US 5,524,341 AGranted

Method of making a row of mix-tuned turbomachine blades

AssigneeWestinghouse Electric Corp.

InventorsJurek Ferleger, Douglas C. Hofer

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Abstract

A row of mix-tuned rotor blades for use in a turbomachine in which the first mode vibratory frequency of each of the blades falls into either of two distinct groups. The blades from the first group alternate with the blades from the second group so that no two adjacent blades have the same frequency, thereby inhibiting the onset of stall flutter. The blades are made by forging a forging blank between upper and lower die halves. The orientation of the upper die half relative to the lower die half when the die is fully closed is different depending on whether blades are being made for the first or second group, the difference being an offset in the position of the upper die half. As a result, the airfoils of the blades in the first and second groups have slightly different shapes, thereby resulting in the difference in resonant frequency.

Claims18

Dependent claims

A method of making a row of airfoils for use in a turbomachine, each of said airfoils having a shape, comprising the steps of:

a) forming a plurality of forging blanks;
b) disposing a first one of said forging blanks between first and second portions of a die, said first and second die portions having first and second forming surfaces thereon, respectively;
c) bringing said first die portion toward said second die portion so as to close said die, thereby forging said first forging blank disposed therebetween into a first one of said airfoils in said row, said first die portion being brought toward said second die portion so that said first die portion assumes a first orientation with respect to said second die portion when said die is closed;
d) removing said first airfoil;
and
e) disposing a second one of said forging blanks between said first and second portions of said die, and bringing said first die portion toward said second die portion so as to close said die, thereby forging said second forging blank disposed therebetween into a second one of said airfoils in said row, said first die portion being brought toward said second die portion so that said first die portion assumes a second orientation with respect to said second die portion when said die is closed, said first and second orientations of said first die relative to said second die differing by a predetermined amount.

3 more elements

A method of making a mix-tuned row of turbomachine blades including first and second groups of blades, each of said blades in said first group of blades having a first resonant frequency and each of said blades in said second group of blades having a second resonant frequency different from said first resonant frequency, each of said blades having an airfoil portion forming a surface for directing the flow of a working fluid through said turbomachine, said airfoil surface having a shape, said first and second resonant frequencies of said blades being a function of said shape of said airfoil in said respective blade group, the method comprising the steps of:

a) forming a plurality of forging blanks;
b) disposing each of said forging blanks between first and second halves of a die, said first and second dies halves having first and second forming surfaces, respectively, thereon that together conform to said surfaces of said blade airfoils, whereby said shape of said airfoil surfaces is dependent upon the relative position between said first and second die halves when said die is closed;
and
c) forging each of said airfoil portions of said blades in said row by bringing said first die portion toward said second die portion so as to close said die on one of said forging blanks, removing each of said airfoil portions after said forging step, said die being closed so that said first die half assumes a first position relative to said second die half when forming said airfoil portions of said blades in said first group of blades, and said die being closed so that said first die half assumes a second position relative to said second die half when forming said airfoil portions of said blades in said second group of blades, said first position being offset from said second position by a predetermined amount, whereby said first and second resonant frequencies are not equal.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 08/312,419Filed 26 Sep 1994
Granted: 11 Jun 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

F01D 5/16
Form or construction: for counteracting blade vibration
B21K 3/04
Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like: blades, e.g. for turbines; Upsetting of…
B23P 15/02
Making specific metal objects by operations not covered by a single other subclass or a group in this subclass: turbine or like blades from one piece
Y10T 29/49321
Turbomachine making: assembling individual fluid flow interacting members, e.g., blades, vanes, buckets, on rotary support member