JP2000097108A - Bearing mechanism of turbo-pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep away a dangerous rotation frequency from the rotation frequency of a turbo-pump which varies following to the thrust of an engine. SOLUTION: As a bearing to support the rotary shaft of a turbo-pump, a static pressure type slide bearing is used, and for the pressure feeding to the static pressure type slide bearing, the output pressure of the turbo-pump, that is, a part of the liquid fuel 1 from a liquid outlet, is utilized. The rigidity of the bearing is changed by regulating the feeding pressure, by a pressure governing mechanism 63 provided in a feeding route 61, to convert the natural frequency of the bearing, so as to keep away a dangerous rotation frequency area from the rotation frequency of the turbo-pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing mechanism of a turbopump provided for performing high-pressure combustion of liquid fuel in a pump-type rocket engine, and more particularly, to changing a critical rotation speed by changing the rigidity of the bearing. Regarding what you did.

[0002]

2. Description of the Related Art Two types of rocket engines using liquid fuel for burning fuel at high pressure have been proposed. One is a gas pressure supply type in which liquid fuel is stored in a high-pressure tank and supplied to the engine by the pressure. The other is a pump type in which liquid fuel is boosted in pressure by a turbo pump and then supplied to an engine, and is mainly used for a large rocket engine. There is a pump type that drives a turbo pump using high-pressure gas generated in a rocket engine.

FIG. 7 shows a longitudinal section of a turbo pump of a conventional pump type rocket engine. In FIG. 7, a liquid fuel 1 such as liquid hydrogen or a liquid oxygen 3 as an oxidant is taken in from a liquid inlet 5, guided to a centrifugal pump 10 having a rotating inducer 7 and an impeller 9, and is pressurized by centrifugal force. Is discharged from the liquid outlet 11. Thereafter, the working gas 13 such as hydrogen gas generated by vaporizing the liquid fuel 1 is taken in from the gas inlet 15 and rotates the turbine 17. That is, the working gas 13 pushes the turbine blade 21 provided at the tip of the turbine disk 19 constituting the turbine 17 to rotate the turbine 17 and the rotating shaft 23. Thus, the centrifugal pump 10 provided on the other side of the rotating shaft 23, that is, the inducer 7 and the impeller 9 are rotated. The working gas 13 is sent from a gas outlet 24 to a combustion chamber or the like. In such a pump type rocket engine, the rotating shaft 23 is conventionally supported by a ball bearing, that is, a rolling bearing 27 with respect to the housing 25.

[0004]

The turbo pump used in the pump-type rocket engine has a rotating shaft 2
In order to avoid resonance due to use near the natural frequency (primary critical speed of the shaft system), that is, near the critical speed (critical speed), use at a rotational speed apart from this critical speed. Generally, the higher rotation side is used as the rated point. However, some rocket engines require throttling to reduce the rotation speed from the high rotation state of the turbo pump in order to adjust the thrust, in which case the rotation speed is lower than the rated point where the rotation speed is high. The speed must be controlled on the side and there is a possibility that the speed will interfere with the critical speed. Conventionally, the thrust control of a rocket engine has been greatly restricted in order to perform control that avoids the possibility of this interference.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can prevent the rotation speed of the rotary shaft of the turbo pump from interfering with the dangerous rotation speed by changing the dangerous rotation speed. It is an object of the present invention to provide a turbopump bearing mechanism capable of relaxing restrictions on thrust control.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, an invention according to claim 1 is provided with a hydrostatic sliding bearing for supporting a rotary shaft of a turbo pump in a pump-type rocket engine, and a rotation of the rotary shaft. A technology including a pressure supply system for supplying a predetermined pressure to the hydrostatic sliding bearings according to the number is adopted. According to the bearing mechanism of this turbo pump, when the rotation speed approaches the dangerous rotation speed according to the rotation speed of the turbo pump, the natural frequency is changed by changing the pressure of the hydrostatic sliding bearing to change the rigidity. Can be changed, and the critical rotation speed can be changed to move away from the rotation speed.

According to a second aspect of the present invention, in the bearing mechanism for a turbo pump according to the first aspect, the pressure supply system includes a supply path for supplying an output pressure by driving the turbo pump as a predetermined pressure to the hydrostatic sliding bearing. Technology is applied. According to the bearing mechanism of this turbo pump, by supplying the output pressure of the turbo pump to the hydrostatic type smooth bearing, the turbo pump that has been rated at a higher rotation speed than the dangerous rotation speed gradually reduced the rotation speed. In that case, the output pressure of the turbo pump also gradually decreases,
As a result, the pressure and rigidity of the hydrostatic sliding bearing are automatically reduced, and the critical rotation speed can be kept away from the low rotation side.

