PDF Publication Title:
Text from PDF Page: 003
UnitedStatesPatent0 iice 1 3,135,496 Patented June .2, 1964 2 3,135,496 AXIAL FLOW TURBINE WITH RADIAL TEMPERATURE GRADIENT George W. Scheper, Jr., Schenectady, N.Y., assignor to GeneralElectricCompany,acorporationofNew York Filed Mar. 2, 1962, Ser. No. 177,059 8Claims. (Cl.253—39.15) This invention relates to improvements in turbines operating with high-temperature elastic ?uid, and more' particularly to a more e?icient axial ?ow gas turbine design with improved correlation between bucket mate rials, operating temperatures, and aerodynamic charac teristics. ' June 12, 1945 in the name of Frank Whittle), are based on the assumption of constant temperature motive fluid. The “free vortex” principle recognizes that radial equi librium of the ?uid requires the ?uid to rotate more rapidly (have a higher tangential velocity component) near the radially inner parts of the flow annulus as it ?owsaxiallythroughthebucket-wheel. InotherWords, the “whirl velocity,” or tangential component of the abso lute gas velocity leaving the ?rst-stage nozzle should be greater near the root of the bucket than near the tip, in ordertoprovideradialequilibriumand,ifconstantstag nation temperature and stagnation pressure of the gas is assumed, free vortex design will be achieved if the tan gential velocity component of gas leaving the ?rst-stage _ It is known that higher initial operating temperatures 15 nozzle is inversely proportional to the radius (distance from the axis of rotation) and if the axial component is bine,willgenerallygivehighercyclethermalef?ciency constantovertheheightofthebucket. Thismaybe in an elastic ?uid turbine, such as an axial '?ow gas tur andspeci?cpower. Thelimitingfactorinpresent-day design to raising gas turbine operating temperatures is the physical capability of the material used in the highly 20 stressedturbinebucketsatthesetemperatures. Thisis because the allowable stress to which the buckets can be subjected for a given bucket “life” decreases with increas ingtemperature. Althoughallowablestresscanberaised somewhatbyresortingtotheuseofmoreexpensivealloys 25 or special cooling designs, the cost of such measures may gvelcounteract any improved eficiencyresultingthere rom Turbines buckets are generally made individually and expressedbytheformula where VU is the tangential component of the absolute velocity of the gas leaving the nozzle at any radius r, and where VUR isthe same velocity component at the root or reference radius rR. IthasbeensuggestedinUS. Patent2,426,270issued to A. R. Howell on August 26, 1947, that blades of axial flow compressors might be designed so as to minimize compressibility or cavitation by choosing the local Mach number as a design’parameter, where the local Mach attached to the rim of the turbine wheel so as to extend radially. They are subjected to a tensile stress in the radial direction due to centrifugal force as the wheel rotates. Thisstress,duetotheweightofthebucketit self, is generally the greatest near the root or radiallyv innerportionofthebucketvanewhereitisattachedto35 asthetangentialcomponentoftheabsolutevelocityleav the wheel, and it decreases toward the bucket tip or radi ally outer portion, reaching a value of zero stress at the bucket tip. The stress at any bucket cross-section will dependontherotorspeed,theareaofthecross-section,40 ployedforconvenienceofmathematicalexpressionand and the distribution of the metal radially outward from the cross-section. For a bucket of constant cross sectional area from root to tip, the radial stress gradient willbegenerallyparabolicinform. Conventionaltur bine design, however, usually employs a bucket tapered 45 allows an increased initial mean operating temperature. to decrease in area from root to tip, so as to decrease the stress at the root. Since the “root stress” is generally the greatest, and since the gas temperature sets the allowable stress for the particular bucket material, the root stress at a speci 50 improved method of designing a turbine nozzle and ?ed temperature is generally taken as the limiting factor and the remainder of the bucket is designed, using the bucket shape at the root as a reference, to achieve a desired extraction of energy from the motive ?uid with proper aerodynamic e?iciency and stability. However, 55 theeffectofradialtemperaturegradients. the conventional approaches to determining the “blade angles,” and the blade cross-section area at a ?xed tem perature over the radial height, etc., are inherently waste ful of the potential capabilities of the bucket material in theouterlesserstressedportionsofthebuckettowith 60 stand higher temperatures. A commonly used design philosophy assumes a con stant temperature of motive ?uid from bucket root to tip, and the combustion chambers and ?ow ducts supplying the ?rst-stage nozzle and ?rst-stage bucket are designed 65 flow gas turbine showing the ?rst-stage nozzle ring and accordingly. Actually,theradiallyouterportionsofthe bucket are capable of withstanding a much higher tem perature due to the lower stresses. Utilization of this fact would provide a higher mean gas temperature and hence higher thermal efficiency. However, present 70 vortex”design; design philosophies, such as the “free vortex” design (for instance as disclosed in US. Patent 2,378,372 issued FIG. 4 is a vector diagram for the invention, employ~ ing the same root velocities as in FIG. 3 for comparison; 'number was de?ned as the velocity relative to the blade, dividedbythelocalacousticvelocity. Onefeatureof the present invention is to employ an expression desig nated as “tangential Mach number” as a design parame ter. The tangential Mach number MU is de?ned here ing the nozzle at a given radius divided by the local acousticvelocityatthesameradius. Itistobeunder stood, however, that the tangential Mach number is em has no real physical signi?cance, as does the local Mach number de?ned in the aforementioned Patent 2,426,270. Accordingly, one object of the present invention is to provide an improved axial ?ow turbine design which Another object of the invention is to provide a turbine bucket which utilizes the bucket material to a greater extent so as to more fully achieve its inherent capabilities. Still another object of the invention is to provide an bucket to make effective use of radial temperature gra dients. ‘ _ Another object of the invention is to provide a turbine bucket designed by varying a parameter which includes Yet another object of the invention is to provide a tur bine bucket which achieves optimum correlation between allowable stres,operating temperature, and aerodynamic stability. Theseandmanyotherobjectsoftheinventionmay best be understood by reference to the following descrip tion taken in connection with the accompanying drawings inwhich: FIG. 1 is a longitudinal section of a portion of an axial ?rst-stage turbine bucket wheel. FIG. 2 is a graph showing the radial temperature gradientinthemotivefluidoftheturbineofFIG. 1; FIG. 3 is a velocity vector diagram of a typical “freePDF Image | FLOW TURBINE WITH RADIAL TEMPERATURE GRADIENT
PDF Search Title:
FLOW TURBINE WITH RADIAL TEMPERATURE GRADIENTOriginal File Name Searched:
US3135496.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |