experiments using air as the fluid. Under conditions that do not consider the vibration of the valve body, when the valve is at an intermediate opening, the flow adheres to the valve body (the valve body attached flow, Fig. 4), thereby generating a local spike-like pressure pulsation ( 5), it was newly found that it rotates in the circumferential direction of the pipe and gives a large fluctuating force to the valve. This is one of the causes of the vibration generated in the valve body / pipe when the valve body is at an intermediate opening degree. I understood that.
次に、これらの圧力脈動の抑制方法について検討した。中間開度における圧力脈動は、弁体付着流の発生が周期的な圧力脈動を引き起こす原因であり、流れを弁座に付着させるか、付着せずに噴流の状態で下流へと流れていけば、弁体付着流が発生しないので、この変動を抑制できるといえる。そこで、幾つかの弁体・弁座の形状を用いて、中間開度時に弁体・弁座の形状が流れ場に与える影響を実験的に調べ、流れ場の乱れが少ない最適な弁体形状の提案を試みた。 Next, the suppression method of these pressure pulsations was examined. Pressure pulsation at an intermediate opening is the cause of the occurrence of periodic pressure pulsation due to the valve body adhering flow, and if the flow adheres to the valve seat or flows downstream in the jet state without adhering In addition, it can be said that this fluctuation can be suppressed because the valve body attached flow does not occur. Therefore, by using several valve body / valve seat shapes, we experimentally investigated the effect of the valve body / valve seat shape on the flow field at the intermediate opening, and the optimal valve body shape with less disturbance of the flow field I tried to propose.
前述の通り、スパイク状の圧力脈動は、弁体に付着する流れ（弁体付着流）が原因である事が分かっている。流体が物体に沿って流れようとする効果（コアンダ効果）は、曲率半径の大きな方が大きくなるという事から考えると、弁座の曲率半径が弁体の曲率半径より大きい（弁体半径＜弁座半径）と、流れが弁座側に沿いやすくなり、弁体付着流が発生しにくくなるといえる。 As described above, it is known that the spike-like pressure pulsation is caused by the flow adhering to the valve body (valve body adhering flow). Considering that the effect of the fluid flowing along the object (Coanda effect) is larger when the curvature radius is larger, the curvature radius of the valve seat is larger than the curvature radius of the valve body (valve body radius <valve It can be said that the flow becomes easier to follow along the valve seat side and the valve body attached flow is less likely to occur.
まず、弁座の曲率半径変化の影響を見るために、弁座の曲率半径（即ち弁体と弁座の曲率半径比）をパラメータとして実験を行い、弁座形状のみを変化させた場合の流れ場に与える影響を調べた。次に、弁体そのものの形状を変更させ、積極的に弁体付着流を抑制した場合の効果を見るために、半球状の弁体の他に２種類の弁体を用意して幾つかの弁座形状で実験を行い、流れ場の変動の様子を調べた。その後、上述の実験結果から、スパイク状の圧力脈動を最も抑制できる形状を提案する事とした。 First, in order to see the effect of the change in the radius of curvature of the valve seat, an experiment was conducted using the radius of curvature of the valve seat (that is, the ratio of the radius of curvature of the valve body and the valve seat) as a parameter, and the flow when only the valve seat shape was changed The effect on the field was investigated. Next, in order to see the effect when the shape of the valve body itself is changed and the valve body attachment flow is actively suppressed, two types of valve bodies are prepared in addition to the hemispherical valve body. Experiments were carried out on the valve seat shape, and the behavior of the flow field was investigated. After that, from the above experimental results, a shape that can most suppress spike-like pressure pulsations was proposed.
（２）実機との対比
実際のプラントにおける主蒸気加減弁は直径数十ｃｍで、流体も蒸気が用いられており、本実験とはスケール・作動流体が異なる（弁体径φ６０、流体：空気）。また、圧力も実機では約７ＭＰａ、本実験は最大０．５ＭＰａで異なり、弁形状も実験では実機の形状よりも単純化されている。そのため、実機における流れの状態を完全に再現する事は出来ないが、流れ場を支配するパラメータを実機に近づけ基本的な流れ場を模擬する事で、実機に起こりうる不安定現象を把握する事は可能であると言える。
(2) Comparison with the actual machine The main steam control valve in the actual plant has a diameter of several tens of centimeters and the fluid is steam, and the scale and working fluid are different from this experiment (valve body diameter φ60, fluid: air ). In addition, the pressure is about 7 MPa in the actual machine, and the maximum in this experiment is 0.5 MPa, and the valve shape is simplified in comparison with the actual machine. For this reason, the flow state in the actual machine cannot be completely reproduced, but the instability phenomenon that can occur in the actual machine can be grasped by simulating the basic flow field by bringing the parameters governing the flow field closer to the actual machine. Can be said to be possible.
