RU2548228C1 - Centrifugal breather - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: centrifugal breather is related to aircraft engine technology, namely, to the design of a centrifugal breather of an aircraft gas turbine engine (GTE) breathing system. The centrifugal breather comprises a rotor with a centrifugal impeller set on it and placed in the straight boring of a casing in which an annular groove for oil draining is made. The impeller blades set opposite the oil draining groove are provided with a protrusion inserted in the groove. The impeller can be fitted by cross partitions forming cavities which are communicated with each other sequentially. An outlet channel from the annular groove of the casing is made tangential to the groove. The cylindrical surface of the casing and the impeller part mating it can be made stepwise.

EFFECT: better separation of oil from gas, lower oil consumption in an engine and reduced atmosphere pollution.

4 cl, 5 dwg

Description

The invention relates to the field of aircraft engine manufacturing, namely, to the design of a centrifugal prompter of a venting system for an aircraft gas turbine engine (GTE).

A known centrifugal breather containing a rotor with a centrifugal impeller mounted on it, placed in a cylindrical bore of the housing, in which an annular groove for oil drainage is made (see G.S. Skubachevsky. Aircraft gas turbine engines. M .: Mechanical Engineering, 1969, p. .484, 485).

This prompter is designed to separate oil from gas when venting the oil cavities of power plants with the atmosphere. At the same time, the effectiveness of the prompter is estimated by the amount of unseparated oil contained in the gas leaving the prompter.

It is known that the prompter's efficiency decreases with an increase in the oil concentration in the gas-oil mixture and with an increase in its flow rate through the prompter, and this, in turn, leads to the loss of oil in the engine and to air pollution.

The reason for the deterioration of oil separation by the prompter is the insufficient efficiency of oil drainage from the annular groove, since the oil that has got into it from the impeller is inhibited against the fixed walls of the annular groove of the housing; the pressure head and the centrifugal force acting on the oil in the annular groove decrease, and the pressure under which the oil flows through the pipeline into the engine oil system drops sharply. With insufficient efficiency of oil drainage from the annular groove, it overflows it and again enters the interscapular part of the impeller, which facilitates the penetration of individual oil particles into the gas outlet channel into the atmosphere.

The objective of the present invention is to increase the efficiency of the centrifugal prompter, including with an increased concentration of oil in the gas-oil mixture and with an increase in its flow rate through the prompter.

This problem is solved in that in a centrifugal breather containing a rotor with a centrifugal impeller mounted on it, placed in a cylindrical bore of the housing, in which an annular groove for oil drainage is made, according to the invention, the impeller blades located opposite the groove for oil drainage are made with a protrusion wound up at last. In this case, the impeller can be provided with transverse partitions forming cavities in series with each other. In addition, the output channel from the annular groove of the housing is made tangentially with respect to the annular groove. Also, the cylindrical surface of the housing and the corresponding part of the impeller can be made stepwise.

The efficiency of oil separation in the proposed centrifugal prompter increases due to the implementation of the impeller blades located opposite the groove for oil drainage, with a protrusion brought into the groove of the housing. From this groove, oil is drained from the breather through a pipeline into the engine oil system. The presence of a protrusion in the impeller allows you to keep the angular velocity of the oil in the groove the same as inside the rotor, and this, in turn, increases the pressure head and centrifugal force acting on the oil in the ring bore, and thereby contributes to its faster evacuation from the prompter to the engine.

The stepwise execution of the outer diameter of the impeller and the corresponding cylindrical bore of the housing when performing the rotor with transverse baffles forming cavities successively communicated with each other, practically eliminates the possibility of the separated oil located on the periphery of the impeller from the cavity with a higher concentration of oil particles in the gas in the cavity with a lower concentration.

The execution of the output oil channel from the annular groove of the housing with a tangential direction with respect to this groove also contributes to a better drainage of oil from the prompter with minimal loss.

It is also proposed that the cylindrical surface of the housing and the corresponding part of the impeller be made stepwise. This solution will allow to avoid the flow of separated oil from a stage with a smaller diameter to a stage with a larger diameter, since it is difficult for the oil to overcome the movement against centrifugal forces. This means that the oil located in the previous stage will not get into the step located closer to the outlet air channel. Such multi-stage air purification from oil will significantly reduce the emission of oil into the atmosphere.

An example embodiment of the invention is shown in the accompanying drawings.

Figure 1 shows a longitudinal section of a centrifugal breather;

figure 2 is a longitudinal section of a centrifugal breather with transverse partitions;

figure 3 - element a of figure 2;

figure 4 is a section bB of figure 2;

figure 5 - section bb In figure 2.

