RU2633974C1 - Centrifugal turbine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: centrifugal turbine comprises a housing, am impeller disk of a centrifugal turbine with a blade ring and a band, a nozzle cascade, according to the invention, a counter-protrusion 5 is formed on the impeller disk of the centrifugal turbine 3 on the opposite side of the blade ring 6, forming a labyrinth seal 11 with the housing of the turbine 1 and equal in weight to the blade ring with the bandage.

EFFECT: simplified design, reduced weight of the turbo-pump unit, increased reliability for long-term operation of turbo-pump units at high rotational speeds and at high temperatures of the working body after the gas generator, eliminated axial force influencing the turbine.

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Description

The invention relates to the field of rocket propulsion and can be used in turbopump units (TNA) LRE of rockets with long operating time using any fuel components, both high-boiling and low-boiling.

Known reactive centripetal steps containing a housing, an impeller with blades mounted in it and a guiding apparatus (see, for example, the book "Design and Design of Liquid Rocket Engines" edited by Professor GG Gakhun. M., Mechanical Engineering, 1989, pp. . 220, Fig. 10-19; RF patent No. 2518703, F01D 1/06). These designs are fully functional, but have the following disadvantages:

a) gas (working fluid) of high pressure (up to 400-500 atm) and high temperature (up to 700 ° C) is supplied to the turbine along the outer diameter of the blade rim, i.e. the underwater branch pipe from the gas generator and the collector with the nozzle apparatus must be thick-walled, which makes the design heavier and complicates the manufacturing and assembly technology of the turbopump unit;

b) during manufacture it is necessary to use heat-resistant and heat-resistant steels and alloys, especially those steels and alloys for which the long-term strength is highest compared to other steels (for example, EP741 alloy, etc.).

This design is unacceptable for the TNA LRE of the upper stages of missiles as booster blocks of reusable inclusion and with a long operating time due to the large weight.

A known design of centrifugal turbines, in which high pressure gas and high temperature gas are supplied along the inner diameter of the turbine blade rim — the blade rim is parallel to the axis of rotation. This design allows gas to be supplied through a cylindrical pipe, and the outlet manifolds and pipelines can be made thin-walled from ordinary stainless steels (type 07X16H6), because behind the turbine, the pressure and temperature of the gas will be 1.5-2 times lower than in front of the nozzle apparatus (see V. Traunel’s book “Thermal Turbomachines”, Moscow, State Power Publishing House, 1981, Volume One, p. 117, Fig. 4-1.11, 4-1.12). This reduces the weight of the TNA, improves manufacturability and increases reliability. However, these designs have the disadvantage that, at high rotational speed of the TNA rotor (~ 60,000 rpm or more), on which modern TNA liquid propellant engines operate, they are inoperative in strength parameters in the area of the connection of the disk of the impeller of a centrifugal turbine with a bandage where, according to calculations, stresses of about 270 kg / mm occur. This is due to the fact that when operating at high speeds of rotation under the action of centrifugal forces, the blade ring with the turbine bandage bends together with the disk of the impeller of the centrifugal turbine, like a membrane, which leads to an increase in stresses.

A known design of a centrifugal turbine (radial) with a double blade rim, taken as a prototype of the invention, in which, when operating at high speeds and a high temperature, the deflection of one blade rim 1 is compensated by the deflection of the opposite blade rim 7 together with a bandage 8 (see RF patent No. 20048435 , F01D 1/06, Fig. 1). The specified design of the prototype has the following disadvantages:

a) two-jet low-pressure jet turbine, pos. 4 and 7, together with a straightening device 9 and a bandage 8 between the stages of the turbine is extremely difficult to manufacture;

b) the presence on the periphery of the disk of the impeller of a centrifugal turbine of blade vanes, a straightening device together with a bandage makes the strength of the disk of the impeller of a centrifugal turbine at the root as the most loaded place of the turbine problematic;

c) the practice of developing low-pressure jet turbines shows that the design of a two-stage turbine increases the efficiency in comparison with a single-stage low-pressure turbine by a maximum of 1.5-2%. Moreover, the power loss of a single-stage turbine is easily compensated by increasing the temperature of the gas generator by 20-30 ° C with closed LRE circuits, which does not affect the reliability of the turbine, because usually in "acidic" schemes, for example, the operating temperature is 500-700 ° C;

d) due to the difference in the internal diameters of the blade rims, a significant axial force arises, which is associated with high pressure behind the nozzle apparatus.

