阅读说明：本技术 一种液体火箭发动机涡轮泵氦气阻燃密封结构 (Helium flame-retardant sealing structure of turbopump of liquid rocket engine ) 是由 沈文金 黄克松 蒋文山 崔垒 柴皓 李小芬 刘恒 金志磊 林奇燕 叶小强 于 2019-09-30 设计创作，主要内容包括：一种液体火箭发动机涡轮泵氦气阻燃密封结构,属于火箭发动机技术领域,包括转轴1、密封壳体2、浮动环3、波形弹簧4、盖板5、第一轴套7、第二轴套8、密封轴套9；第一轴套7、密封轴套9、第二轴套8依次套装在转轴1上；密封轴套9靠近转轴1的表面设有环形槽,环形槽与转轴1之间形成环形腔14；密封轴套9在环形槽处设有径向孔13；密封壳体2套装在密封轴套9上,其上设有相互连通的进氦孔11、隔离腔12；盖板5与密封壳体2连接后使浮动环3位于隔离腔12内；波形弹簧4用于向浮动环3施加轴向预载,同时使隔离腔12与径向孔13连通。本发明实现了氧化剂与燃料的隔离,大幅提高了涡轮泵的安全性。(A helium flame-retardant sealing structure of a turbopump of a liquid rocket engine belongs to the technical field of rocket engines and comprises a rotating shaft 1, a sealing shell 2, a floating ring 3, a wave spring 4, a cover plate 5, a first shaft sleeve 7, a second shaft sleeve 8 and a sealing shaft sleeve 9; the first shaft sleeve 7, the sealing shaft sleeve 9 and the second shaft sleeve 8 are sequentially sleeved on the rotating shaft 1; the surface of the sealing shaft sleeve 9 close to the rotating shaft 1 is provided with an annular groove, and an annular cavity 14 is formed between the annular groove and the rotating shaft 1; the sealing shaft sleeve 9 is provided with a radial hole 13 at the annular groove; the sealing shell 2 is sleeved on the sealing shaft sleeve 9 and is provided with a helium inlet hole 11 and an isolation cavity 12 which are communicated with each other; after the cover plate 5 is connected with the sealing shell 2, the floating ring 3 is positioned in the isolation cavity 12; the wave spring 4 is used to apply an axial preload to the floating ring 3 while placing the isolation chamber 12 in communication with the radial bore 13. The invention realizes the isolation of the oxidant and the fuel and greatly improves the safety of the turbopump.)

1. A helium flame-retardant sealing structure of a turbopump of a liquid rocket engine is characterized by comprising a rotating shaft (1), a sealing shell (2), a floating ring (3), a wave spring (4), a cover plate (5), a first shaft sleeve (7), a second shaft sleeve (8) and a sealing shaft sleeve (9);

the first shaft sleeve (7), the sealing shaft sleeve (9) and the second shaft sleeve (8) are sequentially sleeved on the rotating shaft (1), and the sealing shaft sleeve (9) is hermetically connected with the first shaft sleeve (7) and the second shaft sleeve (8); an annular groove is formed in the surface, close to the rotating shaft (1), of the sealing shaft sleeve (9), and when the sealing shaft sleeve (9) is sleeved on the rotating shaft (1), an annular cavity (14) is formed between the annular groove and the rotating shaft (1); the sealing shaft sleeve (9) is provided with a radial hole (13) at the annular groove;

the sealing shell (2) is sleeved on the sealing shaft sleeve (9), and a helium inlet hole (11) and an isolation cavity (12) which are communicated with each other are formed in the sealing shell (2); the floating ring (3) is positioned in the isolation cavity (12) after the cover plate (5) is connected with the sealing shell (2); the wave spring (4) is used for applying axial preload to the floating ring (3) and simultaneously enabling the isolation cavity (12) to be communicated with the radial hole (13).

