A method for dynamically adjusting axial force of a marine gas turbine rotor

Abstract

The application aims to provide a marine gas turbine rotor axial force dynamic adjustment method, which completes axial force test before the gas turbine leaves factory, forms a database of rotor axial force changing with working condition and bleed valve opening, uses an axial force test system to monitor rotor axial force in real time, when the rotor axial force deviates from the optimal rotor axial force curve, a control system detects the working condition and bleed valve opening of the gas turbine, determines an adjustment scheme according to the database, outputs an adjustment signal to an electric cylinder actuator, adjusts the bleed valve opening, and then adjusts the rotor axial force to the optimal state, reduces bearing damage, and improves the service life and reliability of the gas turbine. When the rotor axial force deviates from the optimal rotor axial force curve changing with working condition, the application can dynamically adjust the rotor axial force, so that the rolling bearing is always in the optimal working state, greatly improving the service life and reliability of the rolling bearing.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas turbine adjustment method, in particular to a gas turbine rotor axial force adjustment method. BACKGROUND

[0002] The gas turbine has the advantages of high power density, fast starting speed, fuel flexibility, etc., and is widely used in industrial and offshore platform power generation, natural gas transportation, ship power and other fields.

[0003] As one of the key components in the gas turbine, the stability of the rolling bearing directly relates to the stability of the unit operation. The rotor axial force of the gas turbine is mainly borne by the ball bearing. Excessive or insufficient axial load will aggravate the wear of the bearing and affect the safe operation of the gas turbine. Therefore, during the factory test of the gas turbine, the rotor axial force needs to be tested and adjusted to make the rotor axial force value within a reasonable range.

[0004] Unlike land-based gas turbines, marine gas turbines have variable operating conditions. Under different operating conditions, the rotor axial force differs greatly. In addition, after long-term use of the gas turbine, the clearance between the gas seals changes, causing the cavity pressure to change, and in turn causing the rotor axial force to change greatly. Therefore, the traditional fixed axial force adjustment method cannot keep the gas turbine rotor in the best working state all the time, affecting the bearing life and in turn affecting the reliability of the gas turbine operation. Therefore, there is an urgent need for a dynamic adjustment method for the rotor axial force of the gas turbine to dynamically adjust the rotor axial force according to the state of the gas turbine and improve the reliability of the gas turbine operation. SUMMARY

[0005] The purpose of the present application is to provide a dynamic adjustment method for the rotor axial force of a marine gas turbine to solve the problem of the rotor axial force deviating from the best working point after long-term operation of the marine gas turbine.

[0006] The purpose of the present application is achieved as follows:

[0007] The dynamic adjustment method for the rotor axial force of a marine gas turbine according to the present application is characterized in that:

[0008] (1) Before the gas turbine is shipped, the rotor axial force of the gas turbine is tested to obtain the rotor axial force values under various operating conditions. The gas bleed valve opening is adjusted under each operating condition, and the rotor axial force values under different gas bleed valve openings are recorded to obtain a database of the rotor axial force changes with operating conditions and gas bleed valve openings, and a best rotor axial force curve with operating conditions is determined;

[0009] (2) An electric cylinder actuator is arranged at the position of the gas bleed valve to control the opening of the gas bleed valve through the electric cylinder actuator;

[0010] (3) using the axial force test system to monitor the rotor axial force in real time, when the rotor axial force deviates from the optimal rotor axial force with the working condition change curve, if the deviation is not more than 2KN, no adjustment is made, if the deviation exceeds 2KN, the working condition of the gas turbine and the opening degree of the air exhaust valve are detected, an adjustment scheme is determined according to the database of the rotor axial force with the working condition and the air exhaust valve opening degree change, an adjustment signal is output to the electric cylinder actuator, the air exhaust valve opening degree is adjusted, the rotor axial force is adjusted to the optimal rotor axial force with the working condition change curve, and a warning is sent to the gas turbine operator.

[0011] The application can also include:

[0012] 1. When the gas turbine rotor axial force is tested, the gas turbine rotor works, the axial force of the compressor blade and the compressor disc is forward, the axial force of the turbine blade and the turbine disc is backward, and the rotor axial force is tested by the force ring.

