CN215292597U

CN215292597U - Internal cooling system of 2-stage turbine rotor of small and medium-sized gas turbine with intermediate disc

Info

Publication number: CN215292597U
Application number: CN202121273459.0U
Authority: CN
Inventors: 葛春醒; 冯永志; 王文博; 姜东坡; 单维佶; 赵俊明; 张华杰; 苑馨予; 周驰
Original assignee: Hadian Power Equipment National Engineering Research Center Co Ltd
Current assignee: Hadian Power Equipment National Engineering Research Center Co Ltd
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2021-12-24
Anticipated expiration: 2031-06-08

Abstract

The utility model relates to a middle-size and small-size gas turbine 2 grade turbine rotor internal cooling system with intermediate disk belongs to middle-size and small-size gas turbine's internal cooling system technical field. The problems of low cooling efficiency and complex cooling structure of the turbine rotor of the traditional small and medium-sized 2-stage turbine combustion engine are solved. The front side of the shaft is sequentially and coaxially provided with the first-stage turbine wheel disc, the front supporting ring, the turbine front end shaft and the lower supporting ring, and the rear side of the shaft is sequentially and coaxially provided with the middle disc, the second-stage turbine wheel disc, the rear supporting ring and the turbine rear end shaft. The cooling device has the advantages that the turbine rotor part of the gas turbine is fully and reasonably cooled, sufficient cooling air is provided for the turbine blades, the structure is reasonable, and the safety and the high efficiency of mechanical operation are ensured.

Description

Internal cooling system of 2-stage turbine rotor of small and medium-sized gas turbine with intermediate disc

Technical Field

The utility model relates to an inside cooling system of 2 grades of turbine rotors of middle-size and small-size gas turbine belongs to middle-size and small-size gas turbine's inside cooling system technical field.

Background

The gas turbine is an internal combustion type power machine which takes continuously flowing gas as a working medium to drive an impeller to rotate at a high speed and converts the energy of fuel into useful work, and is a rotary impeller type heat engine. The inlet operation temperature of the design of the small and medium-sized gas turbine is higher and exceeds the temperature limit of the current material, besides the temperature limit of the material and the heat insulation layer is improved, a cooling technology is also needed to ensure the service life of the material and the normal operation of the material at high temperature, and for the small and medium-sized gas turbine with the 2-stage turbine, the problems of low cooling efficiency, complex cooling structure and the like still exist in the cooling of the turbine rotor aiming at the continuously improved gas inlet temperature and the continuously improved heat load environment of the turbine.

Therefore, it is necessary to provide an internal cooling system for the 2-stage turbine rotor of a small and medium-sized gas turbine with an intermediate disk to solve the above technical problems.

SUMMERY OF THE UTILITY MODEL

The utility model discloses research and development solve is that the turbine rotor cooling efficiency of current middle-size and small-size 2 grades of turbine combustion engines is low, cooling structure complex problem. A brief summary of the present invention is provided below in order to provide a basic understanding of some aspects of the present invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention.

The technical scheme of the utility model:

the internal cooling system of the 2-stage turbine rotor of the medium and small-sized gas turbine with the intermediate disc comprises a front holding ring, a first-stage turbine wheel disc, the intermediate disc, a second-stage turbine wheel disc, a rear holding ring, a turbine rear end shaft, a turbine front end shaft and a lower holding ring, wherein the first-stage turbine wheel disc, the front holding ring, the turbine front end shaft and the lower holding ring are coaxially arranged on the front side of the shaft in sequence, and the intermediate disc, the second-stage turbine wheel disc, the rear holding ring and the turbine rear end shaft are coaxially arranged on the rear side of the shaft in sequence;

the first-stage turbine wheel disc, the middle disc and the second-stage turbine wheel disc are sequentially connected, a front holding ring is connected to the upper side of the first-stage turbine wheel disc, a first-stage turbine wheel disc rear chamber is formed between the first-stage turbine wheel disc and the middle disc, a turbine front end shaft is connected to the lower side of the first-stage turbine wheel disc, a first-stage turbine wheel disc lower chamber is formed between the first-stage turbine wheel disc, the shaft and the turbine front end shaft, a lower holding ring is connected with the front holding ring, a first-stage turbine wheel disc front chamber is formed between the lower holding ring and the turbine front end shaft, and the first-stage turbine wheel disc lower chamber is respectively communicated with the first-stage turbine wheel disc rear chamber and the first-stage turbine wheel disc front chamber; a second-stage turbine wheel disc front chamber is formed between the second-stage turbine wheel disc and the middle disc, the second-stage turbine wheel disc is connected with the rear supporting ring, the turbine rear end shaft is connected with the rear supporting ring, a second-stage turbine wheel disc lower chamber is formed between the second-stage turbine wheel disc, the shaft and the turbine rear end shaft, and the first-stage turbine wheel disc rear chamber, the second-stage turbine wheel disc front chamber and the second-stage turbine wheel disc lower chamber are sequentially communicated.

