Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
  • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
  • F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
  • F01D11/20—Actively adjusting tip-clearance
  • F01D11/24—Actively adjusting tip-clearance by selectively cooling-heating stator or rotor components
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D19/00—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith
  • F01D19/02—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith dependent on temperature of component parts, e.g. of turbine-casing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
  • F01D25/08—Cooling; Heating; Heat-insulation
  • F01D25/10—Heating, e.g. warming-up before starting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/26—Starting; Ignition
  • F02C7/262—Restarting after flame-out
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the invention relates to a method in or relating to the start of a power turbine in order to avoid start damage on the turbine wheel and/or housing.
• the invention relates to an arrangements in a power turbine which, unitary to the purpose of the method aspect, is intended to prevent damage on the turbine wheel and/or housing, especially in connection with start up.
• a power turbine is a separate expansion turbine driven by the combustion gas from a gas generator.
• a cooling jacket cannot prevent a start damage and one has, therefore, tried to solve the problem through monitoring the power turbine's rotational speed. If the turbine does not start or accelerates when admission is given, this is considered as indicative of a non-satisfactory clearance between turbine housing and wheel, and the start trial is interrupted. Before the next trial, one has to wait a while.
• a substantial disadvantage of such a monitoring of rotational speed is that the turbine wheel may rotate a number of times before the problem is discovered and, then, damage will already have arisen.
• the main object of the invention is to provide a method and a device to prevent damage upon start of a power turbine.
• a subordinate aspect of the invention one has aimed at enabling pointing out indications of possible damage risks at such an early point of time that damage would be avoidable.
• said object is achieved by proceeding in accordance with the method as set forth in claim 1, in which it is proposed to heat the turbine housing before start, respectively by equipping a power turbine housing with a heating jacket disposed outside the housing, generally in connection to a cooling jacket as known per se.
• the turbine housing Upon a start after a non-planned stop, the turbine housing is first heated such that it becomes approximately as hot as the remainder of the turbine, whereafter the turbine is started.
• the housing When the turbine has reached the working temperature, the housing may, possibly, be cooled in order to reduce the clearance to the turbine wheel, achieving optimal efficiency.
• the device Upon pointing out such vibration phenomena, the device is adapted such that a starting trial can be interrupted in time, simultaneously as too much cooling is avoided if a cooling jacket is used, as known per se.
• Vibration and acoustic signals not due to unbalance are usually to weak to be used for analysis or for influencing shut down systems. The reason is that such signals become "drowned" by the gas turbine after which the power turbine is coupled, a special technology being required to separate out the signals from the background noise.
• the "envelope” or “enveloping technique” used in connection with the above mentioned vibration measurements has for its purpose to amplify weak signals from e.g. an accelerometer. Through this method, higher frequencies are first separated from low-frequent machine vibrations by excluding unnecessary frequency ranges. The problem is to identify the weak signals. A signal from e.g. a bearing ball rolling in the ball race is very weak, and is diffused across a wide frequency range. Therefore, such a signal is well “hidden” in the remainder of the machine noise.
• the “envelope circuit” amplifies the filtered signal approximately corresponding to the square thereof. Since the sound of members rotating within the machine is repeatable, they may be simulated by harmonic series of sinus waves corresponding to integer multiples of repeatable signals.
• Figure 1 shows a side elevational view/axial section of a gas turbine with a power turbine shaped and designed in accordance with the present invention
• Figure 2 shows a rear partial view of the power turbine
• Figure 3 shows a detail view III stippled encircled in figure 2, on a larger scale
• Figure 4 shows a sectional view corresponding to the section line IV-IV in figure 3.
• reference numerals 10 and 12 respectively, denote a compressor rotor and a gas turbine rotor, 14 indicating the rotor of the power turbine.
• a compressor shaft 16 is suspended in a front frame bearing 18, an intermediate frame bearing 20 and a rear frame bearing 22, the shaft 16' of the power turbine being suspended in a front bearing 22' and a power turbine bearing 24.
• the inlet 26 to the compressor portion is trumpet-shaped, the exhaust channel being denoted at 28.
• the housing 30 of the power turbine is, according to the invention, surrounded by a heating jacket 32 which, within the range of subjects, is mentioned as a "thermal manifold"; 34 denoting a heating coil for supplying heat energy to the heating jacket 32.
• 14a denotes turbine blades.
• 36 denotes a seal.
• S denotes a slot between the seal 36
• a cooling jacket in combination with the heating jacket 32 (stippled in figures 2 - 4) , may be disposed.
• the turbine housing 30 Upon start up such a gas generator assigned a power turbine, the turbine housing 30 is first heated when one desires start up a short time after stoppage, so that the turbine housing becomes approximately as hot as the remainder of the turbine, whereafter the turbine is started.
• a brake (not shown) can be used on the shaft 16' of the power turbine. Subsequently to a stoppage not planned, the brake is activated so that the rotor 14 of the power turbine cannot rotate. Thereafter, compressor and gas turbine are started and, then, hot gas from the gas turbine will heat the housing 30 of the power turbine. When the housing 30 of the power turbine has reached a satisfactory temperature, the brake is released.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Control Of Turbines (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=19900783

Family Applications (1)

Country Status (4)

Families Citing this family (5)

Family Cites Families (9)

• 1997
  • 1997-06-05 NO NO972553A patent/NO306271B1/no not_active IP Right Cessation
• 1998
  • 1998-06-02 AU AU74579/98A patent/AU7457998A/en not_active Abandoned
  • 1998-06-02 WO PCT/NO1998/000162 patent/WO1998055738A1/no not_active Application Discontinuation
  • 1998-06-02 EP EP98921927A patent/EP0985083A1/en not_active Withdrawn

Non-Patent Citations (1)

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