本実験で着目する現象は、超音速領域における流れ場の変動現象であるため、流入速度は流入圧力の大きさで決まるのではなく、流入圧力と流出圧力の比で決定される。更に、スロート部分で流れ場はチョークするので流量はスロート部分断面積で一意的に決定される。つまり、流入流量は弁体の開度によって決まる事となる。以上より、作動流体の違いを除くと、流れ場に最も影響を与えるパラメータは、流入圧力と流出圧力の比と弁体の開度であると考えられるため、これらの量を実機と合わせる事で、実機で起こりうる不安定現象を把握する事は可能であると考えられる。 Since the phenomenon focused on in this experiment is a fluctuation phenomenon of the flow field in the supersonic region, the inflow speed is not determined by the magnitude of the inflow pressure, but is determined by the ratio of the inflow pressure to the outflow pressure. Further, since the flow field chokes at the throat portion, the flow rate is uniquely determined by the throat partial cross-sectional area. That is, the inflow flow rate is determined by the opening degree of the valve body. From the above, except for the difference in working fluid, the parameters that have the most influence on the flow field are thought to be the ratio of the inflow pressure to the outflow pressure and the opening of the valve body. It is considered possible to grasp the unstable phenomenon that can occur in actual machines.
実際、実機での各出力の流れ場条件は、弁体の開度を弁体シート径（弁中心から弁体と弁座が接触する位置（シート位置）までの距離）で割ったリフト比と流出／流入圧力比によって表され、これらの量をパラメータとして実機と整合を取る事は妥当であると言える。 Actually, the flow field condition of each output in the actual machine is the lift ratio obtained by dividing the opening of the valve body by the valve body seat diameter (the distance from the valve center to the position where the valve body and the valve seat contact (seat position)). Expressed by the outflow / inflow pressure ratio, it can be said that it is appropriate to match these quantities with the actual equipment as parameters.
スケールの違いによる影響に関しては、下流配管位置での流量と配管径を基にしたレイノルズ数が、実機も本研究のスケールも１０５以上であること、スパイク状の圧力脈動は弁体に流れが付着して生じる現象で、乱流が原因で生じる流動現象ではない事から考えて、弁体周辺の流れ場に与えるスケール（レイノルズ数）の影響はそこまで大きくないといえる。 For the influence due to difference in scale, the Reynolds number was based on the flow rate and the pipe diameter of downstream pipe position, it actual is also even 10 5 or more scales of the present study, a spike-shaped pressure pulsation flows into the valve body Considering that this phenomenon is caused by adhesion and not a flow phenomenon caused by turbulent flow, it can be said that the influence of the scale (Reynolds number) on the flow field around the valve element is not so large.
また、流体の違いによる影響であるが、空気と比べると蒸気は密度・音速などが異なる他、比熱などが温度・圧力などに大きく依存する、超音速状態の蒸気の急激な凝縮（凝縮衝撃波）による圧力の上昇が生じる、などがあるが、スパイク状の圧力脈動は流体自身の変動によって発生している現象であるため、発生領域などが若干異なる事はあっても流体に蒸気を用いた際にも発生する事は十分に考えられる。つまり、基本的な現象の把握をするために空気を用いる事は妥当であるといえる。 In addition, due to the difference in fluids, the density and sound speed of steam differs from that of air, and the rapid condensation of supersonic steam (condensation shock wave), in which specific heat greatly depends on temperature and pressure, etc. However, since the spike-like pressure pulsation is a phenomenon that occurs due to fluctuations in the fluid itself, even when the generation area is slightly different, when steam is used for the fluid It is quite possible that this will occur. In other words, it is reasonable to use air to understand basic phenomena.
以上より、リフト比と流出／流入圧力比を実機と合わせることで、基礎的な現象の把握としての空気によるスケール実験実施の妥当性は十分にあると言える。 From the above, it can be said that by combining the lift ratio and the outflow / inflow pressure ratio with the actual machine, the validity of the scale experiment using air as a grasp of the basic phenomenon is sufficient.
（３）中間開度における圧力脈動現象の抑制−弁座形状の影響−
弁座形状を変化させた時の流れ場の変化について述べる。なお、中間開度の時に弁体に生じる圧力脈動を表１に示す。
(3) Suppression of pressure pulsation phenomenon at intermediate opening -Influence of valve seat shape-
The change of the flow field when the valve seat shape is changed is described. Table 1 shows pressure pulsations generated in the valve body at the intermediate opening.