Preferably: the upside processing of first order turbine wheel dish has the first order rim plate upper hole, the first order rim plate upper hole communicates with the preceding cavity of first order turbine wheel dish, the first order rim plate upper hole is established the cooperation with first order movable vane root and is cooled off first order movable vane root, the last rear side of intermediate disk is processed in order and is had intermediate disk second radial aperture and intermediate disk upper through-hole, intermediate disk second radial aperture and intermediate disk upper through-hole all communicate with the preceding cavity of second order turbine wheel dish, the cooperation is established with main gas passageway to intermediate disk second radial aperture, intermediate disk upper through-hole and second level blade root establish the cooperation and cool off second order movable vane root.

Preferably: the turbine front end shaft is provided with a seventh through hole, a first-stage turbine wheel disc front cavity is communicated with a first-stage turbine wheel disc lower cavity through the seventh through hole, a sixth through hole is formed in the lower side of the first-stage turbine wheel disc, the first-stage turbine wheel disc lower cavity is communicated with a first-stage turbine wheel disc rear cavity through the sixth through hole, a first through hole is formed in the middle disc, the first-stage turbine wheel disc rear cavity is connected with a second-stage turbine wheel disc front cavity through the first through hole, a fifth through hole is formed in the lower front side of the second-stage turbine wheel disc, and the second-stage turbine wheel disc front cavity is connected with the second-stage turbine wheel disc lower cavity through the fifth through hole.

Preferably: the second-stage turbine wheel disc and the rear holding ring are connected to form a second-stage turbine wheel disc rear chamber, a fourth through hole is machined in the lower rear side of the second-stage turbine wheel disc, a third through hole is machined in the upper side of the rear holding ring, the second-stage turbine wheel disc rear chamber is communicated with the second-stage turbine wheel disc lower chamber through the fourth through hole, the third through hole is communicated with the second-stage turbine wheel disc rear chamber, and the third through hole is matched with the second-stage movable blade root and cools the other side of the second-stage movable blade root.

Preferably: and the front cavity of the first stage turbine wheel disc is communicated with the compressor.

Preferably: the shaft is provided with a connecting part, the lower side of the middle disc is connected with the connecting part of the shaft, the lower side of the first-stage turbine wheel disc is connected with the connecting part of the connecting shaft, and the upper side and the lower side of the second-stage turbine wheel disc are respectively connected with the connecting parts of the middle disc and the shaft to form a front cavity of the second-stage turbine wheel disc.

The utility model discloses following beneficial effect has:

the utility model discloses well first order turbine rim plate and second level turbine rim plate and the intermediate disk is coaxial with the rotational speed between the two, adopt cavity intercommunication structure to carry out flow path control and flow distribution to turbine rotor inside, make the utility model discloses satisfy for the two-stage turbine provides moving blade cooling gas, the inside cooling of turbine rim plate and seal thermal-insulated function to main gas channel, carry out abundant, reasonable cooling to gas turbine rotor part to for the turbine blade provides sufficient cooling air, guarantee the security and the high efficiency of mechanical operation.

Drawings

Fig. 1 is a front view of the internal cooling system of the 2-stage turbine rotor of a small and medium-sized gas turbine with an intermediate disk.

