Low temperature storage tank gas diffuser

Abstract

The utility model provides a low temperature storage tank gas diffuser, and the gas diffuser comprises a diffuser shell, the diffuser shell is the conical hollow structure, the diffuser shell top axial center place is linked with the pressurization gas conveying pipe, and the pressurization gas conveying pipe stretches into the diffuser shell inside. Uniformly set up a plurality of gas outlets on the lateral wall of diffuser shell, and the gas outlet gas direction is towards obliquely upwards. The lateral wall of the gas diffuser is uniformly provided with the gas outlet, the pressurization airflow is transported to the inner chamber of the gas diffuser through the pipeline and is decelerated, and then is obliquely sprayed upwards through the gas outlet on the lateral wall, so that the airflow cannot blow the liquid surface directly, and the stability of the liquid surface and the stability of the gas pressure in the storage tank are ensured.

Description

Technical Field

[0001] This utility model relates to the field of rocket tank pressurization technology, specifically a cryogenic tank gas diffuser. Background Technology

[0002] Before testing a liquid oxygen-methane rocket engine, the cryogenic tanks for liquid oxygen and liquid methane propellants must be pressurized. Only when the tank pressure reaches a set value can the liquid oxygen and liquid methane propellants be stably delivered to the rocket engine via pipeline for ignition testing. The nitrogen pressurization system plays a crucial role in maintaining stable pressure within the tanks, ensuring stable propellant delivery during engine testing and influencing the test results. If the nitrogen pressurization system fails to accurately maintain the tank pressure at a suitable level, the flow rate of liquid oxygen or methane propellant entering the engine will be unstable during ignition testing, leading to deviations in the fuel mixture ratio. Deviations in the liquid oxygen and liquid methane flow ratio can cause engine ablation or insufficient engine power, resulting in cavitation in the liquid oxygen or liquid methane pumps, ultimately causing ignition test failure.

[0003] The propellant diffuser is one of the cryogenic propellant management components in a rocket propellant tank. Its main function is to maintain stable liquid levels and pressure within the tank, thereby ensuring stable engine operation and preventing power instability. The diffuser reduces the velocity of the gas pressurized into the tank to the required level and ensures uniform outflow, minimizing the impact of high-speed gas flow on the liquid surface and preventing resulting instability in liquid level and tank pressure. While conventional diffusers optimize the outlet to reduce kinetic energy through multiple holes, the gas outlet still faces the liquid inside the tank. The outflowing gas still impacts the liquid surface, causing fluctuations. Therefore, traditional diffusers can still affect the stable liquid supply to the engine to some extent, thus impacting the stability of engine power output. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gas diffuser for cryogenic storage tanks to solve the problem that in the prior art, pressurized gas is directly blown onto the liquid surface inside the storage tank, and the airflow impact force is large, which affects the stability of the storage tank pressure and liquid surface.

[0005] This utility model provides a gas diffuser for a cryogenic storage tank. The gas diffuser includes: a diffuser shell, which is a conical hollow structure. A pressurized gas supply pipe is connected to the top axis of the diffuser shell and extends into the interior of the diffuser shell.

[0006] The diffuser housing has multiple air outlets evenly arranged on its side wall, with the air outlets facing obliquely upwards.

[0007] Furthermore, multiple reinforcing plates are fixedly installed on the bottom plate of the diffuser housing, with the lower end of the reinforcing plate fixed to the bottom plate and the upper end fixedly connected to the pressurized gas supply pipe.

[0008] Furthermore, the pressurized gas supply pipe is inserted into the bottom of the diffuser housing and contacts the base plate.

[0009] Furthermore, the end of the pressurized gas supply pipe that extends into the diffuser housing has multiple ventilation slots parallel to the axis of the pressurized gas supply pipe.

[0010] Furthermore, the ventilation slot is located between two adjacent reinforcing plates.

[0011] Furthermore, the diffuser housing sidewall is evenly divided into multiple annular layers perpendicular to the axis, and each annular layer is evenly provided with multiple air outlet holes.

[0012] As can be seen from the above embodiments, the cryogenic tank gas diffuser provided by this utility model has at least the following advantages: The gas diffuser adopts a conical structure with evenly distributed air outlets on its sidewalls. The pressurized airflow is delivered to the inner cavity of the gas diffuser through a pipeline and decelerated, then sprayed upwards at an angle through the air outlets on its sidewalls, preventing the airflow from directly blowing onto the liquid surface and ensuring the stability of the liquid surface. In addition, this diffuser uses a multi-hole design, and the even flow of airflow from multiple air outlets also ensures the stability of the pressure inside the tank.

