TURBINE NOZZLE PIECE PARTS WITH HVOC COATINGS

Abstract

A nozzle for an air cycle machine. The nozzle has a disk section having a central axis. The nozzle also includes a plurality of blades which extend a blade height H from a bladed face of the disk section. The plurality of blades are arranged radially about the disk section. The nozzle has a throat width W defined between each radially adjacent pair of the plurality of turbine blades. The nozzle includes a coating substantially encapsulating the disk section and the plurality of blades, wherein the coating contains more than 91 percent tungsten carbide by volume.

Description

BACKGROUND

The present invention relates to Air Cycle Machines (ACM), such as the type used in Environmental Control Systems in aircraft. In particular, the present invention relates to novel dimensions and coatings of turbine nozzles used in ACMs.

ACMs may be used to compress air in a compressor section. The compressed air is discharged to a downstream heat exchanger and further routed to a turbine. The turbine extracts energy from the expanded air to drive the compressor. The air output from the turbine may be utilized as an air supply for a vehicle, such as the cabin of an aircraft.

ACMs often have a three-wheel or four-wheel configuration. In a three-wheel ACM, a turbine drives both a compressor and a fan which rotate on a common shaft. In a four-wheel ACM, two turbine sections drive a compressor and a fan on a common shaft.

Airflow must be directed into the fan section to the compressor section, away from the compressor section towards the heat exchanger, from the heat exchanger to the turbine or turbines, and from the final turbine stage out of the ACM. In at least some of these transfers, it is desirable to direct air radially with respect to the central axis of the ACM. To accomplish this, rotating nozzles may be used to generate radial in-flow and/or out-flow.

Often, it is desirable for components such as nozzles to include coatings that protect the components from damage. For example, tungsten carbide coatings have been applied using detonation gun coating.

Thermal spraying techniques are known in the art and are often used to apply thick coatings to change surface properties of the component. Examples of known thermal spraying techniques include detonation gun coating, in which high pressure shock waves pass through a gas stream and cause the emission of bursts of the material to be deposited. Another known method of thermal spraying is high velocity oxy fuel (HVOF), in which the fuel combusts continuously, allowing for a continuous stream of material to be deposited.

SUMMARY

In one embodiment, a nozzle for an air cycle machine is disclosed which includes a disk section having a central axis. The nozzle also includes blades which extend from a bladed face of the disk section by a blade height H. The blades are arranged radially about the disk section. A throat width W is defined between each radially adjacent pair of the plurality of turbine blades. A coating substantially encapsulates the disk section and the plurality of blades, wherein the coating contains more than 91 percent tungsten carbide by volume.

In another embodiment, a nozzle for an air cycle machine is disclosed which also includes a disk section having a central axis. The nozzle also includes blades which extend from a bladed face of the disk section by a blade height H. The blades are arranged radially about the disk section. A throat width W is defined between each radially adjacent pair of the plurality of turbine blades. The coating substantially encapsulating the disk section and the plurality of blades has a thickness between 50.8 μm and 101.6 μm.

In a third embodiment, a nozzle for an air cycle machine is disclosed which also includes a disk section having a central axis. The nozzle also includes blades which extend from a bladed face of the disk section by a blade height H. The blades are arranged radially about the disk section. A throat width W is defined between each radially adjacent pair of the plurality of turbine blades. The coating substantially encapsulating the disk section and the plurality of blades comprises a metal alloy having a bond strength greater than 10,000 psi.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a four-wheel Air Cycle Machine.

FIG. 2 is a plan view of a turbine nozzle in the four-wheel Air Cycle Machine of FIG. 1.

FIG. 3 is a side view of the turbine nozzle of FIG. 2.

FIG. 4 is a plan view of a portion of the turbine nozzle of FIG. 2, showing the dimensions of the nozzle.

FIG. 5 is a plan view of a turbine nozzle in the four-wheel Air Cycle Machine of FIG. 1.

FIG. 6 is a side view of the turbine nozzle of FIG. 5.

FIG. 7 is a plan view of a portion of the turbine nozzle of FIG. 5, showing the dimensions of the nozzle.

FIG. 8 is a cross-sectional view of a three-wheel Air Cycle Machine.

FIG. 9 is a plan view of a turbine nozzle in the three-wheel Air Cycle Machine of FIG. 8.

FIG. 10 is a side view of the turbine nozzle of FIG. 9.