2. The liquid rocket engine turbopump helium gas flame retardant sealing structure of claim 1, further comprising an aluminum pad (10); two ends of the sealing shaft sleeve (9) are provided with sealing teeth (19), and the aluminum gasket (10) is arranged on the sealing teeth (19) and used for sealing the sealing shaft sleeve (9) with the first shaft sleeve (7) and the second shaft sleeve (8).

3. The helium flame retardant sealing structure of the turbopump of the liquid rocket engine as claimed in claim 1, wherein the surface of the sealing shaft sleeve (9) is modified by chromium nitride.

4. The helium flame retardant sealing structure of the turbopump of the liquid rocket engine according to claim 1, wherein the sealing shaft sleeve (9) is provided with 4-6 radial holes at the annular groove, and the 4-6 radial holes (13) are distributed along the circumference of the sealing shaft sleeve (9).

5. The liquid rocket engine turbopump helium flame retardant sealing structure of any one of claims 1 to 4, wherein the axial preload applied to the floating ring (3) by the wave spring (4) is greater than or equal to 15N.

6. The liquid rocket engine turbopump helium flame-retardant sealing structure is characterized in that the pressure of helium introduced into the annular cavity (14) through the radial holes (13) is greater than the pressure of an external oxidant, and the pressure of the helium is greater than the pressure of an external fuel.

7. The liquid rocket engine turbopump helium flame retardant sealing structure of claim 6, wherein the pressure of the helium is 0.4-0.5 MPa greater than the pressure of the external oxidant, and the pressure of the helium is 0.4-0.5 MPa greater than the pressure of the external fuel.

8. The liquid rocket engine turbopump helium flame retardant sealing structure of claim 1 to 4, wherein the diameter of the radial hole (13) is 1.5 to 1.8 mm.

9. The helium flame retardant sealing structure of the turbopump of the liquid rocket engine according to claim 2, wherein the cone angle of the sealing teeth (19) is 55-65 degrees, and the height is 0.3-0.5 mm.

10. The helium flame retardant sealing structure of the turbopump of the liquid rocket engine as claimed in claim 2, wherein the thickness of the aluminum pad (10) is 0.6-0.9 mm.

Technical Field

The invention relates to a helium flame-retardant sealing structure of a turbopump of a liquid rocket engine, belonging to the technical field of rocket engines.

Background

When an oxidant and a fuel exist in a turbopump of the liquid rocket engine at the same time, the contact combustion of the two media is a typical disaster-causing fault and has great harm. Once the oxidant comes into contact with the fuel, it will fission and burn, causing turbine blade ablation, casing burn-through, and even explosion of the entire engine. Therefore, the turbine pump needs to be completely isolated from the oxidant and the fuel during operation. At present, a turbine pump usually adopts a dynamic seal in the form of a floating ring or a labyrinth seal, and helium with a certain pressure is introduced into the middle of the floating ring or the labyrinth seal to isolate an oxidant and a fuel in cavities at two sides. Usually, a seal shaft sleeve is mounted on the rotating shaft, and forms a friction pair with a floating ring or a labyrinth seal. However, the seal sleeve is in clearance fit with the rotating shaft, and an oxidant and a fuel are also present in the fit clearance, so that destructive failure that the oxidant and the fuel are in contact for combustion or even explosion is induced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the helium flame-retardant sealing structure comprises a rotating shaft, a sealing shell, a floating ring, a wave spring, a cover plate, a first shaft sleeve, a second shaft sleeve and a sealing shaft sleeve; the first shaft sleeve, the sealing shaft sleeve and the second shaft sleeve are sequentially sleeved on the rotating shaft, and the sealing shaft sleeve is hermetically connected with the first shaft sleeve and the second shaft sleeve; the surface of the sealing shaft sleeve, which is close to the rotating shaft, is provided with an annular groove, and an annular cavity is formed between the annular groove and the rotating shaft; the sealing shaft sleeve is provided with a radial hole at the annular groove; the sealing shell is sleeved on the sealing shaft sleeve and is provided with a helium inlet hole and an isolation cavity which are communicated with each other; the cover plate is connected with the sealing shell to enable the floating ring to be located in the isolation cavity; the wave spring is used to apply an axial preload to the floating ring while placing the isolation chamber in communication with the radial bore.

