A groove milling inner cooling ring belt structure

Abstract

The application relates to a milling groove type inner cooling ring belt structure, which comprises an outer wall and an inner wall, the outer wall is provided with a separate liquid collecting ring, the liquid collecting ring is provided with a ring belt inlet pipe, the inner wall is provided with cooling milling grooves which are divided into two branches, the outer wall and the inner wall are brazed, a first ring belt outlet and a second ring belt outlet are respectively machined on the upstream and downstream of the inner cooling ring belt structure, the first ring belt outlet and the second ring belt outlet penetrate through the inner wall and extend to the outer wall; during the working of a thrust chamber, the cooling liquid is supplied from the ring belt inlet pipe of the outer wall, is divided into two streams through the "herringbone" cooling milling grooves of the inner wall, forms two inner cooling ring belts, is sprayed out along the first ring belt outlet and the second ring belt outlet, and forms a cooling liquid film which is closely attached to the inner surface of the inner wall, thereby protecting the downstream inner wall of the first ring belt outlet and the second ring belt outlet. The application can increase the effective protection length of the liquid film, accurately adjust the flow of the inner coolant, and meet the application requirements of the heat protection of the inner wall of the high-pressure and high-temperature thrust chamber.

Description

Technical Field

[0001] This invention belongs to the field of liquid rocket engine cooling technology and relates to a milled groove type internal cooling ring structure. Background Technology

[0002] Liquid rocket engine thrust chambers operate under high temperature and high pressure environments, making internal wall thermal protection a crucial issue that must be addressed during thrust chamber development. Common thermal protection methods for liquid rocket engine thrust chambers include external cooling and internal cooling. Internal cooling involves using a small amount of propellant to create a protective layer near the inner wall of the thrust chamber, reducing heat transfer to the wall and thus protecting it. Common internal cooling zone structures include... Figure 1 As shown. Although the internal cooling ring structure is simple, its main problems are: 1) the flow rate of the internal coolant cannot be precisely adjusted according to the results of the thrust chamber fluid flow test; 2) the tangential momentum of the liquid film at the small orifice outlet is insufficient, the wall adhesion effect of the internal coolant film is poor, the protection length range is short, and the cooling effect on the inner wall is poor. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a milled groove type internal cooling ring structure to achieve an effective protection length of the extended liquid film, accurately adjust the flow rate of the internal coolant, and meet the application requirements of high pressure and high temperature thrust chamber wall thermal protection.

[0004] The solution of the present invention is: a milled groove type internal cooling ring structure, including an outer wall and an inner wall, the outer wall having an independent liquid collecting ring, the liquid collecting ring having a ring inlet pipe, the inner wall having a cooling milled groove divided into two branches, the outer wall and the inner wall being brazed together, a first ring outlet and a second ring outlet being machined at the upstream and downstream of the internal cooling ring structure respectively, the first ring outlet and the second ring outlet penetrating the inner wall and extending to the outer wall;

[0005] When the thrust chamber is working, the coolant is supplied from the ring inlet pipe on the outer wall, and then splits into two inner cooling rings by the "V"-shaped cooling grooves on the inner wall. The coolant is sprayed out along the outlet of the first ring and the outlet of the second ring, forming a coolant film that adheres closely to the inner surface of the inner wall and protects the inner wall downstream of the outlets of the first and second rings.

[0006] Furthermore, the milled groove of the cooling milling groove is a spiral milling groove.

[0007] Furthermore, the milled grooves on the inner wall have a rectangular cross-section and adopt a design with equal groove width.

[0008] Furthermore, the selection method for the number of grooves, groove width, and groove depth on the left and right sides of the cooling milling groove is as follows:

[0009] Based on the total coolant flow rate of the internal cooling ring Based on the required flow distribution ratio k, set the number of slots n for each of the two inner cooling rings. i , slot width c i , groove depth h i Given the coolant density ρ, calculate the flow velocity v in the spiral grooves of the two inner cooling rings. i :

[0010]

[0011]

[0012]

[0013] Where the subscripts i = A and B, subscript A represents the parameters flowing through the outlet of the first annular zone, and subscript B represents the parameters flowing through the outlet of the second annular zone;

[0014] Based on the flow velocity v in the spiral milled groove of the internal cooling ring i The length L of the spiral milled groove i Calculate the flow resistance ΔP of the internal cooling ring. i :

[0015]

[0016]

[0017] Wherein, ΔP i The friction resistance of the internal cooling ring with spiral milled grooves is λ, where λ is the friction resistance coefficient, and D is the friction resistance coefficient. h Let α be the equivalent diameter of the helical groove. i The helix angle of the spiral groove;

[0018] Adjust the number of slots n i , slot width c i , groove depth h i until ΔP is satisfied. A =ΔP B .