FIG. 11 is a plan view of a portion of the turbine nozzle of FIG. 9, showing the dimensions of the nozzle.

FIG. 12 is a plan view of a turbine nozzle in the three-wheel Air Cycle Machine of FIG. 8.

FIG. 13 is a side view of the turbine nozzle of FIG. 12.

FIG. 14 is a plan view of a portion of the turbine nozzle of FIG. 12, showing the dimensions of the nozzle.

DETAILED DESCRIPTION

FIG. 1 is a cross-sectional view of Air Cycle Machine (ACM) 2. ACM 2 is a four-wheel ACM, containing fan section 4, compressor section 6, first turbine section 8, and second turbine section 10, which are all connected to shaft 12. Shaft 12 rotates about central axis 14.

Fan section 4 includes fan inlet 16 and fan outlet 18. Fan inlet 16 is an opening in ACM 2 that receives working fluid from another source, such as a ram air scoop. Fan outlet 18 allows working fluid to escape fan section 4. Fan blades 20 may be used to draw working fluid into fan section 4.

Compressor section 6 includes compressor inlet 22, compressor outlet 24, compressor nozzle 26, and compressor blades 27. Compressor inlet 22 is a duct defining an aperture through which working fluid to be compressed is received from another source. Compressor outlet 24 allows working fluid to be routed to other systems after it has been compressed. Compressor nozzle 26 is a nozzle section that rotates through working fluid in compressor section 6. Compressor nozzle 26 directs working fluid from compressor inlet 22 to compressor outlet 24 via compressor blades 27. Compressor nozzle 26 is a radial out-flow rotor.

First turbine section 8 includes first stage turbine inlet 28, first stage turbine outlet 30, first stage turbine nozzle 32, and first turbine blades 33. First stage turbine inlet 28 is a duct defining an aperture through which working fluid passes prior to expansion in first turbine section 8. First stage turbine outlet 30 is a duct defining an aperture through which working fluid (which has expanded) departs first turbine section 8. First stage turbine nozzle 32 is a nozzle section that rotates through working fluid in first turbine section 8. First stage turbine nozzle 32 cooperates with first stage turbine blades 37 to extract energy from working fluid passing therethrough, driving the rotation of first turbine section 8 and attached components, including shaft 12, fan section 4, and compressor section 6. First stage turbine nozzle 32 is a radial in-flow rotor.

Second turbine section 10 includes second stage turbine inlet 34, second stage turbine outlet 36, second stage turbine nozzle 38, and second stage turbine blades 39. Second stage turbine inlet 34 is a duct defining an aperture through which working fluid passes prior to expansion in second turbine section 10. Second stage turbine outlet 36 is a duct defining an aperture through which working fluid (which has expanded) departs second turbine section 10. Second stage turbine nozzle 38 is a nozzle section that cooperates with second stage turbine blades 39 to extract energy from working fluid passing therethrough, driving the rotation of second turbine section 10 and attached components, including shaft 12, fan section 4, and compressor section 6. In particular, second stage turbine nozzle 38 is a radial out-flow rotor. Working fluid passes from second stage turbine inlet 34 to cavity 35, where it is incident upon second stage turbine nozzle 38. Working fluid then passes between nozzle blades 50 and 52 (FIGS. 5-7). Turbine nozzle 38 is stationary, and the nozzle vanes guide the flow for optimum entry into the turbine rotor. The flow of causes turbine blades 39 to rotate and turb shaft 12.

Shaft 12 is a rod, such as a titanium tie-rod, used to connect other components of ACM 2. Central axis 14 is an axis with respect to which other components may be arranged.

Fan section 4 is connected to compressor section 6. In particular, fan outlet 18 is coupled to compressor inlet 22. Working fluid is drawn through fan inlet 16 and discharged through fan outlet 18 by fan blades 20. Working fluid from fan outlet 18 is routed to compressor inlet 22 for compression in compressor section 6. Similarly, compressor section 6 is coupled with first turbine section 8. Working fluid from compressor outlet 24 is routed to first stage turbine inlet 28.

Similarly, first turbine section 8 is coupled to second turbine section 10. Working fluid from first stage turbine outlet 30 is routed to second stage turbine inlet 34. In this way, working fluid passes through ACM 2: first through fan inlet 16, then fan outlet 18, compressor inlet 22, compressor outlet 24, first stage turbine inlet 28, first stage turbine outlet 30, second stage turbine inlet 34, and second stage turbine outlet 38. Additional stages may exist between those shown in FIG. 1. For example, often a heat exchanger (not shown) is located between compressor section 6 and first turbine section 8.