The invention according to claim 3 is the invention according to claim 1 or 2
In the bearing mechanism of the turbo pump described above, a technique in which the pressure supply system includes a pressure adjusting mechanism for changing a predetermined pressure is applied. According to the bearing mechanism of this turbo pump, by controlling the pressure supplied to the hydrostatic slide bearing by the pressure regulating mechanism, the supply pressure can be positively changed, and the dangerous rotation speed can be set arbitrarily. It becomes possible to keep the dangerous rotation speed sufficiently away from the rotation speed at the time.

According to a fourth aspect of the present invention, in the bearing mechanism for a turbo pump according to the third aspect, the rotation speed of the rotary shaft is compared with a preset dangerous rotation speed, and the rotation speed is set to the dangerous rotation speed. A technique including a control means for controlling the pressure regulating mechanism when approaching to change the supply pressure and changing the rigidity of the hydrostatic sliding bearing to control the dangerous rotation speed from the rotation speed is applied. According to the bearing mechanism of the turbo pump, the dangerous speed is controlled as appropriate by the control means so that the dangerous speed is quickly and appropriately changed when performing thrust control of the engine. Therefore, it is possible to easily cope with automation in performing thrust control.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a longitudinal section of a turbo pump to which a bearing mechanism according to the present invention is applied. FIG.
FIG. 2 is an overall schematic diagram of a circuit for supplying pressurized liquid fuel 1 (liquid hydrogen LH ₂ ) and liquid oxygen 3 (LOX) to the combustion chamber 31 of the rocket engine using the first and second turbo pumps 33 and 35. ing. A cooling jacket 39 is provided in the combustion chamber body 37 of the rocket engine, and an injection plate 43 having a manifold 41 to which the liquid fuel 1 and the liquid oxygen 3 are supplied is attached above.
An igniter 45 is provided at the center of the injection plate 43, and a nozzle extension (nozzle skirt) is provided below the combustion chamber main body 37.

Liquid hydrogen (LH ₂ ) as liquid fuel 1 is:
FUEL TURBOPU for fuel
MP) 33, the pressure is increased by the centrifugal pump 10, and the flow meter 47 and the remote shutoff valve (MAIN FUEL VALVE)
After passing through 49 to the cooling jacket 39 to be vaporized and turned into hydrogen gas 50, a part of the thrust control valve (TURBOPUMP CONTROL VALVE) 5
After passing through 1, the turbine 17 of the first turbo pump 33 is rotated.

The hydrogen gas 50 rotating the turbine 17 of the first turbo pump 33 is further supplied to a second turbo pump (LIQUID OXIDIZER TURBO) for liquid oxygen.
PUMP) 35 to the turbine 17a and rotate the turbine 17a.
Air is exhausted to No. 1 nozzle extension.

The liquid fuel 1 is pressurized by the centrifugal pump 10 of the first turbo pump 33 in which the turbine 17 is rotated as described above, and is oxidized by the centrifugal pump 10a of the second turbo pump 35 every time the turbine 17a is rotated. The pressure of the liquid oxygen 3 as the agent is increased. It should be noted that after the pressure is increased, the hydrogen gas 5
Most of the remaining zeros are sent to the manifold 41.

The pressurized liquid oxygen 3 passes through a flow meter 55, and is a remote shutoff valve MLV (MAIN LIQUID).
OXIDIZER VALVE) 57 and diaphragm 59
Through to the manifold 41. The hydrogen gas 50 and the liquid oxygen 3 sent to the manifold 41 are respectively injected from the injection plate 43 into the engine combustion chamber 31 and ignited by the igniter 45 to become combustion gas and injected from the combustion chamber 31, A predetermined thrust is generated.

Here, as the bearings of the two first and second turbo pumps 33 and 35, hydrostatic sliding bearings are used, and a part of the output pressure of the first and second turbo pumps 33 and 35 is reduced. These are supplied via supply paths 61 and 61a, respectively.
In other words, the pressure supply system for the bearings includes the centrifugal pumps 1 of the first and second turbo pumps 33 and 35, which are pressure supply sources.
0, 10a and supply paths 61, 61a for the pressure. The supply paths 61, 61a are provided with pressure regulating mechanisms 63, 63a, respectively, and the supply pressure is set by remotely controlling or automatically controlling these.

