Online rotor thrust adjustment system

Abstract

An online rotor thrust adjustment system is disclosed. The online rotor thrust adjustment system comprises at least an axial thrust balancing flow net (16) located between a compressor (12) and an expander (11) of the gas turbine, the axial thrust balancing flow net (16) feeding high pressure gas from the compressor (12) to an axial thrust balancing piston cavity; wherein an open loop flow regulator (17) is arranged along the axial thrust balancing flow net (16).

Description

Technical Field

[0001] The present disclosure relates to a system for balancing the load on the thrust bearing of a gas turbine engine rotor. The embodiments disclosed herein are particularly directed to regulating rotor thrust in real time using a regulating valve manually operated from outside the engine block. Background Art

[0002] The rotating parts of the turbine unit always generate axial thrust due to the pressure difference between the intake and exhaust gases.

[0003] For example, in "oil and gas" applications, the axial thrust on the bearings of a gas turbine may typically be in the range of 10,000N to 100,000N.

[0004] Providing a thrust bearing capable of withstanding such high axial thrust forces is very difficult and expensive.

[0005] To solve this problem, high pressure gas from the compressor is used and fed into the piston cavity to balance at least a portion of the axial thrust.

[0006] Methods have been developed for testing balancing systems and their associated control units during production in order to correctly calibrate the complex algorithms. However, similar methods or systems are unable to recalibrate the complex algorithms in the field once the original operating profile and configuration of the engine has changed, such as changes caused by degradation, wear or replacement of parts. Typically, this also occurs at first installation or in the event of a change in the operating configuration (e.g., water injection). Each of these factors has a direct impact on the engine components, thereby affecting the loads on the rotor thrust bearings and, correspondingly, the amount of pressure required in the balancing piston cavity to offset such loads. Currently, the regulation of this air flow is managed by appropriately designed in-line fixed orifices on the machine. Each time recalibration is required, the fixed orifice is replaced by physical disassembly of the pipeline, resulting in machine downtime.

[0007] Therefore, it is highly desirable to develop a system in which the axial thrust balance control unit is calibrated while the engine is running in the field. In addition, it is also desirable to perform the calibration process during normal engine operation without shutting down the engine.

[0008] Most importantly, it is desirable that such a rotor thrust regulation system be operated via an open loop control system to improve the overall reliability of the system. Summary of the invention

[0009] In one aspect, the subject matter disclosed herein relates to an online rotor thrust regulation system, which includes at least an axial thrust balancing flow network arranged between a compressor and an expander of a gas turbine, wherein the axial thrust balancing flow network feeds high-pressure gas from the compressor to the expander so as to at least partially balance the axial thrust; wherein an open-loop flow regulator is arranged along the axial thrust balancing flow network to adjust the size of a channel through the axial thrust balancing flow network.

[0010] In another aspect, the subject matter disclosed herein relates to an online rotor thrust adjustment system, wherein a manual valve is arranged along the axial thrust balancing flow net, the manual valve comprises a rod and a wheel, a portion of the rod and the wheel are arranged outside the gas turbine casing, and the wheel is removably coupled to the rod. In particular, according to this aspect of the subject matter disclosed herein, at least a portion of the axial thrust balancing flow net is composed of a flexible hose.

[0011] In another aspect, an online rotor thrust regulation system is disclosed herein, wherein an open-loop flow regulator is arranged along the axial thrust balancing flow network, and the rotor thrust regulation system includes an instrument for reading the thrust balancing pressure, a safety instrument, and a graphical control panel page for identifying the balancing pressure, valve position, and equivalent reference orifice size.

[0012] The rotor thrust regulating system according to the present disclosure is intended to replace the rotor thrust regulating system of the prior art with a new circuit based on the use of manual valves (instead of the orifices currently used) to regulate the correct flow and pressure of the balancing line. The weight and size of the components of the rotor thrust regulating system according to the present disclosure enable them to be assembled on site by an operator without the need for lifting equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more complete appreciation thereof will be readily obtained as the disclosed embodiments of the present invention and many of its attendant advantages become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0014] Figure 1 shows a schematic diagram of a first gas turbine including an online rotor thrust regulation system according to the present disclosure; and

[0015] Figure 2 A schematic diagram of a second gas turbine including an online rotor thrust regulation system according to the present disclosure is shown. DETAILED DESCRIPTION

[0016] Reference will now be made in detail to an embodiment of the present disclosure, examples of which are shown in the accompanying drawings. Such examples are provided by way of explanation of the present disclosure rather than by way of limitation. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the scope or substance of the present disclosure. References to "one embodiment" or "embodiment" or "some embodiments" throughout this specification refer to specific features, structures or characteristics described in conjunction with the embodiments being included in at least one embodiment of the disclosed subject matter. Therefore, the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" that appear in multiple places throughout the specification do not necessarily refer to the same embodiment. In addition, in one or more embodiments, specific features, structures or characteristics may be combined in any suitable manner.

[0017] When introducing elements of various embodiments, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0018] Now refer to the accompanying drawings, Figure 1 A schematic diagram of an exemplary gas turbine is shown. The gas turbine engine consists of an expander 11 and a compressor 12, the expander 11 being mechanically connected to the compressor 12 by a shaft 20. The expander 11 is also connected to the compressor 12 by a pipeline 14 to feed gas from the compressor 12 to the expander 11. The burner 13 is arranged along the pipeline 14 and is configured to achieve combustion of the gas received from the compressor 12, thereby increasing its volume. The combustion gas is then provided to the expander 11, where the potential energy of the combustion gas is converted into kinetic energy. The gas turbine is housed in a casing 15 so as to isolate it from the outside. In particular, cooling air is fed into the space between the gas turbine and the casing 15 to control the temperature of the gas turbine and to keep the temperature of the casing 15 within a safe level.

[0019] Figure 1 A rotor thrust regulation system according to an embodiment of the present disclosure is also shown. In particular, the rotor thrust regulation system includes an axial thrust balancing flow network 16 arranged between the compressor 12 and the expander 11, in particular connecting the secondary flow system of the compressor with the secondary flow system of the turbine. A portion of the high-pressure gas from the compressor 12 is extracted from the compressor 12 and fed to the turbine 11, in particular to the axial thrust balancing piston cavity, where the pressure of the gas is used to counterbalance the rotor thrust.

[0020] Also shown is a flow regulator 17 arranged along the axial thrust balancing flow net 16. In particular, the flow regulator 17 is an open-loop flow regulator 17 and consists of a manual valve 17 comprising a rod 18 and a wheel 19, a portion 18' of the rod 18 and the wheel 19 being arranged outside the gas turbine housing 15. Manual operation with the hand wheel 19 does not exclude the possibility of motorized actuation.

[0021] At least a portion of the axial thrust balancing flow net 16 is composed of a flexible hose to absorb the thermal expansion and vibration of the engine, prevent mechanical stress from being transmitted to the casing 15, support the manual valve 17, and prevent static and dynamic stress from being transmitted to the flange on the machine. The valve requires the wheel 19 to be placed outside the casing 15 for manual actuation from the outside. However, considering the high temperatures and noise generated during the operation of the gas turbine, the valve body and all the pipes of the axial thrust balancing flow net 16 are kept inside the casing. Flexible metal hoses can be conveniently used, minimizing their diameter to avoid obstruction, and therefore using solutions with linings to allow operation at high-speed flows. The materials and hose construction are designed for any specific gas turbine operating pressure and temperature.

[0022] The valve wheel 19 is removable and located outside the housing wall to avoid overheating which could cause harm to the operator.

[0023] In some embodiments, a ball valve is used because it is one of the most reliable valves in terms of position holding and fault recovery capabilities.

[0024] The operating position of the valve 17 must simulate the function of an orifice according to the prior art, which is ensured by using calculations and diagrams relating the valve opening to the sizes of different orifices.

[0025] See now Figure 2 , the online rotor thrust regulation system according to the present disclosure can also be applied to turbine engines. Figure 1 The same or corresponding parts, elements or components as described above are shown in the figure, and these parts, elements or components will not be described again. A power turbine 21 (which may be referred to as a "high-pressure turbine" or "high-pressure expander") is also shown downstream of the compressor 12 and the expander 11, which provides kinetic energy to the load 22.

[0026] Although various aspects of the present invention have been described in terms of various specific embodiments, it will be apparent to those skilled in the art that various modifications, variations, and omissions are possible without departing from the spirit and scope of the claims. In addition, unless otherwise indicated herein, the order or sequence of any process or method steps may be changed or reordered according to alternative embodiments.

Claims

1. An online rotor thrust regulation system for balancing the load on the rotor thrust of the gas turbine during operation in response to the designed operating profile and configuration of the gas turbine, the gas turbine comprising an expander (11) located downstream of a compressor (12); a burner (13), the burner being configured to receive gas from the compressor (12) through a pipeline (14), to achieve gas combustion and to provide the combustion gas to the expander (11); the gas turbine (10) being accommodated in a casing (15); the rotor thrust regulation system comprising an axial thrust balancing flow network (16) located between the compressor (12) and the expander (11) to feed high-pressure gas from the compressor (12) to the axial thrust balancing piston cavity; the rotor thrust regulation system is characterized in that an open-loop flow regulator (17) is arranged along the axial thrust balancing flow network (16).

2. An online rotor thrust regulation system according to claim 1, wherein the open-loop flow regulator (17) is a manual valve (17) comprising a rod (18) and a wheel (19), and the wheel (19) and a portion (18') of the rod (18) are arranged outside the gas turbine casing (15).

3. The online rotor thrust adjustment system according to claim 2, wherein the wheel (19) is removably coupled to the rod (18).

4. The online rotor thrust regulation system according to claim 1, wherein at least a portion of the axial thrust balancing flow net (16) is composed of a flexible hose.

5. The online rotor thrust regulation system according to claim 1, wherein the open-loop flow regulator (17) is a ball valve.

6. The online rotor thrust regulation system according to claim 1, wherein the open loop flow regulator (17) is regulated by copying a table of equivalent reference orifice sizes.

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