Turbine vane hollow inner rail

Guide vane device for a turbine, the guide vane device comprising:

• an inner platform having a body defining a through hole through which a cooling fluid flows, wherein the inner platform extends in a circumferential direction around a shaft of a turbine,
• an aerofoil having sidewalls defining a cavity in fluid communication with the through hole, wherein the aerofoil is fixed to a first surface of the inner platform,
• a rail comprising a recessed portion extending in the circumferential direction and having a cooling fluid passage formed in the recessed portion and extending from the recessed portion through a body of the rail, the cooling fluid passage overlapping a cross-section of the through hole such that the cooling fluid flows through the cooling fluid passage, the through hole, and into the cavity, wherein the rail is fixed to a second surface of the inner platform and the rail extends along the second surface in the circumferential direction around the shaft, and
• wherein the cooling fluid passage comprises in the circumferential direction at least the dimension of the through hole;
• a further aerofoil fixed to the surface of the inner platform and in flow communication with the through hole,
• wherein the inner platform comprises a further through hole for flow of the cooling fluid there through,
• wherein the rail comprises a further recessed portion comprising a further cooling fluid passage formed therein for the cooling fluid to flow through the further cooling fluid passage and to the further through hole, and
• wherein the further cooling flow passage comprises in circumferential direction at least the dimension of the further through hole.