In the figure, 1-a front holding ring, 2-a first stage disk upper hole, 3-a first stage disk, 4-a first stage disk rear chamber, 5-a middle disk first radial hole, 6-a middle disk, 7-a first through hole, 8-a middle disk second radial hole, 9-a second stage disk front chamber, 10-a second through hole, 11-a second stage disk, 12-a third through hole, 13-a second stage disk rear chamber, 14-a rear holding ring, 15-a fourth through hole, 16-a turbine rear end shaft, 17-a second stage disk lower chamber, 18-a fifth through hole, 19-a shaft, 20-a sixth through hole, 21-a first stage disk lower chamber, 22-a turbine front end shaft, 23-a seventh through hole, 24-a first stage disk front chamber, 25-lower holding ring.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described below with reference to specific embodiments shown in the accompanying drawings. It should be understood that the description is intended to be illustrative only and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The first embodiment is as follows: the embodiment is described with reference to fig. 1, the internal cooling system of the 2-stage turbine rotor of the medium and small-sized gas turbine with the intermediate disk of the embodiment comprises a front supporting ring 1, a first-stage turbine disk 3, an intermediate disk 6, a second-stage turbine disk 11, a rear supporting ring 14, a turbine rear end shaft 16, a shaft 19, a turbine front end shaft 22 and a lower supporting ring 25, the first-stage turbine disk 3, the front supporting ring 1, the turbine front end shaft 22 and the lower supporting ring 25 are coaxially arranged on the front side of the shaft 19 in sequence, the intermediate disk 6, the second-stage turbine disk 11, the rear supporting ring 14 and the turbine rear end shaft 16 are coaxially arranged on the rear side of the shaft 19 in sequence, an intermediate disk structure is adopted among the 2-stage rotors, the structure is simplified, the structural strength is enhanced, the intermediate disk 6 separates and adjusts flow paths, the internal cooling system scheme of the 2-stage turbine rotor of the medium and small-sized gas turbine is realized, the system is provided with a cooling turbine rotor component for cooling blades, the gas is prevented from flowing backwards, and the sealing effect is achieved;

the first-stage turbine wheel disc 3, the middle disc 6 and the second-stage turbine wheel disc 11 are sequentially connected, the upper side of the first-stage turbine wheel disc 3 is connected with a front holding ring 1, a first-stage turbine wheel disc rear chamber 4 is formed between the first-stage turbine wheel disc 3 and the middle disc 6, the lower side of the first-stage turbine wheel disc 3 is connected with a turbine front end shaft 22, a first-stage turbine wheel disc lower chamber 21 is formed among the first-stage turbine wheel disc 3, the shaft 19 and the turbine front end shaft 22, a lower holding ring 25 is connected with the front holding ring 1, a first-stage turbine wheel disc front chamber 24 is formed between the lower holding ring 25 and the turbine front end shaft 22, and the first-stage turbine wheel disc lower chamber 21 is respectively communicated with the first-stage turbine wheel disc rear chamber 4 and the first-stage turbine wheel disc front chamber 24; a second-stage turbine wheel disc front chamber 9 is formed between the second-stage turbine wheel disc 11 and the middle disc 6, the second-stage turbine wheel disc 11 is connected with a rear supporting ring 14, a turbine rear end shaft 16 is connected with the rear supporting ring 14, a second-stage turbine wheel disc lower chamber 17 is formed among the second-stage turbine wheel disc 11, a shaft 19 and the turbine rear end shaft 16, and the first-stage turbine wheel disc rear chamber 4, the second-stage turbine wheel disc front chamber 9 and the second-stage turbine wheel disc lower chamber 17 are sequentially communicated; first order turbine wheel dish 3 and second level turbine wheel dish 11 and intermediate disk 6 coaxial with the rotational speed between the two adopt cavity connectivity structure to carry out flow path control and flow distribution to turbine rotor inside, make the utility model discloses satisfy for the two-stage turbine provides moving blade cooling gas, turbine wheel dish internal cooling and seal thermal-insulated function to main gas channel, carry out abundant, reasonable cooling to gas turbine rotor part to for turbine blade provides sufficient cooling air, rational in infrastructure, guarantee mechanical operation's security and high efficiency.

The second embodiment is as follows: the embodiment is described with reference to fig. 1, in the internal cooling system of the 2-stage turbine rotor of the medium and small gas turbine with an intermediate disk of the embodiment, a first-stage disk upper hole 2 is formed in the upper side of a first-stage turbine disk 3, the first-stage disk upper hole 2 is communicated with a first-stage turbine disk front chamber 24, the first-stage disk upper hole 2 is matched with a first-stage movable blade root and cools the first-stage movable blade root, an intermediate disk second radial small hole 8 and an intermediate disk upper through hole 10 are sequentially formed in the upper rear side of the intermediate disk 6, the intermediate disk first radial small hole 5 is communicated with a first-stage turbine disk rear chamber 4, the intermediate disk second radial small hole 8 and the intermediate disk upper through hole 10 are both communicated with a second-stage turbine disk front chamber 9, the intermediate disk first radial small hole 5, the second radial small holes 8 of the middle disc are matched with the main gas channel, and the through holes 10 on the middle disc are matched with the roots of the second-stage blades and cool the roots of the second-stage movable blades.

