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An integrated strut and turbine vane nozzle (ISV) comprising: inner and outer duct walls defining a flow passage therebetween, an array of circumferentially spaced-apart struts extending radially across the flow passage, and an array of circumferentially spaced-apart vanes extending radially across

An integrated strut and turbine vane nozzle (ISV) comprising: inner and outer duct walls defining a flow passage therebetween, an array of circumferentially spaced-apart struts extending radially across the flow passage, and an array of circumferentially spaced-apart vanes extending radially across the flow passage. At least one of the struts is aligned in the circumferential direction with an associated one of the vanes and forms therewith an integrated strut-vane airfoil. The adjacent vanes on opposed sides of the integrated strut-vane airfoil have uneven axial chords relative to the other vanes.

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1. An integrated strut and turbine vane nozzle (ISV) for a gas turbine engine, the ISV comprising: inner and outer duct walls defining an annular flow passage therebetween, an array of circumferentially spaced-apart struts extending radially across the flow passage, and an array of circumferentially

1. An integrated strut and turbine vane nozzle (ISV) for a gas turbine engine, the ISV comprising: inner and outer duct walls defining an annular flow passage therebetween, an array of circumferentially spaced-apart struts extending radially across the flow passage, and an array of circumferentially spaced-apart vanes extending radially across the flow passage, the vanes having leading edges disposed downstream of leading edges of the struts relative to a direction of gas flow through the annular flow passage, at least one of the struts being aligned in the circumferential direction with an associated one of the vanes and forming therewith an integrated strut-vane airfoil, wherein at least one of adjacent vanes on opposed sides of the integrated strut-vane airfoil has a shorter axial chord than the axial chord of the other vanes of the array of circumferentially spaced-apart vanes. 2. The ISV defined in claim 1, wherein both the adjacent vanes on the opposed sides of the integrated strut-vane have a shorter axial chord than the axial chord of the other vanes. 3. The ISV defined in claim 1, wherein a first one of the adjacent vanes has a longer axial chord than the axial chord of the other vanes while a second one of the adjacent vanes has a shorter axial chord than the axial chord of the other vanes. 4. The ISV defined in claim 1, wherein both adjacent vanes on opposed sides of the integrated strut-vane airfoil have uneven axial chords relative to the other vanes. 5. The ISV defined in claim 1, wherein the adjacent vanes have substantially a same axial chord which is different from the axial chord of the other vanes. 6. The ISV defined in claim 3, wherein the first one of the adjacent vanes extends upstream relative to the other vanes to a location where flow separation is anticipated during operation. 7. The ISV defined in claim 1, wherein the at least one of the adjacent vanes having a shorter axial chord is disposed on a suction side of the integrated-strut vane airfoil. 8. The ISV defined in claim 1, wherein the adjacent vanes and the integrated strut-vane airfoil define first and second inter-vane passages respectively on opposed sides of the integrated strut-vane airfoil, and wherein the at least one of the adjacent vanes having an axial chord shorter than the axial chord of the other vanes is shorter by a distance sufficient to avoid the of a throat at an inlet end of the first and second inter-vane flow passages. 9. The ISV defined in claim 8, wherein the throat of the first and second inter-vane flow passages is substantially positioned at a trailing edge of the adjacent vanes. 10. The ISV defined in claim 1, wherein the at least one of the adjacent vanes is shorter relative to the other vanes so that an area of maximum thickness of the integrated strut-vane airfoil and a leading edge portion of the at least one of the adjacent vanes is spaced by a distance less than a distance between a trailing edge of the at least one of the adjacent vanes and the integrated strut-vane airfoil as measured perpendicularly thereto. 11. The ISV defined in claim 1, wherein the leading edge of the at least one of the adjacent vanes is downstream of the leading edges of the other vanes having a nominal axial chord relative to the direction of gas flow through the annular flow passage, and wherein the leading edge of the at least one of the adjacent vanes having a shorter axial chord is downstream of an axial point at which a distance between the integrated strut-vane airfoil and the leading edge of the at least one of the adjacent vanes become less than a shortest distance between the integrated-strut vane airfoil and the at least one of the adjacent vanes downstream of the leading edge of the at least one of the adjacent vanes. 