Gas turbine engine stator vane assembly

A method of assembling gas turbine engine front architecture includes positioning inner and outer fairings relative to one another. Multiple vanes are arranged circumferentially between the inner and outer fairings. A liquid sealant is applied around a perimeter of the vanes to seal between the vanes and at least one of the fairings.

BACKGROUND

This disclosure relates to a gas turbine engine front architecture. More particularly, the disclosure relates to a stator vane assembly and a method of installing stators vanes within a front architecture.

One type of gas turbine engine includes a core supported by a fan case. The core rotationally drives a fan within the fan case. Multiple circumferentially arranged stator vanes are supported at an inlet of the core by its front architecture.

The stator vanes are supported to limit displacement of the vane, and the vanes are subjected to vibratory stress by the supporting structure. That is, loads are transmitted through the front architecture to the stator vanes. Typically, the stator vanes are constructed from titanium, stainless steel or a high grade aluminum, such as a 2618 alloy, to withstand the stresses to which the stator vanes are subjected.

Some front architectures support the stator vanes relative to inner and outer fairings using rubber grommets. A fastening strap is wrapped around the circumferential array of stator vanes to provide mechanical retention of the stator vanes with respect to the fairings. As a result, mechanical loads and vibration from the fairings are transmitted to the stator vanes through the fastening strap.

SUMMARY

A method of assembling gas turbine engine front architecture includes positioning inner and outer fairings relative to one another. Multiple vanes are arranged circumferentially between the inner and outer fairings. A liquid sealant is applied around a perimeter of the vanes to seal between the vanes and at least one of the fairings.

A gas turbine engine front architecture includes an inlet case having first and second inlet flanges integrally joined by inlet vanes. Outer and inlet fairings respectively fastened to the first and second inlet flanges. The outer and inner fairings respectively include first and second walls having first and second slots respectively. Multiple stator vanes are arranged upstream from the inlet vanes and are circumferentially spaced from one another. Each of the stator vanes extend radially between the inner and outer fairings and include outer and inner perimeters respectively within the first and second slots. Sealant is provided about the inner and outer perimeters at the inner and outer fairings.

The stator vanes include inner and outer ends and provide leading and trailing edges. A notch is provided on the inner end at the trailing edge and seated over the inner fairing. Opposing tabs extend from opposing sides of the stator vanes at the out end. The sealant is provided beneath the notch and the opposing tabs.

DETAILED DESCRIPTION

A gas turbine engine10is illustrated schematically inFIG. 1. The gas turbine engine10includes a fan case12supporting a core14via circumferentially arranged flow exit guide vanes16. A bypass flow path18is provided between the fan case12and the core14. A fan20is arranged within the fan case12and rotationally driven by the core14.

The core14includes a low pressure spool22and a high pressure spool24independently rotatable about an axis A. The low pressure spool22rotationally drives a low pressure compressor section26and a low pressure turbine section34. The high pressure spool24supports a high pressure compressor section28and a high pressure turbine section32. A combustor30is arranged between the high pressure compressor section28and the high pressure turbine section32.

The core14includes a front architecture36, having fixed structure, provided within the fan case12downstream from the fan20. The front architecture36includes stator vanes44arranged upstream from inlet guide vanes84, which are also arranged upstream from the first stage of the low compressor section26.

The front architecture36supports a stator vane assembly38, which is shown inFIGS. 2A,2B and6. The stator vane assembly38includes inner and outer fairings40,42radially spaced from one another. Multiple stator vanes44are arranged circumferentially relative to one another about the axis A and extend between the inner and outer fairings40,42. The stator vanes44provide an airfoil having opposing sides extending between leading and trailing edges LE, TE (FIG. 6).

Each stator vane44includes opposing inner and outer ends46,48. The outer fairing42has a first wall50that includes circumferential first slots52for receiving the outer ends48of the stator vane44. A first flange54extends from the first wall50and includes first and second attachment features56,58.

The inner fairing40is provided by a second wall60that includes circumferentially arranged second slots62for receiving the inner ends46of the stator vanes44. A second flange64extends from the second wall60and provides a third attachment feature66.

