JPH05231175A - Bearing cooling device for air circulator - Google Patents

Abstract

PURPOSE: To simplify a seal structure and enhance efficiency of micro-particle collection by obtaining output for driving a compressor or a fan by compressing air, effecting heat exchange and cooling the compressed air with low temperature ambient air blown by a fan, and then expanding the air in a turbine. CONSTITUTION: A hollow shaft 10 is connected to a turbine 12, a compressor 14 and a fan respectively. Supply air from, for example, a compressor bleed of an aircraft engine is further compressed in the compressor 14. After the exhaust air from the compressor 14 is heated in the compressing process, the air is directed to a heater conduit of a heat exchanger 22. As the temperature of the exhaust air is lowered at that time, the low temperature ambient air is directed to a cool air conduit of the heat exchanger 22 by a fan 16. The cooled air exhausted from the heater conduit of a heat exchanger 22 is directed to the turbine 12. By expanding the cooled air in the turbine 12, output for driving the compressor 14 and the fan 16 can be obtained and used in the refrigerator or air conditioning of the aircraft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air circulation device having a fluid bearing.

[0002]

BACKGROUND OF THE INVENTION Aircraft environmental protection systems typically include an air circulation system and a heat exchanger to cool and condition the high pressure air supplied by the engine and auxiliary power units. The compressors and fans of these devices are driven by shafts connected to the turbine. The pressurized feed air is first introduced into the compressor. The airflow that is heated by the compressor and that is further pressurized and flows out of the compressor outlet is cooled in the process of passing through the warm air passage of the heat exchanger. In order to sufficiently reduce the temperature of the air flowing through the warm air passage, the cooler atmosphere is introduced into the cold air passage of the heat exchanger by the fan. The cooled air exits the warm air passages of the heat exchanger and expands and is further cooled in the turbine before it enters the aircraft cabin, and the cabin is maintained at a lower pressure than the supply air, so it is properly designed. The device is provided with air conditioned at a temperature suitable for cooling the cabin and aircraft electronics.

To support a shaft for connecting a turbine and a compressor, an air circulation device generally uses three bearings. Two of these three bearings are journal bearings, which regulate the radial displacement of the shaft. The third bearing is a thrust bearing and is fixed in the axial direction of the shaft. To obtain optimum performance of the device, the clearance between the stator fixed to the device housing and the tip of the fan and the rotor blades of the compressor must be kept very small. Since the compressor and the turbine rotor to which the blades are mounted are connected by a shaft, if the bearings allow more shaft play than a slight amount, the addition will displace the shaft so that the blade tips surround it. Contact the stator surface.

Fluid film journals and thrust bearings are used to radially and axially position the shaft for minimum play and reliable operation at high speeds. The inner race of each of these bearings is connected to the shaft or is constituted by a part of the shaft, and the respective outer race is attached to the housing. When the shaft rotates, hydrodynamic forces are generated on the fluid in the space between the inner race and the outer race. These forces combine to create a high pressure region at each bearing to oppose the load presented to the shaft.

In order to keep the magnitude of these hydrodynamic bearing forces constant during operation, the spacing between the inner and outer races must be kept very narrow. However, the fluid effect that creates a high pressure region between the races of the rotating fluid bearing produces heat with it. Refrigerant is used to remove this heat from the bearings to minimize non-uniform thermal expansion and to maintain a constant gap between the inner and outer races.

US Pat. No. 4,500,143 discloses a roller bearing and journal device which uses both oil and air to keep the clearance between the inner and outer races constant and to lubricate the device. ing. Cold pressurized oil circulates through passages proximate both the inner race of the roller bearing and the journal surrounding the bearing. The cold oil flow rate is selected to limit the thermal expansion of the inner and outer surfaces to a particular range during high temperature operation.
The holes formed at predetermined intervals in the cooling passage in the radial direction introduce a part of this oil flow into the bearing chamber to directly lubricate and cool the rollers forming the bearing. In order to prevent overcooling of the inner race at locations where the roller bearing and journal spaces increase beyond a predetermined range, warm air is introduced into a second passage proximate to the inner race. By supplying air in this way,
Only the inner race expands, keeping the bearing-journal gap small enough.