図６に実験装置の概略図（図６（ａ））及びテストセクションの拡大図（図６（ｂ））を示す。蒸気加減弁を模擬した弁体・弁座を有するテストセクションに高圧の空気を送り込んで、外部へと放出される。また、弁体と弁座がちょうど接した部分を起点とし、そこから弁を開く方向に動かした距離をリフト量と定義する。
図７に弁体（図７（ａ）〜（ｃ））及び弁座（図７（ｄ）〜（ｅ））の拡大図を示す。本実験では、弁体の形状は半径３０ｍｍの半球形状の弁体を用いた。中心から３０°の位置（半径１５ｍｍの位置）に周方向に９０°間隔で４カ所の圧力測定用の孔を設けており、そのそれぞれをＡ１〜Ａ４と呼ぶことにする。弁座は弁体と接する部分が、内側に凸の球面形状であり、曲面が終わる直下流部分に、弁体と同じ位置になるよう４カ所の静圧測定孔を設けている。そのそれぞれをＢ１〜Ｂ４と呼ぶことにする。 FIG. 7 shows an enlarged view of the valve body (FIGS. 7A to 7C) and the valve seat (FIGS. 7D to 7E). In this experiment, a valve body having a hemispherical shape with a radius of 30 mm was used. Four pressure measurement holes are provided at 90 ° intervals in the circumferential direction at 30 ° positions (positions with a radius of 15 mm) from the center, and each of these holes is referred to as A 1 to A 4 . The valve seat has a spherical shape that protrudes inward at the portion in contact with the valve body, and is provided with four static pressure measurement holes at the same downstream position as the valve body at the end immediately downstream of the curved surface. Each of these will be referred to as B 1 to B 4 .
図８（ａ）〜（ｄ）に実験を行った弁座の形状を示す。弁座部の半径はｒ＝２１、３０、３９、９０ｍｍとなっており、弁座／弁体半径比はそれぞれ０．７、１．０、１．３、３．０となっている（シート径はそれぞれ４９．２、５０．８、５２．０、５５．４ｍｍ）。前述のように、スパイク状の圧力脈動は、弁体に付着する流れ（弁体付着流）が原因である事が分かったので、物体に沿って流れようとする効果（コアンダ効果）は、曲率半径のより大きな弁座ほど弁体付着流が抑制される事が予想される。パラメータとして、流入圧力を０．２５、０．３、０．４、０．５ＭＰａ（流出／流入圧力比０．４０、０．３３、０．２５、０．２０）と変化させ、そのそれぞれの流入圧力において、小〜中間開度にあたるリフト比領域で、リフト量を変えて何点か計測を実施した。表２に実験の主な条件をまとめておく。なお、今回対象としているのは、流れ場がチョークして超音速流となる弁体の小〜中間開度時であるため、実験もチョーク状態となる小〜中間開度時のリフト比の範囲で実施した。
（３．２）実験結果
図９（ａ）〜（ｄ）は、リフト量と流入圧力を軸として流れ場の状況を記した特性マップである。図中の×は流れ場にスパイク状の圧力脈動が発生しなかった条件、図中●は弁体部分にスパイク状の圧力脈動が発生した条件、図中○は弁座部分にスパイク状の圧力脈動が発生した条件である。また、記号の大きさは、変動の大きさを表している。変動の発生の有無は、測定した圧力の平均値と標準偏差σを求め、測定の平均値よりも３σ以上離れている値が、測定結果から判断して１．５％以上あるものを、変動が発生している条件とした。なお、弁座半径９０ｍｍ（弁座／弁体半径比３．０）の時は、リフト量を０ｍｍから増加させて実験した時はスパイク状の変動が発生し、大開度から減少させて実験した時は安定した流れ場になるというヒステリシスが見られたので、保守側の結果としてスパイク状の圧力脈動が発生した時の値を採用した。図から、今回実験を行った全ての弁座の形状において、特定のリフト量の領域でスパイク状の圧力脈動が発生し、流入圧力が小さいほど変動が発生するリフト量の領域が広く、その圧力脈動の大きさが小さくなっていることが分かる。また、全ての流入圧力条件において、圧力脈動が発生している時、変動の発生位置がリフト量の増加と共に弁体部分から弁座部分へと移行しており、圧力脈動の位置がリフト量の増加と共に配管壁面側に移動しているという事がここからも分かる。弁座形状の変化の影響を見てみると、弁座半径が２１〜３９ｍｍ（弁座／弁体半径比０．７〜１．３）の範囲では流れ場の状態に殆ど変化は見られない。弁座半径を９０ｍｍ（弁座／弁体半径比３．０）まで大きくすることで、ようやくスパイク状の圧力脈動が発生する領域が狭くなり、その大きさも小さくなったが、完全にスパイク状の圧力脈動を抑制する事は出来なかった。
(3.2) Experimental Results FIGS. 9A to 9D are characteristic maps describing the flow field conditions with the lift amount and the inflow pressure as axes. X in the figure indicates the condition in which spike-like pressure pulsation did not occur in the flow field, ● in the figure indicates the condition in which spike-like pressure pulsation occurred in the valve body, and ○ in the figure indicates spike-like pressure in the valve seat part This is a condition where pulsation has occurred. The size of the symbol represents the magnitude of fluctuation. For the presence or absence of fluctuation, the average value of measured pressure and the standard deviation σ are obtained, and the value that is 3σ or more away from the measured average value is 1.5% or more as judged from the measurement result. It was set as the conditions which generate | occur | produced. When the valve seat radius was 90 mm (valve seat / valve body radius