Each of fan section 4, compressor section 6, first turbine section 8, and second turbine section 10 are also connected to one another via shaft 12. Shaft 12 runs along central axis 14, and is connected to at least compressor nozzle 26, first stage turbine nozzle 32, and second stage turbine nozzle 38. Fan blades 20 may also be connected to shaft 12.

When working fluid passes through ACM 2, it is first compressed in compressor section 6, then expanded in first turbine section 8 and second turbine section 10. Often, the working fluid is also heated or cooled in a heat exchanger (not shown) through which working fluid is routed as it passes between compressor section 6 and first turbine section 8. First turbine section 8 and second turbine section 10 extract energy from the working fluid, turning shaft 12 about central axis 14.

Working fluid passing through ACM 2 may be conditioned for use in the central cabin of a vehicle powered by a gas turbine engine. By compressing, heating, and expanding the working fluid, it may be adjusted to a desired temperature, pressure, and/or relative humidity. However, due to the rapid rotation of compressor nozzle 26, first stage turbine nozzle 32, and second stage turbine nozzle 38 with respect to the working fluid flowpath, these parts need frequent replacement.

FIG. 2 is a plan view of first stage turbine nozzle 32 arranged about central axis 14. First stage turbine nozzle 32 includes nineteen full blades 40 arranged along a surface of disk 42. Full blades 40 and disk 42 are made of a durable material such as steel, aluminum, or titanium. First stage turbine nozzle 32 is coated with tungsten carbide. The tungsten carbide coating on first stage turbine nozzle 32 is applied using HVOF, allowing for increased hardness and a higher percentage of tungsten carbide as opposed to other materials, such as cobalt. HVOF spraying also results in reduced variability in coating thickness as compared to traditional coating methods, such as deposition gun spraying.

Disk 42 is radially symmetrical about central axis 14. Full blades 40 are spaced equidistantly from one another about the circumferential length of disk 42. Each of full blades 40 are also equidistant radially from central axis 14.

First stage turbine nozzle 32 is a high value component that is relatively frequently replaced. Damage to first stage turbine nozzle 32 may occur due to contact with abrasive particles. Thus, a high strength, durable coating may increase the service life of first stage turbine nozzle 32.

FIG. 3 is a side view of first stage turbine nozzle 32. First stage turbine nozzle 32 contains full blades 40 and disk 42, as described with respect to FIG. 2.

FIG. 3 illustrates the thickness of first stage turbine nozzle 32. In particular, first stage turbine nozzle 32 includes blade height H32. Blade height H32 is the amount of head space between disk 42 and an adjacent component such as a shroud (not shown). Blade height H32 as shown in FIG. 3 is 0.686 cm (0.270 in.). In some embodiments, blade height H32 may vary by as much as 0.01 cm (0.005 in.). However, blade height H32 of 0.686 cm is ideal for the passage of the desired quantity of working fluid through first turbine section 8 (FIG. 1).

FIG. 4 is an enlarged view of a portion of first stage turbine nozzle 32. The portion shown in FIG. 4 shows full blades 40 arranged on disk 42.

FIG. 4 illustrates various specific dimensions of first stage turbine nozzle 32. Nozzle passage width W32 is the distance between each full blade 40 and the radially adjacent full blade 40. In effect, nozzle passage width W32 is the width of a throat through which working air may be routed. Nozzle passage width W32 is 0.340 cm. (0.134 in.), but may deviate by as much as 0.013 cm. (0.005 in.). Flow area A32 is the region through which working fluid may flow. Flow area A32 converges between the vanes until it reaches the throat of first stage turbine nozzle 32, and has a surface area of nozzle height H32×nozzle passage width W32. Due to machining tolerances, flow area A32 area may vary by up to 5%. Flow area A32 is approximately 4.432 square centimeters (0.687 square in.).

Nozzle passage width W32 is optimized to ensure proper flow and energy extraction from first stage turbine nozzle 32. Increasing or decreasing nozzle passage width W32 would result in too much or too little flow through first stage turbine nozzle 32 Likewise, flow area A32 is optimized to ensure an appropriate quantity of working fluid is transmitted by first stage turbine nozzle 32. A larger flow area A32 would result in too much working fluid passing through first stage turbine nozzle 32, while a smaller flow area A32 would result in too little.