In US Pat. Nos. 4,503,683 and 4,507,939, the shafts supporting the turbines, compressors and fans of the air circulation system have their axial and radial displacements It is regulated by a thrust bearing and two air journal bearings. A portion of the air introduced into the turbine is used as a coolant to lubricate, cool and support these three bearings. The first portion of this refrigerant is first circulated in the thrust bearing cooling passage. The labyrinth seal provided at one end of the thrust bearing discharges the refrigerant from the other end. The slightly warmed refrigerant then flows into the cooling passage inlet of the first journal bearing. The labyrinth seal provided at the outlet of the cooling passage measures and adjusts the mass flow rate of air flowing through the cooling passages of both the thrust bearing and the journal bearing. This seal is important because the cooling passages in the first journal bearing introduce refrigerant directly into the fan circuit. If a mechanism for adjusting the flow rate of cooling air is not provided, excess air mass is introduced from the inlet of the turbine and is wasted.
Further, when the seal is not provided, the pressure of the refrigerant in the cooling passages of both bearings is reduced to the air pressure of the fan circuit which is almost equal to the atmospheric pressure. Since the density of the refrigerant at atmospheric pressure is insufficient to support the bearing, the inner race may come into contact with the outer race and cause excessive friction, resulting in destructive wear.

The second portion of the refrigerant taken out from the inlet of the turbine is introduced into the cooling passage of the second journal bearing. Labyrinth seals are provided at both ends of the cooling passage of the second journal bearing. The first seal of these seals blocks the flow of the refrigerant, and the second seal distributes the flow rate of the refrigerant flowing through the second journal bearing through the cooling passages of the thrust bearing and the first journal bearing. The refrigerant to be metered is adjusted in the same manner as the seal of the first journal bearing for metering. The inlet of the second journal bearing cooling passage is located adjacent to the first seal. The refrigerant therefore circulates along the length of the bearing and is discharged into the fan circuit via the second seal.

Other prior art relating to fluid bearings is US Pat. Nos. 4,306,755 and 4,580,4.
There is No. 06 etc.

[0010]

In the prior art device described above, the flow of refrigerant in the hydrodynamic bearing cooling circuit is limited by the labyrinth seal at the cooling circuit outlet or by a metering hole surrounding the labyrinth seal.
Regardless of the flow limiting means selected in these devices, a labyrinth seal or other rotating seal is always placed at the outlet of the circuit to seal the space between the inner and outer races of the bearing and to prevent excess in the circuit. It is necessary to prevent the circulation of such a refrigerant. Therefore, in order to maintain the pressure of the refrigerant at an appropriate value, it is necessary to properly adjust the flow rate through these labyrinth seals or metering holes.

Therefore, an object of the present invention is to propose an improvement of a cooling circuit of a fluid bearing which can meet this demand.

Another object of the present invention is to provide a bearing cooling device capable of trapping fine particles from the bearing cooling air before being introduced into the bearing cooling passage.

[0013]

According to the present invention, the mass flow rate and pressure of the refrigerant flowing through the bearing cooling circuit are arranged to be metered and adjusted upstream of the cooling circuit.

Further, according to the present invention, the refrigerant is circulated through the annular high pressure portion on the upstream side of the bearing cooling circuit, the flow velocity of the refrigerant is reduced, and the fine particles in the refrigerant are dropped and eliminated from the flow of the refrigerant. To configure.

