Guide vane and fluid machine

Abstract

In a guide vane according to an embodiment of the invention, where in a section perpendicular to a guide vane rotation axis, a curvature of a contour line forming a runner side vane surface of the guide vane is referred to as a positive curvature when the contour line is formed to be convex, while the curvature of the contour line is referred to as a negative curvature when the contour line is formed to be concave, a negative curvature portion where the curvature of the contour line becomes negative is provided on the runner side vane surface. The negative curvature portion is formed from an upper end portion to a lower end portion of the runner side vane surface.

1 . A guide vane provided on an outer circumferential side of a runner of a fluid machine to control a flow rate of water into the runner by rotating about a guide vane rotation axis,
 wherein, where in a section perpendicular to the guide vane rotation axis, a curvature of a contour line forming a runner side vane surface of the guide vane is referred to as a positive curvature when the contour line is formed to be convex, while the curvature of the contour line forming the runner side vane surface of the guide vane is referred to as a negative curvature when the contour line is formed to be concave, a negative curvature portion where the curvature of the contour line becomes negative is provided on the runner side vane surface, and   wherein the negative curvature portion is formed from an upper end portion to a lower end portion of the runner side vane surface.   
     
     
         2 . The guide vane according to  claim 1 ,
 wherein an inlet non-negative curvature portion where the curvature of the contour line becomes positive or zero is provided at a portion lying closer to an inlet end than the negative curvature portion, and   wherein an outlet non-negative curvature portion where the curvature of the contour line becomes positive or zero is provided at a portion lying closer to an outlet end than the negative curvature portion.   
     
     
         3 . The guide vane according to  claim 2 ,
 wherein the negative curvature portion is disposed at a portion of the runner side vane surface lying closer to the outlet end than a contact point where the other guide vane is brought into contact when the guide vanes are closed fully.   
     
     
         4 . The guide vane according to  claim 3 ,
 wherein, where a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a first section perpendicular to the guide vane rotation axis is referred to as a first curvature maximum value, while a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a second section lying below the first section and parallel to the first section is referred to as a second curvature maximum value, the second curvature maximum value is larger than the first curvature maximum value.   
     
     
         5 . The guide vane according to  claim 1 ,
 wherein the negative curvature portion is disposed at a portion of the runner side vane surface lying closer to the outlet end than a contact point where the other guide vane is brought into contact when the guide vanes are closed fully.   
     
     
         6 . The guide vane according to  claim 5 ,
 wherein, where a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a first section perpendicular to the guide vane rotation axis is referred to as a first curvature maximum value, while a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a second section lying below the first section and parallel to the first section is referred to as a second curvature maximum value, the second curvature maximum value is larger than the first curvature maximum value.   
     
     
         7 . The guide vane according to  claim 1 ,
 wherein, where a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a first section perpendicular to the guide vane rotation axis is referred to as a first curvature maximum value, while a maximum value of an absolute value of the curvature of the contour line at the negative curvature portion in a second section lying below the first section and parallel to the first section is referred to as a second curvature maximum value, the second curvature maximum value is larger than the first curvature maximum value.   
     
     
         8 . A fluid machine comprising:
 the runner; and   the guide vane according to  claim 1 , the guide vane being provided on the outer circumferential side of the runner.