Water-flow testing apparatus

This invention relates to the water-testing of an article by running a flow of water through the article, and more particularly to the water-testing of a hollow turbine airfoil component having multiple flow channels therethrough.

BACKGROUND OF THE INVENTION

Some types of turbine airfoil components are made hollow with air flow channels therethrough, extending from the base of the turbine airfoil component to openings at various locations on the surface of the turbine airfoil component. During service, a flow of cooling air is introduced into the air flow channels at the base. The cooling air flows through the interior of the turbine airfoil component to emerge from the openings. Heat is removed from the turbine airfoil component by the air flow. Additionally, the air flow from the openings provides a film of cool air over the surface of the turbine airfoil component to protect it from hot combustion gases.

The hollow interior of the turbine airfoil component is typically divided into multiple regions, both to provide internal structural stiffening and also to define separate air flow channels. The separate air flow channels may lead, for example, to respective sets of exterior surface openings along the leading edge of the turbine airfoil component, along the trailing edge of the turbine airfoil component, and along the concave or pressure-side of the turbine airfoil component which is directly contacted by the flow of hot combustion gases.

The turbine airfoil component is typically manufactured by casting it with the internal air flow channels in place, and then drilling the openings from the exterior surface to the air flow channels. The turbine airfoil component is thereafter coated on portions of its exterior surface, and optionally on its interior surface of the air flow channels. The coatings form protective layers and possibly insulating layers on the surfaces, to extend the life of the turbine airfoil component.

At various stages of the manufacturing operation, the turbine airfoil component is water tested to ensure that the openings from the gas-flow channels to the exterior surface are clear and free from blockage. Blocked or nearly blocked openings may result, for example, from a defect when the opening is formed or from a partial or complete closure of the opening during the coating process. In water testing, the base of the turbine airfoil component is held in a fixture to a water source, and water flows along generally the same flow path as air flows in service, from the base, through the air flow channels, and out the openings. The water flow out of the openings is observed to determine whether the flow from each and every opening is sufficient and indicative of an unobstructed opening.

In the work leading to this invention, the inventors have observed that in some cases it is very difficult to visualize the flow from each of the openings served by the various flow air channels. Consequently, it is difficult to be certain that the openings are properly sized and free of obstructions. Accordingly, there is a need for a better technique and apparatus for testing water flow through such hollow articles. The present invention fulfills this need, and further provides related advantages.

SUMMARY OF THE INVENTION

The present invention provides an apparatus and method for water-flow testing of hollow articles such as turbine airfoil components with multiple internal water-flow channels. The present approach allows the water flow through the various sets of openings to be more readily visualized. Additionally, the apparatus is mechanically easier to use than available conventional devices.

A water-flow testing apparatus for testing an article having at least two water flow passage article inlets comprises an apparatus body having a water inlet and an attachment head integral with the apparatus body. The attachment head includes a holder that receives the article therein in sealing contact with an article seal, and at least two ports, each port being in registry with at least one of the water flow passage article inlets. A water flow controller within the apparatus body has a controller inlet in water-flow communication with the water inlet, at least two controller outlets, with each controller outlet being in water-flow communication with one of the ports of the attachment head, and a flow-control valve disposed in a water flow path between the controller inlet and the controller outlets. The flow-control valve is controllable to controllably connect a single one of the controller outlets at a time to the controller inlet.

In one preferred embodiment, the holder comprises a jaw mechanism that engages the article on two opposite sides of the article when open and draws the article toward the article seal as the jaw moves toward a closed position. The holder may further comprise a spring that biases the jaw toward the closed position. The article seal comprises a piece of rubber with the at least two seal inlets therethrough. The flow-control valve comprises a valve bore in water-flow communication with each of the controller outlets, a valve core slidably received within the valve bore, the valve having a channel therethrough that may be slidably aligned with each controller outlet, and a sliding core seal at each end of the valve bore to slidingly seal the valve core to the valve bore.

Preferably, a water-flow testing apparatus is provided for testing a turbine airfoil component having at least two water flow passage turbine airfoil component inlets in a base thereof and an external dovetail region on an external surface of the base. The water-flow testing apparatus comprises an apparatus body having a water inlet, and an attachment head integral with the apparatus body. The attachment head includes an article seal, wherein the article seal comprises a piece of rubber with at least two seal inlets therethrough, each seal inlet being in registry with at least one of the at least two water flow passage turbine airfoil component inlets, and a holder that receives the turbine airfoil component therein in sealing contact with the article seal. The holder comprises a jaw mechanism having camming surfaces that engage the turbine airfoil component on the dovetail region when open and draws the base of the turbine airfoil component toward the article seal as the jaw mechanism moves toward a closed position. A spring biases the jaw mechanism toward the closed position. A water flow controller within the apparatus body has a controller inlet in water-flow communication with the water inlet, at least two controller outlets, with each controller outlet being in water-flow communication with one of the seal inlets of the attachment head, and a flow-control valve disposed in a water flow path between the controller inlet and the controller outlets. The flow-control valve is controllable to controllably connect a single one of the controller outlets at a time to the controller inlet. The flow-control valve comprises a valve bore in water-flow communication with each of the controller outlets, a valve core slidably received within the valve bore, with the valve core having a channel therethrough that may be slidable aligned with each controller outlet, and a sliding core seal at each end of the valve bore to slidingly seal the valve core to the valve bore.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The scope of the invention is not, however, limited to this preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view of a turbine airfoil component;