The third concrete implementation mode: the present embodiment will be described with reference to fig. 1, which shows a cooling system for the inner part of a 2-stage turbine rotor of a small and medium-sized gas turbine having an intermediate disk, a seventh through hole 23 is processed on the turbine front end shaft 22, a first-stage turbine wheel disc front cavity 24 is communicated with a first-stage turbine wheel disc lower cavity 21 through the seventh through hole 23, a sixth through hole 20 is processed on the lower side of the first-stage turbine wheel disc 3, the first-stage turbine wheel disc lower cavity 21 is communicated with a first-stage turbine wheel disc rear cavity 4 through the sixth through hole 20, a first through hole 7 is processed on the middle disc 6 to strengthen the cooling effect, the first-stage turbine wheel disc rear cavity 4 is connected with a second-stage turbine wheel disc front cavity 9 through the first through hole 7, a fifth through hole 18 is processed on the lower front side of the second-stage turbine wheel disc 11, and the second-stage turbine wheel disc front cavity 9 is connected with the second-stage turbine wheel disc lower cavity 17 through the fifth through hole 18; one stage of bleed air of the compressor is divided into two parts in a front cavity 24 of the first stage turbine wheel disc, one part of bleed air is supplied to the first stage movable blades through the upper holes 2 of the first stage wheel disc, the other part of bleed air is supplied to the second stage movable blades through the seventh through holes 23, and other structures along the path are cooled.

The fourth concrete implementation mode: the embodiment is described with reference to fig. 1, in the internal cooling system of a 2-stage turbine rotor of a medium-small sized gas turbine with an intermediate disk of the embodiment, the second-stage turbine disk 11 is connected with a backing ring 14 to form a second-stage turbine disk rear chamber 13, a fourth through hole 15 is processed on the lower rear side of the second-stage turbine disk 11, a third through hole 12 is processed on the upper side of the backing ring 14, the second-stage turbine disk rear chamber 13 is communicated with a second-stage turbine disk lower chamber 17 through the fourth through hole 15, the third through hole 12 is communicated with the second-stage turbine disk rear chamber 13, the third through hole 12 is matched with the second-stage movable blade root to cool the other side of the second-stage movable blade root, and the area where the hole connecting chamber and the blade root are located is used for flow path control and flow distribution inside the turbine rotor; the first-stage wheel disc upper hole 2, the middle disc upper through hole 10 and the third through hole 12 are communicated with the interior of the moving blade to cool the whole moving blade.

The fifth concrete implementation mode: the embodiment is described with reference to fig. 1, the internal cooling system of the 2-stage turbine rotor of the medium and small-sized gas turbine with the intermediate disk of the embodiment is characterized in that the front cavity 24 of the first-stage turbine disk is communicated with the compressor, compressed air led out from a certain stage of the compressor is used as a cooling medium, a bleed air structure is simplified, the internal cooling system is suitable for the internal cooling system of the rotor of the medium and small-sized gas turbine with the 2-stage turbine, the 2-stage turbine rotor is coaxial and rotates at the same speed, the intermediate disk rotating simultaneously is arranged between the two rotors, the cooling medium passes through the internal flow path of the turbine rotor disk, cools the rotor disk and the path part along the path, and is finally supplied to the root of the turbine moving blade or is discharged into the main gas flow channel of the turbine through a hole.

The sixth specific implementation mode: in the present embodiment, the internal cooling system of the 2-stage turbine rotor of the small and medium-sized gas turbine having the intermediate disk according to the present embodiment is described with reference to fig. 1, the shaft 19 has a connecting portion, the lower side of the intermediate disk 6 is connected to the connecting portion of the shaft 19, the lower side of the first-stage turbine disk 3 is connected to the connecting portion of the shaft 19, and the upper and lower sides of the second-stage turbine disk 11 are connected to the connecting portions of the intermediate disk 6 and the shaft 19, respectively, to form the second-stage turbine disk front chamber 9.