ratio 3.0), when experimenting with the lift amount increased from 0 mm, spike-like fluctuations occurred and the experiment was performed with a decrease from a large opening. Since there was a hysteresis that the flow field was stable at time, the value when spike pressure pulsation occurred as a result of the maintenance side was adopted. From the figure, in all valve seat shapes tested this time, spike-like pressure pulsations occur in a specific lift amount region, and the lower the inflow pressure, the wider the lift amount region, and the pressure It turns out that the magnitude | size of a pulsation is small. In all inflow pressure conditions, when pressure pulsation occurs, the position of the fluctuation shifts from the valve body part to the valve seat part as the lift amount increases, and the position of the pressure pulsation is the lift amount. It can also be seen from here that the pipe moves to the pipe wall surface side with the increase. Looking at the influence of the change in the valve seat shape, there is almost no change in the state of the flow field when the valve seat radius is 21 to 39 mm (valve seat / valve body radius ratio 0.7 to 1.3). . By increasing the valve seat radius to 90 mm (valve seat / valve body radius ratio 3.0), the area where spike-like pressure pulsation is generated is finally narrowed and its size is reduced. Pressure pulsation could not be suppressed.
図９のように、リフト量を横軸に取ると、圧力脈動の発生する領域が流入圧力に大きく依存しているため、リフト量から算出した質量流量を横軸として特性マップを描き直した。その図を図１０に示す。図から、スパイク状の圧力脈動の発生する質量流量の領域は流入圧力にあまり依存せず、各弁座で領域の大小はあるものの、特定の質量流量領域でスパイク状の変動が発生している事が分かる。つまり、半球形状の弁体では、今回実験を行った全ての弁座でスパイク状の変動が発生するといえる。 As shown in FIG. 9, when the lift amount is taken on the horizontal axis, the region where pressure pulsation occurs greatly depends on the inflow pressure. Therefore, the characteristic map is redrawn with the mass flow rate calculated from the lift amount as the horizontal axis. The figure is shown in FIG. From the figure, the mass flow region where spike-like pressure pulsation occurs does not depend much on the inflow pressure, and although there is a size of each region in each valve seat, spike-like fluctuations occur in a specific mass flow region I understand that. In other words, in the hemispherical valve body, it can be said that spike-like fluctuations occur in all the valve seats tested this time.
図１１は、横軸を質量流量とした時の、弁体壁面静圧（Ａ１〜Ａ４）、及び弁座壁面静圧（Ｂ１〜Ｂ４）のＲ．Ｍ．Ｓ．振幅（二乗平均振幅）をプロットしたものである。弁体（Ａ１〜Ａ４）の圧力脈動を見てみると、弁座半径９０ｍｍ（弁座／弁体半径比３．０）以外の弁座形状では、０．１ｋｇ／ｓ付近で圧力脈動のピークを持ち、その後、なだらかに減衰している。また、弁座側の圧力脈動（Ｂ１〜Ｂ４）を見ると、０．２ｋｇ／ｓ近傍でピークを持っている。つまり、流量の増加と共に、圧力脈動のピークが弁体側から弁座側へと移動していると考えられる。これは、図１０と同様の結果となっており、Ｒ．Ｍ．Ｓ．振幅のピークはスパイク状の圧力脈動が原因であると考えられる。弁座半径９０ｍｍ（弁座／弁体半径比３．０）では、スパイク状の圧力脈動が発生しない流入圧力０．２５ＭＰａの時は、Ｒ．Ｍ．Ｓ．振幅は全域において小さな値であり、その他の流入圧力でも若干の振幅の盛り上がりはあるものの、他の弁座に比べるとＲ．Ｍ．Ｓ．振幅は小さくなっており、スパイク状の圧力脈動の発生領域も狭くなっているといえる。以上より、弁座半径を大きく変化させる事でスパイク状の発生領域は狭くなり、また、その振幅も小さくなる事が判明したが、今回実施した弁座半径では、スパイク状の圧力脈動を完全に抑制できる事は出来なかった。言い換えると、半球状の弁体形状では、弁座／弁体半径比を３．０にまで大きくしてもスパイク状の圧力脈動を抑制できないため、極端に弁体形状を変更できない場合には新たな弁体形状を提案する必要があると言える。 