FIG. 2

is a sectional view of the turbine airfoil component of

FIG. 1

, taken along line

2

—

2

;

FIG. 3

is a partially exploded perspective view of a water-flow testing apparatus for testing the turbine airfoil component;

FIG. 4

is an elevational view of the water-flow testing apparatus of

FIG. 3

, with a portion in section and with a turbine airfoil component in position for water-flow testing;

FIG. 5

is a sectional view of the water-flow controller of the water-flow testing apparatus, taken on line

5

—

5

of

FIG. 3

;

FIG. 6

is a sectional view of the water-flow controller, taken on line

6

—

6

of

FIG. 5

;

FIG. 7

is a sectional view of the water-flow controller of

FIG. 5

, taken along line

7

—

7

of

FIG. 5

;

FIG. 8

is an elevational view of the water-flow distribution plate of the water-flow controller; and

FIG. 9

is a perspective view of the seal between the water-flow testing apparatus and the turbine airfoil component.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1

depicts a turbine airfoil component

20

, in this case a turbine blade for an aircraft gas turbine engine. The turbine airfoil component

20

is formed of any operable material, but is preferably a nickel-base superalloy. The turbine airfoil component

20

includes an airfoil

22

against which the flow of hot exhaust gas is directed. The turbine airfoil component

20

is mounted to a turbine disk (not shown) by a dovetail

24

which extends downwardly from the airfoil

22

and engages a slot on the turbine disk. A platform

26

extends outwardly from the area where the airfoil

22

joins the dovetail

24

.

Internal passages extend through the interior of the turbine airfoil component

20

, ending in openings in the surface of the airfoil

22

. In service, a flow of cooling air is directed through the internal passages, to remove heat from the airfoil

22

and to create a film-cooling effect as the flow of air leaves the openings. In some designs, there are at least two, and typically more, internal passages, each ending in its own set of openings.

FIG. 2

illustrates a case where the turbine airfoil component

20

has three internal passages and a separate set of openings associated with each of the internal passages. A first internal passage

28

extends from a first turbine airfoil component inlet

30

in a base

32

of the dovetail

24

to a first set of openings

34

on the leading-edge of the turbine airfoil component

20

. A second internal passage

36

extends from a second turbine airfoil component inlet

38

in the base

32

of the dovetail

24

to a second set of openings

40

on the pressure (concave) face of the turbine airfoil component

20

. A third internal passage

42

extends from a third turbine airfoil component inlet

44

in the base

32

of the dovetail

24

to a third set of openings

46

on the trailing-edge of the turbine airfoil component

20

.

When the turbine airfoil component is manufactured, the respective passages and sets of openings are tested with a flow of water that passes into the turbine airfoil component inlets, along the passages, and out the openings. In conventional practice, the water flow is directed into all of the turbine airfoil component inlets at the same time so that water flows from all of the openings at the same time. This approach makes observation of the flows from the various openings difficult. In the present approach, on the other hand, water flows are controllably directed through individual ones or combinations of the passages and sets of openings.

FIGS. 3-9

depict a preferred water-flow testing apparatus

50

for water-flow testing the turbine airfoil component

20

having at least two, and in this case three, water flow passage turbine airfoil component inlets

30

,

38

, and

44

in the base

32

. As seen in

FIGS. 3-4

, the apparatus

50

has an apparatus body

52

having a water inlet

54

.

Referring to

FIG. 4

, an attachment head

56

is integral with the apparatus body

52

. The attachment head

56

temporarily attaches the article being water-flow tested, in this case the turbine airfoil component

20

, to the apparatus body

52

for the period of the water flow testing. The attachment head

56

includes an article seal

58

that seals the base

32

of the dovetail

24

of the turbine airfoil component

20

to the apparatus body

52

. The article seal

58

, shown in detail in

FIG. 9

, preferably is a piece of rubber with at least two seal inlets therethrough, with each seal inlet being in registry with at least one of the water flow passage inlets. In this case, the article seal

58

has three seal inlets

60

,

62

, and

64

. Each one of the seal inlets

60

,

62

, and

64

is in registry with a respective one of the turbine airfoil component inlets

30

,

38

, and

44

.