[0013] It should be understood that the above general description and the following specific embodiments are merely exemplary and illustrative, and do not limit the scope of the present invention. Attached Figure Description

[0014] The accompanying drawings are part of the specification of this utility model and illustrate exemplary embodiments of the utility model. The drawings, together with the description in the specification, are used to illustrate the principles of this utility model.

[0015] Figure 1 A schematic diagram of the structure of the cryogenic storage tank gas diffuser provided by this utility model.

[0016] Figure 2 A top view of the internal structure of the diffuser housing of the cryogenic storage tank gas diffuser provided by this utility model.

[0017] Figure 3 A schematic diagram of the implementation state of the cryogenic storage tank gas diffuser provided by this utility model.

[0018] Explanation of reference numerals in the attached figures:

[0019] 1-Diffuser housing, 2-Exhaust vent, 3-Reinforcing plate, 4-Pressure supply pipe;

[0020] 11-Base plate;

[0021] 41-Ventilation slot. Detailed Implementation

[0022] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and implementations of the present invention.

[0023] Various improvements and variations can be made to the specific embodiments described in this utility model without departing from the scope or spirit of this utility model, which will be obvious to those skilled in the art. Other embodiments derived from this utility model description will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0024] This invention provides a gas diffuser for a cryogenic storage tank, such as... Figure 1 The diagram shows the structure of the gas diffuser. In a specific embodiment, the gas diffuser includes: a diffuser housing 1, which is a conical hollow structure. A pressurized gas delivery pipe 4 is connected to the top axis of the diffuser housing 1, extending into the interior of the diffuser housing 1. In this embodiment, the pressurized gas delivery pipe 4 is inserted to the bottom of the diffuser housing 1 and contacts the bottom plate 11 of the diffuser housing 1. Furthermore, the side of the end of the pressurized gas delivery pipe 4 extending into the diffuser housing 1 has multiple ventilation slots 41 parallel to the axis of the pressurized gas delivery pipe 4. Gas is pressurized and delivered through the pressurized gas delivery pipe 4 and then transported into the diffuser housing 1 through the ventilation slots 41. The elongated ventilation slots 41 also serve as a primary speed reduction mechanism, typically with a speed reduction ratio of 40%. A higher reduction ratio would generate significant noise. Preferably, the pressurized gas delivery pipe 4 has four ventilation slots 41.

[0025] In this embodiment, the mass flow rate of boosted nitrogen is calculated as follows: taking the engine climbing condition as an example, the target pressure of the reservoir and the engine flow rate are determined, and the required gas flow rate for boosting is calculated using the following equation:

[0026]

[0027] Where, q m —Mass flow rate of pressurized nitrogen, kg / s;

[0028] p x —Maximum pressure (absolute pressure) of the propellant tank;

[0029] q r—The volumetric flow rate of the booster gas is equal to the volumetric flow rate of the propellant;

[0030] T x —The temperature of the pressurized gas in the tank; for cryogenic propellants, the average of the atmospheric temperature and the boiling point temperature of the propellant is used.

[0031] Z x —The compressibility coefficient of nitrogen at room temperature and pressure is taken as 0.971;

[0032] R—gas constant, 296.9 J / (kg·K);

[0033] M—molar mass of pressurized nitrogen gas, 28.

[0034] Gas diffusion velocity: It is necessary to avoid excessively high local flow velocities that could lead to unstable flow within the gas cushion. Generally, the flow velocity should be less than 10 m / s, and preferably less than 5 m / s.

[0035] Total flow area calculation: The total flow area is determined based on the calculated pressurized nitrogen mass flow rate and the preliminary tentative gas diffusion rate.

[0036]

[0037] Where A—total circulation area, square meters;

[0038] q m —Calculated mass of pressurized nitrogen, kg / s;

[0039] ρ—the density of nitrogen gas under chamber pressure, kg / m³ 3 ;

[0040] V—is a provisional diffusion rate, in m / s.

[0041] Furthermore, calculations show that the area of ​​the four ventilation slots 41 is 5 / 3 times the flow area of ​​the pressurization pipeline, thus reducing the flow velocity of the pressurized gas. Preferably, in this embodiment, the dimensions of the ventilation slots 41 are 150mm × 6mm (slot length × slot width).

