Patent Application
20180094543
The field of the disclosure relates generally to gas turbine engines and, more particularly, to an apparatus and system for enhancing oil jet streams in an oil nozzle.
At least some known high-speed turbine machinery use dedicated nozzles to provide oil lubrication to key rotating hardware, such as bearings, gears, and the like. The oil is delivered to specific locations, such as, but not limited to, bearing rolling elements, oil scoops, carbon seals, gear mesh areas, gaps between bearing cage, guide flanges, to maximize the lubrication to those areas and also to the interior of air tubes for cooling purposes. Under high-speed rotation where windage is strong, the oil jet stream is impaired by the windage effects. In some cases, the flow stream is broken by the windage effects, depriving the location with oil flow for brief periods of time until the oil jet stream is restored. Brooming of the oil jet stream may occur when a nozzle jet is not performing well and jet integrity is lost or reduced. A broomed oil jet stream not only fails to deliver required amount of lubricant to the desired locations, but also tends to generate unnecessary heat due to stronger churning.
Oil jet stream brooming is a very complicated problem in oil nozzle design. Uniform oil flow with a minimum of a turbulent kinetic energy and velocity variation profile at the orifice is desired for a good jet stream. It is usually required to have a smooth transition of piping and larger length to orifice diameter ratio (L/D). However, in many cases, limited space and complex upstream geometric conditions make it impossible to have desired mechanical and geometric characteristics. High pressure oil lubricating and supply systems make the oil jet stream prone to brooming.
Controlled brooming may be desirable in certain applications when for example, cooling a wide area is desired. Controlled brooming is the result of a careful design and proper flow and pressure conditions. Current attempts at controlled brooming have not produced reliable and repeatable results.
Furthermore, a significant amount of pressure energy delivered by the lube oil pump is lost inside the nozzle. Recirculation regions combined with small diameters cause the large pressure drop inside the oil nozzle.
Such problems have largely been addressed at each application by past experience. Many factors, as mentioned above like upstream geometry, L/D (length/diameter ratio), etc., are adjusted based on space available, piping routes available, and by adjusting oil pumping capability and/or flow characteristics, such as, but not limited to viscosity to facilitate establishing an adequate oil jet stream. Special manufacturing processes, including proprietary procedures of nozzle suppliers are also used in an attempt to improve the integrity of the oil jet stream.
In one aspect, a boundary layer injection insert assembly includes an insert body and a central bore extending through the insert body from an inlet opening positioned at a first end to an outlet opening positioned at a second end of the insert body opposite the first end. The insert body is approximately cylindrical about a longitudinal axis and includes a thickness in a radial direction orthogonal to the longitudinal axis. The first end includes a plurality of injection holes extending through the thickness for a first distance. The first distance being less than the length. The boundary layer injection insert assembly also includes an annular spacer at least partially surrounding the second end and including a radially inner surface and a radially outer surface spaced apart by a thickness of the annular spacer.
In another aspect, an oil nozzle includes a hollow elongate body coupled in flow communication to a source of a pressurized lubricating oil and a boundary layer injection insert coupled to an inner surface of the body. The boundary layer injection insert includes an insert tube including an insert body and a central bore extending through the insert body from an inlet opening positioned at a first end of the insert body to an outlet opening positioned at a second end of the insert body. The second end is positioned opposite the first end. The insert body extends circumferentially about a longitudinal axis and includes a thickness in a radial direction orthogonal to the longitudinal axis. The insert body also includes a plurality of injection holes extending through the thickness for a first distance along a length of the insert body, the first distance being less than the length. The insert body further includes an annular spacer at least partially surrounding the second end. The annular spacer includes a radially inner surface and a radially outer surface spaced apart by a thickness of the annular spacer.
In yet another aspect, a gas turbine engine includes a core engine configured to generate a flow of high energy combustion gases, a fan assembly powered by a power turbine driven by the combustion gases, and an oil lubricating and supply system configured to channel a flow of pressurized lubricating fluid to one or more components of the gas turbine engine. The oil lubricating and supply system includes a nozzle including a hollow elongated nozzle body coupled in flow communication with a source of a pressurized lubricating fluid and a boundary layer injection insert coupled to an inner surface of the nozzle body. The boundary layer injection insert includes an insert body having a central bore extending through the insert body between an inlet opening and an outlet opening. The insert body extends circumferentially about a longitudinal axis and including a thickness in a radial direction orthogonal to the longitudinal axis. The insert body also includes a plurality of injection holes extending through the thickness for a first distance along a length of the insert body. The first distance is less than the length. The insert body further includes a flange at least partially surrounding a portion of the insert body. The flange is configured to couple the insert body to the nozzle body.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
As used herein, the terms “axial” and “axially” refer to directions and orientations that extend substantially parallel to a centerline of the nozzle body orientation. Moreover, the terms “radial” and “radially” refer to directions and orientations that extend substantially perpendicular to the centerline of the turbine engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the turbine engine.
Embodiments of the oil nozzle having a boundary layer injection insert described herein provide a cost-effective apparatus for improving an oil jet stream exiting the oil nozzle. An oil nozzle with good stream integrity is important for the healthy operation of rotating components as well as for the whole of a rotatable machine, such as, a gas turbine engine. An oil nozzle with a uniform jet stream is important for meeting target requirements. The oil nozzle and boundary layer injection insert is formed for stringent stream integrity requirements. A series of injection holes are formed on an upstream portion of the insert. Oil flow from the injection holes joins the main flow and the combined flow supplies the nozzle orifice. Any flow recirculation, and skewness of velocity and turbulence kinetic energy distribution, which are key contributors to oil jet brooming, can be corrected by the boundary layer injection induced by the injection holes. Oil jet streams experiencing less than satisfactory stream characteristics can be improved, and a more uniform oil jet stream can be achieved. The oil jet stream can be precisely delivered to the target and the lubrication of the machinery can be ensured. In addition, injection of oil in the boundary layer through these holes reduces the pressure loss through the nozzle. A significant reduction in the pressure drop through the nozzle can help to reduce a size of the lube oil pump.
Side flow injection on the main stream eliminates local recirculation and corrects any skewness of velocity and kinetic energy profiles, which are the two key contributors of nozzle jet brooming. The boundary layer injection insert provides oil jet stream integrity within limited space, is usable in very high oil supply pressures and temperature, which are the trend of advanced engine systems, and increases lubrication efficiency (oil scoop capture efficiency) and reduces overall flow requirements, such as, reduces engine oil volume. The boundary layer injection insert also enhances the integrity of oil jet stream, which facilitates oil capturing efficiency and also reduces potential oil churning and heat generation.
In the example embodiment, core turbine engine 206 includes an engine case 208 that defines an annular inlet 220. Engine case 208 at least partially surrounds, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor 222 and a high pressure (HP) compressor 224; a combustion section 226; a turbine section including a high pressure (HP) turbine 228 and a low pressure (LP) turbine 230; and a jet exhaust nozzle section 232. A high pressure (HP) shaft or spool 234 drivingly connects HP turbine 228 to HP compressor 224.
A low pressure (LP) shaft or spool 236 drivingly connects LP turbine 230 to LP compressor 222. The compressor section, combustion section 226, turbine section, and jet exhaust nozzle section 232 together define a core air flowpath 237.
In the example embodiment, fan assembly 204 includes a variable pitch fan 238 having a plurality of fan blades 240 coupled to a disk 242 in a spaced apart relationship. Fan blades 240 extend radially outwardly from disk 242. Each fan blade 240 is rotatable relative to disk 242 about a pitch axis P by virtue of fan blades 240 being operatively coupled to a suitable pitch change mechanism (PCM) 244 configured to vary the pitch of fan blades 240. In other embodiments, pitch change mechanism (PCM) 244 is configured to collectively vary the pitch of fan blades 240 in unison. Fan blades 240, disk 242, and pitch change mechanism 244 are together rotatable about longitudinal axis 202 by LP shaft 236 across a power gear box 246. Power gear box 246 includes a plurality of gears for adjusting the rotational speed of fan 238 relative to LP shaft 236 to a more efficient rotational fan speed. An oil lubricating and supply system 245 directs an oil jet stream 247 to PCM 244 and/or power gear box 246 through an oil nozzle assembly 243 including a boundary layer injection insert 249.