11 shows valve body wall surface static pressure (A 1 to A 4 ) and valve seat wall surface static pressure (B 1 to B 4 ) R.D. M.M. S. Amplitude (root mean square amplitude) is plotted. Looking at the pressure pulsations of the valve bodies (A 1 to A 4 ), the pressure pulsation is around 0.1 kg / s for valve seat shapes other than the valve seat radius 90 mm (valve seat / valve body radius ratio 3.0). It has a peak of, and after that, it is gradually attenuated. Further, when the pressure pulsation (B 1 to B 4 ) on the valve seat side is seen, it has a peak in the vicinity of 0.2 kg / s. That is, it is considered that the peak of the pressure pulsation moves from the valve body side to the valve seat side as the flow rate increases. This is the same result as in FIG. M.M. S. The peak of the amplitude is considered to be caused by spike-like pressure pulsation. When the valve seat radius is 90 mm (valve seat / valve body radius ratio: 3.0) and the inflow pressure is 0.25 MPa at which spike-like pressure pulsation does not occur, R.P. M.M. S. The amplitude is a small value in the entire region, and although there is a slight increase in the amplitude even at other inflow pressures, the R.R. M.M. S. It can be said that the amplitude is small and the region where the spike-like pressure pulsation is generated is narrow. From the above, it has been found that the spike-like generation area becomes narrower and the amplitude becomes smaller when the valve seat radius is greatly changed, but with the valve seat radius that was implemented this time, the spike-like pressure pulsation was completely eliminated. I couldn't suppress it. In other words, with the hemispherical valve body shape, spike pressure pulsation cannot be suppressed even if the valve seat / valve body radius ratio is increased to 3.0. It can be said that it is necessary to propose an appropriate valve body shape.
（４）中間開度における圧力脈動現象の抑制−弁体形状の影響−
弁体形状を変化させた時の流れ場の変化について述べる。
(4) Suppression of pressure pulsation phenomenon at intermediate opening-Influence of valve body shape-
The change of the flow field when the valve body shape is changed will be described.
（４．１）実験の概要・条件
図１２（ａ）〜（ｂ）に、実験を実施した弁体形状の概略図を示す。弁体は、半球状の弁体形状（通常弁、normal valve）の他に、通常弁と同形状で４５°の位置で切り落とした切断弁（cut valve）、４５°の位置まで通常弁と同形状でその後の部分を半径１８．４ｍｍで逆に曲率半径を付けた延長弁（extendedvalve）の３種類である。前記（１）で述べたように、弁体形状を変更する事で積極的に弁体付着流を抑制する事を目的としているので、
（ａ）弁体に流れが沿う事のないようにする（切断弁、cut valve）
（ｂ）弁体に流れが沿ったとしても、弁体通過後の流れが衝突することなく下流へと流れていく（延長弁、extended valve）
という考え方で２形状を決めた。ただし、シート径は通常弁と同じであり、リフト量に対して流れる質量流量は３形状とも同じである。また、弁座の形状に関しては、弁座／弁体半径比が最も小さな弁座（弁座半径＝２１ｍｍ、弁座／弁体半径比＝０．７）形状と、最も弁座／弁体半径比が大きな弁座半径９０ｍｍ（弁座／弁体半径比＝３．０）の２種類で実験を実施した。新形状弁はその形状から弁体部に静圧孔を設けても乱れの少ない超音速領域しか測定できないため、以降の結果で示される圧力脈動は全て弁座壁面側（Ｂ１〜Ｂ４）の値である。
(4.1) Outline and Conditions of Experiment FIGS. 12A to 12B are schematic views of the shape of the valve body in which the experiment was performed. In addition to the hemispherical valve body shape (normal valve, normal valve), the valve body has the same shape as the normal valve, but is a cut valve cut off at a 45 ° position. There are three types of extended valves (extendedvalve) that have a shape with a radius of 18.4 mm and a radius of curvature. As stated in the above (1), because the purpose is to positively suppress the valve body attached flow by changing the valve body shape,
(A) Ensure that the flow does not follow the valve body (cut valve)
(B) Even if the flow follows the valve body, the flow after passing through the valve body flows downstream without colliding (extended valve).