Referring toFIGS. 3A-3B, the inner ends46are secured relative to the inner fairing40within the second slots62with a liquid sealant74that provides a bonded joint. In one example, the liquid sealant is a silicone rubber having, for example, a thicksotropic formulation or a room temperature vulcanization formulation. The liquid sealant cures to a solid state subsequent to its application about an inner perimeter72at the inner fairing40, providing a filleted joint.

The inner end46includes a notch68at a trailing edge TE (FIG. 6) providing an edge70that is in close proximity to the wall60, as illustrated inFIG. 2B, for example. The edge70provides an additional safeguard that prevents the stator vanes44from being forced inward through the inner fairing40during engine operation.

The stator vane44is supported relative to the inner fairing40such that a gap71is provided between the inner end46and the inner fairing40about the inner perimeter72. Said another way, a clearance is provided about the inner perimeter72within the second slot62. The liquid sealant74is injected into the gap71to vibrationally isolate the inner end46from the inner fairing40during the engine operation and provide a seal.

Referring toFIGS. 4-5, the outer ends48are secured relative to the outer fairing42within the first slots52with the liquid sealant80that provides a bonded joint. The liquid sealant cures to a solid state subsequent to its application about the outer perimeter78at the outer fairing42, providing a filleted joint.

The stator vane44is supported relative to the outer fairing42such that a gap79is provided between the outer end48and the outer fairing42about the outer perimeter78. Said another way, a clearance is provided about the outer perimeter78within the first slot52. The liquid sealant80is injected into the gap79to vibrationally isolate the outer end48from the outer fairing42during the engine operation and provide a seal.

The outer end48includes opposing, laterally extending tabs76arranged radially outwardly from the outer fairing42and spaced from the first wall50. The tabs76also prevent the stator vanes44from being forced radially inward during engine operation. The liquid sealant is provided between the tabs76and the first wall50.

The front architecture36is shown in more detail inFIG. 6. An inlet case82includes circumferentially arranged inlet vanes84radially extending between and integrally formed with first and second inlet flanges86,88. The inlet case82provides a compressor flow path100from the bypass flow path18to the first compressor stage. The outer fairing42is secured to the first inlet flange86at the first attachment feature56with fasteners87. The inner fairing40is secured to the second inlet flange88at the third attachment feature66with fasteners89.

A splitter90is secured over the outer fairing42to the second attachment feature58with fasteners91. The splitter90includes an annular groove92arranged opposite the second attachment feature58. The outer fairing42includes a lip94opposite the first flange54that is received in the annular groove92. A projection96extends from an inside surface of the splitter90and is arranged in close proximity to, but spaced from, an edge98of the outer ends48to prevent undesired radial outward movement of the stator vanes44from the outer fairing42. The inner and outer fairings40,42and splitter90are constructed from an aluminum 6061 alloy in one example.

The front architecture36is assembled by positioning the inner and outer fairings40,42relative to one another. The stator vanes44are arranged circumferentially and suspended between the inner and outer fairings40,42. That is, the stator vanes44are mechanically isolated from the inner and outer fairings40,42. The liquid sealant is applied and layed in the gaps71,79, which are maintained during the sealing step, to vibrationally isolate the stator vanes44from the adjoining structure. The sealant adheres to and bonds the stator vanes and the inner and outer fairings to provide a flexible connection between these components. In the example arrangement, there is no direct mechanical engagement between the stator vanes and fairings. The sealant provides the only mechanical connection and support of the stator vanes relative to the fairings.

Since the sealant bonds the stator vanes to the inner and outer fairings, the stator vane ends are under virtually no moment constraint such that there is a significant reduction in stress on the stator vanes. No precision machined surfaces are required on the stator vanes for connection to the fairings. In one example, a stress reduction of over four times is achieved with the disclosed configuration compared with stator vanes that are mechanically supported in a conventional manner at one or both ends of the stator vanes. As a result of being subjected to considerably smaller loads, lower cost, lighter materials can be used, such as an aluminum 2014 alloy, which is also more suitable to forging. Since the liquid sealant is applied after the stator vanes44have been arranged in a desired position, any imperfections or irregularities in the slots or stator vane perimeters are accommodated by the sealant, unlike prior art grommets that are preformed.