[0013] 2. The air exhaust valve and the air exhaust pipe are arranged on the casing, the air exhaust pipe is communicated with the chamber at the front end of the compressor disc, the air exhaust amount is controlled through the air exhaust valve, and the pressure in the chamber is adjusted; when the opening degree of the air exhaust valve is increased, the air exhaust amount is increased, the pressure in the chamber is reduced, the axial force of the compressor disc forward is increased, and the axial force of the gas turbine rotor backward is reduced; when the opening degree of the air exhaust valve is reduced, the air exhaust amount is reduced, the pressure in the chamber is increased, the axial force of the compressor disc forward is reduced, and the axial force of the gas turbine rotor backward is increased.

[0014] The application has the advantages that when the rotor axial force deviates from the optimal rotor axial force with the working condition change curve, the rotor axial force can be dynamically adjusted, the rolling bearing is always in the optimal working state, and the service life and reliability of the rolling bearing are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a schematic diagram of the gas turbine rotor structure of the application;

[0016] Figure 2 It is a schematic diagram of the air exhaust valve structure of the gas turbine of the application;

[0017] Figure 3 It is a flow chart of the application. DETAILED DESCRIPTION

[0018] The application will be described in more detail below with examples combined with the drawings:

[0019] Combined with the drawings, the application is described in more detail as follows: Figures 1-3The axial force of the gas turbine rotor is mainly composed of two parts: the axial force generated by the gas on the blade in the flow area and the axial force generated by the pressure difference of the disc cavity. The axial force generated by the gas on the blade is difficult to adjust, so adjusting the disc cavity pressure becomes the main method for adjusting the rotor axial force. The gas exhaust valve can adjust the pressure in the front cavity of the compressor, thereby changing the rotor axial force.

[0020] The ship gas turbine rotor axial force dynamic adjustment method provided by the application comprises the following steps:

[0021] Step one: before the gas turbine leaves the factory, the gas turbine rotor axial force test is completed, the rotor axial force values under each working condition are obtained, and the gas exhaust valve opening is adjusted under each working condition. The rotor axial force values under different gas exhaust valve opening conditions are recorded, a database of the rotor axial force change with the working condition and the gas exhaust valve opening is obtained, and an optimal rotor axial force change curve with the working condition is determined.

[0022] Step two: an electric cylinder actuator is arranged at the position of the gas exhaust valve, and the opening of the gas exhaust valve can be controlled through the electric cylinder actuator.

[0023] Step three: the axial force test system is used to monitor the rotor axial force in real time. When the rotor axial force deviates from the optimal rotor axial force change curve with the working condition, if the deviation is less than 2KN, no adjustment is made; if the deviation exceeds 2KN, the control system detects the working condition of the gas turbine and the opening of the gas exhaust valve, determines an adjustment scheme according to the database of the rotor axial force change with the working condition and the gas exhaust valve opening, outputs an adjustment signal to the electric cylinder actuator, adjusts the opening of the gas exhaust valve, and then adjusts the rotor axial force to the optimal rotor axial force change curve with the working condition, and issues a warning to the gas turbine operator.

[0024] The structure of the application mainly comprises compressor blades 1, turbine blades 2, a turbine disc 3, a roller bearing 4, a rotating shaft 5, a compressor disc 6 and a ball bearing 7.

[0025] When the gas turbine rotor is working, the compressor blades 1 and the compressor disc 6 generate axial force forward, the turbine blades 2 and the turbine disc 3 generate axial force backward, and the total axial force of the gas turbine rotor is determined to be backward, i.e. pointing to the turbine side, through the test results in the early stage. In order to obtain the rotor axial force, force rings 8 are arranged on both sides of the ball bearing 7 to test the size of the rotor axial force.

[0026] The gas exhaust valve 9 and the gas exhaust pipe 10 are arranged on the casing 11, the gas exhaust pipe 10 is connected to the cavity A at the front end of the compressor disc 6, the gas exhaust amount is controlled through the gas exhaust valve 9, and then the pressure in the cavity A is adjusted.

[0027] When the opening of the gas exhaust valve 9 is increased, the gas exhaust amount is increased, the pressure in the cavity A is reduced, the axial force of the compressor disc 6 forward is increased, and then the axial force of the gas turbine rotor backward is reduced.

[0028] When the opening of the bleed valve 9 is reduced, the amount of bleed air is reduced, the pressure in the chamber A is increased, the axial force of the compressor disc 6 in the forward direction is reduced, and the axial force of the gas turbine rotor in the backward direction is increased.