Returning to FIG. 1, the first turbo pump 33 (second
Turbo pump 35) is provided at each end of rotating shaft 23 arranged at the center of housing 25 with turbine 17 (17).
a) and the centrifugal pump 10 (10a) are fixed. The turbine 17 has a turbine rotor blade 21 provided around a disk 19. A vaporized hydrogen gas 50 (see FIG. 2), which is the working gas 13, is taken in from the gas inlet 15 toward the rotor blade 21, and is sent out from the gas outlet 24 after rotating the turbine 17. Liquid fuel 1 or liquid oxygen 3
Is taken in from the liquid inlet 5, and is pressurized by the inducer 7, the impeller 9 and the impeller shroud 8 constituting the rotating part of the centrifugal pump 10, and sent out from the liquid outlet 11.

Between the rotating shaft 23 and the housing 25,
Journal bearings 65 which are hydrostatic (hydrostatic) plain bearings are used in two places. This journal bearing 6
The liquid fuel 1 or a part of the liquid oxygen 3 sent out from the liquid outlet 11 is supplied to the supply passages 61 and 61 to the liquid supply port 67 of FIG.
a (see FIG. 2). A thrust bearing 69 is provided between the rotating shaft 23 and the housing 25.

FIGS. 3A and 3B show the journal bearing 65, in which FIG. 3A is a longitudinal sectional view, FIG. 3B is a side view of a part of FIG. 3A, and FIG. It is.
In this journal bearing 65, the rotating shaft 23 passes through the inside of the bearing sleeve 71, and a predetermined clearance 73 is provided between the surface of the rotating shaft 23 and the inner surface of the bearing sleeve 71, and a liquid 75 ( Liquid fuel 1 or liquid oxygen 3) is led.

When the liquid to be pressurized by the turbo pump is liquid oxygen, it is preferable that the liquid supplied to the clearance 73 is also liquid oxygen. Similarly, when the liquid to be pressurized is liquid hydrogen, It is desirable that the liquid supplied is also liquid hydrogen. This is to prevent the fluid to be pressurized and the fluid supplied to the clearance 73 from reacting carelessly.

As shown in FIGS. 3A and 3B, a plurality of pressure supply ports 77 are formed in an array on the inner peripheral surface of the bearing sleeve 71 facing the clearance 73 along the circumferential direction. . A pressure supply path 79 is formed in the back of the pressure supply port 77, penetrates the bearing sleeve 71, and communicates with the pressure supply chamber 67 on the outer peripheral surface of the sleeve. That is, the pressure supply chamber 67 exists on the outer peripheral surface of the bearing sleeve 71. The pressure supply ports 77 are provided in two rows as shown in FIG.

As described above, the liquid pressure supplied to the clearance 73 is set in accordance with the pressure supplied through the pressure supply port 77, and as a result, the journal bearing 65 has a rigidity supporting the rotary shaft 23. To change. For example, increasing the supply pressure to the clearance 73 increases the rigidity of the bearing, while decreasing the supply pressure to the clearance 73 decreases the rigidity of the bearing. Then, the natural frequency of the bearing also changes in accordance with such a change in the rigidity, and the above-mentioned dangerous rotation speed can be changed.

FIG. 4 shows the results of an experiment conducted to confirm that the dangerous speed range can be changed by using a bearing mechanism of the type that supplies a part of the liquid to be pressurized to the bearing. FIG. In FIG. 4A, the horizontal axis represents the pressure supplied to the bearing by the liquid 75, and the vertical axis represents the rigidity of the bearing. The pressure is 27.8 kg / cm ² and 2
The experiment was performed in two ways of 2.5 kg / cm ² . The oblique line in the figure indicates a range where an original value may exist in consideration of a measurement error. From FIG. 4 (A), it was confirmed that the rigidity was lowered by lowering the pressure. It is likely that these ranges deviate slightly from the expected curves, ignoring other minor conditions that contribute to bearing stiffness.

In FIG. 4B, the horizontal axis represents time, and the vertical axis represents the rotational speed of the turbo pump and the rigidity of the bearing.
The solid line in the figure indicates the number of rotations. The other plural dashed lines show the case where the shape of the hydrostatic sliding bearing is variously changed, and in each case, the rigidity changes according to the rotation speed. Aside from the time when the rotation speed suddenly rises from 0 at the start of the experiment and the time when the rotation speed goes to 0 at the end of the experiment, it was confirmed that there is an effect that the rigidity decreases as the rotation speed decreases.