Two shapes were decided based on this idea. However, the seat diameter is the same as that of the normal valve, and the mass flow rate flowing with respect to the lift amount is the same for all three shapes. As for the shape of the valve seat, the valve seat / valve body radius ratio has the smallest valve seat (valve seat radius = 21 mm, valve seat / valve body radius ratio = 0.7) shape and the most valve seat / valve body radius. The experiment was conducted with two types of valve seat radii having a large ratio of 90 mm (valve seat / valve body radius ratio = 3.0). Since the new shape valve can measure only the supersonic region with little disturbance even if a static pressure hole is provided in the valve body part from the shape, all pressure pulsations shown in the subsequent results are on the valve seat wall surface side (B 1 to B 4 ). Is the value of
（４．２）実験結果−弁座半径２１ｍｍ（弁座／弁体半径比＝０．７）−
図１３（ａ）〜（ｃ）は質量流量と流入圧力を軸として流れ場の状況を記した特性マップである。図中の×は流れ場にスパイク状の圧力脈動が発生しなかった条件、図中○は弁座部分にスパイク状の圧力脈動が発生した条件である（弁体部には静圧孔を設けていないため、弁体部に変動が発生した条件は考慮していない）。また、記号の大きさは、変動の大きさを表している。図から、切断弁の変動発生領域は、弁座半径が２１ｍｍ（弁座／弁体半径比０．７）の弁座での実験では、通常弁でスパイク状の圧力脈動が発生している領域と殆ど変化が無く、その変動の大きさにもあまり差がない。一方、延長弁では測定した全域においてスパイク状の圧力脈動は発生しておらず、安定した流れ場を形成している。
(4.2) Experimental results-valve seat radius 21 mm (valve seat / valve radius ratio = 0.7)-
FIGS. 13A to 13C are characteristic maps describing the flow field with the mass flow rate and the inflow pressure as axes. X in the figure is the condition in which spike-like pressure pulsation did not occur in the flow field, and ○ in the figure is the condition in which spike-like pressure pulsation occurred in the valve seat (the valve body was provided with a static pressure hole) Therefore, the conditions for fluctuations in the valve body are not taken into account). The size of the symbol represents the magnitude of fluctuation. From the figure, the variation generation region of the cutting valve is a region where spike pressure pulsation is generated in the normal valve in the experiment with the valve seat having a valve seat radius of 21 mm (valve seat / valve body radius ratio 0.7). There is almost no change, and there is not much difference in the magnitude of the fluctuation. On the other hand, in the extension valve, spike-like pressure pulsation does not occur in the entire measured area, and a stable flow field is formed.
図１４は、それぞれの弁体の圧力のＲ．Ｍ．Ｓ．振幅である。先述のように、切断弁は弁座半径が小さいと通常弁と殆ど変わらない流れ場の特性を示すため、Ｒ．Ｍ．Ｓ．振幅も通常弁と殆ど変わらないことがこの図からも分かる。また、延長弁に関しては流れ場に大きな圧力脈動が発生しないために小さな振幅となっている事が分かる。 FIG. 14 shows the R.D. M.M. S. Amplitude. As described above, since the cutting valve exhibits a flow field characteristic that is almost the same as that of a normal valve when the valve seat radius is small, R.C. M.M. S. It can also be seen from this figure that the amplitude is almost the same as that of the normal valve. It can also be seen that the extension valve has a small amplitude because no large pressure pulsation occurs in the flow field.
この状態の流れ場を確認するために、流入圧力０．５ＭＰａ、リフト量１．６ｍｍの条件（通常弁でスパイク状の圧力脈動が発生する条件）において、３次元流体解析コードＭＡＴＩＳで切断弁・延長弁の流れ場を計算した。その時の計算格子を図１５に、マッハ数等高線と静圧の分布を図１６に示す。図から、切断弁では、弁体を通過した流れが噴流となって互いに衝突している様子が分かる。また、それによって流れが偏って局所的な高圧が発生している。一方、延長弁では流れが強制的に弁座に付着させられており、噴流同士の衝突が起きていないため、大きな圧力脈動が生じていない。これらの理由として、弁体先端を切り取って弁体付着流を作らない切断弁でも、弁座側の曲率半径が弁体側より小さい、つまり弁座半径＜弁体半径の時には流れが配管中心方向に向かってしまい、弁体通過後の噴流が下流へとスムーズに流れずに、噴流同士が衝突して圧力脈動が生じてしまう。一方、流れを強制的に弁座側へと沿わせる延長弁では、弁体通過後の噴流同士を衝突させる事はないので圧力脈動が生じない、という事が考えられる。また、延長弁に関しては流れ場に大きな圧力脈動が発生しないために小さな振幅となっている事が分かる。 In order to confirm the flow field in this state, under the conditions of an inflow pressure of 0.5 MPa and a lift amount of 1.6 mm (conditions in which spike-like pressure pulsation is generated with a normal valve), the three-dimensional fluid analysis code MATIS The flow field of the extension valve was calculated. FIG. 15 shows the calculation lattice at that time, and FIG. 16 shows the distribution of Mach number contours and static pressure. From the figure, it can be seen that in the cutting valve, the flow passing through the valve body becomes a jet and collides with each other. In addition, the flow is uneven and local high pressure is generated. On the other hand, in the extension valve, the flow is forcibly adhered to the valve seat, and no collision between the jets occurs, so that a large pressure pulsation does not occur. For these reasons, even with a cutting valve that cuts off the tip of the valve body and does not create a valve body attached flow, the curvature radius on the valve seat side is smaller than that on the valve body side. The jet flow after passing through the valve body does not flow smoothly downstream, but the jet flows collide with each other and pressure pulsation occurs. On the other hand, in the extension valve that forces the flow to the valve seat side, the jet pulsations after passing through the valve body do not collide with each other, so that pressure pulsation does not occur. It can also be seen that the extension valve has a small amplitude because no large pressure pulsation occurs in the flow field.
