Method of forming a stator assembly for rotary machine

A method for forming a modular unit for a gas turbine engine, the modular unit including a first rotor assembly, a second rotor assembly which is attached to the first rotor assembly and a stator assembly having a first side and a second side which is disposed between the rotor assemblies, which extends circumferentially about an axis A in the installed condition and which is assembled in a fixture to the rotor assemblies to form the modular unit, the stator assembly further including a stator case and vane assembly which includes a case which extends circumferentially about the axis A, further including a plurality of vane clusters supported from the case, each vane cluster having at least one coolable stator vane having at least one opening which places the interior of the vane in flow communication with the exterior of the vane, and further including a seal member which extends circumferentially about the axis A and which has a plurality of seal segments, each seal segment being supported by at least one stator vane and each seal segment having a feather seal slots which face circumferentially for receiving associated feather seal members which each extend between a pair of the adjacent seal segments, comprising:

• disposing the stator case and vane assembly in a horizontal position such that the axis A is oriented in a substantially vertical direction, the first side faces upwardly, the second side faces downwardly, and the seal member surface faces radially in the horizontal direction;
• machining the horizontally facing surface of the seal member to remove material from the seal member to form the contour of the seal element;
• flowing fluid adjacent the seal element, the fluid carrying seal particles resulting from the machining process;
• blocking the movement of particles into the interior of the vane including disposing a shield between the source of fluid and the interior of the stator vane which further includes,
• disposing a first self-supporting shield element which extends between the upper side of the seal member to the case for blocking particles from the interior of the stator vane,
• disposing a second self-supporting shield element which extends between the lower side of the seal member to the case for blocking particles from the interior of the stator vane,
• disposing feather seal elements in each of the feather seal slots, each extending circumferentially between the associated pair of seal segments and axially between first and second shield elements;
• thereafter, without disassembly of any vane clusters from the case during the subsequent build period,
• cleaning the stator assembly after machining to further remove seal particles, and
• assembling the modular unit that contains the stator assembly including disposing the rotor assemblies on either side of the stator assembly and attaching the rotor assemblies one to the other;
• wherein the first and second shield elements cooperate with the seal segments and feather seal elements to block the flow of fluid into the interior of the stator vanes, wherein not disassembling the stator vane clusters for cleaning stator vanes avoids disrupting the as ground contour of the seal segments and avoids the need to reassemble the stator vane cluster to the case prior to the final build of the modular unit.