According to the first aspect of the present invention, the compressor for introducing the flow of low temperature air from the compressed air source and the refrigerant taken out from the first region on the downstream side of the compressor are provided on the upstream side of the compressor. Means for supplying to the second area, a fluid bearing having a cooling passage arranged in the refrigerant supplying means, and arranged in the refrigerant supplying means on the upstream side of the cooling passage, in the second area And a means for lowering the pressure of the refrigerant in order to reduce the pressure of the air in the air circulation device.

According to the second aspect of the present invention, the compressed air source
The compressor that receives the flow of cooler air and the shaft
Turbine connected to the compressor and a rotary
Inner race and outer side with a sealed end
A cool air stream is introduced through the gap between the races
Fluid that has a cooling passage discharged from the end on the side not covered
Journal bearings and cool air from the turbine inlet
Means for supplying a portion to the inlet of the throttle orifice;
The cold air flowing out of the outlet of the orifice
Guided from the sealed end of the null bearing to the cooling passage inlet.
Means for inserting and unsealed journal bearing
Supply low temperature air flowing out from the end to the compressor inlet
Air circulation characterized by comprising
A device is provided.

According to the third aspect of the present invention, the flow of the refrigerant is generated from the downstream side of the air flow of the compressor, the refrigerant is supplied to the throttle orifice, and the refrigerant flowing in the throttle orifice forms the fluid journal bearing. A method for cooling a fluid journal bearing in an air circulation device, comprising cooling and discharging heated refrigerant to an upstream side of a compressor in a cooling process.

According to the fourth aspect of the present invention, the flow of the refrigerant is generated from the turbine inlet, the refrigerant is supplied to the throttle orifice, and the fluid journal bearing is cooled by the refrigerant flowing through the throttle orifice. Disclosed is a method for cooling a fluid journal bearing in an air circulation device having a turbine and a compressor, characterized in that heated refrigerant is discharged to the upstream side of the compressor.

According to the fifth aspect of the present invention, it has an inlet and an outlet, and the inlet is arranged to circulate in a circumferential direction before the air introduced from the inlet is discharged from the outlet. An apparatus for removing fine particles contained in the air from the air at the turbine inlet, characterized by comprising the formed annular high-pressure area and means for introducing a part of the air at the turbine inlet into the annular high-pressure area. Will be provided.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an air circulating device of an aircraft, in which a hollow shaft 10 includes a turbine 12 and a compressor 14.
And a fan 16. The compressor 14 is a supply air 18 supplied from a compressor bleed device (not shown) or an auxiliary power unit (not shown) of an aircraft engine.
Is further compressed. The exhaust air 20 discharged from the compressor 14 is heated in the compression process and then flows into the warm air passage of the heat exchanger 22. A cool atmosphere 24 is introduced by the fan 16 into the cold air passages of the heat exchanger in order to reduce the temperature of the exhaust air 20. The cooled air 26 discharged from the warm air passages of the heat exchanger 22 is then fed to the turbine 12
Distribute to. The expansion of this air 26 within the turbine 12 provides power to drive the compressor 14 and fan 16 and further cools this air for use in air conditioning (not shown) and air conditioning of the aircraft. And

As shown in FIG. 2, the first gas flow type journal bearing 28 is disposed between the compressor 14 and the turbine 12, and the second gas flow type journal bearing 30 is connected to the compressor 14 at the tip of the apparatus. It is arranged between the fans 16. These journal bearings 28 and 30 are radially arranged to regulate the radial movement of the shaft 10. The gas flow thrust bearing 32 is located at the rear end of the device, close to the turbine inlet 34, to ensure that the shaft is held in place when axial loads act on the shaft 10. Each bearing is composed of an inner race and an outer race. 3 and 4 show the second journal bearing 30 in an enlarged manner. The inner race 31 is formed integrally with the shaft 10. The outer race 33 has a groove cut out on the outer peripheral surface. The compression O-ring 35 is housed in the groove of the outer race 33 and abuts on the inner surface of the housing 39, so that the second journal bearing 30 is attached to the housing 39.
Fixed to. The foil pack 41 separates the inner race 31 and the outer race 33.

