Patent Application
20210231306
This disclosure relates to fluid nozzles, e.g., for use as fuel injectors.
Certain fluid nozzles, e.g., fuel injectors for gas turbine engines, are subjected to system vibration, e.g., engine vibration, during operation. Certain fluid nozzle designs incorporate a fluid carrying tube that is attached at one or both ends to the injector support structure. This results in the tube acting as a simply supported beam. This tube design often has a vibration natural frequency that can be excited by engine operational vibration. The resulting tube vibration can result in tube braze/weld joint high cycle fatigue failure.
To reduce the tube vibration amplitude, some designs in the past have added a spacer component. This spacer is usually brazed to the inner tube, but not to the outer tube. Brazing the spacer disc to the outer tube is often not an option, for example, if the outer tube is significantly hotter than the inner in operation. This spacer limits the radial distance of travel, thus reducing the bending stresses at the braze joint. However, the additional component weight reduces the natural frequency of the inner tube and still allows vibration and relative motion, so there is still a risk of wear.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved fluid nozzles and spacers and the present disclosure provides a solution for this need.
A spacer for a fluid nozzle can include a body configured to fit within a sheath of the fluid nozzle such that a fluid tube positioned within the sheath is held bent over its longitudinal dimension by the body thereby altering a natural frequency of the fuel tube compared to if the fuel tube were not held bent. The space can include an off-center hole defined through the body at least in an orthogonal direction to a plane that is coplanar with the body. The off-center hole can be configured to receive a fluid tube within the sheath of the fluid nozzle to bend the fluid tube within the sheath.
The body can be a disk. The off-center hole can be symmetrically shaped. The off-center hole may not be aligned with a center of the disk such that an axis defining a center of the off-center hole and an axis defining the center of the disk are separated from each other in a radial direction.
In certain embodiments, body may include one or more features configured to reduce a weight of the disk. The body can be made of a nickel alloy or stainless steel, or any other suitable material.
In accordance with at least one aspect of this disclosure, a fluid nozzle (e.g., a fuel injection nozzle) can include a sheath, a nozzle base, a nozzle tip, a fluid tube configured to be contained within the sheath and supported at the nozzle base and the nozzle tip, and at least one spacer disposed within the sheath such that the fluid tube is held bent over its longitudinal dimension thereby altering a natural frequency of the fuel tube compared to if the fuel tube were not held bent. In certain embodiments, the at least one spacer can be disposed such that the spacer contacts an inner wall of the sheath and the fluid tube passes through the spacer. The spacer can be configured to bend the fluid tube within the sheath to modify a vibrational characteristic of the fluid tube. In certain embodiments, the fluid tube can be center mounted in the sheath at the nozzle base and the nozzle tip.
The at least one spacer can be any suitable embodiment of a spacer disclosed herein, e.g., as described above. In certain embodiments, the outer shape of the spacer can be the same shape as the inner wall of the sheath (e.g., cylindrical).
The sheath can have a cylindrical tube shape. Any other suitable shape for the sheath is contemplated herein.
At least one spacer can be disposed at about a middle of the fluid tube along a length of the fluid tube. Any other suitable position is contemplated herein. In certain embodiments, the nozzle can further include one or more centered spacers having a centered hole. Each centered spacer can be disposed apart from the at least one spacer (with the off-center hole) along a length of the fluid tube within the sheath.
In accordance with at least one aspect of this disclosure, a method can include bending a fluid tube of a nozzle within a sheath of the nozzle, and modifying a vibrational characteristic of the fluid tube. The method can include installing a bending spacer within the sheath to cause the bending of the fluid tube. The method can include any other suitable method(s) and/or portion(s) thereof are contemplated herein.
These and other features of the embodiments of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings.
So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a spacer in accordance with the disclosure is shown in
Other embodiments and/or aspects of this disclosure are shown in
Referring to
The body 101 can be a planar shaped body in certain embodiments. For example, the body 101 can be a disk (e.g., a planar circular body as shown). Any other suitable shape is contemplated herein. The off-center hole 105 can be symmetrically shaped (e.g., a circular hole as shown).
Any other suitable shape is contemplated herein. Being off-center can be such that the off-center hole 105 may not be aligned with a center of the disk such that an axis defining a center of the off-center hole 105 and an axis defining the center of the disk are separated from each other in a radial direction. The further away from the center, a great force can be applied to the tube 207, for example (e.g., where the tube 207 is centered).
