Abstract: A suction surface of a blade forming a blade row of an axial compressor includes a concave region having a negative curvature at a leading edge part, and a flat region having substantially zero curvature continued rearwardly of the concave region, so that multiple compression waves are generated, enabling moderation of magnitude of a 1st passage shock to reduce pressure loss and suppress boundary layer separation on the suction surface. Providing a concave region having a negative curvature in a frontal part on a pressure surface of the blade suppresses an increase in the airflow velocity in the frontal part, thus weakening a 2nd passage shock generated on the pressure surface to enable reduction of pressure loss. The concave region of the pressure surface may be extended from a position having a chord length of no greater than 10% to a position having at least 20%.

Abstract: A vane for an axial-flow compressor has a pressure surface generating positive pressure and a suction surface generating negative pressure, and both are located on one side of the chord line. The pressure surface includes a bulging portion, having a maximum curvature of 1.5 or more between a chordal position of 70% and 95%, in a central section of the vane's span. This configuration increases the flow velocity around the bulging portion of the pressure surface to locally decrease the static pressure. By flow continuity the flow velocity on the suction surface that faces the pressure surface is decreased, and thus locally the static pressure on the suction surface is increased. Secondary flow from the pressure surface with positive pressure to the suction surface with negative pressure from the hub region, is suppressed due to the locally increased static pressure on the suction surface.

Abstract: A suction surface of a blade forming a blade row of an axial compressor includes a concave region having a negative curvature at a leading edge part, and a flat region having substantially zero curvature continued rearwardly of the concave region, so that multiple compression waves are generated, enabling moderation of magnitude of a 1st passage shock to reduce pressure loss and suppress boundary layer separation on the suction surface. Providing a concave region having a negative curvature in a frontal part on a pressure surface of the blade suppresses an increase in the airflow velocity in the frontal part, thus weakening a 2nd passage shock generated on the pressure surface to enable reduction of pressure loss. The concave region of the pressure surface may be extended from a position having a chord length of no greater than 10% to a position having at least 20%.

Abstract: A vane for an axial-flow compressor has a pressure surface generating positive pressure and a suction surface generating negative pressure, and both are located on one side of the chord line. The pressure surface includes a bulging portion, having a maximum curvature of 1.5 or more between a chordal position of 70% and 95%, in a central section of the vane's span. This configuration increases the flow velocity around the bulging portion of the pressure surface to locally decrease the static pressure. By flow continuity the flow velocity on the suction surface that faces the pressure surface is decreased, and thus locally the static pressure on the suction surface is increased. Secondary flow from the pressure surface with positive pressure to the suction surface with negative pressure from the hub region, is suppressed due to the locally increased static pressure on the suction surface.

Abstract: A generating line of a casing surrounding an outer periphery of vanes of a stator disposed downstream of a rotor of the axial-flow compressor includes: a recessed region recessed outward in a radial direction from a position forward of a front edge of each of the vanes to a position rearward of a rear edge of the vane; and a protruding region bulging inward in the radial direction at an intermediate position of the recessed region in a front-rear direction thereof. Thus, a distribution of static pressure in the radial direction on a surface of the vane is improved by a first recessed portion forward of the protruding region, and the static pressure on the tip side is raised by a second recessed portion rearward of the protruding region.

Abstract: A first bent portion bent toward an intrados and a second bent portion located in the rear of the first bent portion and bent toward an extrados are provided on a camber line on a trailing edge in the rear of 90% of a chord length of a turbine blade having an extremely low aspect ratio for an axial-flow turbine. The inclination of the camber line immediately in the rear of the second bent portion on the side of a blade root is substantially equal to the inclination of the camber line immediately in front of the first bent portion, and the curvature of the second bent portion is decreased from the side of the blade root toward a blade tip. As a result, a higher-pressure portion on the intrados which is a pressure surface of the turbine blade is displaced toward the trailing edge, and thus a secondary flow from the side of the blade tip toward the blade root can be suppressed, whereby a pressure loss particularly in the vicinity of the blade root can be suppressed to the minimum.

Abstract: A first bent portion bent toward an intrados and a second bent portion located in the rear of the first bent portion and bent toward an extrados are provided on a camber line on a trailing edge in the rear of 90% of a chord length of a turbine blade having an extremely low aspect ratio for an axial-flow turbine. The inclination of the camber line immediately in the rear of the second bent portion on the side of a blade root is substantially equal to the inclination of the camber line immediately in front of the first bent portion, and the curvature of the second bent portion is decreased from the side of the blade root toward a blade tip. As a result, a higher-pressure portion on the intrados which is a pressure surface of the turbine blade is displaced toward the trailing edge, and thus a secondary flow from the side of the blade tip toward the blade root can be suppressed, whereby a pressure loss particularly in the vicinity of the blade root can be suppressed to the minimum.