From this, it was confirmed that the rigidity of the bearing was reduced when the rotation speed of the turbopump was lowered and the pressure supplied to the bearing was lowered. Then, if the rigidity is reduced, it is possible to move the dangerous rotation speed range to the low rotation side. More specifically, it is theorized that the critical speed is approximately proportional to the square root of the stiffness of the bearing.

FIG. 5 is a graph for explaining that interference between the rotation speed of the turbo pump and the dangerous rotation speed can be avoided by changing the dangerous rotation speed region. The horizontal axis in FIG. 5 indicates the thrust of the rocket engine, and the vertical axis indicates the rotation speed of the turbo pump. As shown by the curve, the higher the rotational speed of the pump, the higher the thrust. Then, the rated rotation speed of the turbo pump is set on the high rotation side of the dangerous rotation speed which is approximately determined by the rigidity of the bearing. Then, when the turbo pump is operated at the rated rotation speed (dotted circle) and the rotation speed is reduced by throttling, the rotation speed approaches the dangerous rotation speed range (dotted square).

However, as the rotational speed decreases, the pressure supplied to the bearing decreases, and the rigidity of the bearing decreases. Therefore, the natural frequency of the bearing is also reduced, so that the critical rotation speed range can be moved away to the low rotation side (solid line square). A new rated rotation speed (solid circle) is set for the dangerous rotation speed region that has gone away. By doing this,
It is possible to reduce restrictions on thrust control.

Returning to FIG. 2, the above-described change of the critical rotation speed may be performed based on an instruction from the control means 70. The control means 70 monitors the number of rotations of each of the turbines 17 and 17a, determines whether or not the number of rotations is approaching a preset dangerous number of rotations. By adjusting 63a, the rigidity of the bearing is changed so as to keep the critical rotation speed away.

[Other Embodiments] In the above embodiment, the output pressures of the first and second turbo pumps 33 and 35, that is, a part of the liquid oxygen 3 or the liquid fuel 1 from the liquid outlet 11 (FIG. 1) are used. When the rotation speeds of the first and second turbo pumps 33 and 35 decrease by approaching the dangerous rotation speed range by supplying to the hydrostatic slide bearing, the dangerous rotation speed range is automatically moved away to the low rotation speed side. I explained that you can do it,
In another embodiment, the pressure supplied to the bearing can be positively adjusted by operating the pressure adjusting mechanisms 63 and 63a. As the operation of the pressure adjusting mechanisms 63, 63a, the number of rotations of the rotating shaft 23 is monitored, and in addition to remote control by an operator, automatic control by a controller or the like is also possible. In addition, the supply pressure can be made lower by the positive pressure adjustment, and the rotation speed of the turbo pump can be further away from the dangerous rotation speed.

In the above embodiment, the rated rotation speeds of the first and second turbo pumps 33 and 35 are set to be higher than the dangerous rotation speed. However, the present invention is not limited to this. However, it is also possible to set to the low rotation side. In this case, when the rotation speed of the turbo pump increases and approaches the dangerous rotation speed, the pressure supplied to the bearing is increased by the pressure adjusting mechanism 63, so that the dangerous rotation speed can be controlled to move away from the high rotation side. It is possible.

In the above embodiment, the liquid fuel 1 sent out from the liquid outlet 11 of the first and second turbo pumps 33 and 35 is used as a supply source for supplying pressure to the bearing.
Alternatively, a pressure supply system that uses a part of the output pressure of the liquid oxygen 3 is used, but the present invention is not limited to this, and a pressure supply system that supplies pressure to the bearing from another supply source may be used. It is possible.

In the above embodiment, the turbines 17 and 17a of the first and second turbo pumps 33 and 35 are used.
Is the hydrogen gas 50 (see FIG. 2) vaporized through the cooling jacket 39 of the engine combustion chamber 31. What kind of fluid is used for this working gas 13? There are conventionally a plurality of methods (schematically shown in FIG. 6 (the same parts as in FIG. 2 are denoted by the same reference numerals)), and any of these methods can be implemented in the present invention.

That is, as shown in FIG. 6 (A), the gas generator 8 uses a part of the pressurized liquid fuel or liquid oxygen.
1 to generate gas, and the gas
7, 17a can be rotated. FIG.
As shown in (B), it is also possible to guide a part of the combustion gas in the engine combustion chamber 31 to rotate the turbines 17 and 17a. Also, as shown in FIG. 6C, the turbines 17 and 1 of the two first and second turbo pumps 33 and 35 are provided.
Instead of exhausting the working gas after driving 7a to the nozzle (FIG. 2), it is also possible to send and inject the operating gas to the manifold 41 of the injection plate 43. As shown in FIG. 6 (D), a part of the liquid fuel 1 and the liquid oxygen 3 sent to the manifold 41 of the injection plate 43 is guided to the pre-combustion chamber (PREBU).
RNER) 83 for combustion, and using the combustion gas to rotate the turbines 17 and 17a.