In certain embodiments, body 101 may include one or more weight reduction features 109 (e.g., holes, removed material portions, etc.) configured to reduce a weight of the disk, and/or to allow fluid flow through the disk. The body 101 can be made of a nickel alloy or stainless steel, or any other suitable material.
Referring additionally to
In certain embodiments, the fluid tube 307 can be center mounted in the sheath 303 at the nozzle base 311 and the nozzle tip 313, e.g., as shown. In certain embodiments, any other suitable mounting of the fluid tube 307 at the ends thereof is contemplated herein, as long as the spacer 100 is designed to impart a bend on the fluid tube 307.
The at least one spacer 100 can be any suitable embodiment of a spacer disclosed herein, e.g., as described above, for example. In certain embodiments, the outer shape (e.g., the outer diameter of the body 101) of the spacer 100 can be the same shape as the inner wall 303a of the sheath 303 (e.g., cylindrical).
The sheath 303 can have a cylindrical tube shape (e.g., along at least a portion of the length of the sheath 303 as shown), for example. Any other suitable shape for the sheath 303 is contemplated herein.
In certain embodiments, the tube 307 can be inserted at the tip 313 and brazed at the base 311. The tube 307 can be brazed at both ends in certain embodiments, or attached in any other suitable way.
The at least one spacer 100 can be disposed at about a middle of the fluid tube 307 along a length of the fluid tube 307, for example. Any other suitable position is contemplated herein. The fluid nozzle 300 can include any other suitable number of spacers 100 with off-center holes 105 (e.g., a plurality spaced evenly or unevenly along the length of the fluid tube 307).
In certain embodiments, referring additionally to
For example, as shown, the spacer 100 can be placed about centered along the length of the fluid tube 307 and the centered spacers 400 can be disposed closer to the base 311 and tip 313 (e.g., such that spacer is between a plurality of centered spacers 400). While two centered spacers 400 and one spacer 100 is shown in
Referring additionally to
As shown in
In accordance with at least one aspect of this disclosure, a method can include bending a fluid tube of a nozzle within a sheath of the nozzle, and modifying a vibrational characteristic of the fluid tube. The method can include installing a bending spacer within the sheath to cause the bending of the fluid tube. The method can include any other suitable method(s) and/or portion(s) thereof are contemplated herein.
Embodiments include an off-centered hole in a spacer which causes bending of the tube when installed, which causes it to push against the wall. The amount of off-center of the hole can be selected to produce predetermined amount of force against the outer wall, and/or to a preselected maximum stress (e.g., 10 ksi). Embodiments can be spaced and selected in any suitable way to control stress, natural frequency, and radial force, for example. Embodiments of a spacer can have less than an inch, e.g. a quarter inch diameter, can be elliptical shape or any other shape that matches whatever the sheath shape is, can be a stainless steel or nickel based alloy, and/or can have an offset hole diameter of about 60 thousands of an inch to about 300 thousandths of an inch. Any other suitable features are contemplated herein.
Embodiments can be used for any fluid nozzles. For example, certain embodiments can be used for fuel injection nozzles (e.g., for turbomachines).
Embodiments force a small bend in a fuel tube and press the spacer against the sheath. The stresses in a fuel tube braze joint can be kept below 10 ksi, are steady state, and not subject to failures because the vibrations are arrested and the spacer disk is not bonded to the sheath, so it is free to slide in response to thermal growths. A combination of spacers (with and without offsets) can be used to achieve various amounts side-loads and minimize the stress in the braze joint.
Those having ordinary skill in the art understand that any numerical values disclosed herein can be exact values or can be values within a range. Further, any terms of approximation (e.g., “about”, “approximately”, “around”) used in this disclosure can mean the stated value within a range. For example, in certain embodiments, the range can be within (plus or minus) 20%, or within 10%, or within 5%, or within 2%, or within any other suitable percentage or number as appreciated by those having ordinary skill in the art (e.g., for known tolerance limits or error ranges).
The articles “a”, “an”, and “the” as used herein and in the appended claims are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article unless the context clearly indicates otherwise. By way of example, “an element” means one element or more than one element.
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.”
Any suitable combination(s) of any disclosed embodiments and/or any suitable portion(s) thereof are contemplated herein as appreciated by those having ordinary skill in the art in view of this disclosure.
The embodiments of the present disclosure, as described above and shown in the drawings, provide for improvement in the art to which they pertain. While the subject disclosure includes reference to certain embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure.
