The technology described herein relates generally to electrical devices, particularly to electrical devices for supporting and securing electrical cables, and more particularly, to electrical cable supports.
Many gas turbine engine assemblies include a fan assembly that is mounted upstream from a core gas turbine engine. During operation, a portion of the airflow discharged from the fan assembly is channeled downstream to the core gas turbine engine wherein the airflow is further compressed. The compressed airflow is then channeled into a combustor, mixed with fuel, and ignited to generate hot combustion gases. The combustion gases are then channeled to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight. The other portion of the airflow discharged from the fan assembly exits the engine through a fan stream nozzle.
To facilitate channeling the airflow into the fan assembly, some known gas turbine engine assemblies includes an inlet guide vane assembly that is used to direct the air in a desirable orientation toward the fan blades. Inlet guide vanes (IVGs) may be provided in either a fixed orientation or may be constructed in a variable inlet guide vane configuration. Variable inlet guide vanes (VIGVs) may be adjusted for various operating conditions and environments, often by pivoting the guide vanes about an axis, to achieve the desired airflow characteristics leading into the fan assembly. In addition to turning the fan airflow, the inlet guide vane assembly may also provide structural stiffness to the fan frame. More specifically, inlet guide vane assemblies generally include a plurality of inlet guide vanes that are coupled to the fan frame.
Inlet guide vane assemblies, along with other structural elements of aircraft and aircraft engines, such as struts, may be susceptible of forming ice accumulation under certain operating and environmental conditions. Ice accumulation on such structures, besides adding weight to the structures, often has a detrimental effect on performance through alteration of the surface texture and structural shape of the element undergoing ice accumulation.
Various approaches to addressing ice accumulation have been developed, including the use of electrically powered heater elements on guide vanes, struts, and other structural elements. Such heater elements require electrical cables to deliver the power from the power source to the elements. Depending upon the power distribution and control scheme, a plurality of cables may be required so that power may be independently delivered to individual elements or selected groups of elements. Such cables require retention and support to maintain them in position and to protect them from wear and damage. There remains a need for improved electrical devices for supporting and securing electrical cables.
In one aspect, an integrated cable support, the support comprising a grommet portion for enclosing at least one first elongated cable and a bracket portion for securing at least one second elongated cable in spaced and substantially fixed relation to said at least one first elongated cable. The at least one first elongated cable and the at least one second elongated cable are in a non-parallel orientation.
Fan assembly 12 includes an array of fan blades 24 extending radially outward from a rotor disk 26. Gas turbine engine assembly 10 has an intake or inlet side 28 and an exhaust side 30. Fan assembly 12, booster 22, and turbine 20 are coupled together by a first rotor shaft 31, and compressor 14 and turbine 18 are coupled together by a second rotor shaft 32.
In operation, air flows through fan assembly 12 and booster 22. The compressed air that is discharged from booster 22 is channeled through compressor 14 wherein the airflow is further compressed and delivered to combustor 16. Hot products of combustion (not shown in
A plurality of inlet guide vanes 40 that typically extend substantially radially, between a radially-outer mounting flange and a radially-inner mounting flange, and are circumferentially-spaced around inlet 28, guide incoming airflow 14 into the fan assembly 12. Inlet guide vanes 40 serve to turn the airflow upstream from rotating blades such as fan blades 24 for aerodynamic purposes to achieve the desired airflow characteristics into and through the fan assembly 12 under various operating conditions. Guide vanes 40 are secured in place by suitable mounting features such as inner and outer mountings, respectively. Mounting features may provide for adjustment of the orientation of guide vane 40 on a one-time or continuous basis, or may maintain it in a fixed position relative to the gas turbine engine 10. Outlet guide vanes (shown but not numbered in
Struts 51 include electrical heater elements (not shown) which require electrical power supplied through electrical cables from a suitable source (not shown). Heater elements are suitably sized and shaped, and configured to deliver sufficient heating value, to provide the desired anti-ice-accumulation benefit to struts 61 and/or other components under various operating conditions. Also shown in
Individual guide vanes or struts, or groups of guide vanes or struts under common control, may be energized in various patterns or sequences as desired. The respective time periods for energization and de-energization may also be determined as necessary to obtain the desired performance. Such an operating scheme may also be called a “duty cycle” and may be measured in terms of time on in comparison with time off and/or in terms of the periodic nature of the cycle (interval between repetitive events). Such control may require that each of the heater elements be individually fed electrical power via electrical cables from a suitable power source so they can be operated in the desired manner.
The outer portion 63 is secured to the outer casing 53 of the fan frame 50 via fasteners 65 through apertures 64 in the outer portion 63, and the shroud 60 is preferably sized and shaped so as to provide a biasing force against the bottom of annular groove 56 and the fastener 65 to achieve a pre-loaded condition. The biasing force and pre-load depend upon such factors as shroud geometry and materials, and a comparatively small pre-load angle may be selected to aid in generating the biasing force upon completed installation. A pre-load angle such as 1 to 3 degrees, for example, could be specified to provide the desired degree of compression force upon completed installation. This helps to ensure that the shroud 60 is secured within the groove 56 under a variety of conditions. Fabrication of the shroud 60 in multiple segments may prove useful in terms of ease of installation of the tab extension 61 into annular groove 56.
Also shown in
The integrated cable support 70 (hereinafter “cable support 70”) is illustrated in greater detail in
The upper bracket portion 71 includes a top portion 72 formed in the embodiment shown by a pair of upper arms separated by a slot 73 and forms a nearly complete ring around passage 77, through which cable bundle 80 passes. Slot 73 is optional but provides access to the passage 77 to aid in the removal or replacement of cables and/or cable supports without having to pull the cable bundle 80 lengthwise through the passage 77. Top portion 72 may also optionally include grooves as shown to retain edges of a cable tray or conduit, if desired.
The lower grommet portion includes an aperture 76 extending therethrough for passage of electrical cable 82 as shown in
In the embodiment shown in
Shroud 60 and integrated cable support 70 may be sized, shaped, and configured such as shown in
The shroud and integrated cable support may be fabricated from any suitable materials using any suitable fabrication methods as are known in the art and suitable for the intended configuration and operating environment. For example, the shroud may be fabricated from composite materials having the desired characteristics, such as a fiberglass prepreg composite hand lay-up, and may include metal mesh for rigidity and shielding against electrical interference. The integrated cable support may be fabricated from any suitable materials, including elastomeric materials such as fluorosilicones and/or silicone, with or without internal or external reinforcement such as fiberglass weave. One such material is AMS-R-25988, a fluorosilicone material which provides for desired temperature properties as well as resistance to degradation from a variety of fluids commonly used in aerospace environments.
While much of the discussion has focused on an aviation gas turbine engine as the context for integration of the guide vane and bifurcation, it is foreseeable that such geometries and integrations may be suitable for use in other environments wherein a stationary guide vane and bifurcation are located downstream from rotating turbomachinery, such as wind or steam turbines.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
This application claims priority to U.S. Provisional Application Ser. No. 61/228,456, filed Jul. 24, 2009.
The US Government may have certain rights in this invention pursuant to Contract No. N00019-96-C-0176 awarded by the US Department of the Air Force.
Number | Date | Country | |
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61228456 | Jul 2009 | US |