The utility model discloses a theory of operation: leading out a stream of compressed air from a certain part of the compressor as cooling air, and dividing the stream of cooling air into 2 streams serving as cooling flow path media inside the turbine rotor;

one cold air passes through a first stage turbine wheel disc front chamber 24 formed by a first stage turbine wheel disc 3, a front holding ring 1 and a lower holding ring 25 and then is introduced into the root part of the first stage movable vane through a first stage wheel disc upper hole 2, and the front holding ring 1, the lower holding ring 25 and the front side of the first stage turbine wheel disc 3 are cooled along the way, and the cold air is provided for the first stage movable vane;

another strand of cooling gas enters a lower chamber 21 of the first turbine wheel disc through a seventh through hole 23 on a front end shaft 22 of the turbine, cools the lower part of the first stage turbine wheel disc 3 and the corresponding surface of a shaft 19, and then enters a rear chamber 4 of the first stage turbine wheel disc formed by the first stage turbine wheel disc 3 and the middle disc 6 through a plurality of radial sixth through holes 20 on the first stage turbine wheel disc 3 to cool the rear side of the first stage turbine wheel disc 3 and the front side of the middle disc 6, and the flow direction of the cold gas is from the inner radial outer diameter to the upper part of the rear chamber 4 of the first stage turbine wheel disc and is divided into 2 strands again;

one flow enters the main gas channel through a first radial small hole 5 of the middle disk on the middle disk 6, and the flow cools the upper part of the middle disk 6 and simultaneously can cool the corresponding stator surface; the other air flow enters a front chamber 9 of a second-stage turbine wheel disc formed by the intermediate disc 6 and a second-stage turbine wheel disc 11 through a plurality of axial first through holes 7 in the upper part of the intermediate disc 6, and cools the upper part of the intermediate disc 6 along the way;

the cooling gas entering the front chamber 9 of the second stage turbine wheel disc is divided into 3 strands again; one flow enters the main gas channel through a second radial small hole 8 of the middle disk 6, and the flow cools the upper part of the middle disk 6 and simultaneously can cool the corresponding stator surface; one strand of cooling air enters the root part of the second-stage moving blade through a second through hole 10 of the middle disc 6 to provide cooling air for the second-stage moving blade; and the other strand of the cooling medium enters a lower cavity 17 of the second-stage turbine disk from the outer diameter to the inner diameter through a fifth through hole 18, cools the lower part of the second-stage turbine disk 11, then enters a rear cavity 13 of the second-stage turbine disk formed by the second-stage turbine disk 11 and a rear supporting ring 14 through a radial fourth through hole 15 on the second-stage turbine disk 11, cools the rear side of the second-stage turbine disk 11 and the corresponding surface of the rear supporting ring 14, and finally enters the root part of the second-stage turbine movable blade from the rear side through a third through hole 12 of the rear supporting ring 14.

It should be noted that, in the above embodiments, as long as the technical solutions can be aligned and combined without contradiction, those skilled in the art can exhaust all possibilities according to the mathematical knowledge of the alignment and combination, and therefore the present invention does not describe the technical solutions after alignment and combination one by one, but it should be understood that the technical solutions after alignment and combination have been disclosed by the present invention.

This embodiment is only illustrative of the patent and does not limit the scope of protection thereof, and those skilled in the art can make modifications to its part without departing from the spirit of the patent.

Claims

1. The internal cooling system of the 2-stage turbine rotor of the small and medium-sized gas turbine with the intermediate disk is characterized in that: the front side of the shaft (19) is sequentially and coaxially provided with the first-stage turbine wheel disc (3), the front holding ring (1), the turbine front end shaft (22) and the lower holding ring (25), and the rear side of the shaft (19) is sequentially and coaxially provided with the middle disc (6), the second-stage turbine wheel disc (11), the rear holding ring (14) and the turbine rear end shaft (16);