FIG. 5 is a plan view of second stage turbine nozzle 38 arranged about central axis 14. Second stage turbine nozzle 38 includes seventeen full blades 50 and seventeen splitter blades 52 arranged along a surface of disk 54. Full blades 50, splitter blades 52, and disk 54 are made of a durable material such as steel, aluminum, or titanium. Second stage turbine nozzle 38 is coated with tungsten carbide. The tungsten carbide coating on second stage turbine nozzle 38 is applied using High-Velocity Oxy-Fuel (HVOF) spraying, allowing for increased hardness and a higher percentage of tungsten carbide as opposed to other materials, such as cobalt.

Disk 54 is radially symmetrical about central axis 14. Full blades 50 and splitter blades 52 are interdigitated and spaced equidistantly from one another about the circumferential length of disk 54. Thus, full blades 50 are each located between two adjacent splitter blades 52, and splitter blades 52 are each located between two adjacent full blades 50. Each of splitter blades 52, and each of full blades 50, are equidistant radially from central axis 14.

Second stage turbine nozzle 38 is a high value component that is relatively frequently replaced. Damage to second stage turbine nozzle 38 may occur due to abrasive particulates in the high velocity airflow directed by second stage turbine nozzle 38. Thus, a highly durable coating on second stage turbine nozzle 38 may increase its service life.

HVOF coating of second stage turbine nozzle causes unique physical characteristics that are not possible using traditional coating technologies, such as deposition gun coating. HVOF coating may, for example, allow for levels of tungsten carbide in excess of 91%. In addition, HVOF coating provides for surface hardness in excess of 10,000 psi. Furthermore, HVOF coating provides for reduced variability in surface coating thickness as compared to detonation gun coating.

FIG. 6 is a side view of second stage turbine nozzle 38. Second stage turbine nozzle 38 contains full blades 50, splitter blades 52, and disk 54, as described with respect to FIG. 5.

FIG. 6 illustrates the thickness of second stage turbine nozzle 38. In particular, second stage turbine nozzle 38 includes blade height H38. Blade height H38 is the amount of head space between disk 54 and an adjacent component such as a shroud (not shown). Blade height H38 as shown in FIG. 6 is 0.940 cm (0.370 in). In some embodiments, blade height H38 may vary by as much as 0.01 cm (0.005 in). However, blade height H38 of 0.940 cm is ideal for the passage of the desired quantity of working fluid through second turbine section 10 (FIG. 1).

FIG. 7 is an enlarged view of a portion of second stage turbine nozzle 38. The enlarged portion shown in FIG. 7 shows full blades 50 and splitter blades 52 arranged on disk 54.

FIG. 7 illustrates various specific dimensions of second stage turbine nozzle 38. Nozzle passage width W38 is the distance between each full blade 50 and adjacent splitter blade 52. In effect, nozzle passage width W38 is the width of a throat through which working air may be routed. Nozzle passage width W38 is 0.222 cm (0.0875 in), but may deviate by as much as 0.013 cm (0.005 in). Flow area A38 is the region through which working fluid may flow. Flow area A38 is the total cross-sectional area orthogonal to the surface of disk 54 on the bladed side that is not covered by full blades 50 and splitter blades 52 and through which working fluid flows. The portion of flow area A38 identified in FIG. 7 is the flow area A between one full blade 50 and one splitter blade 52. In sum, over the entire surface of second stage turbine nozzle 38, flow area A38 is 7.103 square centimeters (1.101 square inches). Due to minor differences in machining and/or coating, this value may be as high as 7.458 of as low as 6.748 square centimeters.

Nozzle passage width W38 is optimized to ensure proper flow and energy extraction from second stage turbine nozzle 38. Increasing or decreasing nozzle passage width W38 would result in too little or too much flow through second stage turbine nozzle 38. Likewise, flow area A38 is optimized to ensure an appropriate quantity of working fluid is transmitted by second stage turbine nozzle 38. A larger flow area A38 would result in too much working fluid passing through second stage turbine nozzle 38, while a smaller flow area A38 would result in too little.

FIG. 8 is a cross-sectional view of ACM 100. ACM 100 is a three-wheel ACM, containing fan section 102, compressor section 104, and turbine section 106, all of which are connected to shaft 108. Shaft 108 rotates about central axis 110.