The invention solves the following problems:

a) simplification of the design of the centrifugal turbine;

b) increasing the structural strength of a centrifugal turbine;

c) ensuring an acceptable efficiency of the turbine in order to exclude the influence on the specific thrust of the engine of a closed circuit;

d) increased reliability during long-term operation of the TNA (more than 3000 s), for example, as part of upper stage rocket booster blocks;

e) reduction in the weight of the TNA structure, which is especially important for the upper stages of missiles;

f) elimination of the axial force acting on the disk of the impeller of the centrifugal turbine by selecting the diameters of the labyrinth seals D1 and D2 (see the attached drawing), ensuring the equality of the areas affected by the pressure behind the nozzle apparatus in front of the blade ring.

For this, in a single-stage centrifugal jet turbine on the periphery of the disk of the impeller of a centrifugal turbine having discharge holes, an annular protrusion-counterweight is made integrally with the disk of the impeller of the centrifugal turbine, forming a labyrinth gap seal with the turbine body, on the same radius from the opposite side of the blade rim with a bandage. . In this case, the mass of the annular protrusion is equal to the mass of the scapular crown with a bandage.

With this design of the jet centrifugal turbine design, the bend from the blade ring with the bandage under the action of centrifugal forces is compensated by the bend from the annular protrusion-counterweight, and there is no total bend of the impeller disk of the centrifugal turbine.

The invention is illustrated in the drawing, which shows the design of a jet centrifugal turbine.

The centrifugal turbine includes a turbine housing 1 with an exhaust pipe 2, a turbine 3, a nozzle apparatus 4, an annular protrusion-counterweight 5, forming an additional labyrinth slotted seal 11, a blade ring 6 with a bandage, a labyrinth seal 7, discharge holes 8 in the centrifugal impeller disk turbines 3, cavities of equal pressure 9 and 10 behind the nozzle apparatus in front of the turbine, diameters D1 and D2 of gap seals. The selection of the ratio of D1 and D2 provides the minimum axial force acting on the turbine 3. In this case, the mass of the annular protrusion-counterweight 5 is equal to the mass of the blade ring 6 with a bandage. When operating a centrifugal turbine 3 under conditions of increased speed and temperature, the angular velocity in modern ТНА can reach more than 500 m / s. Under the action of centrifugal forces acting on the blade ring 6 with a bandage and an annular protrusion-counterweight 5, the disk of the impeller of the centrifugal turbine 3 does not bend, because the masses of these elements are equal and the deflection of the disk of the impeller of the centrifugal turbine from the blade ring with the bandage is compensated by the deflection of the disk of the impeller of the centrifugal turbine from the counterweight protrusion, and, thus, the total deflection of the disk of the impeller of the centrifugal turbine is practically zero, which ensures reliable operation of the turbine and total TNA.

The use of the invention will simplify the design of a centrifugal turbine, increase the structural strength, eliminate the influence of the TNA on the specific thrust of a closed circuit engine, increase the reliability of the TNA during long-term operation (more than 3000 s), reduce the weight of the TNA design, which is important for the upper stages of missiles, and eliminate axial force acting on the disk of the impeller of a centrifugal turbine, ensuring the operability of the bearings TNA.

Claims (1)

A centrifugal turbine comprising a casing, a rotor disk of a centrifugal turbine with a blade ring and a bandage, a nozzle apparatus, characterized in that a counterbalance protrusion is made on the disk of the centrifugal turbine wheel from the opposite side of the blade ring with a bandage, forming a labyrinth seal with the turbine body and equal in mass to the shoulder blade with a bandage.

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