Rotor assembly having a closure group of rotor blades with fixturing and alignment features

A steam turbine comprising:

• a casing;
• and
• a rotor assembly disposed in the casing, the rotor assembly comprising:
• a rotor defining an annular slot that includes a main portion and a gate portion;
• a plurality of rotor blades positioned in the annular slot, the plurality of rotor blades including a standard group of rotor blades and a closure group of rotor blades, the standard group of rotor blades positioned in the main portion of the annular slot, and wherein the closure group of rotor blades comprises:
• a first auxiliary rotor blade having a first auxiliary mounting portion that includes a first fixturing tab, and wherein the first auxiliary mounting portion partially defines a first pin hole;
• a second auxiliary rotor blade having a second auxiliary mounting portion that includes a second fixturing tab, and wherein the second auxiliary mounting portion partially defines a second pin hole;
• and
• a closure rotor blade positioned in the gate portion of the annular slot between the first auxiliary rotor blade and the second auxiliary rotor blade, the closure rotor blade having a closure mounting portion defining a radially innermost surface, the radially innermost surface being in contact with the first fixturing tab and the second fixturing tab, and wherein the closure rotor blade partially defines the first pin hole and the second pin hole.

A method of installing a plurality of rotor blades in a rotor, the plurality of rotor blades including a standard group of rotor blades and a closure group of rotor blades, the method comprising:

• inserting each standard rotor blade in the group of standard rotor blades through a gate portion of an annular slot and into a main portion of the annular slot;
• inserting a first auxiliary rotor blade through the gate portion of the annular slot and into the main portion of the annular slot, the first auxiliary rotor blade having a first auxiliary mounting portion that includes a first fixturing tab, and wherein the first auxiliary mounting portion partially defines a first pin hole;
• inserting a second auxiliary rotor blade through the gate portion of the annular slot and into the main portion of the annular slot, the second auxiliary rotor blade having a second auxiliary mounting portion that includes a second fixturing tab, and where in the second auxiliary mounting portion partially defines a second pin hole;
• and
• inserting a closure rotor blade through the gate portion until a radially inner most surface of a closure mounting portion of the closure rotor blade contacts the first fixturing tab and the second fixturing tab, wherein the closure rotor blade partially defines the first pin hole and the second pin hole.