Fan section 102 includes fan inlet 112 and fan outlet 114. Fan inlet 112 is an opening in ACM 100 that receives working fluid from another source, such as a bleed valve in a gas turbine engine (not shown). Fan outlet 114 allows working fluid to escape fan section 102. Fan blades 116 may be used to draw working fluid into fan section 102.

Compressor section 104 includes compressor inlet 118, compressor outlet 120, and compressor nozzle 122. Compressor inlet 118 is a duct defining an aperture through which working fluid to be compressed is received from another source, such as fan section 102. Compressor outlet 120 allows working fluid to be routed to other systems once it has been compressed. Compressor nozzle 122 is a nozzle section that rotates through working fluid in compressor section 104. In particular, compressor nozzle 122 is a radial out-flow rotor.

Turbine section 106 includes turbine inlet 124, turbine outlet 126, and turbine nozzle 128. Turbine inlet 124 is a duct defining an aperture through which working fluid passes prior to expansion in turbine section 106. Turbine outlet 126 is a duct defining an aperture through which working fluid which has expanded departs turbine section 106. Turbine nozzle 128 is a nozzle section that extracts energy from working fluid passing therethrough, driving the rotation of turbine section 106 and attached components, including shaft 108, fan section 102, and compressor section 104.

Shaft 108 is a rod, such as a titanium tie-rod, used to connect other components of ACM 100. Central axis 110 is an axis with respect to which other components may be arranged.

Fan section 102 is connected to compressor section 104. In particular, fan outlet 114 is coupled to compressor inlet 118 such that working fluid may be transferred from fan outlet 114 to compressor inlet 118. Working fluid is drawn through fan inlet 112 and discharged through fan outlet 114 by fan blades 116. Working fluid from fan outlet 114 is routed to compressor inlet 118 for compression in compressor section 104.

Similarly, compressor section 104 is coupled with first turbine section 106. Working fluid from compressor outlet 120 is routed to turbine inlet 124. In this way, working fluid passes through ACM 100: first through fan inlet 112, then fan outlet 114, compressor inlet 118, compressor outlet 120, turbine inlet 124, and turbine outlet 126. Additional stages may exist between those shown in FIG. 8. For example, often a heat exchanger (not shown) is located between compressor section 104 and turbine section 106.

Each of fan section 102, compressor section 104, and turbine section 106 are also connected to one another via shaft 108. Shaft 108 runs along central axis 110, and is connected to at least compressor nozzle 122 and turbine nozzle 128. Fan blades 116 may also be connected to shaft 20.

When working fluid passes through ACM 100, it is first compressed in compressor section 104, then expanded in turbine section 106. Often, the working fluid is also heated or cooled in a heat exchanger (not shown) through which working fluid is routed as it passes between compressor section 104 and turbine section 106. Turbine section 106 to extract energy from the working fluid, turning shaft 20 about central axis 110.

Working fluid passing through ACM 100 may be conditioned for use in the central cabin of a vehicle powered by a gas turbine engine. By compressing, heating, and expanding the working fluid, it may be adjusted to a desired temperature, pressure, and/or relative humidity. However, due to the rapid rotation of compressor nozzle 122 and turbine nozzle 128 with respect to the working fluid flowpath, these parts need frequent replacement.

FIG. 9 is a plan view of turbine nozzle 128 arranged about central axis 110. Turbine nozzle 128 includes nineteen full blades 130 arranged along a surface of disk 132. Full blades 130 and disk 132 are made of a durable material such as steel, aluminum, or titanium. Turbine nozzle 128 is coated with tungsten carbide. The tungsten carbide coating on first stage turbine nozzle 128 is applied using HVOF, allowing for increased hardness and a higher percentage of tungsten carbide as opposed to other materials, such as cobalt. HVOF spraying also results in reduced variability in coating thickness as compared to traditional coating methods, such as deposition gun spraying, as will be described in more detail with respect to FIGS. 15A-15B.

Disk 132 is radially symmetrical about central axis 110. Full blades 130 are spaced equidistantly from one another about the circumferential length of disk 132. Each of full blades 130 are also equidistant radially from central axis 110.

Turbine nozzle 128 is a high value component that is relatively frequently replaced. Damage to turbine nozzle 128 may occur due to contact with abrasive particles. Thus, a high strength, durable coating may increase the service life of turbine nozzle 128.