Abstract: Fluid analyzing apparatus includes: an advection step density analyzing unit; an advection step internal energy analyzing unit; and an advection step pressure analyzing unit. The apparatus further includes: an advection step velocity analyzing unit; a nonadvection step small perturbation analyzing unit; and a nonadvection step velocity analyzing unit. The apparatus further includes: a nonadvection step density analyzing unit; a nonadvection step internal energy analyzing unit; and an iterative calculation control unit which iterates calculation in a predetermined order.

Abstract: A high-turning and high-transonic blade for use in a blade cascade of an axial-flow compressor, wherein a distribution of flow speed on an extrados at a leading edge of the blade has a supersonic region of a substantially constant flow speed in the rear of a first large value of the flow speed and inside a position corresponding to 15% of a chord length from the leading edge. The supersonic region is established so that a value obtained by the division of a difference between Mach numbers at front and rear ends of the supersonic region by a chord-wise length of the supersonic region is smaller than 1, and the maximum Mach number in the supersonic region is smaller than 1.4. A first large shock wave is positively generated at a position where the flow speed assumes a first maximum value, whereby a second shock wave generated in the supersonic region of the substantially constant flow speed in the rear of such a position can be weakened.

Abstract: An initial set of individuals having design parameters of a blade as a gene, is determined at random (S12). Next, an analysis using Navier-Stokes equations is performed. On the basis of the analysis result, ranking (evaluation) of respective individuals are performed using a pressure loss coefficient, a trailing edge deviation angle and the like as objective functions (S14). When a shape of a blade having a desirable performance is obtained, or when a predetermined number of generations is achieved, the analysis is terminated assuming that a termination condition has been met (S22). When the termination condition has not been met, processes about individual selection, crossing between individuals and mutation are performed so that generation is incremented by 1. The above processes are repeated, so that Pareto solutions can be obtained according to MOGA in consideration of a trade-off relationship between the objective functions.

Abstract: The invention provides a fluid analyzing apparatus, a fluid analyzing method, and a fluid analyzing program which can analyze an unsteady fluid with time developing, which do not depend on nonphysical parameters, and which can perform calculation with good convergence. The apparatus includes: an advection step density analyzing unit which calculates a density in an advection step; an advection step internal energy analyzing unit which calculates an internal energy in the advection step; and an advection step pressure analyzing unit which calculates a pressure developing after advection.

Abstract: A high-turning and high-transonic blade for use in a blade cascade of an axial-flow compressor, wherein a distribution of flow speed on an extrados at a leading edge of the blade has a supersonic region of a substantially constant flow speed in the rear of a first large value of the flow speed and inside a position corresponding to 15% of a chord length from the leading edge. The supersonic region is established so that a value obtained by the division of a difference between Mach numbers at front and rear ends of the supersonic region by a chord-wise length of the supersonic region is smaller than 1, and the maximum Mach number in the supersonic region is smaller than 1.4. A first large shock wave is positively generated at a position where the flow speed assumes a first maximum value, whereby a second shock wave generated in the supersonic region of the substantially constant flow speed in the rear of such a position can be weakened.

Abstract: In a high turning airfoil capable of being suitably applied to each of blades constituting a blade row of an axial flow-type compressor, both of an intrados generating a positive pressure and an extrados generating a negative pressure exist on one side of a chord line, and the curvature of the extrados made non-dimensional by a chord length has a maximum value between a position corresponding to 10% of the chord length and a position corresponding to 35% of the chord length, and a minimum value in the rear of the position of the maximum value and between a position corresponding to 30% of the chord length and a position corresponding to 50% of the chord length. Preferably, a difference between the maximum value and the minimum value of the curvature is equal to or larger than 0.5, and a turning angle is equal to or larger than 40°.

Abstract: In a high turning airfoil capable of being suitably applied to each of blades constituting a blade row of an axial flow-type compressor, both of an intrados generating a positive pressure and an extrados generating a negative pressure exist on one side of a chord line, and the curvature of the extrados made non-dimensional by a chord length has a maximum value between a position corresponding to 10% of the chord length and a position corresponding to 35% of the chord length, and a minimum value in the rear of the position of the maximum value and between a position corresponding to 30% of the chord length and a position corresponding to 50% of the chord length. Preferably, a difference between the maximum value and the minimum value of the curvature is equal to or larger than 0.5, and a turning angle is equal to or larger than 40°.

