Rapid calculation method for gas injection amount of labyrinth seal of high-temperature axial flow compressor

Abstract

The invention provides a rapid calculation method for the labyrinth seal gas injection amount of a high-temperature axial flow compressor. The rapid calculation method has the technical effects that the seal gas injection amount of the high-temperature compressor is rapidly calculated, and the accuracy is high. The invention discloses a rapid calculation method for the labyrinth seal gas injection amount of a high-temperature axial flow compressor. The method comprises the steps that a first parameter is obtained; second parameters are collected, wherein the second parameters comprise the upstream pressure, the downstream pressure and the sealing downstream temperature; and the leakage amount and the gas injection amount are calculated, and after the first parameter and the second parameter are obtained, the gas injection amount required by sealing of the high-temperature compressor is obtained through calculation, so that the effects of sealing a compressor medium and isolating oil stains in a bearing area are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and particularly to a method for quickly calculating the injection gas volume of a labyrinth seal for a high-temperature axial-flow compressor. Background Art

[0002] In high-temperature heat pump projects, the shaft-end seal adopts a U-shaped tooth labyrinth seal, and a primary seal gas is set to achieve the purpose of sealing the compressor medium and isolating the oil stain in the bearing area. Generally, a primary seal gas and a primary isolation gas are used for the shaft-end seal to achieve the above purpose.

[0003] Usually, the method for calculating the injection gas volume of the compressor seal is to estimate by assuming that the medium is an ideal gas using a formula. This method is simple and fast but has low accuracy.

[0004] Since the formula calculation method only has a certain accuracy within a certain temperature and pressure range, when the pressure difference and temperature difference are too large, the accuracy of the formula calculation will not meet the engineering requirements. And for some high-temperature compressors, the outlet temperature is relatively high, and it is not accurate enough to calculate the seal injection gas volume using the general formula. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the present invention provides a method for quickly calculating the injection gas volume of a labyrinth seal for a high-temperature axial-flow compressor, which has the technical effects of quickly calculating and high accuracy for the seal injection gas volume of a high-temperature compressor.

[0006] The above technical object of the present invention is achieved through the following technical solutions:

[0007] A method for quickly calculating the injection gas volume of a labyrinth seal for a high-temperature axial-flow compressor includes the following steps:

[0008] Obtain the first parameters, where the first parameters include the upstream pressure, the downstream pressure, and the downstream temperature of the seal;

[0009] Calculate the leakage amount of the labyrinth seal through the first parameters;

[0010] Obtain the injection gas volume of the labyrinth seal from the leakage amount of the labyrinth seal.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] After obtaining the data of the first parameters, calculate the leakage amount of the labyrinth seal for the high-temperature axial-flow compressor. Through the calculation of the leakage amount, obtain the injection gas volume required for the seal of the high-temperature compressor. When the high-temperature compressor is in use, inject gas into the injection hole according to the calculated injection gas volume to achieve the effects of sealing the compressor medium and isolating the oil stain in the bearing area. Brief Description of the Drawings

[0013] Figure 1Schematic diagram of the structure of the embodiment of the present invention. Detailed implementation manners

[0014] The technical solutions in the present invention will be further described below in conjunction with embodiments.

[0015] Embodiment:

[0016] A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor, comprising:

[0017] S1. Obtain the first parameters, which include the seal radius clearance, seal tooth pitch, seal nominal diameter, average molecular weight of the medium, upstream pressure, downstream pressure, and seal downstream temperature. The operator can adjust the seal radius clearance, seal tooth pitch, seal nominal diameter, average molecular weight of the medium, upstream pressure, downstream pressure, and seal downstream temperature according to actual needs to achieve a better sealing effect. The first parameters are known engineering conditions, that is, all are design values.

[0018] S2. Calculate the leakage volume.

[0019] In specific implementation, each leakage volume calculation includes the following steps.

[0020] S21. Calculate the seal adjustment coefficient in combination with the existing structure as

[0021] where k is the seal adjustment coefficient, t is the seal radius clearance, and l is the seal tooth pitch.

[0022] S22. Calculate the leakage area of the seal as s = π × t × d;

[0023] where s is the leakage area, t is the seal radius clearance, and d is the seal nominal diameter.

[0024] S23. Calculate the specific volume as

[0025] where v is the specific volume, T is the seal downstream temperature, p2 is the seal downstream pressure, and w is the average molecular weight of the medium.

[0026] S24. Calculate the pressure ratio as

[0027] where p0 is the upstream and downstream pressure ratio, p1 is the upstream pressure (injection gas pressure), and p2 is the downstream pressure.