FIG. 10 is a side view of turbine nozzle 128. Turbine nozzle 128 contains full blades 130 and disk 132, as described with respect to FIG. 9.

FIG. 10 illustrates the thickness of turbine nozzle 128. In particular, turbine nozzle 128 includes blade height H128. Blade height H128 is the amount of head space between disk 132 and an adjacent component such as a shroud (not shown). In a first embodiment, blade height H128 as shown in FIG. 10 is 0.318 cm (0.125 in). In a second embodiment in which an increased quantity of working fluid flow is desired, blade height H as shown in FIG. 10 may be 0.393 cm (0.155 in). In some versions of the first and second embodiments described above, blade height H128 may vary by as much as 0.01 cm (0.005 in.). However, blade heights H 134 of 0.318 cm or 0.393 cm are ideal for ACM 100 (FIG. 8) to pass a desired quantity of working fluid through turbine section 106 (FIG. 8).

FIG. 11 is an enlarged view of a portion of turbine nozzle 128. The enlarged portion shown in FIG. 11 shows full blades 130 arranged on disk 132.

FIG. 11 illustrates various specific dimensions of turbine nozzle 128. Nozzle passage width W128 is the distance between each full blade 130 and the radially adjacent full blade 130. In effect, nozzle passage width W128 is the width of a throat through which working air may be routed. Nozzle passage width W128 is 0.241 cm (0.095 in.), but may deviate by as much as 0.013 cm. (0.005 in.). Flow area A128 is the region through which working fluid may flow. Flow area A128 is the total surface area of disk 132 on the bladed side through which working fluid may flow between full blades 130. The portion of flow area A128 identified in FIG. 11 is the flow area A between one full blade 130 and its adjacent full blade 130. In sum, over the entire surface of turbine nozzle 128, flow area A128 is 1.451 cm. squared (0.225 square inches) in the first embodiment described above, and 1.806 cm. squared (0.255 square inches) in the second embodiment described above. Due to minor differences in machining and/or coating, these values may vary by as much as 5%.

Nozzle passage width W128 is optimized to ensure proper flow and energy extraction from turbine nozzle 128. Increasing or decreasing nozzle passage width W128 would result in either too much or too little fluid flow through nozzle 128A. Likewise, flow area A128 is optimized to ensure an appropriate quantity of working fluid is transmitted by first stage turbine nozzle 128. A larger flow area A128 would result in too much working fluid passing through turbine nozzle 128, while a smaller flow area A128 would result in too little.

FIG. 12 is a plan view of turbine nozzle 128A, an alternative embodiment capable of being used in three-wheel ACM 100. Turbine nozzle 128A may also be arranged about central axis 110. As with turbine nozzle 128, described above with respect to FIGS. 8-11, turbine nozzle 128A may be used in ACM 100 (FIG. 8). Turbine nozzle 128A includes twenty-three full blades 130A arranged along a surface of disk 132A. Full blades 130A and disk 132A are made of a durable material such as steel, aluminum, or titanium. Turbine nozzle 128A is coated with tungsten carbide. The tungsten carbide coating on turbine nozzle 128A is applied using HVOF spraying, allowing for increased hardness and a higher percentage of tungsten carbide as opposed to other materials, such as cobalt.

Disk 132A is radially symmetrical about central axis 110. Full blades 130A are spaced equidistantly from one another about the circumferential length of disk 132A. Thus, full blades 130A are located between two adjacent full blades 130A, and each of full blades 130A are equidistant radially from central axis 110.

Turbine nozzle 128A is a high value component that is relatively frequently replaced. Damage to turbine nozzle 128A may occur due to abrasive particulates in the high velocity airflow directed by turbine nozzle 128A. Thus, a highly durable coating on second stage turbine nozzle 128A may increase its surface life.

FIG. 13 is a side view of turbine nozzle 128A. Turbine nozzle 128A contains full blades 130A and disk 132A, as described with respect to FIG. 12.

FIG. 13 illustrates the thickness of turbine nozzle 128A. In particular, turbine nozzle 128A includes blade height H128A. Blade height H128A is the amount of head space between disk 132A and an adjacent component such as a shroud (not shown). Blade height H128A as shown in FIG. 13 is 0.305 cm. (0.120 in.). In some embodiments, blade height H128A may vary by as much as 0.01 cm. (0.005 in.). However, blade height H128A of 0.305 cm. is ideal for the passage of the desired quantity of working fluid through turbine section 106 (FIG. 8).