Disk 242 is covered by rotatable front hub 248 aerodynamically contoured to promote an airflow through the plurality of fan blades 240. Additionally, fan assembly 204 includes an annular fan casing or outer nacelle 250 that circumferentially surrounds fan 238 and/or at least a portion of core turbine engine 206. In the example embodiment, nacelle 250 is configured to be supported relative to core turbine engine 206 by a plurality of circumferentially-spaced outlet guide vanes 252. Moreover, a downstream section 254 of nacelle 250 may extend over an outer portion of core turbine engine 206 so as to define a bypass airflow passage 256 therebetween.
During operation of turbofan engine 120, a volume of air 258 enters turbofan 120 through an associated inlet 260 of nacelle 250 and/or fan assembly 204. As volume of air 258 passes across fan blades 240, a first portion 262 of volume of air 258 is directed or routed into bypass airflow passage 256 and a second portion 264 of volume of air 258 is directed or routed into core air flowpath 237, or more specifically into LP compressor 222. A ratio between first portion 262 and second portion 264 is commonly referred to as a bypass ratio. The pressure of second portion 264 is then increased as it is routed through high pressure (HP) compressor 224 and into combustion section 226, where it is mixed with fuel and burned to provide combustion gases 266.
Combustion gases 266 are routed through HP turbine 228 where a portion of thermal and/or kinetic energy from combustion gases 266 is extracted via sequential stages of HP turbine stator vanes 268 that are coupled to engine case 208 and HP turbine rotor blades 270 that are coupled to HP shaft or spool 234, thus causing HP shaft or spool 234 to rotate, which then drives a rotation of HP compressor 224. Combustion gases 266 are then routed through LP turbine 230 where a second portion of thermal and kinetic energy is extracted from combustion gases 266 via sequential stages of LP turbine stator vanes 272 that are coupled to engine case 208 and LP turbine rotor blades 274 that are coupled to LP shaft or spool 236, which drives a rotation of LP shaft or spool 236 and LP compressor 222 and/or rotation of fan 238.
Combustion gases 266 are subsequently routed through jet exhaust nozzle section 232 of core turbine engine 206 to provide propulsive thrust. Simultaneously, the pressure of first portion 262 is substantially increased as first portion 262 is routed through bypass airflow passage 256 before it is exhausted from a fan nozzle exhaust section 276 of turbofan 120, also providing propulsive thrust. HP turbine 228, LP turbine 230, and jet exhaust nozzle section 232 at least partially define a hot gas path 278 for routing combustion gases 266 through core turbine engine 206.
Turbofan engine 120 is depicted in the figures by way of example only, in other exemplary embodiments, turbofan engine 120 may have any other suitable configuration including for example, a turboprop engine, a military purpose engine, and a marine or land-based aero-derivative engine.
Boundary layer injection insert assembly 300 includes an insert tube 316 including an insert body 318 and a central bore 320 extending through insert body 318 from an inlet opening 322 positioned at a first end 324 of insert body 318 to an outlet opening 326 positioned at a second end 328 of insert body 318 opposite first end 324. In various embodiments, insert body 318 is approximately cylindrical about a longitudinal axis 329 and includes a thickness 330 in a radial direction 332 orthogonal to longitudinal axis 329. First end 324 includes a plurality of injection holes 334 extending through thickness 330 for a first distance 336 along a length 338 of insert body 318. In the example embodiment, first distance 336 is less than length 338. In one embodiment, injection holes 334 are radially oriented. In other embodiments, injection holes 334 are non-uniformly directed with respect to others of injection holes 334. Additionally, injection holes 334 may be uniformly or non-uniformly spaced with respect to each other.