[0029] The structure of the bleed valve 9 is shown in Figure 2 The structure mainly consists of a shell 9-1, a valve 9-2, a base 9-3, and an electric cylinder actuator 9-4.

[0030] The valve 9-2 is driven by the electric cylinder actuator 9-4 to move in the shell 9-1, the outlet area of the bleed valve is adjusted, and the pressure in the chamber A is adjusted to achieve the purpose of adjusting the axial force of the gas turbine rotor.

[0031] The flow chart of the method for dynamically adjusting the axial force of the marine gas turbine rotor is shown in Figure 1 The specific implementation method is as follows:

[0032] The opening of the bleed valve is set to the middle position, the axial force test of the rotor is completed under various working conditions, and the data of the change of the axial force of the rotor with the working condition are obtained;

[0033] Under various working conditions, the opening of the bleed valve is adjusted by the electric cylinder actuator 9-4, the data of the change of the axial force of the rotor with the opening of the valve under different working conditions are obtained, and the optimal working curve is determined;

[0034] The data are input into the control system, the control strategy is programmed, and the control adjustment is performed when the deviation from the optimal working curve is more than 2KN;

[0035] The axial force test system is used to monitor the axial force of the rotor in real time, and the deviation from the optimal working curve is judged;

[0036] When the deviation exceeds the allowable value, the control system detects the working condition of the gas turbine and the opening of the bleed valve 9, determines the adjustment scheme according to the database of the change of the axial force of the rotor with the working condition and the opening of the bleed valve 9, outputs the adjustment signal to the electric cylinder actuator 9-4, adjusts the opening of the bleed valve 9, and then adjusts the axial force, detects the adjusted axial force again, judges the adjustment effect, and notifies the operator of the gas turbine.

[0037] The method for dynamically adjusting the axial force of the gas turbine rotor can effectively correct the deviation of the axial force of the rotor from the allowable range when the marine gas turbine is used for a long time, can correct the deviation of the axial force within a certain range, can protect the bearing, can reduce the damage to the bearing, and can improve the service life and reliability of the gas turbine.

Claims

1. A method for dynamically adjusting the axial force of a marine gas turbine rotor, characterized in that: (1) Before the gas turbine leaves the factory, complete the axial force test of the gas turbine rotor, obtain the rotor axial force value under each working condition, and adjust the opening of the vent valve under each working condition, record the rotor axial force value under different vent valve opening conditions, obtain a database of rotor axial force changes with working conditions and vent valve opening, and determine the optimal rotor axial force change curve with working conditions. (2) An electric cylinder actuator is installed at the position of the vent valve to control the valve opening of the vent valve; (3) Use an axial force testing system to monitor the rotor axial force in real time. When the rotor axial force deviates from the optimal rotor axial force variation curve with operating conditions, if the deviation is no greater than 2KN, no adjustment is made. If the deviation exceeds 2KN, detect the operating conditions of the gas turbine and the opening of the vent valve. Determine the adjustment scheme based on the database of rotor axial force variation with operating conditions and vent valve opening. Output the adjustment signal to the electric cylinder actuator to adjust the vent valve opening, thereby adjusting the rotor axial force to the optimal rotor axial force variation curve with operating conditions, and issue a warning to the gas turbine operator.

2. The method for dynamically adjusting the axial force of a marine gas turbine rotor according to claim 1, characterized in that: During the axial force test of the gas turbine rotor, the gas turbine rotor is working. The compressor blades and compressor disk generate an axial force forward, and the turbine blades and turbine disk generate an axial force backward. The magnitude of the rotor axial force is measured by a force measuring ring.

3. The method for dynamically adjusting the axial force of a marine gas turbine rotor according to claim 2, characterized in that: in The casing is equipped with a vent valve and a vent pipe. The vent pipe connects to the chamber at the front end of the compressor disc. The vent valve controls the venting volume, thereby adjusting the pressure in the chamber. When the vent valve opening is increased, the venting volume increases, the pressure in the chamber decreases, the forward axial force of the compressor disc increases, and thus the backward axial force of the gas turbine rotor decreases. When the vent valve opening is decreased, the venting volume decreases, the pressure in the chamber increases, the forward axial force of the compressor disc decreases, and thus the backward axial force of the gas turbine rotor increases.

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