FIG. 14 is an enlarged view of a portion of turbine nozzle 128A. The enlarged portion shown in FIG. 14 shows full blades 130A arranged on disk 132A.

FIG. 14 illustrates various specific dimensions of turbine nozzle 128A. Nozzle passage width W128A is the distance between each full blade 130A and its adjacent full blade 130A. In effect, nozzle passage width W128A is the width of a throat through which working fluid may be routed. Nozzle passage width W128A is 0.234 cm. (0.092 in.), but may deviate by as much as 0.013 cm. (0.005 cm.). Flow area A128A is the cross-sectional area through which fluid may flow on the bladed side of disk 132A between full blades 130A. The portion of flow area A128A identified in FIG. 14 is the flow area A between one full blade 130A and the adjacent full blade 130A. In sum, over the entire bladed surface side of disk 132A in turbine nozzle 128A, flow area A128A is 1.639 square centimeters (0.254 square inches). Due to minor differences in machining and/or coating, this value may be as high as 1.721 square centimeters or as low as 1.557 square centimeters.

Nozzle passage width W128A is optimized to ensure proper flow and energy extraction from turbine nozzle 128A. Increasing or decreasing nozzle passage width W128A would result in either too much or too little fluid flow passing across turbine nozzle 128A. Likewise, flow area A128A is optimized to ensure an appropriate quantity of working fluid is transmitted by turbine nozzle 128A. A larger flow area A128A would result in too much working fluid passing through turbine nozzle 128A, while a smaller flow area A128A would result in too little.

Each previously described turbine nozzle embodiments is coated. The coatings are applied using HVOF. Thus, each previously described turbine nozzle has a base made of any of a range of acceptable base materials, such as steel, aluminum, ceramic, or titanium. A coating is sprayed onto the base using HVOF, the coating primarily consisting of tungsten carbide. Previously, detonation gun coating was used to apply the coating.

The coating applied is not pure tungsten carbide. In order to facilitate coating using detonation gun technology, the coating is often composed of 12% cobalt, plus or minus 2%. Accordingly, the surface coating has an adhesion strength of 8500 psi, plus or minus 5%. However, using HVOF, the coating may have a higher percentage of tungsten carbide. A coating applied using HVOF is often composed of 9% cobalt, plus or minus 2%. Often, the coating may contain less than 8% cobalt by volume. Accordingly, the surface coating 164 has an adhesion strength of 10,000 psi, plus or minus 5%.

A coating applied using detonation gun technology typically has a minimum thickness of approximately 0.00254 cm. (0.001 in.). These prior art coatings often have a range of approximately 0.00762 cm. (0.003 in.), plus or minus 2%. A coating applied using HVOF will typically have a minimum thickness of approximately 0.00508 cm. (0.002 in.), and a range of 0.00508 cm. (0.002 in.).

While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.

Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A nozzle for an air cycle machine, comprising:

a disk section having a central axis;

a plurality of blades which extend a blade height H from a bladed face of the disk section, the plurality of blades arranged radially about the disk section;

a throat width W defined between each radially adjacent pair of the plurality of turbine blades; and

a coating substantially encapsulating the disk section and the plurality of blades, wherein the coating contains more than 91 percent tungsten carbide by volume.

2. The nozzle of claim 1, wherein the coating contains less than 8 percent cobalt by volume.

3. The nozzle of claim 1, wherein the plurality of blades consists of 34 blades.

4. The nozzle of claim 1, wherein the blade height H is 0.940 cm.

5. The nozzle of claim 1, wherein the throat width is 0.222 cm.

6. The nozzle of claim 1, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 7.103 cm square.

7. The nozzle of claim 1, wherein the plurality of blades consists of 19 blades.

8. The nozzle of claim 1, wherein the blade height H is 0.686 cm.

9. The nozzle of claim 1, wherein the throat width is 0.340 cm.

10. The nozzle of claim 1, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 4.432 cm square.

11. The nozzle of claim 1, wherein the blade height H is 0.318 cm.

12. The nozzle of claim 1, wherein the blade height H is 0.393 cm.

13. The nozzle of claim 1, wherein the throat width is 0.241 cm.

14. The nozzle of claim 1, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.451 cm square.

15. The nozzle of claim 1, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.806 cm square.

16. The nozzle of claim 1, wherein the plurality of blades consists of 23 blades.

17. The nozzle of claim 1, wherein the blade height H is 0.305 cm.

18. The nozzle of claim 1, wherein the throat width is 0.234 cm.

19. The nozzle of claim 1, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.639 cm square.

20. The nozzle of claim 1, wherein the coating has a thickness between 50.8 μm and 101.6 μm.

21. The nozzle of claim 1, wherein the coating comprises a metal alloy having a surface coating adhesion strength greater than 10,000 psi.

