Gas turbine long-time test checking lubricating oil consumption calculation method and lubricating oil system for checking

Abstract

The invention relates to a gas turbine long-time test lubricating oil consumption calculation method and a lubricating oil system for examination, and belongs to the field of gas turbines. The liquid level height of a lubricating oil tank is obtained through measurement of a radar liquid level meter and calculation of a data acquisition system, the recording opportunity of the lubricating oil liquid level is stipulated, and the lubricating oil consumption is calculated according to the numerical relationship between the lubricating oil liquid level and accumulated operation time. Therefore, the lubricating oil consumption rate of the to-be-calculated and assessed map section is obtained. The method is of great significance to stable operation of the gas turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a calculation method for lubricating oil consumption in long-term test assessment of gas turbines and a lubricating oil system for assessment. Background Art

[0002] During the operation of a gas turbine, the lubricating oil system is an important part to ensure its normal operation. The lubricating oil not only plays a lubricating role, but also undertakes the functions of cooling and cleaning. The consumption of lubricating oil is directly related to the operation efficiency and maintenance cost of the gas turbine.

[0003] During the long-term test assessment of a gas turbine, it is necessary to calculate the lubricating oil consumption rate; during the long-term atlas assessment operation process, there is a phenomenon that the lubricating oil tank liquid level continuously fluctuates due to the lubricating oil circulation. During the interval of the unit atlas assessment, the shutdown interval time is relatively short, and after shutdown, lubricating oil circulation is still required to cool and lubricate the bearings. At the same time, due to the long-term lubricating oil circulation, there are phenomena such as a large amount of air bubbles in the oil product. Due to the above reasons, it is difficult to calculate the lubricating oil consumption of the gas turbine. Therefore, a calculation method for lubricating oil consumption for long-term test assessment of gas turbines is needed. Summary of the Invention

[0004] The applicant of the present invention aims at the above-mentioned disadvantages in the existing production technology, provides a reasonable-structured calculation method for lubricating oil consumption in long-term test assessment of gas turbines, and provides a lubricating oil system for assessment used in this method, which is applicable to the working conditions with a short shutdown time interval; and using this method can avoid the problem of inaccurate calculation caused by individual numerical measurement errors.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A calculation method for lubricating oil consumption in long-term test assessment of gas turbines includes the following steps:

[0007] Step 1: Select an assessment atlas; the cumulative operation time and the lubricating oil liquid level height in the lubricating oil tank after the completion of the atlas are respectively recorded as T and h.

[0008] Step 2: Take the lubricating oil liquid level before the operation of the first atlas and the lubricating oil liquid level after the operation of each atlas as the ordinate, and the cumulative operation time as the abscissa to form a broken line graph.

[0009] Step 3: Calculate the lubricating oil consumption in a specific time period according to the following formula:

[0010] Q = S×Δh×ρ / τ

[0011] In the formula:

[0012] Q is the lubricating oil consumption rate, with the unit of kg / h;

[0013] △h is the liquid level difference, with the unit of mm; the liquid level difference is obtained from the broken line graph in Step 2.

[0014] τ is the operating time of the gas turbine during two measurements, in hours;

[0015] S is the interface area of the lubricating oil tank, in m 2 ;

[0016] ρ is the density of the lubricating oil, in kg / m 3 .

[0017] In step one, the height of the lubricating oil level in the lubricating oil tank is measured by a radar level gauge, and the height of the level is transmitted to the data acquisition system in real time.

[0018] To select the height of the lubricating oil level in the lubricating oil tank for calculation, it is necessary to record when the electric oil return pump is disconnected for 5 minutes after the gas turbine stops.

[0019] To record the lubricating oil level before the first spectrum runs, it is necessary to record when the unit is cold-blown and the electric oil return pump is disconnected for 5 minutes.

[0020] In step two, when selecting the lubricating oil level before the first spectrum runs and after each spectrum runs, the lubricating oil temperature difference is controlled within 5°C.

[0021] In step three, the selected calculation time period omits the duration of the additional lubricating oil consumption event; substitute the cumulative operating time points required for calculation into the numerical relationship between the lubricating oil level and the cumulative operating time in step two to obtain the liquid level difference △h before and after the time period τ.