A water-flow distribution plate

66

, shown in

FIG. 8

, is positioned so that the article seal

58

lies between the water-flow distribution plate

66

and the base

32

of the dovetail

24

of the turbine airfoil component

20

. The water-flow distribution plate

66

allows water to be directed into individual ones of the seal inlets

60

,

62

, and

64

, or selected combinations of the seal inlets

60

,

62

, and

64

, and thence into the respective turbine airfoil component inlets

30

,

38

, and

44

. In the illustrated case, water is to be directed into the seal inlet

60

by itself, or alternatively into the seal inlets

62

and

64

together. To this end, the water-flow distribution plate

66

has a first distribution plate outlet

68

that aligns with and communicates with the seal inlet

60

, and a second distribution plate outlet

70

that aligns with and communicates with the seal inlets

62

and

64

.

A holder

72

receives the turbine airfoil component

20

and holds the base

32

of the dovetail

24

in sealing contact with the article seal

58

. The holder

72

preferably comprises a jaw mechanism

74

including a fixed jaw

76

located on the apparatus body

52

and a movable jaw

78

. The movable jaw

78

is at the end of a pivot arm

80

that is pivotably fixed to the apparatus body

52

at a pivot point

82

. A handle

84

of the pivot arm

80

on the opposite side of the pivot point

82

from the movable jaw

78

may be depressed to open the jaw mechanism

74

and move the jaws

76

and

78

apart from each other so that the base

32

may be inserted between the jaws

76

and

78

. The handle

84

is then released to capture the base

32

between the jaws

76

and

78

. A compression spring

86

extends between the handle

84

and the apparatus body

52

to bias the jaw mechanism

74

to the closed position with the base

32

captured between the jaws

76

and

78

. The jaws

76

and

78

have respective camming surfaces

77

and

79

that engage the turbine airfoil component

20

on the dovetail region

24

when open and draw the base

32

of the turbine airfoil component

20

toward and into sealing contact with the article seal

58

as the jaw mechanism

74

moves toward the closed position.

The jaw mechanism

74

engages the article being water-tested, here the turbine airfoil component

20

, and holds it in sealing contact with the article seal

58

during water testing. The use of the jaw mechanism allows the person doing the water testing to make this engagement and seal with a simple, easily performed grasping action that opens and closes the jaw mechanism, rather than a twisting action or other complex action. The jaw approach is more ergonomic than these other possible approaches.

A water flow controller

88

, illustrated in

FIGS. 5-7

, is located within the apparatus body

52

to control the flow of water from the water inlet

54

to the seal inlets

60

,

62

, and

64

, and thence into the respective turbine airfoil component inlets

30

,

38

, and

44

. The water flow controller

88

has a controller inlet

90

in water-flow communication with the water inlet

54

of the apparatus body

52

. The controller inlet

90

communicates with an inlet plenum

92

of the water flow controller

88

. The water flow controller

88

has at least two controller outlets. In this case, the controller outlets are the distribution plate outlets

68

and

70

of the distribution plate

66

. Each controller outlet is in water-flow communication with at least one of the seal inlets

60

,

62

, and

64

.

A flow-control valve

94

of the water flow controller

88

is disposed in a water flow path between the controller inlet

90

and the distribution plate outlets

68

and

70

. The flow-control valve

94

is controllable to controllably connect a single one of the distribution plate outlets

68

and

70

at a time to the controller inlet

90

. The flow-control valve may be of any operable type. In a preferred embodiment, the flow control valve

94

is a slide-actuated valve. The slide flow control valve

94

includes a valve bore

96

that extends transversely (i.e., parallel to the pivot pin at the pivot point

82

) between the sides of the apparatus body

52

. The valve bore

96

is in water-flow communication with the inlet plenum

92

, and thence with the controller inlet

90

and the water inlet

54

on one side, and with each of the distribution plate outlets

68

and

70

on the other side. A generally cylindrically symmetric valve core

98

is slidably received within the valve bore

96

and is sealed to the valve bore

96

at each end with O-ring seals

100

. The sliding valve core

98

has a channel

102

therethrough that may be slidable aligned with each distribution plate outlet

68

and

70

. In the illustrated embodiment, the channel

102

is a circumferential channel that provides water flow regardless of whether the valve core

98

is rotated about its longitudinal axis.

To operate the water-flow testing apparatus

50

, the water inlet

54

is connected to any operable source of water and water pressure. The inventors have found a water pressure of from about 20 to about 30 psi to be satisfactory, although the invention is not so limited. The handle

84

is depressed and the turbine airfoil component

20

is inserted between the jaws

76

and

78

. The handle

84

is released, so that the dovetail

24

of the turbine airfoil component

20

is captured between the camming surfaces

77

and

79

of the jaws

76

and

78

, thereby sealing the base

32

to the article seal

58

. The valve core

98

of the water-flow controller

88

is moved longitudinally within the valve bore

96

to establish a water flow path between the pressurized water inlet

54

and either of the outlets

68

or

70

, one at a time. This allows the water flow to be directed into the internal passages

28

,

36

, and

42

, and thence to the respective sets of openings

34

,

40

, and

46

of the turbine airfoil component

20

. Flow from the sets of openings is observed to determine whether each opening is freely flowing or is obstructed. When water flow testing is complete, the handle

84

is depressed, and the turbine airfoil component

20

is removed from the jaw mechanism

74

.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.