以上より、弁座半径が２１ｍｍ（弁座／弁体半径比０．７）の時は、切断弁では流れが弁座側に沿いにくい為に弁体通過後の噴流が互いに衝突して通常弁と変わらない流れ場の傾向となり、延長弁では強制的に弁座付着流を形成するために流れ場に大きな圧力脈動が発生しない事が判明した。また、大きな圧力脈動が発生しない延長弁の流れ場では、スパイク状の圧力脈動が発生する通常弁や切断弁と比べるとその振幅がかなり小さくなる事も判明した。 From the above, when the valve seat radius is 21 mm (valve seat / valve body radius ratio 0.7), since the flow is difficult to follow along the valve seat side with the cutting valve, the jets after passing through the valve body collide with each other and the normal valve However, it was found that the extension valve forcibly forms a valve-attached flow, so that no large pressure pulsation occurs in the flow field. It has also been found that the amplitude of the flow field of the extension valve, in which no large pressure pulsation occurs, is considerably smaller than that of a normal valve or a cutting valve in which spike-like pressure pulsation occurs.
（４．３）実験結果−弁座半径９０ｍｍ（弁座／弁体半径比＝３．０）−
図１７（ａ）〜（ｃ）は質量流量と流入圧力を軸として流れ場の状況を記した特性マップである。図中の×は流れ場にスパイク状の圧力脈動が発生しなかった条件、図中○は弁座部分にスパイク状の圧力脈動が発生した条件である（弁体部には静圧孔を設けていないため、弁体部に変動が発生した条件は考慮していない）。また、記号の大きさは、変動の大きさを表している。図から、切断弁・延長弁ともに実験の範囲全域でスパイク状の圧力脈動は発生しておらず、安定した流れ場を形成している事が分かる。
(4.3) Experimental results-valve seat radius 90 mm (valve seat / valve body radius ratio = 3.0)-
FIGS. 17A to 17C are characteristic maps describing the flow field with the mass flow rate and the inflow pressure as axes. X in the figure is the condition in which spike-like pressure pulsation did not occur in the flow field, and ○ in the figure is the condition in which spike-like pressure pulsation occurred in the valve seat (the valve body is provided with a static pressure hole) Therefore, the conditions for fluctuations in the valve body are not taken into account). The size of the symbol represents the magnitude of fluctuation. From the figure, it can be seen that there is no spike-like pressure pulsation in the entire range of the experiment for both the cutting valve and the extension valve, and a stable flow field is formed.
図１８は、各弁体の圧力のＲ．Ｍ．Ｓ．振幅である。通常弁では、前述の通り弁座半径９０ｍｍの時に、リフト増加時と減少時でヒステリシスが見られたので、リフト増加時と減少時でＲ．Ｍ．Ｓ．振幅が異なっている。図から、切断弁・延長弁のＲ．Ｍ．Ｓ．振幅は、通常弁のリフト減少時、つまりスパイク状の圧力脈動が発生していない安定な流れ場の時とほぼ同じ値となっていて低い振幅となっており、切断弁・延長弁ともスパイク状の圧力脈動が発生しておらず、安定な流れ場を形成しているといえる。 18 shows the R.V. of the pressure of each valve element. M.M. S. Amplitude. In the normal valve, as described above, when the valve seat radius is 90 mm, hysteresis was observed when the lift increased and decreased. M.M. S. The amplitude is different. From the figure, R. M.M. S. The amplitude is almost the same as that when a normal valve lift is reduced, that is, when a stable flow field without spike-like pressure pulsation is generated. Therefore, it can be said that a stable flow field is formed.