[0022] An inspection lubricating oil system for a calculation method of lubricating oil consumption during long-term testing of a gas turbine, characterized in that an oil supply pipeline and an oil return pipeline are led out from the lubricating oil tank, and the lubricating oil tank is also connected with a data acquisition system and a thermal resistor,

[0023] An oil supply pump is connected to the oil supply pipeline; an oil return pump is connected to the oil return pipeline, and a cooling water inlet and return pipeline is also connected to the oil return pipeline.

[0024] The beneficial effects of the present invention are as follows:

[0025] The calculation method of lubricating oil consumption during long-term testing of a gas turbine disclosed in this application sets a radar level gauge on the top of the oil tank and uses the radar level gauge for measurement. The measured data is transmitted to the data acquisition system in real time. To record the lubricating oil level before the first spectrum runs, it is necessary to record when the unit is cold-blown and the electric oil return pump is disconnected for 5 minutes. The liquid level after each spectrum is completed needs to be recorded when the electric oil return pump is disconnected for 5 minutes after the unit stops. In this way, the lubricating oil in the unit is pumped back, which can also avoid the situation that the measurement of the lubricating oil level in the lubricating oil tank fluctuates continuously and is inaccurate, and at the same time meets the requirement of a short shutdown interval for the unit spectrum inspection.

[0026] When selecting the lubricating oil level, the temperature difference of the lubricating oil is within 5°C, avoiding the problem of inaccurate consumption calculation caused by the change of the lubricating oil performance due to the temperature difference.

[0027] Take the lubricating oil level before the first spectrum runs and the lubricating oil level after each spectrum runs as the ordinate, and the cumulative running time as the abscissa. Establish the numerical relationship between the two. The selected calculation time period does not include the time of additional lubricating oil consumption, excluding the problem of inaccurate consumption calculation caused by events such as cleaning the lubricating oil filter. Substitute the cumulative running time points required for calculation into the numerical relationship in step two to obtain the liquid level difference △ h before and after the time period τ, avoiding the problem of inaccurate calculation caused by individual numerical measurement errors.

[0028] This method can calculate the lubricating oil consumption during the long-term test assessment of the gas turbine, which is of great significance to the stable operation of the gas turbine. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the lubricating oil system for the long-term test assessment of the gas turbine used in the present invention.

[0030] Figure 2 It is the line graph obtained in step two.

[0031] Figure 3 It is a relationship diagram between the lubricating oil level and the cumulative running time of the gas turbine.

[0032] Figure 4 It is a relationship diagram between the lubricating oil level and the cumulative running time of the gas turbine used to calculate the lubricating oil consumption rate during the 10th spectrum to the 20th spectrum.

[0033] Wherein: 1. Lubricating oil tank; 2. Lubricating oil level; 3. Lubricating oil component supply pipe; 4. Electric lubricating oil pump supply pipe; 5. Lubricating oil component supply pump; 6. Electric lubricating oil supply pump; 7. Lubricating oil component return pump; 8. Electric lubricating oil return pump; 9. Gas turbine fuel supply main pipe; 10. Gas turbine return pipe; 11. Lubricating oil cooling water return pipe; 12. Lubricating oil cooling water inlet pipe; 13. Electric control valve; 14. Cooler; 15. Radar level gauge; 16. Data acquisition system; 17. Data transmission line; 20. Thermal resistor. Detailed Embodiment

[0034] The following combines the drawings to illustrate the detailed embodiment of the present invention.

[0035] This embodiment takes the specific process of a full-life reliability test of a certain gas turbine as an example. As Figure 1 shown, it is a schematic diagram of the system structure used. A data acquisition system 16 is connected to the lubricating oil tank 1 and is connected to the lubricating oil tank 1 through a data transmission line 17. A thermal resistor 20 is also connected to the lubricating oil tank 1.

[0036] The lubricating oil level 2 of the lubricating oil tank 1 is variable and is regulated through the oil supply circuit and the oil return circuit.

[0037] The oil supply circuit consists of two branches, namely the lubricating oil component supply pipe 3 and the motor-driven lubricating oil pump supply pipe 4. A lubricating oil component supply pump 5 and a motor-driven lubricating oil supply pump 6 are respectively installed on the two branches, and the two supply pumps merge into the gas turbine oil supply main pipe 9.

[0038] Similarly, a lubricating oil component return pump 7 and a motor-driven lubricating oil return pump 8 are connected in parallel on the oil return pipeline, and the two return pumps are led out from the gas turbine oil return pipe 10.