[0019] Furthermore, the flow distribution ratio k of the two inner cooling rings flowing through the outlet of the first ring belt and the outlet of the second ring belt is taken as 1:2 to 2:1.

[0020] Furthermore, there is a regenerative cooling channel between the outer and inner walls, which is not connected to the two inner cooling rings.

[0021] The beneficial effects of this invention compared to the prior art are:

[0022] (1) The present invention is characterized in that two inner cooling annular belts can be formed through one annular belt inlet, providing a certain initial tangential velocity for the liquid film at the annular belt outlet, ensuring the liquid film at the annular belt outlet flows rotationally against the wall, reducing mixing with the main fuel gas flow, extending the effective protection length of the liquid film, accurately adjusting the flow rate of the inner coolant, and meeting the application requirements of thermal protection for the inner wall of a high-pressure and high-temperature thrust chamber. Brief Description of the Drawings

[0023] Figure 1 is a schematic diagram of a conventional inner cooling annular belt structure;

[0024] Figure 2 is a partial schematic structural diagram of a thrust chamber applying a slotted inner cooling annular belt structure;

[0025] Figure 3 is a herringbone milling groove for coolant flow splitting on the inner wall;

[0026] Figure 4 is a schematic cross-sectional view of the herringbone milling groove;

[0027] In the figures: 1 - outer wall, 2 - inner wall, 3 - main cooling flow path, 4 - liquid collecting ring, 5 - annular belt inlet pipe, 6 - first annular belt outlet, 7 - second annular belt outlet, 8 - herringbone cooling milling groove. Detailed Description of the Embodiments

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] As shown in Figure 2 , Figure 3 , the proposed slotted inner cooling annular belt structure of the present invention is formed by brazing an outer wall 1 and an inner wall 2. A main cooling flow path 3 (i.e., a regenerative cooling channel) is provided between the outer wall 1 and the inner wall 2. The outer wall 1 is provided with an independent liquid collecting ring 4, in which an annular belt inlet pipe 5 is arranged. The inner wall 2 is provided with a cooling milling groove 8 divided into two branches, and the cooling milling groove 8 is in a herringbone shape, as shown in Figure 3 . After the outer wall 1 and the inner wall 2 are brazed, a first annular belt outlet 6 and a second annular belt outlet 7 are respectively machined at the upstream and downstream of the inner cooling annular belt structure, and the first annular belt outlet 6 and the second annular belt outlet 7 penetrate through the inner wall 2 and extend to the outer wall 1;

[0030] When the thrust chamber is in operation, the coolant is supplied from the annular belt inlet pipe 5 of the outer wall 1, split left and right through the herringbone cooling milling groove 8 of the inner wall 2 to form two inner cooling annular belts, which are ejected rotationally along the first annular belt outlet 6 and the second annular belt outlet 7, and closely attach to the inner surface of the inner wall 2 to form a coolant film, so as to protect the inner wall 2 downstream of the first annular belt outlet 6 and the second annular belt outlet 7. The two formed inner cooling annular belts are not in communication with the main cooling flow path 3.

[0031] Referring to Figure 3 and Figure 4 The milling groove of the "human" shaped cooling milling groove 8 is a spiral milling groove, which splits the coolant entering from the ring belt inlet pipe 5 to the left and right, so that the coolant rotates and spreads into a coolant film, which enters the combustion chamber along the wall and cools and protects the inner wall of the combustion chamber downstream of the ring belt.

[0032] The cross-section of the milled groove on inner wall 2 is rectangular, and a uniform groove width design is adopted. By selecting the number of grooves n, groove width c, and groove depth h on the left and right sides of the "V"-shaped cooling milled groove, the required flow distribution for the two inner cooling rings is achieved, the velocity of the liquid film at the ring outlet is controlled, the mixing with the mainstream combustion gas is reduced, and the effective protection length of the liquid film is increased. Details are as follows:

[0033] Based on the total coolant flow rate of the internal cooling ring Based on the required flow distribution ratio k, set the number of slots n for each of the two inner cooling rings. i , slot width c i , groove depth h i Given the coolant density ρ, calculate the flow velocity v in the spiral grooves of the two inner cooling rings. i :

[0034]

[0035]

[0036]

[0037] Where the subscripts i = A and B, subscript A represents the parameters flowing through the first annular belt outlet 6, and subscript B represents the parameters flowing through the second annular belt outlet 7;

[0038] Based on the flow velocity v in the spiral milled groove of the internal cooling ring i The length L of the spiral milled groove i Calculate the flow resistance ΔP of the internal cooling ring. i ΔP is required A =ΔP B .