The shapes, combinations, and the like of the components shown in the above embodiment are merely examples, and various changes can be made based on design requirements without departing from the spirit of the present invention.

[0034]

As described above, according to the bearing mechanism of the turbo pump according to the first aspect, when the rotation speed approaches the dangerous rotation speed in accordance with the rotation speed of the turbo pump, the pressure of the hydrostatic slide bearing is reduced. , The natural frequency can be changed by changing the rigidity, and the critical rotation speed can be changed to keep away from the rotation speed. Thereby, in controlling the thrust of the engine, the limitation due to the dangerous rotation speed of the turbo pump is relaxed, and the engine can be operated over a wide range. Claim 2
The turbopump bearing mechanism according to the above, by supplying the output pressure of the turbopump to the hydrostatic type smooth bearing, when the turbopump that has been rated at a higher rotation side than the dangerous rotation speed gradually reduces the rotation speed In addition, the output pressure of the turbo pump gradually decreases, whereby the pressure and rigidity of the hydrostatic slide bearing automatically decrease, and the dangerous rotation speed can be automatically moved away to the low rotation side. In the turbo pump bearing mechanism according to the third aspect, the supply pressure is positively changed by controlling the pressure supplied to the hydrostatic slide bearing by the pressure regulating mechanism, and the dangerous rotation speed can be arbitrarily set. The dangerous rotation speed can be sufficiently kept away from the rotation speed when the turbo pump is driven. In the bearing mechanism of the turbo pump according to claim 4, the dangerous speed is controlled as appropriate by the control means so that the dangerous speed is quickly and appropriately adjusted when performing thrust control of the engine. The change is made, and it is possible to easily cope with automation in performing thrust control.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing flows of liquid fuel and liquid oxygen.

3A and 3B show an outline of a hydrostatic sliding bearing, in which FIG. 3A is a sectional view, FIG. 3B is a side view of A, and FIG. 3C is a developed view of a bearing sleeve.

FIG. 4 is a graph showing test results of a hydrostatic slide bearing;
(A) shows a change in pressure and rigidity, and (B) shows a change in rigidity according to the number of rotations.

FIG. 5 is a graph illustrating a change in a critical rotation speed based on a relationship between an engine thrust and a rotation speed of a turbo pump.

FIG. 6 is a schematic diagram showing another embodiment according to (A) to (D).

FIG. 7 is a cross-sectional view showing a bearing mechanism of a conventional turbo pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid fuel 3 Liquid oxygen 10, 10a Centrifugal pump (pressure supply system) 17, 17a Turbine 23 Rotary shaft 33 First turbo pump 35 Second turbo pump 61, 61a Supply path 63, 63a Pressure regulating mechanism 65 Static pressure type sliding bearing (Journal bearing) 70 Control means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H022 AA01 BA06 CA14 CA17 CA18 CA48 CA50 CA56 DA00 DA08 DA09 DA11 DA15 3J011 AA04 AA20 BA02 MA03 MA26 3J102 AA02 BA03 BA13 CA02 EA03 EA09 EA13 EA17 EB02 EB07 GA14 GA20

Claims (4)

[Claims] 1. A pump in a pump type rocket engine.
A bearing mechanism for a turbo pump, comprising: a hydrostatic slide bearing for supporting a rotary shaft of a pump; and a pressure supply system for supplying a predetermined pressure to the hydrostatic slide bearing in accordance with the rotation speed of the rotary shaft. . 2. The pressure supply system according to claim 1, further comprising a supply path for supplying an output pressure generated by driving the turbo pump as the predetermined pressure to the hydrostatic slide bearing.
A bearing mechanism for the turbo pump according to the above. 3. The turbo pump bearing mechanism according to claim 1, wherein said pressure supply system includes a pressure adjusting mechanism for changing said predetermined pressure. 4. The method according to claim 1, further comprising: comparing the rotation speed of the rotating shaft with a preset dangerous rotation speed; and controlling the pressure regulating mechanism when the rotation speed approaches the dangerous rotation speed to reduce the supply pressure. 4. The turbo pump bearing mechanism according to claim 3, further comprising control means for changing the critical rotation speed and changing the rigidity of the hydrostatic slide bearing so as to keep the dangerous rotation speed away from the rotation speed.