[0028] In specific implementation, the pressures at both the medium side and the bearing area side need to be calculated separately. The upstream and downstream pressure ratio on the medium side is p 2介 is the pressure in the chamber on the medium side; the upstream and downstream pressure ratio on the bearing area side is p 2轴is the pressure in the chamber on the bearing area side.

[0029] S25, calculate the leakage rate as

[0030] where Q is the leakage rate on one side of the labyrinth seal;

[0031] In specific implementation, to calculate the total leakage rate, the leakage rates on both sides need to be calculated separately and then added together to obtain the total leakage rate of the labyrinth seal. That is, it is necessary to calculate the leakage rate on the medium side and the leakage rate on the bearing area side separately. The leakage rate on the medium side is:

[0032]

[0033] The leakage rate on the bearing area side is

[0034] The total leakage rate of the labyrinth seal is Q 总 = Q 介 + Q 轴 .

[0035] S3, the total injection volume Q of the labyrinth seal 注 = Q 总 .

[0036] Through calculation, the total injection volume of the labyrinth seal is the same as the total leakage rate of the labyrinth seal. When it is necessary to seal the compressor medium and isolate the oil stain in the bearing area, an external injection device is connected through the injection hole, and the corresponding amount of air is introduced into the injection hole according to the calculation result, so as to achieve the effect of sealing the compressor medium and isolating the oil stain in the bearing area.

[0037] In specific implementation, the calculation process of a certain calculation example is shown in Table 1.

[0038] Table 1 Calculation example of the injection volume of the U-shaped tooth labyrinth seal of a high-temperature compressor

[0039]

[0040]

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor, characterized in that, It includes the following steps: Obtain the first parameter, where the first parameter includes the upstream pressure, downstream pressure, and sealed downstream temperature; Calculate the labyrinth seal leakage rate through the first parameter; Obtain the labyrinth seal gas injection rate based on the labyrinth seal leakage rate.

2. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 1, characterized in that, The first parameter further includes the seal radius clearance, seal pitch, seal nominal diameter, and average molecular weight of the medium.

3. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 2, characterized in that, The leakage rate calculation includes the following steps: Step 1: Calculate the seal adjustment coefficient k in combination with the existing structure; Step 2: Calculate the leakage area s of the seal; Step 3: Calculate the specific volume v; Step 4: Calculate the pressure ratio p0; Step 5: Calculate the leakage rate Q.

4. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 3, characterized in that The calculation formula for the seal adjustment coefficient k is: In the above formula, k is the seal adjustment coefficient, t is the seal radius clearance, and l is the seal pitch.

5. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 4, characterized in that The calculation formula for the seal leakage area s is: s = π × t × d In the above formula, s is the leakage area, t is the seal radius clearance, and d is the seal nominal diameter.

6. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 5, characterized in that The calculation formula for the specific volume v is: In the above formula, v is the specific volume, T is the sealed downstream temperature, p2 is the downstream pressure, and w is the average molecular weight of the medium.

7. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 6, characterized in that, The calculation formula for the pressure ratio p0 is: In the above formula, p0 is the upstream and downstream pressure ratio, p1 is the upstream pressure (injection pressure), and p2 is the downstream pressure; Medium side pressure ratio p 0介 The calculation formula is p 2介 is the pressure in the chamber on the medium side; Side pressure ratio p in the bearing area 0轴 The calculation formula is p 2轴 is the pressure in the chamber on the bearing area side.

8. A rapid calculation method for the injection gas volume of a labyrinth seal of a high-temperature axial flow compressor according to claim 7, characterized in that The calculation formula for the leakage rate Q is: In the above formula, Q is the single-sided gas injection rate of the labyrinth seal; The leakage rate Q on the medium side 介 The calculation formula is Q 介 is the gas leakage rate on the medium side; The side leakage volume Q of the bearing area 介 The calculation formula is Q 轴 is the gas leakage volume on the side of the bearing area; The total leakage of the labyrinth seal is Q 总 = Q 介 + Q 轴 ; In the above formula, Q 总 is the total leakage of the labyrinth seal.

9. A rapid calculation method for the injection gas volume of the labyrinth seal of a high-temperature axial flow compressor according to claim 8, characterized in that, The total injection gas volume of the labyrinth seal is equal to the total leakage volume of the labyrinth seal, i.e., Q 注 = Q 总 ; In the above formula, Q 注 is the total gas injection volume of the labyrinth seal.

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