58 results about "Francis turbine" patented technology

A Francis turbine with a improved shape of blades to reduce the secondary flow around the blades and improve the hydraulic efficiency is provided. A Francis turbine comprises a rotating shaft, a crown, a plurality of blades and a band. The band is coaxially coupled with the crown by the blades and the rotating shaft, the crown, the blades, and the band as a whole are driven by water and rotate toward a turbine direction during a turbine operation. On a leading edge of at least one of the blades, a local maximum point exists between the crown and the band. The leading edge leans toward the turbine direction from the band connecting point, where the band and the leading edge are connected. And, a circumferential distance in the rotating direction between the band connecting point and the leading edge is the largest at the local maximum point.

A Francis runner and a hydraulic turbine equipped with such a runner, wherein the runner includes a ceiling, a belt, and blades which extend between the ceiling and the belt and which define liquid flow channels therebetween. A ratio (e/L) of a maximum thickness Ce) of each blade to an average developed length (L) of an average fibre of each blade is between 0.1 and 0.2. At a leading edge of each blade, the average fibre is oriented, over essentially an entire height of the leading edge, along a straight line (Δ₂₃), which forms an angle (α) greater than 90° relative to a line (U) defining a direction of rotation of the leading edge of the runner.

The invention relates to a Francis turbine runner with ultra-low specific rotating speed specially used for a driving cooling tower fan, which effectively solves the problems of the matching of the water turbine runner and the water flow system of the cooling tower and the fan parameters and the reduction of noise and vibration; the structure of the Francis turbine runner is characterized in that vanes are uniformly distributed between an upper coronal and a lower ring; the diameter ratio of a runner inlet and a runner outlet is 1.5-2.5; the ratio of the height of the runner inlet edge and the diameter of the runner outlet is 0.07-0.1; the specific rotating speed of the runner is 60-70m.kW; the unit rotating speed is 40-500r/min; therefore, characteristics of ultra-low rotating speed and ultra-low unit rotating speed are formed; and the space between the vane inlet and the vane outlet is a bent shape and the bending degree is decided by the difference of the vane inlet installation angle and the vane outlet installation angle and the amount of the vanes is 10-19. The Francis turbine runner has unique structure, ultra-low specific rotating speed and ultra-low unit rotating speed, sufficiently utilizes water flow energy, carries out conversion effectively and has excellent stability and huge economical and social benefits.

The invention discloses a processing technology of runner drain holes of a Francis turbine, a bored shaft is moved to point to a point to start the drilling according to a coordinate position Beta of the point to start the drilling on a cross central line and an rotation angle Alpha of a top crown that is relative to the bored shaft which are obtained by calculation, a first slant hole is drilled at the point to start the drilling, the bored shaft and the rotation center of the top crown are motionless, the top crown is rotated, thus allowing the point to start the drilling of the next drainage hole on the top crown to be pointed to the central line of the bored shaft and carrying out the processing of other holes sequentially. The processing method of the drain holes of the crown simplifies the processing steps, improves the processing precision and provides the powerful guarantee for the long-term stable operation of the Francis turbine unit.

A Francis turbine with an improved shape of blades, which can reduce a circumferential velocity component generated in the flow downstream of the blades in a condition of a partial load operation, or reduce the secondary flow around the blades, is provided. A Francis turbine comprises a crown, a plurality of blades, and a band. The crown can rotate around a rotating axis. The blades are circumferentially arranged on the crown, each of which including an inner end as a trailing edge. The band is coaxially coupled with the crown by the blades. A distance Rc can be defined as a distance between the rotation axis and an end by the crown side of the trailing edge. A distance Rb can be defined as a distance between the rotation axis and an end by the band side of the trailing edge. The distance Rc and the distance Rb satisfy $0.2\le \frac{R_c}{R_b}\le 0.4.$

A Francis turbine with an improved shape of blades, which can reduce cavitations generated on the surface of the blades or reduce the secondary flow around the blades, is provided. A Francis turbine comprises a rotating shaft, a crown, a plurality of blades, and a band. The crown can rotate with the rotating shaft. The blades are circumferentially arranged on the crown, each of which including an inner end as a trailing edge. The band is coaxially coupled with the crown by the blades. The rotating shaft, the crown, the blades, and the band as a whole rotate toward a turbine direction during a turbine operation. A projected profile of the trailing edge on a perpendicular plane, which is perpendicular to a center axis of the rotating shaft, is curved toward a direction opposite to the turbine direction at least in the crown side.

The invention relates to a positioning device, in particular to a welding positioning device for francis turbine runner vanes and a positioning measuring method thereof. The device comprises a runner vane and further comprises a bottom plate, wherein a runner crown is arranged in the bottom plate, the runner crown is fixed with the bottom plate by a strut, adjustable lower ring supports are respectively arranged at two ends of the upper part of the bottom plate, a runner lower ring is arranged at the upper part of the adjustable lower ring support, the bottom end of the runner vane is fixed with the runner upper crown, and the upper end of the runner vane is in movable contact with the runner lower ring. The welding positioning device for francis turbine runner vanes and the positioning measuring method thereof are compact in structure, simple and convenient to operate and high in use performances.

A blade for a runner of a Francis turbine having a throat diameter (Dth), the blade including: a maximum thickness of no less than 0.03 Dth and a leading edge having a maximum lean angle of no less than 45 degrees, wherein the lean angle is defined by a vertical line and the leading edge.

A split runner for a Francis turbine has runner segments that are adapted to be joined together along confronting surface portions thereof to form a composite runner having a crown, a band and a plurality of blades extending between the crown and the band. The confronting surface portions of the runner segments are located only along portions of the crown and portions of the band, and the confronting surface portions of the runner segments are located in between and spaced from adjacent blades of the composite runner. Since the confronting surface portions are located only along portions of the crown and portions of the band, none of the blades are split eliminating the need to weld together blades during formation of the composite runner. Accordingly, the composite runner does not have weld joints formed in the blades which are highly stressed operating parts of the runner.

The invention relates to a generation method of blade cutter rail of francis turbine, which belongs to the field of multi-axis milling processing of complex curved surfaces. By constructing a multi-axis milling feature library of Francis turbine blade, matching the model of the blade to be processed with the feature library, and updating the feature library according to the matching results, the generation method of blade cutter tracks of francis turbine provides a new idea and basis for generating tool path based on surface features of the blade model to be machined.

Disclosed is a Francis turbine, and more particularly a double-flow type volute casing having a structure for changing the direction of flow in a turbine inlet, wherein a partition plate for partitioning a volute defined in the casing into an inner flow channel and an outer flow channel is provided so as to surround a turbine, the ratio in sectional area of the inner flow channel to the outer flow channel in a volute inlet, into which a fluid is introduced, is 4:6, a plurality of flow-rate adjustment holes is formed in the partition plate so as to be arranged at a gradually decreasing interval such that a high-pressure fluid flowing in the outer flow channel is introduced into the inner flow channel and the fluid flowing in the inner flow channel is directed perpendicularly to the turbine blades, in order to minimize the amount of energy that is lost and to reduce imbalanced variation of torque applied to the turbine blades, whereby it is possible to prevent the generation of vibration and to obtain high rotational force based on the guarantee of stable output, and therefore it is possible to improve the performance of a hydraulic turbine and to increase the lifespan of the hydraulic turbine through the stable driving thereof.

There is disclosed a runner for a Francis-type hydraulic turbine where each runner blade has an outlet edge with two stress relieving grooves cut through the blade from the outlet edge adjacent the crown and the band. The grooves each present an opening across the outlet edge and the grooves each extend a predetermined distance from the outlet edge into the blade.