[0039] A lubricating oil cooling water inlet pipe 12 and a lubricating oil cooling water return pipe 11 are also introduced on the oil return pipeline to form a cooling inlet and return water pipeline. A cooler 14 is connected to the cooling water inlet and return water pipeline.

[0040] A certain gas turbine conducts a full-life reliability test, with a cumulative operation of 200 operation cycles. Each cycle lasts for 12 hours continuously, and the interval between cycles is 50 minutes.

[0041] It is known that the cross-sectional area of the gas turbine lubricating oil tank is 2 m², and the density of the lubricating oil at 35 °C is 862.5 kg / m 3 ;

[0042] A radar level gauge 15 is installed on the top of the gas turbine lubricating oil tank 1. Before operation, the fixed depth of the tank is measured as L, and the radar level gauge measures the distance D to the liquid level surface in real time. The signal (D) is transmitted to the data acquisition system 16, and through real-time calculation by the data acquisition system, the lubricating oil level in the tank is h = L - D.

[0043] Step 1: Record the lubricating oil level before the first operation cycle. Conduct cold blowing of the unit. After the cold blowing of the unit is completed, continue the lubricating oil circulation according to the operation specifications. When the lubricating oil circulation is completed and the motor-driven return pump is disconnected for 5 minutes, record the lubricating oil level in the lubricating oil tank as 741.5 mm.

[0044] Record the cumulative operation time of the gas turbine and the height h of the lubricating oil level 2 in the data acquisition system when the motor-driven return pump 8 is disconnected for 5 minutes after the gas turbine stops running after each operation cycle is completed.

[0045] Step 2:

[0046] When selecting the lubricating oil level before the first operation cycle and after each operation cycle, the lubricating oil temperature difference should not be greater than 5 °C.

[0047] During the assessment process of this gas turbine, the lubricating oil temperature is within the range of 35 - 37 °C, meeting the requirement that the lubricating oil temperature difference should not be greater than 5 °C.

[0048] Take the lubricating oil level before the first spectrum run and the lubricating oil level after each spectrum run as the vertical axis, and the cumulative operating time as the horizontal axis. For example, the data of 31 spectrum runs completed are as Figure 2 shown.

[0049] Step 3: Calculate the lubricating oil consumption in a specific time period.

[0050] According to the requirements, the lubricating oil consumption should be calculated every 10 spectrum runs. After the 7th spectrum run of this unit, the lubricating oil filter was cleaned, resulting in lubricating oil loss. When calculating the lubricating oil consumption of the first 10 spectra, the lubricating oil level data after the 8th, 9th, and 10th spectrum runs should not be included. The operating data of the first 7 spectra should be selected as the analysis sample.

[0051] The relationship between the lubricating oil level and the cumulative operating time of the gas turbine is as Figure 3 shown, and the relationship between the lubricating oil level and the cumulative operating time of the gas turbine is

[0052] y = 0.00000000032559524868x 6 -0.00000010575047371120x 5 +

[0053] 0.00001264961130686970x 4 -0.00069071452708158200x 3 +0.01691114010463930000x 2 -0.21205381373874800000x + 741.49950142932400000000(1)

[0054] After the 10th spectrum is completed, the unit has run for 120 hours in total. The lubricating oil level is obtained through formula (1) as 729.85 = 3.2559524868E-10 * 120^6 - 0.0000001057504737112 * 120^5 + 0.0000126496113068697 * 120^4 - 0.000690714527081582 * 120^3 + 0.0169111401046393 * 120^2 - 0.212053813738748 * 120^2 - 0.212053813738748 * 120^1 + 741.499501429324.

[0055] Then after 10 spectrum runs, the lubricating oil level drops by △h = 741.5 - 729.85 = 11.65 mm.

[0056] The lubricating oil consumption rate during this operation period is calculated using the following formula:

[0057] Q = S×Δh×ρ / τ = 2×11.65×0.001×862.5 / 120 = 0.167 kg / h

[0058] Where:

[0059] Q—the lubricating oil consumption rate, kg / h;

[0060] △h—the liquid level difference, mm;

[0061] τ—the operating time of the gas turbine during two measurements, h;

[0062] S—the interface area of the lubricating oil tank, m2;

[0063] ρ—the density of the lubricating oil, kg / m3.