The first journal bearing 28 has the same inner race, outer race and foil pack construction as the second journal bearing 30. 32 has the same principle as that of the journal bearing described above, but the inner race, the outer race and the foil pack are formed in a flat disk shape instead of a cylindrical sleeve. As the shaft 10 rotates, hydrodynamic forces press these gas flow bearings 28, 30, 32 inward and combine to form a high pressure region between the inner and outer race mating surfaces. , The foil pack is biased in a direction away from the inner race, and is opposed to the axial and radial loads used in the direction in which the foil pack is displaced from the desired position.

The clearance between the inner and outer races of each bearing is reduced in order to create the required fluid pressure during shaft rotation and to minimize axial and radial play. When this gap is increased, the inner race comes into contact with the outer race to cause wear or increase frictional resistance. With respect to this clearance variation, creating and maintaining high pressure regions within each of these bearings:
Heat is generated to expand the inner and outer races. Therefore, the refrigerant 36 is circulated in the race of each bearing to control the thermal expansion of each member so that the gap between the inner race and the outer race is within a predetermined limit.

As shown in FIG. 2, a part of the air at the turbine inlet 34 is used as the refrigerant 36. The air at the turbine inlet has the lowest temperature because it passes through the heat exchanger 22 as shown in FIG. 1, and the highest temperature of the air that can be used in the apparatus. Generally, the pressure of the air at turbine inlet 34 is 40 to 50 psig (280 to 350 kPa) when the system is operated at the same altitude as sea level.
Becomes The pressure and density of the coolant 36 is important because it not only cools the bearings, but also lubricates and supports them. The higher the pressure of the refrigerant, the greater the hydrodynamic force generated in each bearing, and the bearing can support a larger load. Therefore, based on the predicted maximum load, each bearing 28, 30, 32 has a critical pressure to ensure proper operation of the device.

As shown in FIGS. 2 and 5, the refrigerant 36 flows from the turbine inlet to the flow tube 38. Depending on the design and orientation of the flow tube 38, dust, water and other particulates carried by the air at the turbine inlet may
The coolant 36 is prevented from flowing into the cooling circuit 40 that causes the bearings 28, 30, 32 to flow in series and is prevented from accumulating in the cooling circuit 40. The inlet side end 42 of the flow tube 38 is cut out and cut out and inserted at a right angle to the air flowing through the turbine inlet. The distribution tube 38 is
The opening 42 formed by the cutout notch surface rotates away from the air flow 44. With this configuration, it is possible to rapidly change the flow direction of only the fine particles and maintain the circulation of the refrigerant 36 in the tube 38. Since only the light and small particles rapidly flow with the refrigerant in the direction of flow, most of the large particles that may accumulate in the bearing cooling circuit 40 will enter the inlet 42 of the flow tube 38.
Can be eliminated by making the direction of the right angle to the air flow at the turbine inlet.

Further, in order to minimize the concentration of pollutants in the air, the outlet 46 of the flow tube is connected to the turbine 12
To an annular high pressure region 48 separating the compressor 14 from the compressor 14. Before flowing into the inlet hole 50 of the gas flow type thrust bearing 32 arranged near the outlet of the flow tube, the refrigerant 3
6 is circulated around the high pressure region 48 almost all around it. Since the passage area of the high pressure region 48 is much larger than the flow passage cross-sectional area of the bearing cooling passage, the flow velocity of the refrigerant 36 flowing in the high pressure region 48 becomes very low. Most of the contaminants in the refrigerant will lose their flow velocity sufficient to keep particles other than the lightest and smallest particles in the flow, so that the high pressure region 4
It falls into the repair reservoir 52 provided at the lowest position in 8.

