Guide vane arrangement for use in a turbine

A method of operating a guide vane arrangement, comprising:

• supplying a fluid flow to a flow channel defined between a leading surface of a first guide vane and a trailing surface of a second guide vane, and
• guiding the fluid flow along a trailing portion of the trailing surface of the second guide vane which is arranged adjacent to a trailing edge of the second guide vane and thereby deflecting the fluid flow such that the fluid flow exits the flow channel at a first flow angle with respect to a virtual plane defined by a trailing edge of the first guide vane and the trailing edge of the second guide vane and with a desired first flow speed,
• wherein the fluid flow, prior to being guided along the trailing portion of the trailing surface, is guided along a leading portion of the trailing surface of the second guide vane which is arranged adjacent to a leading edge of the second guide vane and thereby deflected such that the fluid flow flows at a second flow angle with respect to the virtual plane defined by the trailing edge of the first guide vane and the trailing edge of the second guide vane, and thereafter is guided
• along an intermediate portion of the trailing surface of the second guide vane which is arranged between the trailing portion and the leading portion and thereby deflected such that the fluid flow flows at a third flow angle with respect to the virtual plane defined by the trailing edge of the first guide vane and the trailing edge of the second guide vane, wherein the second flow angle is larger than each of the third flow angle and the first flow angle, and thereafter is guided
• along a first transition portion of the trailing surface of the second guide vane which is arranged between the intermediate portion and the trailing portion and which defines a recompression portion of the flow channel which has a flow cross-section that decreases in the flow direction of the fluid flow flowing through the flow channel, and wherein the recompression portion is designed in such a manner that the fluid flow, upon flowing through the recompression portion, is decelerated to a second flow speed, and thereafter is guided
• along a second transition portion of the trailing surface of the second guide vane which is arranged between the first transition portion and the trailing portion and which defines an additional expansion portion of the flow channel which has a flow cross-section that increases in the flow direction of the fluid flow flowing through the flow channel, and wherein the additional expansion portion is designed in such a manner that the fluid flow, upon flowing through the expansion portion, is accelerated to a third flow speed.