US20060090822A1

US20060090822A1 - Arrangement for providing heat to a portion of a component

Info

Publication number: US20060090822A1
Application number: US11/294,408
Authority: US
Inventors: John Boswell
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2003-11-26
Filing date: 2005-12-06
Publication date: 2006-05-04
Also published as: US20050109480A1; EP1535679A1; GB0327462D0

Abstract

An arrangement 10 for providing thermal energy to a portion 16 of a component 14 of a gas turbine engine while the component 14 is forming, wherein the component 14 is substantially elongate in a first direction 28 and the portion 16 extends from the component 14 in a second direction 38, substantially perpendicular to the first direction 28, and comprises a first surface area component 32 oriented in the first direction 28. The arrangement 10 further comprising an elongate member 18, connected to the portion 16 for heating the portion 16, wherein the elongate member 18 comprises a second surface area component 36, oriented in the second direction 38, wherein the second surface area component 36 of the elongate member 18 is greater than the first surface area component 32 of the portion 16.

Description

This is a Division of Application Ser. No. 10/978,429 filed Nov. 2, 2004, which claims the benefit of GB 0327462.8 filed Nov. 26, 2003. The entire disclosure of the prior applications is hereby incorporated by reference herein in its entirety.
Embodiments of the present invention relate to an arrangement for providing heat to a portion of a component and in particular a component of a gas turbine engine while the component is forming.
Turbine components may currently be formed by providing a mould, filling the mould with a suitable material in liquid form and then cooling the material. Once the component has solidified within the mould, the mould is removed from the component. This process may be used to form single crystal turbine components and directionally solidified turbine components.
A component may have several portions that protrude from the body of the component. These portions cool faster than the component body and may crystallise before the component. This creates a problem if the component is to be made from a single crystal since the portion may be made from one crystal and the component may be made from another crystal.
Currently, extra material is added to increase the volume of the portion and thereby reduce its rate of cooling. The disadvantage of this method is that the extra material must be removed from the portion once the component has formed and then thrown away.
Therefore it is desirable to provide an alternative arrangement for providing heat to a portion of a component of a gas turbine engine while it is forming.
According to one aspect of the present invention there is provided an arrangement for providing heat to a portion of a component of a gas turbine engine while the component is forming, wherein the component is substantially elongate in a first direction and the portion extends from the component in a second direction, substantially perpendicular to the first direction, and comprises a first surface area component oriented in the first direction; the arrangement further comprising an elongate member, connected to the portion for heating the portion, wherein the elongate member comprises a second surface area component, oriented in the second direction, wherein the second surface area component of the elongate member is greater than the first surface area component of the portion.
One advantage provided by the arrangement is that the thermal energy input to the second surface area component may be greater than the thermal energy output from the first surface area component. The elongate member consequently provides net thermal energy to the portion.
According to a further aspect of the present invention there is provided a method for use in forming a component, wherein the component has a portion that extends from the component in a second direction, substantially perpendicular to a first direction, and an elongate member is connected to the portion for heating the portion, the method comprising: moving the component in the first direction; heating the elongate member as the component moves so that there is net thermal energy input for the portion.
An advantage associated with the arrangement and method as described above is that due to the net thermal energy input to the portion, the portion may not form as a separate crystal to the component.
The portion may comprise a third surface area component, which may be oriented in the second direction. The third surface area component may have an area less than the first surface area component. The combined surface area of the second surface area component and third surface area component may be greater than the area of the first surface area component. The net thermal energy input into the second surface area component and the third surface area component may be greater than the thermal energy output from the first surface area component.
The arrangement may further comprise a heat source for providing thermal energy to the component. The heat source may annularly surround the component and may be oriented substantially perpendicular to the first direction. The heat source may radiate electromagnetic energy.
The cross sectional area of the elongate member may increase with distance from where it joins the portion. One advantage is that the elongate member may be easier to remove from the portion once the portion has formed. The elongate member may be simple to remove from the portion and may cause little or no damage to the portion upon removal.
The elongate member may additionally provide material to the portion, while the portion is forming. This may help maintain the volume of the portion. The elongate member may therefore additionally act as a solidification shrinkage feeder.
An advantage provided by the arrangement and method described above, is that the removal of the elongate member wastes less material than the removal of extra material, added to increase the volume and reduce the rate of cooling of the portion. Therefore, the cost of single crystal and directionally solidified components for turbine assemblies may be reduced. Another advantage is that the time taken for assembly of single crystal and directionally solidified components may be reduced.
The component may be made from a single crystal or may be a directionally solidified component. The component may be a turbine blade, a nozzle guide vane or a seal segment for a turbine assembly of a gas turbine engine. The portion may be a seal fin or a platform of a turbine blade.
For a better understanding of the present invention reference will now be made by way of example only to the accompanying drawings in which:
FIG. 1 illustrates a schematic diagram of an arrangement for providing thermal energy to a portion of a component of a gas turbine engine.
FIG. 2 illustrates the arrangement of FIG. 1 when viewed along direction A.
FIG. 3 illustrates the arrangement of FIG. 1 when viewed along direction B.