the first-stage turbine wheel disc (3), the middle disc (6) and the second-stage turbine wheel disc (11) are sequentially connected, a front holding ring (1) is connected to the upper side of the first-stage turbine wheel disc (3), a first-stage turbine wheel disc rear chamber (4) is formed between the first-stage turbine wheel disc (3) and the middle disc (6), a turbine front end shaft (22) is connected to the lower side of the first-stage turbine wheel disc (3), a first-stage turbine wheel disc lower chamber (21) is formed between the first-stage turbine wheel disc (3), a shaft (19) and the turbine front end shaft (22), a lower holding ring (25) is connected with the front holding ring (1), a first-stage turbine wheel disc front chamber (24) is formed between the lower holding ring (25) and the turbine front end shaft (22), and the first-stage turbine wheel disc lower chamber (21) is respectively communicated with the first-stage turbine wheel disc rear chamber (4) and the first-stage turbine wheel disc front chamber (24); cavity (9) before second level turbine wheel dish is formed between second level turbine wheel dish (11) and intermediate disk (6), second level turbine wheel dish (11) with hold ring (14) after with and be connected, turbine rear end axle (16) hold ring (14) with after and be connected, form second level turbine wheel dish lower part cavity (17) between second level turbine wheel dish (11), axle (19), the turbine rear end axle (16), first level turbine wheel dish rear chamber (4), cavity (9) before the second level turbine wheel dish, second level turbine wheel dish lower part cavity (17) communicate in proper order.

2. The internal cooling system of the rotor of the 2-stage turbine of a small and medium-sized gas turbine with an intermediate disk according to claim 1, characterized in that: the upside processing of first order turbine wheel dish (3) has first order rim plate upper hole (2), first order rim plate upper hole (2) and first order turbine wheel dish front chamber (24) intercommunication, first order rim plate upper hole (2) establish the cooperation with first order movable vane root and cool off first order movable vane root, the last rear side of intermediate disk (6) is processed in order has intermediate disk second radial aperture (8) and intermediate disk upper through-hole (10), intermediate disk second radial aperture (8) and intermediate disk upper through-hole (10) all communicate with second order turbine wheel dish front chamber (9), intermediate disk second radial aperture (8) establish the cooperation with main gas channel, intermediate disk upper through-hole (10) establish the cooperation with second order blade root and cool off second order movable vane root.

3. The internal cooling system of the rotor of the 2-stage turbine of a small and medium-sized gas turbine with an intermediate disk according to claim 1 or 2, characterized in that: processing has seventh through-hole (23) on turbine front end axle (22), first order turbine wheel dish front chamber (24) and first order turbine wheel dish lower part cavity (21) communicate through seventh through-hole (23), the downside processing of first order turbine wheel dish (3) has sixth through-hole (20), first order turbine wheel dish lower part cavity (21) and first order turbine wheel dish rear chamber (4) communicate through sixth through-hole (20), processing has first through-hole (7) on middle dish (6), first order turbine wheel dish rear chamber (4) and second level turbine wheel dish front chamber (9) are connected through first through-hole (7), the lower front side processing of second level turbine wheel dish (11) has fifth through-hole (18), chamber (9) and second level turbine wheel dish lower part cavity (17) are connected through fifth through-hole (18) before the second level wheel dish.

4. The internal cooling system of the 2-stage turbine rotor of a small and medium-sized gas turbine with an intermediate disk according to claim 3, characterized in that: second level turbine wheel dish (11) are connected with back and are formed second level turbine wheel dish rear chamber (13) with back holding ring (14), the lower rear side processing of second level turbine wheel dish (11) has fourth through-hole (15), the upside processing of back holding ring (14) has third through-hole (12), second level turbine wheel dish rear chamber (13) and second level turbine wheel dish lower part chamber (17) are through fourth through-hole (15) intercommunication, third through-hole (12) and second level turbine wheel dish rear chamber (13) intercommunication, third through-hole (12) and second level movable vane root establish to cooperate and cool off the opposite side of second level movable vane root.

5. The internal cooling system of the rotor of the 2-stage turbine of a small and medium-sized gas turbine with an intermediate disk according to claim 4, characterized in that: the front cavity (24) of the first stage turbine wheel disc is communicated with the compressor.

6. The internal cooling system of the rotor of the 2-stage turbine of a small and medium-sized gas turbine with an intermediate disk according to claim 1, characterized in that: the shaft (19) is provided with a connecting part, the lower side of the middle disc (6) is connected with the connecting part of the shaft (19), the lower side of the first-stage turbine wheel disc (3) is connected with the connecting part of the connecting shaft (19), and the upper side and the lower side of the second-stage turbine wheel disc (11) are respectively connected with the connecting parts of the middle disc (6) and the shaft (19) to form a second-stage turbine wheel disc front chamber (9).