The purpose of the invention is realized by the following technical scheme:

a helium flame-retardant sealing structure of a turbopump of a liquid rocket engine comprises a rotating shaft, a sealing shell, a floating ring, a wave spring, a cover plate, a first shaft sleeve, a second shaft sleeve and a sealing shaft sleeve;

the first shaft sleeve, the sealing shaft sleeve and the second shaft sleeve are sequentially sleeved on the rotating shaft, and the sealing shaft sleeve is hermetically connected with the first shaft sleeve and the second shaft sleeve; the surface of the sealing shaft sleeve, which is close to the rotating shaft, is provided with an annular groove, and after the sealing shaft sleeve is sleeved on the rotating shaft, an annular cavity is formed between the annular groove and the rotating shaft; the sealing shaft sleeve is provided with a radial hole at the annular groove;

the sealing shell is sleeved on the sealing shaft sleeve, and a helium inlet hole and an isolation cavity which are communicated with each other are formed in the sealing shell; after the cover plate is connected with the sealing shell, the floating ring is positioned in the isolation cavity; the wave spring is used to apply an axial preload to the floating ring while placing the isolation chamber in communication with the radial bore.

Preferably, the aluminum pad is also included; the two ends of the sealing shaft sleeve are provided with sealing teeth, and the aluminum gasket is arranged on the sealing teeth and used for sealing the sealing shaft sleeve with the first shaft sleeve and the second shaft sleeve.

Preferably, the surface of the sealing shaft sleeve is modified by chromium nitride.

Preferably, the sealing shaft sleeve is provided with 4-6 radial holes in the annular groove, and the 4-6 radial holes are distributed along the circumference of the sealing shaft sleeve.

Preferably, the wave spring applies an axial preload to the floating ring of 15N or greater.

Preferably, the pressure of the helium gas introduced into the annular chamber through the radial holes is greater than the pressure of the external oxidant, while the pressure of the helium gas is greater than the pressure of the external fuel.

Preferably, the pressure of the helium gas is 0.4-0.5 MPa greater than that of the external oxidant, and the pressure of the helium gas is 0.4-0.5 MPa greater than that of the external fuel.

Preferably, the diameter of the radial hole is 1.5-1.8 mm.

Preferably, the cone angle of the sealing tooth is 55-65 degrees, and the height is 0.3-0.5 mm.

Preferably, the thickness of the aluminum pad is 0.6-0.9 mm.

Compared with the prior art, the invention has the following beneficial effects:

(1) the helium gas isolation sealing device designed by the invention is suitable for the turbopump of the liquid rocket engine, can effectively and reliably solve the problem of isolating the oxidant and the fuel at two sides of the sealing gap between the rotating shaft and the shaft sleeve of the turbopump, and greatly improves the working safety of the turbopump;

(2) the sealing shaft sleeve is subjected to chromium nitride surface modification, so that the surface hardness and the friction resistance are improved, the machining of a radial hole structure is facilitated, and the problems of difficult machining and easy edge breakage of a chromium oxide ceramic coating can be solved;

(3) 4 radial holes with phi of 1.6mm are arranged at the sealing shaft sleeve, so that helium is filled in a fit clearance between the sealing shaft sleeve and the rotating shaft, the oxidant and the fuel are safely and reliably isolated, and the harm of contact combustion and explosion of the oxidant and the fuel is avoided;

(4) the sealing teeth are arranged at two ends of the sealing shaft sleeve, and the sealing aluminum gasket is arranged, so that the static sealing effect of the shaft sleeve and the rotating shaft is increased, and the helium leakage rate is further reduced.

Drawings

FIG. 1 is a schematic view of the composition of a flame retardant seal structure of the present invention;

FIG. 2 is a schematic structural view of the seal cartridge of the present invention;

FIG. 3 is a schematic view of a partial structure of the seal cartridge of the present invention;

fig. 4 is a gas flow diagram of helium gas injection into the flame retardant sealing structure of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.