The centrifugal breather contains a rotor 1 with a centrifugal impeller 2 mounted on it, located in a cylindrical bore 3 of the housing 4, in which an annular groove 5 is made for oil drainage. The impeller blades 2, located opposite the oil drain groove 5, are made with a protrusion 6 inserted into the groove 5. The impeller 2 can be provided with transverse partitions 7, 8, 9, forming cavities, successively communicated between themselves by windows 10, 11, 12; moreover, the windows 10 and 12 are located on the outer diameter of the impeller, and the windows 11 on the inner. The cylindrical bore 3 and the corresponding part of the impeller can be made stepwise (figure 2) with transverse steps 13. The cylindrical bore 3 and the corresponding part of the impeller can be made conical with an angle of inclination of the conical surface α. The angle of inclination of the surface can be 2 ... 3 °.

The breather rotor is mounted on ball bearings 14 and 15. The gas-oil mixture is supplied through the inlet 16. The purified gas is vented to the atmosphere through the hole 17. The separated oil is discharged from the breather through a spiral collector 18 tangentially located relative to the annular groove into the outlet channel 19. On the cylindrical bore 3 (Fig. 1) there is a helical groove 20. The direction of oil movement is shown by blackened arrows, the direction of gas movement is shown by blackened arrows, the direction of gas movement oil-oil mixture - arrows, blackened half.

During operation of the centrifugal breather, the gas-oil mixture enters the inlet 16 and through the internal channels of the housing enters the interscapular cavity of the impeller 2 and is twisted by its blades. Under the action of centrifugal forces, heavier oil particles are discarded by the impeller 2 onto the cylindrical bore 3, fall into the helical groove 20 (see Fig. 1) and move along it into the annular groove 5, from which, under the action of centrifugal forces, the oil moves along the spiral collector 18 in output channel 19. In this case, the efficiency of oil drainage from the annular groove 5 is increased (compared with the prototype) due to the location of the part of the impeller 2 with the protrusion 6 inside the annular groove 5. In turn, the gas passes along the impeller and leaves Res opening 17 to the atmosphere. When performing a centrifugal breather with transverse baffles, the gas-oil mixture enters the interscapular cavity of the impeller 2, twists with its blades, reaches the baffle 7, turns in the radial direction, changes direction and passes through the windows 10. At the same time, a part of the oil particles is thrown onto the outer diameter of the impeller and gets into the annular groove 5. Having passed through the windows 10, the gas-oil mixture turns again, changes its direction to the axial, passes through the windows 11, then changes the direction to radial, turning It passes and passes through the windows 12, then once again passes in the radial direction and exits through the hole 17 into the atmosphere. Throughout the entire path of the gas-oil mixture, oil particles are thrown onto the cylindrical (or conical) bore 3 of the body and move towards the annular groove 5. An increase in the number of turns and the path length inside the impeller improves the separation of oil in the breather. In this case, the stepwise execution of the outer diameter of the impeller 2 and the cylindrical bore 3 of the casing does not allow the oil particles located on the periphery of the impeller to move from the section with a higher concentration of oil to the section with a lower concentration, since this is prevented by a step on each of the steps of the casing and the impeller.

The proposed set of design changes will allow to obtain a qualitative improvement in the operation of the centrifugal breather and will reduce the oil content in the air discharged into the atmosphere by several times. The stepwise execution of the impeller with the entry of part of the impeller into the annular groove for oil drainage will significantly increase the speed head and centrifugal force acting on the oil located in the annular bore. The combination of a part of a stepped impeller introduced into an annular groove with a tangential oil outlet turns this part of the breather into a full-fledged centrifugal pump and thereby contributes to a more efficient evacuation of it from the breather back to the engine. This will also allow eliminating oil emissions from the engine during abnormal operation of the oil system and with large reflux of oil into the engine venting system.

The use of the invention will improve the efficiency of oil separation by a breather, significantly reduce oil consumption in the engine and reduce air pollution.

Claims (4)

1. A centrifugal breather containing a rotor with a centrifugal impeller mounted on it, placed in a cylindrical bore of the housing, in which an annular groove for oil drainage is made, characterized in that the impeller blades located opposite the oil drain groove are made with a protrusion brought into the last . 2. The centrifugal breather according to claim 1, characterized in that the impeller is provided with transverse partitions forming cavities in series with each other. 3. The centrifugal breather according to claim 1, characterized in that the output channel from the annular groove of the housing is made tangentially with respect to the annular groove. 4. The centrifugal breather according to claim 2, characterized in that the cylindrical surface of the housing and the corresponding part of the impeller are made stepwise.

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