Turbo-machine with active electrical clearance control

Abstract

The disclosure relates to a turbo-machine comprising a stator and a rotor arranged rotatable inside the stator as well as at least one electric heating device which is arranged on the surface of at least part of the stator for active clearance control. Besides the turbo-machine, a method for operating the active clearance control comprising electric heating devices is disclosed.

1 . A turbo-machine comprising a stator, a rotor arranged rotatable inside the stator, and
 at least one electric heating device arranged on the surface of at least part of the stator for clearance control.   
     
     
         2 . The turbo-machine according  claim 1 , wherein the electrical heating device is arranged in a cavity of the stator part to heat a fluid which is at least partly surrounding the stator part and/or in that the electrical heating device is arranged with direct mechanical contact on the stator part to allow conductive heat transfer from the electrical heating device to the stator part. 
     
     
         3 . The turbo-machine according  claim 1 , wherein the electrical heating device is arranged in a cooling air supply bore of the stator. 
     
     
         4 . The turbo-machine according  claim 1 , wherein the stator part on which the electrical heating device is arranged is an inner and/or outer casing of the turbo-machine. 
     
     
         5 . The turbo-machine according  claim 1 , wherein the electrical heating device is arranged on a connecting wall connecting the inner casing with the outer casing. 
     
     
         6 . The turbo-machine according  claim 1 , wherein the electrical heating device comprises an induction heating. 
     
     
         7 . The turbo-machine according  claim 1 , further comprising a plurality of electrical heating devices distributed in axial and circumferential direction around the casing of the turbo-machine and in that different electrical heating devices are configured and connected to a power source such that they can be individually controlled to control the heating intensity in circumferential and axial direction of the turbo-machine. 
     
     
         8 . The turbo-machine according  claim 1 , further comprising at least one bearing support electrical heating device arranged on a bearing support. 
     
     
         9 . The turbo-machine according  claim 1 , wherein the turbo-machine is a gas turbine or a steam turbine. 
     
     
         10 . A method for operating a turbo-machine comprising a stator and a rotor arranged rotatably inside the stator and at least one electric heating device arranged on the surface of at least part of the stator;
 the method comprising   controlling the at least one electric heating device to heat the at least a part of the stator for controlling the clearance between the rotor and the stator.   
     
     
         11 . The method according to  claim 10 , wherein the controlling further comprises disposing the at least one electrical heating at position on the upper or lower half of the casing; and controlling the at least one electrical heating device to heat the region of the casing on which it is arranged to reduce circumferential temperature inhomogeneity in the casing. 
     
     
         12 . The method according to  claim 10 , wherein the at least one electrical heating device is controlled to keep the temperature profile of the turbo-machine's casing in axial direction within a predetermined range. 
     
     
         13 . The method according to  claim 10 , wherein at least one electrical heating device is arranged at a position on the lower half of the casing and in that it is used for heating during shut down and cooling of the turbo-machine to compensate for an increase in the temperature of the upper half of the casing relative to the temperature of the lower half of the casing due to convective heat transfer from the bottom to the top half to mitigate buckling, and/or at least one electrical heating device is arranged to heat a flange connecting the lower and upper half casing to reduce or avoid ovalisation of the casing. 
     
     
         14 . The method according to  claim 10 , wherein at least one bearing support electrical heating device arranged on a bearing support is used to keep the rotor centrally aligned relative to the casing by controlled heating of the bearing support. 
     
     
         15 . The method according to  claim 10 , wherein the power supplied to the at least one electric heating device is based on one of the following:
 heating according to a schedule   heating depending on an operating parameter of the turbo-machine such as the speed, the power, a mass flow, or an operating temperature   heating to control the temperature of at least one section of the casing based on a temperature measurement   direct measurement of the clearance with a blade clearance transducer and/ or a vane clearance transducer and heating to control the measured clearance   closing the inlet and/or the outlet of the turbo-machine during standstill of the turbo-machine to reduce a fluid flow and heat transfer to the fluid in the turbo-machine.