22. The nozzle of claim 20, wherein the coating comprises a metal alloy having a surface coating adhesion strength greater than 10,000 psi.

23. A nozzle for an air cycle machine, comprising:

a disk section having a central axis;

a plurality of blades which extend a blade height H from a bladed face of the disk section, the plurality of blades arranged radially about the disk section;

a throat width W defined between each radially adjacent pair of the plurality of turbine blades; and

a coating substantially encapsulating the disk section and the plurality of blades, wherein the coating has a thickness between 50.8 μm and 101.6 μm.

24. The nozzle of claim 23, wherein the coating contains less than 8 percent cobalt by volume.

25. The nozzle of claim 23, wherein the plurality of blades consists of 34 blades.

26. The nozzle of claim 23, wherein the blade height His 0.940 cm.

27. The nozzle of claim 23, wherein the throat width is 0.222 cm.

28. The nozzle of claim 23, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 7.103 cm square.

29. The nozzle of claim 23, wherein the plurality of blades consists of 19 blades.

30. The nozzle of claim 23, wherein the blade height H is 0.686 cm.

31. The nozzle of claim 23, wherein the throat width is 0.340 cm.

32. The nozzle of claim 23, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 4.432 cm square.

33. The nozzle of claim 23, wherein the blade height H is 0.318 cm.

34. The nozzle of claim 23, wherein the blade height H is 0.393 cm.

35. The nozzle of claim 23, wherein the throat width is 0.241 cm.

36. The nozzle of claim 23, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.451 cm square.

37. The nozzle of claim 23, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.806 cm square.

38. The nozzle of claim 23, wherein the plurality of blades consists of 23 blades.

39. The nozzle of claim 23, wherein the blade height H is 0.305 cm.

40. The nozzle of claim 23, wherein the throat width is 0.234 cm.

41. The nozzle of claim 23, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.639 cm square.

42. The nozzle of claim 23, wherein the coating comprises a metal alloy having a surface adhesion strength greater than 10,000 psi.

43. A nozzle for an air cycle machine, comprising:

a disk section having a central axis;

a plurality of blades which extend a blade height H from a bladed face of the disk section, the plurality of blades arranged radially about the disk section;

a throat width W defined between each radially adjacent pair of the plurality of turbine blades; and

a coating substantially encapsulating the disk section and the plurality of blades, wherein the coating comprises a metal alloy having a surface coating adhesion strength greater than 10,000 psi.

44. The nozzle of claim 43, wherein the coating contains less than 8 percent cobalt by volume.

45. The nozzle of claim 43, wherein the plurality of blades consists of 34 blades.

46. The nozzle of claim 43, wherein the blade height H is 0.940 cm.

47. The nozzle of claim 43, wherein the throat width is 0.222 cm.

48. The nozzle of claim 43, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 7.103 cm square.

49. The nozzle of claim 43, wherein the plurality of blades consists of 19 blades.

50. The nozzle of claim 43, wherein the blade height H is 0.686 cm.

51. The nozzle of claim 43, wherein the throat width is 0.340 cm.

52. The nozzle of claim 43, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 4.432 cm square.

53. The nozzle of claim 43, wherein the blade height H is 0.318 cm.

54. The nozzle of claim 43, wherein the blade height H is 0.393 cm.

55. The nozzle of claim 43, wherein the throat width H is 0.241 cm.

56. The nozzle of claim 43, and further including a flow area A defined by the surface area of the bladed face of the disk less the area covered by the plurality of blades, and wherein the flow area A is equal to 1.451 cm square.

57. The nozzle of claim 43, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.806 cm square.

58. The nozzle of claim 43, wherein the plurality of blades consists of 23 blades.

59. The nozzle of claim 43, wherein the blade height H is 0.305 cm.

60. The nozzle of claim 43, wherein the throat width is 0.234 cm.

61. The nozzle of claim 43, and further including a flow area A defined by the surface area along the bladed face of the disk and between the blades, and wherein the flow area A is equal to 1.639 cm square.