The refrigerant 36 flows into the thrust bearing inlet hole 50, is separated by the outer edge of the inner race, and flows along the front side surface 56 and the rear side surface 54 of the inner race. The refrigerant that has flowed along the rear side surface 54 is the bearing 3
2 is discharged to the cavity on the back surface of the turbine rotor 58 through the labyrinth seal 60 on the rear side. The size of the gap between the labyrinth seal 60 and the shaft 10 allows the rear side surface 54 of the thrust bearing 32 to flow about one-third of the refrigerant in order to secure a sufficient flow rate of the refrigerant flowing to the other bearings. The remaining two-thirds of the refrigerant selected for the dimensions flows to the front side surface of the inner race before being discharged from the thrust bearing outlet hole 62.

The refrigerant 36 discharged from the outlet hole 62 of the thrust bearing directly flows into the inlet hole 64 of the first journal bearing 28 provided at the rear end of the compressor and flows across the entire length of the bearing. The labyrinth seal 66 prevents the refrigerant 36 at the front end of the bearing 28 from entering the cavity at the back of the compressor rotor 67. Therefore, all the refrigerant 3
6 is discharged from the outlet hole 68 of the inner race and directly flows into the hollow space of the shaft 10.

As shown in FIGS. 2, 3 and 4, the refrigerant 3
6 flows in the hollow space of the shaft 10 and flows from the first journal bearing 28 of the compressor to the second journal bearing 30 of the fan. A throttle orifice 70 formed in the wall of the shaft functions as an inlet hole for the second journal bearing of the fan, allowing the refrigerant 36 to flow to the front surface of the second journal bearing. The labyrinth seal 74 provided at the front end portion of the second journal bearing of the fan is provided with the refrigerant 36
Are prevented from flowing into the fan circuit 76. Since no seal is provided at the rear end of the second journal bearing 30 of the fan, the refrigerant 36 flows from the front end toward the rear end and is discharged directly to the compressor inlet 72.

In order to determine the size of the throttle orifice 70, it is necessary to know the pressure at the inlet and outlet of the orifice required to maintain the desired mass flow rate when operated at basic conditions. The pressure at the inlet is the pressure of the refrigerant contained in the hollow shaft 10. The pressure of the refrigerant that passes through the cooling passages of the thrust bearing 32 and the first journal bearing 29 and reaches the inlet of the cavity of the hollow shaft is 2 to 3 psi higher than the pressure of the turbine inlet.
(15 to 20 kPa). Orifice 7
To determine the zero outlet pressure, a pressure drop is calculated to ensure the desired mass flow rate across the cooling passages of the second journal bearing. The pressure at the exit of the orifice 70 is therefore typically about 35 psig (2
40 kPa) compressor inlet pressure plus the calculated pressure drop. Based on the inlet and outlet pressures, the throttle orifice 70 is selected to pass the desired mass flow rate of the refrigerant 36 through the bearing cooling circuit 40.

[0031]

As described above, according to the present invention, it is possible to obtain an improvement of the cooling circuit of the fluid bearing which can meet the above-mentioned conventional requirements, and further, before the introduction into the bearing cooling passage, It is possible to provide a bearing cooling device that can capture fine particles from the bearing cooling air.

Further, according to the present invention, it is possible to reduce the number of seals used in the cooling circuit. Therefore,
It is possible to reduce the number of parts constituting the air circulation device, simplify the structure, and reduce the manufacturing cost. Further, by reducing the number of seals, the number of consumable parts due to wear in the device is reduced, and as a result, the reliability and durability of the entire device can be improved. Further, by reducing the number of labyrinth seals, it is possible to reduce the possibility of breakage of the seals when the shaft is mounted, and the assembly of the device can be facilitated. Furthermore, by reducing the number of seals, the length of the shaft can be shortened, the size and weight of the device can be reduced, and the natural frequency of the shaft can be increased to increase the maximum speed of the device. Is possible.

[Brief description of drawings]

FIG. 1 is a system diagram of an air circulation device according to the present invention.