The figures illustrate an arrangement 10 for providing thermal energy to a portion 16 of a component 14 of a gas turbine engine while the component 14 is forming, wherein the component 14 is substantially elongate in a first direction 28 and the portion 16 extends from the component 14 in a second direction 38, substantially perpendicular to the first direction 28, and comprises a first surface area component 32 oriented in the first direction 28; the arrangement 10 further comprising an elongate member 18, connected to the portion 16 for heating the portion 16, wherein the elongate member 18 comprises a second surface area component 36, oriented in the second direction 38, wherein the second surface area component 36 of the elongate member 18 is greater than the first surface area component 32 of the portion 16.
FIG. 1 illustrates an arrangement 10 for providing thermal energy from a heat source 12 to a component 14 of a gas turbine engine. The component 14 comprises a portion 16 that is heated by the heat source 12 via an elongate member 18. The elongate member 18 is connected to the portion 16 and shaped so that there is a net thermal energy input into the portion 16, to increase the temperature of the portion 16, while the component 14 is forming.
In more detail, FIGS. 1 & 2, illustrate the arrangement 10 having an annular tunnel 13 through which the component 14 is moved while it is forming. The component 14 is moved from an input 15 to an output 17 in a first direction 28. The annular tunnel 13 comprises a heat source 12, an insulation zone 20 and a cooling zone 22. The heat source 12 is located at, or near, the input 15 of the annular tunnel 13 and receives the component 14. The heat source 12, in this example, has a temperature of approximately 1,500° C. The heat source 12 comprises a heating element which may be graphite. The graphite may be resistance or induction heated. Electric current is passed through the wire to heat the wire to a desired temperature. The heat source 12 radiates electromagnetic energy.
The insulation zone 20 is connected to the heat source 12 and is located beneath the heat source 12. The insulation zone 20 is typically made from a ceramic or mineral fibre. The cooling zone 22 is located at, or near, the output 17 of the annular tunnel 13. The cooling zone 22 has a temperature of approximately 1,200° C. The cooling zone 22 comprises pipes through which water is passed to cool the annular tunnel 13. The temperature of the cooling zone 22 is less than the temperature of the region adjacent to the heat source 12.
The component 14 is formed from a mould 24 that is moved through the annular tunnel 13. The mould 24 is placed on a copper chill plate 26 and moved in a first direction 28 from the input 15 to the output 17. A material (any appropriate metal alloy suitable for the formation of a turbine blade) is fed into the mould from a source 30. The material is introduced in a liquid form which solidifies as it passes from the input 15 to the output 17. The source 30 and the temperature are controlled so that the component is made either from a single crystal or is ‘directionally solidified’.
The component 14 is elongate in the first direction 28. The portion 16 extends from the component 14 in a second direction 38, perpendicular to the first direction 22. The portion 16 comprises a first surface area component 32 and a third surface area component 34. The surface area of the third surface area component 34 is less than the area of the first surface area component 32. The third surface area component 34 is orientated in the second direction 38 and is an input for thermal energy into the portion 16 from the heat source 12. The first surface area component 32 is orientated in the first direction 28, towards the cooling zone 22 and is an output for thermal energy. The elongate member 18 comprises a second surface area component 36. The second surface area component 36 is orientated in the second direction 38.
The area presented toward the heat source 12 (the combination of the second and third surface area components) is greater than the area presented away from the heat source (the first surface area component). Consequently, the net thermal energy input into the second surface area component 36 and the third surface area component 34 is greater than the thermal energy output from the first surface area component 32. Therefore, the portion 16 is heated by the elongate member 18. This may prevent the formation of a second crystal forming in the portion 16.
The elongate member 18 increases in cross sectional area from the join between the elongate member 18 and the portion 16 (base) to define a trapezium shape as illustrated in FIG. 1. Those features which are illustrated in FIG. 3 and are the same as those illustrated in FIG. 1 have been given the same reference numeral. FIG. 3 illustrates the arrangement of FIG. 1 when viewed along direction B. The elongate member 18 is substantially rectangular when viewed in the direction B. It can also be seen from FIG. 3 that the second surface area component 36 has a greater surface area than the third surface area component 34. The elongate member 18 is, in this example, approximately 25 mm long and 3 mm deep. The dimensions of the elongate member 18 are chosen so that there is a net thermal energy input into the portion 16. The advantage provided by the shape of the elongate member 18, is that once the turbine blade has been formed, the elongate member 18 may be easily removed by force from the portion 16 since the width of the elongate member is least at its base.
After the mould 24 has been filled with the material from the source 30 and has moved from the heat source 12 to the cooling zone 22, it is then removed from output 17 of the arrangement 10. The mould 24 is removed from the component 14. The elongate member 18 is removed from the portion 16. The removal of the elongate member 18 is simple and causes little or no damage to the component 14 or the portion 16.
An additional benefit is provided by the elongate member 18 while the component is forming. As the material in the portion 16 cools, the volume of the material decreases. This could result in the portion 16 having internal or surface porosity. However, material from the elongate member 18 flows into the portion 16 to help maintain the volume of the portion 16. In this respect, the elongate member 18 additionally acts as a solidification shrinkage feeder.
The component 14 is a component of a turbine. The component 14 may, for example, be a turbine blade, a nozzle guide vane or a seal segment. The portion 16 may, for example, be a seal fin or a platform.
Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. For example, the mould may be used for the formation of a plurality of components 14. The elongate member 18 may have any suitable shape 18 that allows it to provide thermal energy to the portion 16.
Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A method for use in forming a component of a gas turbine engine, wherein the component has a portion that extends from the component in a second direction, substantially perpendicular to a first direction, and an elongate member is connected to the portion for heating the portion, the method comprising: moving the component in the first direction; and heating the elongate member as the component moves so that there is net thermal energy input for the portion.

2. A method as claimed in claim 1, further comprising removing the elongate member from the component.

3. A component produced by the method as claimed in claim 1.