First stage turbine nozzle with erosion coating surface finish

Abstract

A first stage turbine nozzle includes a first stage hub portion extending axially along a central axis, a first stage disk portion attached to the first stage hub portion and centered on the central axis, and a plurality of first stage vanes positioned radially around and attached to the first stage disk portion. Each vane extends a vane height H away from the first stage disk portion and each vane has a first end positioned at a diameter D away from the central axis. The first stage turbine nozzle also includes a plurality of first stage throats defined between radially adjacent first stage vanes. Each first stage throat has a throat width W between radially adjacent first stage vanes. The first stage turbine nozzle also includes a coating on a sidewall of each first stage vane, wherein a surface roughness of the sidewall is between 125 and 200 microinches Ra.

1 . A first stage turbine nozzle comprising:
 a first stage hub portion extending axially along a central axis;   a first stage disk portion attached to the first stage hub portion and centered on the central axis, wherein the first stage hub portion extends from a radially inner diameter of the first stage disk portion and axially away from the first stage disk portion in a first direction;   a plurality of first stage vanes positioned radially around and attached to the first stage disk portion, wherein each first stage vane extends a vane height H axially away from the first stage disk portion in a second direction opposite the first direction, and wherein each first stage vane has a first end positioned at a diameter D away from the central axis and a sidewall of each first stage vane has a surface roughness between 125 and 200 microinches Ra;   a plurality of first stage throats defined between radially adjacent first stage vanes, wherein each first stage throat has a throat width W between radially adjacent first stage vanes; and   a coating applied directly on a cast surface of the sidewall of each first stage vane, wherein the coating is a high velocity oxygen fuel spray-deposited tungsten carbide coating, and wherein the cast surface has not undergone post-processing to reduce the surface roughness of the sidewall prior to the application of the coating.   
     
     
         2 . The first stage turbine nozzle of  claim 1 , wherein the plurality of first stage vanes includes 19 vanes. 
     
     
         3 . The first stage turbine nozzle of  claim 1 , wherein a ratio of the vane height H to the throat width W is between 1.7377 and 2.1612. 
     
     
         4 . The first stage turbine nozzle of  claim 1 , wherein a ratio of the throat width W to the diameter D is between 0.0356 and 0.0401. 
     
     
         5 . The first stage turbine nozzle of  claim 1 , wherein a ratio of the vane height H to the diameter D is between 0.0690 and 0.0777. 
     
     
         6 . The first stage turbine nozzle of  claim 1 , wherein:
 the diameter D is between 7.5980 inches (19.2989 centimeters) and 7.6780 inches (19.5021 centimeters);   the vane height H is between 0.5300 inches (1.3462 centimeters) and 0.5900 inches (1.4986 centimeters); and   the throat width W is between 0.2730 inches (0.6934 centimeters) and 0.3050 inches (0.7747 centimeters).   
     
     
         7 . The first stage turbine nozzle of  claim 1 , wherein a flow area A is defined by a sum of the flow area in each first stage throat in the first stage turbine nozzle. 
     
     
         8 . The first stage turbine nozzle of  claim 7 , wherein the flow area A is between 2.7491 inches squared (17.7362 centimeters squared) and 3.4191 inches squared (22.0583 centimeters squared). 
     
     
         9 . An air cycle machine comprising:
 a fan section with a fan rotor;   a compressor section with a compressor nozzle;   a first stage turbine section with the first stage turbine nozzle of  claim 1 ; and   a second stage turbine section with a second stage turbine nozzle.