12. A method of designing an integrated strut and turbine vane nozzle (ISV) having a circumferential array of struts and a circumferential array of vanes, the vanes having leading edges disposed downstream of leading edges of the struts relative to a direction of gas flow through the ISV, each of the struts being aligned in the circumferential direction with an associated one of the vanes and forming therewith an integrated strut-vane airfoil, the method comprising: establishing a nominal axial chord of the vanes, conducting a flow field analysis, and then based on the flow field analysis adjusting the axial chord of the vanes adjacent to the integrated strut-vane airfoil by increasing or decreasing the axial chord thereof relative to the nominal axial chord including shortening the axial chord of a vane adjacent to the integrated strut-vane airfoil when a flow constriction is detected between the vane and the integrated strut-vane airfoil. 13. The method of claim 12, wherein increasing or decreasing the axial chord of the vanes adjacent to the integrated strut vane airfoil includes increasing the axial chord of an adjacent vane on a side of the integrated strut-vane airfoil when flow separation is detected on said side of the integrated strut-vane airfoil at a location upstream of the leading edge of the adjacent vane, the axial chord being increased for the leading edge of the adjacent vane to extend axially upstream of where flow separation was detected. 14. The method defined in claim 12, wherein the integrated strut-vane airfoil has a tmax/c ratio, wherein tmax is the maximum thickness of the integrated-strut vane airfoil and c the true chord of the integrated strut-vane airfoil, wherein conducting a flow field analysis comprises calculating the tmax/c ratio, and wherein adjusting the axial chord of the vanes adjacent to the integrated strut-vane airfoil comprises shortening an associated one of the vanes adjacent to the integrated strut-vane airfoil when the tmax/c ratio is superior to a predetermined value. 15. The method defined in claim 12, wherein when a converging and then diverging passage between the integrated strut-vane airfoil and an adjacent vane is detected during the flow filed analysis, the adjacent vane is shortened to eliminate the flow constriction. 16. The method defined in claim 12, wherein at least one of the vanes adjacent to the integrated strut-vane airfoil is shortened relative to the other vanes so as to prevent an area of maximum thickness of the integrated strut-vane airfoil and a leading edge portion of the at least one vane from being spaced by a distance that is less than a distance between a trailing edge of the at least one vane and the integrated strut-vane airfoil as measured perpendicularly thereto. 17. The method defined in claim 12, wherein at least one of the vanes adjacent to the integrated strut-vane airfoil is shortened so that the leading edge thereof is downstream of an axial point at which a distance between the integrated strut-vane airfoil and the leading edge of the at least one vane becomes less than a shortest distance between the integrated-strut vane airfoil and a remainder of the at least one vane. 18. A gas turbine engine comprising a gas path defined between an inner duct wall and an outer duct wall, an array of circumferentially spaced-apart struts extending radially across the gas path, and an array of circumferentially spaced-apart vanes extending radially across the gas path and disposed generally downstream of the struts relative to a direction of gas flow through the gas path, each of the struts being angularly aligned in the circumferential direction with an associated one of the vanes and forming therewith an integrated strut-vane airfoil, each integrated strut-vane airfoil being disposed between two neighbouring vanes, the neighbouring vanes having an uneven axial chord distribution relative to the other vanes, wherein the uneven axial chord distribution comprises at least one of the neighbouring vanes having a shorter axial chord than that of the other vanes. 19. The gas turbine engine defined in claim 18, wherein the at least one neighbouring vane with the shorter axial chord has a leading edge which is disposed downstream of leading edges of the other vanes relative to a direction of gas flow through the gas path. 20. The gas turbine engine defined in claim 18, wherein the uneven axial chord distribution further comprises at least one of the neighbouring vanes having a longer axial chord than that of the other vanes.