Boundary layer injection insert assembly 300 further includes an annular spacer 340 at least partially surrounding second end 328. Annular spacer 340 includes a radially inner surface 342 and a radially outer surface 344 spaced apart by a thickness 346 of annular spacer 340. A radially outer surface 344 of annular spacer 340 is configured to engage a radially inner surface 348 of oil supply nozzle 304. A radially inner surface 342 of annular spacer 340 is configured to engage a radially outer surface 350 of insert body 318. In some embodiments, insert body 318 and annular spacer 340 are integrally formed.
During operation, main flow 308 enters oil supply nozzle 304 and is split into a first portion 352, which is directed down central bore 320 and a second portion 354, which is directed into an annular space 356 surrounding first end 324. Second portion 354 is directed through plurality of radially oriented injection holes 334. Because second portion 354 enters central bore 320 radially inwardly through insert body 318, any laminar flow along central bore 320 is disrupted by second portion 354. The radially inward flow also eliminates local recirculation in the main flow of first portion 352 and corrects any skewness of velocity and turbulent energy profiles, which are key contributors to oil jet brooming. First portion 352 and second portion 354 mix in first end 324 and second end 328 before exiting outlet opening 326. By injecting second portion 354 and correcting the flow in first portion 352, the jet stream integrity is improved. The requirements for upstream geometry and a length-to-diameter ratio (L/D) requirement can be relaxed, and oil lubricating and supply system 245 and oil supply nozzle 304 can be designed more compact to meet increasingly compact design spaces. Furthermore, oil injection in the boundary layer reduces pressure losses in oil supply nozzle 304. This reduction in pressure loss through oil supply nozzle 304 can reduce a size of the lube oil pump and still supply same amount of oil.
A treatment 406 along an edge 408 of outlet opening 326 facilitates contouring the oil stream exiting outlet opening 326. Treatment 406 may include chamfering, angling, modifying the smoothness, creating a knife-edge, and the like, to facilitate sharpening the exiting stream into a narrow directed stream or shaping the exiting stream to create a fanning or brooming stream exiting outlet opening 326. A replaceable insert body 318 permits modifying the stream characteristics to address issues with oil placement of components without having to replace entire nozzles and/or headers.
In some embodiments, intentional brooming is desired. As opposed to a concentrated stream of fluid, brooming may be used to diffuse the stream to cover a larger area of the target. This more diffuse stream may be used to facilitate cooling a component in addition to or instead of just providing lubrication.
Instead of hitting a specific bearing or carbon seal or oil scoop, it may be desirable shoot oil into a tube that has air circulating and that goes through a very hot environment. In such a case, the jet may be configured to broom extensively to cool the inside of the tube. In some embodiments, injection holes 334 are sized, spaced, and directed to improve the solidity and/or the integrity of the jet, however in other embodiments, injection holes 334 are sized, spaced, and directed to increase the brooming of the jet. For example, injection holes 334 are tailored to specific axial, circumferential, radial directions or some tuned combination of those to obtain the shape of the stream desired.
Although described with reference to an oil lubricating and supply system for a gas turbine engine, boundary layer injection insert assembly may be used with any fluid and does not necessarily need to be used in conjunction with rotating machinery.
The above-described boundary layer injection insert assembly provides an efficient apparatus for improving an oil jet stream exiting an oil nozzle and being directed to a specific location in a gas turbine engine. Specifically, the above-described fluid nozzle includes a boundary layer injection insert assembly that can be, for example, pressed into an opening of an oil nozzle to improve the oil nozzle oil jet stream integrity.
The above-described embodiments of a nozzle insert and a boundary layer injection system provides a cost-effective and reliable means for improving an integrity of a fluid stream exiting the nozzle. More specifically, the insert and system described herein facilitate directing the fluid stream to specific points on a lubricated component or contouring the fluid stream into, for example, a fanned configuration for covering a larger area with lubricating fluid. As a result, the nozzle insert and a boundary layer injection system described herein facilitate operating machinery at higher temperatures and under greater load than previously permissible in a cost-effective and reliable manner.
Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201641033763 | Oct 2016 | IN | national |