この状態の流れ場を確認するために、先ほどと同様にＭＡＴＩＳコードを用いて計算を実施して流れ場の状況を確認した。その時のマッハ数等高線と静圧の分布を図１９に示す。図から分かるように、切断弁・延長弁共に弁座付着流となって噴流は衝突せずに安定した流れ場を形成している。これらから考えて、切断弁は、弁座半径が２１ｍｍ（弁座／弁体半径比＝０．７）の時には通常弁と同様の傾向であったが、弁座半径が９０ｍｍと大きくなった事で、流れが弁座側に沿いやすくなって弁座付着流となり、噴流が衝突しなくなったために安定な流れ場になったと考えられる。 In order to confirm the flow field in this state, calculation was performed using the MATIS code in the same manner as before to confirm the flow field condition. The distribution of Mach number contours and static pressure at that time is shown in FIG. As can be seen from the figure, both the cutting valve and the extension valve are attached to the valve seat, and the jet does not collide and forms a stable flow field. Considering these, the cutting valve had the same tendency as the normal valve when the valve seat radius was 21 mm (valve seat / valve body radius ratio = 0.7), but the valve seat radius was increased to 90 mm. Therefore, it is thought that the flow became easier along the valve seat side and became a valve seat attachment flow, and the jet flow no longer collided, so the flow field became stable.
以上より、弁座半径が９０ｍｍ（弁座／弁体半径比３．０）の時は、切断弁・延長弁ともに弁座付着流を形成し、スパイク状の圧力脈動が発生しない安定した流れ場となる事が判明した。 From the above, when the valve seat radius is 90 mm (valve seat / valve body radius ratio 3.0), a stable flow field in which the valve seat adhering flow is formed in both the cutting valve and the extension valve and no spike-like pressure pulsation occurs. It turned out to be.
（５）中間開度での圧力脈動に対する弁体・弁座形状の影響のまとめ
表３に弁体・弁座形状が流れ場に与える影響をまとめておく。表からも明らかなように、通常弁では弁座形状を大きく変更（弁座／弁体半径比０．７→３．０）しても、弁体付着流によるスパイク状の圧力脈動を抑制する事が出来ない。また、切断弁では弁座／弁体半径比が３．０の時には弁体付着流を抑制する事は出来たが、弁座／弁体半径比０．７の時は、通常弁とほぼ同じ領域でスパイク状の圧力脈動が発生している。しかし、長尺弁を用いることで、弁座／弁体半径比に関係なく弁体付着流を抑制でき、安定した流れ場を形成できる事が判明した。
以上から、弁の中間開度時に発生する弁体付着流によるスパイク状の圧力脈動を最も効果的に抑制できる弁形状は、流れの方向を強制的に変更させる延長弁であることが判明した。 From the above, it has been found that the valve shape that can most effectively suppress the spike-like pressure pulsation caused by the valve-attached flow generated at the intermediate opening of the valve is an extension valve that forcibly changes the flow direction.
１ 圧力脈動抑制弁
２ 流体通路
３ 流体通路の壁面
４ 弁座
５ 弁体
６ 縮流部
７ 逆曲率部
１０ シート位置（弁座に当接する部分）
Ｌ３ 弁座の軸線
DESCRIPTION OF SYMBOLS 1 Pressure pulsation suppression valve 2 Fluid passage 3 Wall surface 4 of a fluid passage
L3 Valve seat axis
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS56141257U (en) * | 1980-03-25 | 1981-10-24 | ||
| JPS56138571A (en) * | 1980-03-28 | 1981-10-29 | Toshiba Corp | Steam control valve |
| JPS60138077U (en) * | 1984-02-24 | 1985-09-12 | 石川島播磨重工業株式会社 | Main steam isolation valve for nuclear power generation |
| JPS60208684A (en) * | 1984-03-01 | 1985-10-21 | フラマトム | Method of stabilizing flow of fluid on expansion when kinetic energy simultaneously lower and valve and decompression device for executing said method |
| JPS6273165U (en) * | 1985-10-28 | 1987-05-11 | ||
| JP2001050424A (en) * | 1999-08-10 | 2001-02-23 | Mitsubishi Heavy Ind Ltd | Method of fitting and removing in oblique direction |
| JP2003090458A (en) * | 2001-09-18 | 2003-03-28 | Kurimoto Ltd | Valve device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS56141257U (en) * | 1980-03-25 | 1981-10-24 | ||
| JPS56138571A (en) * | 1980-03-28 | 1981-10-29 | Toshiba Corp | Steam control valve |
| JPS60138077U (en) * | 1984-02-24 | 1985-09-12 | 石川島播磨重工業株式会社 | Main steam isolation valve for nuclear power generation |
| JPS60208684A (en) * | 1984-03-01 | 1985-10-21 | フラマトム | Method of stabilizing flow of fluid on expansion when kinetic energy simultaneously lower and valve and decompression device for executing said method |
| JPS6273165U (en) * | 1985-10-28 | 1987-05-11 | ||
| JP2001050424A (en) * | 1999-08-10 | 2001-02-23 | Mitsubishi Heavy Ind Ltd | Method of fitting and removing in oblique direction |
| JP2003090458A (en) * | 2001-09-18 | 2003-03-28 | Kurimoto Ltd | Valve device |
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