Turbine stator blade and steam turbine
A turbine stator blade ( 21 ) includes a pressure side ( 21 P) extending in a radial direction intersecting a flow direction of steam, and facing upstream in the flow direction. A slit ( 5 ) extending in the radial direction and capturing a liquefied component of the steam is formed on a downstream side of the pressure side ( 21 P). A hydrophilic uneven region ( 6 ) having a liquid film capacity greater than that of the pressure side ( 21 P) by being recessed in a depth direction intersecting the pressure side ( 21 P) is formed in a further upstream position than the slit ( 5 ). The hydrophilic uneven region ( 6 ) has a depth in the depth direction increasing and a flow resistance decreasing toward downstream and toward the slit ( 5 ).
1. A turbine stator blade comprising:
a pressure side extending in a radial direction intersecting a flow direction of steam and facing upstream in the flow direction,
wherein a slit extending in the radial direction and capturing a liquefied component of the steam is formed on a downstream side of the pressure side,
a hydrophilic uneven region having a liquid film capacity greater than that of the pressure side by being recessed in a depth direction intersecting the pressure side is formed in a further upstream position than the slit, and
the hydrophilic uneven region has a depth in the depth direction increasing and a flow resistance decreasing toward downstream and toward the slit.
2. The turbine stator blade according to claim 1 ,
wherein the hydrophilic uneven region includes a plurality of protruding portions arranged at intervals in the flow direction and the radial direction, and
a length between the protruding portions in the flow direction is referred to as La, a length of each of the protruding portions in the flow direction is referred to as Lb, and a value of La/Lb decreases toward downstream and toward the slit.
3. The turbine stator blade according to claim 2 , wherein the protruding portions have rectangular shapes when viewed in a direction orthogonal to the pressure side and have rectangular cross sections when viewed in the radial direction.
4. The turbine stator blade according to claim 1 , wherein the hydrophilic uneven region has the depth in the depth direction increasing stepwise from upstream toward downstream in the flow direction.
5. The turbine stator blade according to claim 1 , further comprising a water-repellent region provided in a further upstream position than the hydrophilic uneven region in the flow direction and has higher water repellency than that of the pressure side.
6. A steam turbine comprising:
a rotary shaft rotatable around an axis;
a plurality of turbine rotor blades arranged in a circumferential direction with respect to an axis direction on an outer peripheral surface of the rotary shaft;
a casing covering the rotary shaft and the turbine rotor blades from an outer peripheral side; and
a plurality of the turbine stator blades according to claim 1 arranged in the circumferential direction around the axis on an inner peripheral surface of the casing and provided adjacent to the turbine rotor blades in the axis direction.