[0064] The first 10 spectra are obtained, and the average lubricating oil consumption is 0.167 kg / h.

[0065] If calculating the lubricating oil consumption rate during the 10th spectrum to the 20th spectrum; it can be based on the relationship between the lubricating oil level and the cumulative operating time of the gas turbine as Figure 4 shown

[0066] The relationship between the lubricating oil level and the cumulative operating time of the gas turbine is y = 0.00000000000065896706x 6 -0.00000000081434002223x 5 +0.00000039327547285851x 4 -0.00009352244896609910x 3 +0.01131601059416900000x 2 -0.70379860818383100000x + 744.59389136571100000000.

[0067] After the 10th spectrum is completed, substituting into the above formula, the unit has run for 120 hours in total, and the lubricating oil level is 724.74 mm; after the 20th spectrum is completed, the unit has run for 240 hours in total, and the lubricating oil level is 716.93 mm.

[0068] The lubricating oil consumption rate during the 10th spectrum to the 20th spectrum is calculated using the following formula for the lubricating oil consumption rate during this operation period:

[0069] Q = S×Δh×ρ / τ = 2×(724.74 - 716.93)×0.001×862.5 / (240 - 120) = 0.112 kg / h

[0070] In the formula:

[0071] Q—Lubricating oil consumption rate, kg / h;

[0072] △h—Liquid level difference, mm;

[0073] τ—Operating time of the gas turbine during two measurements, h;

[0074] S—Interface area of the lubricating oil tank, m 2 ;

[0075] ρ—Lubricating oil density, kg / m 3 .

[0076] The above description is an explanation of the present invention, not a limitation thereof. For the scope defined by the present invention, refer to the claims. Any form of modification may be made within the protection scope of the present invention.

Claims

1. A method for calculating lubricating oil consumption during long-term test of a gas turbine, characterized in that: The steps include: Step 1: Select an assessment graph; the cumulative running time and the oil level height of the oil tank after the graph is completed are recorded as T and h respectively. Step 2: Use the lubricating oil level before the first graph is run and the lubricating oil level after each graph is run as the vertical axis, and the accumulated running time as the horizontal axis to form a line graph. Step 3: Calculate the oil consumption for a specific period of time according to the following formula: Q=S×Δh×ρ / τ In the formula, Q is the lubricating oil consumption rate, in kg / h; △h is the liquid level difference, in mm; the liquid level difference is obtained from the line graph in step 2; τ is the gas turbine operating time between two measurements, in h; S is the interface area of ​​the oil tank, in m 2 ; ρ is the density of lubricating oil, unit is kg / m 3 .

2. The method for calculating lubricating oil consumption during long-term test of a gas turbine according to claim 1, characterized in that: In step 1, the oil level in the oil tank is measured by a radar level gauge and the level is transmitted to the data acquisition system in real time.

3. The method for calculating lubricating oil consumption during long-term test of a gas turbine according to claim 2, characterized in that: The oil level height in the oil tank selected for calculation shall be recorded when the electric return oil pump is disconnected for a specified time interval after the gas turbine is shut down.

4. The method for calculating lubricating oil consumption during long-term test of a gas turbine according to claim 2, characterized in that: Record the lubricating oil level before the first chart is run, and record it when the unit needs to be cooled and the electric return oil pump is disconnected for a specified time interval.

5. The method for calculating lubricating oil consumption during long-term test of a gas turbine according to claim 1, characterized in that: In step 2, when selecting the lubricating oil level height before the first graph is run and after each graph is run, the lubricating oil temperature difference is controlled within 5°C.

6. The method for calculating lubricating oil consumption during long-term test of a gas turbine according to claim 1, characterized in that: In step 3, the selected calculation time period ignores the additional lubricating oil consumption event duration; the cumulative running time points to be calculated are substituted into the numerical relationship between the lubricating oil level and the cumulative running time in step 2 to obtain the level difference before and after the time period τ △ h.

7. A lubricating oil system for evaluation of lubricating oil consumption in a long-term test of a gas turbine according to claim 1, characterized in that: The oil tank is connected to an oil supply pipeline and an oil return pipeline. The oil tank is also connected to a data acquisition system and a thermal resistor. The oil supply pipeline is connected with an oil supply pump; the oil return pipeline is connected with an oil return pump, and the oil return pipeline is also connected with a cooling water inlet and return pipeline.

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