FIG. 2 is a side view showing a fluid bearing cooling cycle of the air circulation device in a cutaway manner.

3 is a detailed view of a second journal bearing shown in FIG.
FIG.

FIG. 4 is a diagram showing the external force at the end of the second journal bearing.
4 is a sectional view taken along line 4-4 of FIG.

5 is a sectional view taken along line 5-5 of FIG. 2 showing the shape of a distribution tube for introducing a refrigerant to be supplied to the cooling circuit.

[Explanation of symbols]

 10 shaft 12 turbine 14 compressor 16 fan 22 heat exchanger 28 first journal bearing 30 second journal bearing 32 thrust bearing 40 cooling circuit 70 throttle orifice

Claims (15)

[Claims] 1. A compressor for introducing a flow of low-temperature air from a compressed air source, and means for supplying a refrigerant taken out from a first region downstream of the compressor to a second region upstream of the compressor. A fluid bearing having a cooling passage arranged in the refrigerant supply means, and arranged in the refrigerant supply means on the upstream side of the cooling passage to reduce the pressure of air in the second region. An air circulation device comprising: means for reducing the pressure of the refrigerant. 2. The apparatus of claim 1 wherein said pressure reducing means comprises a throttle orifice. 3. The apparatus of claim 2 wherein said throttle orifice is located at the inlet of a cooling passage of said fluid bearing. 4. The apparatus of claim 1 having a turbine connected by a shaft to said compressor. 5. The apparatus of claim 1, wherein the first region is an inlet of the turbine. 6. The apparatus of claim 1, wherein the second region is a compressor inlet. 7. The apparatus of claim 1, wherein the fluid bearing is a gas flow bearing. 8. A compressor receiving a flow of low temperature air from a compressed air source, a turbine connected to the compressor by a shaft, a rotary seal at one end, and inner and outer races on the sealed end side. A fluid journal bearing having a cooling passage that introduces a flow of low-temperature air from the gap between the two and discharges it from the end on the unsealed side, and supplies a portion of the low-temperature air from the inlet of the turbine to the inlet of the throttle orifice Means, means for introducing low-temperature air flowing out of the outlet of the throttle orifice into the cooling passage inlet from the sealed end of the journal bearing, and low-temperature air flowing out of the unsealed end of the journal bearing. An air circulation device comprising: a means for supplying to the inlet of the compressor. 9. The apparatus of claim 9, wherein the rotary seal is a labyrinth seal. 10. The apparatus of claim 8, wherein the fluid journal bearing is a gas flow journal bearing. 11. A refrigerant flow is generated from a downstream side of an air flow of a compressor, the refrigerant is supplied to a throttle orifice, the fluid journal bearing is cooled by the refrigerant flowing through the throttle orifice, and heated in a cooling process. A method for cooling a fluid journal bearing in an air circulation device, characterized in that a refrigerant is discharged to an upstream side of a compressor. 12. A refrigerant flow is generated from a turbine inlet, the refrigerant is supplied to a throttle orifice, the fluid journal bearing is cooled by the refrigerant flowing through the throttle orifice, and the refrigerant heated in a cooling process is upstream of a compressor. A method for cooling a fluid journal bearing in an air circulating device having a turbine and a compressor, wherein 13. An annular high pressure region having an inlet and an outlet, the inlet being formed so as to circulate in a circumferential direction before air introduced from the inlet is discharged from the outlet, A device for removing fine particles contained in the air from the air at the turbine inlet, which is configured by means for introducing a part of the air at the turbine inlet to the annular high pressure region. 14. The apparatus of claim 13, wherein the high pressure region inlet is formed adjacent to the high pressure region outlet. 15. The supply means comprises a flow tube having an outlet connected to the inlet of the high pressure region, and a notched inlet, wherein the notched inlet is connected to the turbine inlet. 14. The device of claim 13, wherein the device is oriented away from the circulating air stream.