[0039]

[0040]

[0041] Wherein, ΔP i The friction resistance of the spiral milled groove in the internal cooling ring;

[0042] λ is the friction coefficient.

[0043] ρ is the density of the coolant;

[0044] v i The coolant flow rate in the spiral milled groove of the internal cooling ring;

[0045] L i The length of the spiral groove;

[0046] D h The equivalent diameter of the spiral groove;

[0047] α i The helix angle is the helix angle of the spiral groove.

[0048] Furthermore, the flow distribution ratio k of the two inner cooling rings flowing through the first ring outlet 6 and the second ring outlet 7 is taken as 1:2 to 2:1.

[0049] The flow rates of the two inner cooling rings are determined according to the flow distribution ratio k, and the number of slots n of the two inner cooling rings is set accordingly. i , slot width c i , groove depth h i Calculate the flow velocity v i Then, the flow resistance ΔP of the internal cooling ring is calculated. i Adjust the number of slots n i , slot width c i , groove depth h i Continue until the flow resistance of the two inner cooling rings is the same.

[0050] Currently, the milled groove type internal cooling ring structure proposed in this invention has been successfully applied to the thrust chamber of a high-pressure afterburning circulating liquid oxygen kerosene engine. The two internal cooling liquid films formed are uniform and continuous, with good wall adhesion, effectively achieving thermal protection of the inner surface of the thrust chamber under high pressure and high temperature conditions.

[0051] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0052] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A milled groove type internal cooling ring structure, characterized in that, It includes an outer wall (1) and an inner wall (2). The outer wall (1) has an independent liquid collection ring (4). The liquid collection ring (4) is provided with a ring inlet pipe (5). The inner wall (2) is provided with a cooling milling groove (8) divided into two branches. The outer wall (1) and the inner wall (2) are brazed together. The first ring outlet (6) and the second ring outlet (7) are processed at the upstream and downstream of the inner cooling ring structure, respectively. The first ring outlet (6) and the second ring outlet (7) penetrate the inner wall (2) and extend to the outer wall (1). When the thrust chamber is working, the coolant is supplied from the ring inlet pipe (5) of the outer wall (1), and then splits into two inner cooling rings through the cooling milling groove (8) of the inner wall (2). The coolant is sprayed out along the first ring outlet (6) and the second ring outlet (7) in a rotating manner, forming a coolant film that adheres closely to the inner surface of the inner wall (2) to protect the inner wall (2) downstream of the first ring outlet (6) and the second ring outlet (7).

2. The milled groove type internal cooling ring structure according to claim 1, characterized in that, The groove of the cooling milling groove (8) is a spiral milling groove.

3. The milled groove type internal cooling ring structure according to claim 1, characterized in that, The cross-section of the milled groove in the inner wall (2) is rectangular, and the groove width is designed to be equal.

4. The milled groove type internal cooling ring structure according to claim 2, characterized in that, The selection method for the number of grooves, groove width, and groove depth on the left and right sides of the cooling milling groove is as follows: Based on the total coolant flow rate of the internal cooling ring Based on the required flow distribution ratio k, set the number of slots for each of the two inner cooling rings. , slot width trench depth and coolant density Calculate the flow velocity in the spiral milled grooves of the two inner cooling rings. : Subscript i = A , B , subscript A The parameters representing the flow through the outlet (6) of the first annulus are indicated by the subscript . B The parameters represent the flow through the outlet of the second ring belt (7); Based on the flow rate in the spiral groove of the internal cooling ring Length of spiral milled groove Calculate the flow resistance of the internal cooling ring. : in, To reduce the flow resistance along the spiral grooves of the internal cooling ring, This is the friction coefficient. Let be the equivalent diameter of the helical groove. The helix angle of the spiral groove; Adjust the number of slots , slot width trench depth until satisfied .

5. The milled groove type internal cooling ring structure according to claim 4, characterized in that, The flow distribution ratio k of the two inner cooling rings flowing through the first ring outlet (6) and the second ring outlet (7) is 1:2 ~ 2:

1.

6. The milled groove type internal cooling ring structure according to claim 1, characterized in that, There is a regenerative cooling channel between the outer wall (1) and the inner wall (2), and the regenerative cooling channel is not connected to the two inner cooling rings.

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