Abstract: A blade for an axial-flow turbine includes an intrados producing a positive pressure between a leading edge and a trailing edge, and an extrados producing a negative pressure. The intrados is formed at its rear portion with a flat surface portion connected to the trailing edge, and the extrados has a curved surface portion formed at least at a portion corresponding to the flat surface portion. The trailing edge of the turbine blade is pointed at its end. The angle of intersection between the intrados and the extrados at the trailing edge is a right angle or an acute angle. Thus, it is possible to inhibit the flowing of a gas from the intrados at the trailing edge toward the extrados and to decrease the degree of curvature of the extrados at the trailing edge portion to reduce the flow speed, thereby minimizing a shock wave generated at the trailing edge portion to reduce the pressure loss and enhance the performance of the turbine.

Abstract: A turbine blade for an axial-flow turbine includes an intrados generating a positive pressure, and an extrados generating a negative pressure, wherein the intrados and the extrados are provided between a leading edge and a trailing edge. An inflection point is provided between a concave portion on an upstream side and a convex portion on a downstream side in a region extending from a position of 80% on the intrados to a rear throat, and the length of a normal line drawn downwards from the intrados of one of the turbine blades to an extrados of the other turbine blade has at least one maximum value in a region extending from a front throat of the one turbine blade to a rear throat. Thus, it is possible to disperse a shock wave generated from the intrados at the trailing edge to prevent the generation of a strong shock wave, thereby reducing the pressure loss caused by the shock wave.

Abstract: A blade for an axial-flow turbine includes an intrados producing a positive pressure between a leading edge and a trailing edge, and an extrados producing a negative pressure. The intrados is formed at its rear portion with a flat surface portion connected to the trailing edge, and the extrados has a curved surface portion formed at least at a portion corresponding to the flat surface portion. The trailing edge of the turbine blade is pointed at its end. The angle of intersection between the intrados and the extrados at the trailing edge is a right angle or an acute angle. Thus, it is possible to inhibit the flowing of a gas from the intrados at the trailing edge toward the extrados and to decrease the degree of curvature of the extrados at the trailing edge portion to reduce the flow speed, thereby minimizing a shock wave generated at the trailing edge portion to reduce the pressure loss and enhance the performance of the turbine.

Abstract: It is an object of the present invention to provide a stator blade for an axial-flow compressor, in which the wave drag due to the generation of a shock wave in a transonic speed range can be suppressed to the minimum. For this purpose, the stator blade in the axial-flow compressor has an intrados producing a positive pressure, and an extrados producing a negative pressure. Both of the intrados and the extrados are located on one side of a chord line. A first bulge and a second bulge are formed on the intrados of the stator blade at a location on the side of a leading edge and on the side of a trailing edge, respectively. Thus, the generation of a shock wave on the extrados can be moderated to reduce the wave drag by positively producing the separation of a boundary layer on the intrados by the first bulge.

Abstract: A turbine blade for an axial-flow turbine includes an intrados generating a positive pressure, and an extrados generating a negative pressure, wherein the intrados and the extrados are provided between a leading edge and a trailing edge. An inflection point is provided between a concave portion on an upstream side and a convex portion on a downstream side in a region extending from a position of 80% on the intrados to a rear throat, and the length of a normal line drawn downwards from the intrados of one of the turbine blades to an extrados of the other turbine blade has at least one maximum value in a region extending from a front throat of the one turbine blade to a rear throat. Thus, it is possible to disperse a shock wave generated from the intrados at the trailing edge to prevent the generation of a strong shock wave, thereby reducing the pressure loss caused by the shock wave.

Abstract: An initial set of individuals having design parameters of a blade as a gene, is determined at random (S12). Next, an analysis using Navier-Stokes equations is performed. On the basis of the analysis result, ranking (evaluation) of respective individuals are performed using a pressure loss coefficient, a trailing edge deviation angle and the like as objective functions (S14). When a shape of a blade having a desirable performance is obtained, or when a predetermined number of generations is achieved, the analysis is terminated assuming that a termination condition has been met (S22). When the termination condition has not been met, processes about individual selection, crossing between individuals and mutation are performed so that generation is incremented by 1. The above processes are repeated, so that Pareto solutions can be obtained according to MOGA in consideration of a trade-off relationship between the objective functions.