[0042] like Figure 3As shown, multiple air outlets 2 are evenly arranged on the side wall of the diffuser housing 1. Since the diffuser housing 1 has a conical structure with the smaller opening at the top and the larger opening at the bottom, it can be seen that the side of the diffuser housing 1 is inclined upwards. Therefore, the air outlets 2 on the side wall of the diffuser housing 1 emit air at an angle upwards. The pressurized gas is ejected obliquely upwards through the air outlets 2, colliding and contacting the inner wall of the top of the storage tank. By ejecting the gas obliquely upwards, the impact of the airflow on the liquid surface in the storage tank can be reduced, avoiding instability of the liquid surface and unstable gas pressure in the storage tank. The arrows in the figure indicate the direction of airflow. In this embodiment, the inclination angle of the air outlets 2 is between 30° and 60°, reducing the downward flow speed of the airflow.

[0043] Furthermore, multiple reinforcing plates 3 are fixedly disposed on the base plate 11 of the diffuser housing 1. The lower ends of the reinforcing plates 3 are fixed to the base plate 11, and the upper ends are fixedly connected to the pressurized gas supply pipe 4. Preferably, at least three reinforcing plates 3 are evenly disposed around the axis of the base plate 11 to stably fix the pressurized gas supply pipe 4. In this embodiment, as shown... Figure 2 As shown, four reinforcing plates 3 are fixedly installed on the base plate 11. The four reinforcing plates 3 are evenly distributed around the circumference of the pressurized gas pipeline 4, and the included angle between two adjacent reinforcing plates 3 is 90°. The inclined surfaces of the reinforcing plates 3 are evenly welded to the pressurized gas pipeline 4 at 45°, and are also welded to the circular base plate 11.

[0044] Furthermore, the ventilation slot 41 is located between two adjacent reinforcing plates 3 to avoid affecting gas output.

[0045] In a specific embodiment of this utility model, multiple annular layers are equidistantly and parallelly divided on the side wall of the diffuser housing 1 along the axial direction (the multiple annular layers are divided by dividing the diffuser housing through a section perpendicular to the generatrix of the cone, dividing the side wall of the diffuser housing into multiple parts), and multiple air outlet holes 2 are uniformly arranged in each annular layer to ensure uniform air outlet pressure.

[0046] In this embodiment, the diffuser housing 1 has four annular layers on its sidewall, and the number of air outlets 2 on the annular layers gradually increases along the direction from the top to the bottom of the diffuser housing 1 sidewall.

[0047] Orifice count and orifice diameter calculation: Based on the total flow area A, a suitable orifice diameter is initially selected, the single orifice diameter is calculated, and numerical simulation is used to verify whether it is within a reasonable flow velocity range (avoiding supersonic or turbulent disturbances).

[0048] Calculation of the number of orifices: Considering flow loss, the total flow area needs to be multiplied by an area factor of 1.2. The formula is as follows:

[0049]

[0050] Where, n—total number of holes;

[0051] A—Total circulation area, square meters;

[0052] d—orifice diameter, mm; take 8 mm orifice diameter (contact between propellant and nitrogen may cause local condensation, so the lower limit of orifice diameter needs to be controlled, usually ≥1 mm, to prevent blockage).

[0053] Calculations show that 61 8mm diameter vent holes are required on the diffuser housing 1 in this embodiment. To ensure more uniform nitrogen flow in each layer, the number of holes in each annular layer from top to bottom are 10, 13, 17, and 21, respectively.

[0054] The above description is merely an illustrative embodiment of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model shall fall within the scope of protection of this utility model.

Claims

1. A cryogenic tank gas diffuser, characterized in that, The gas diffuser includes: a diffuser housing (1), the diffuser housing (1) having a conical hollow structure, a pressurized gas supply pipe (4) connected to the top axis of the diffuser housing (1), and the pressurized gas supply pipe (4) extending into the interior of the diffuser housing (1); The diffuser housing (1) has a plurality of air outlets (2) evenly arranged on its side wall, and the air outlets are directed to the upper side.

2. The cryogenic tank gas diffuser according to claim 1, characterized in that, Multiple reinforcing plates (3) are fixedly installed on the bottom plate (11) of the diffuser housing (1). The lower end of the reinforcing plate (3) is fixed to the bottom plate (11), and the upper end is fixedly connected to the pressurized gas supply pipe (4).

3. The cryogenic tank gas diffuser according to claim 2, characterized in that, The four reinforcing plates (3) are evenly distributed around the circumference of the pressurized gas pipeline (4), and the included angle between two adjacent reinforcing plates (3) is 90°.

4. The cryogenic tank gas diffuser according to claim 2, characterized in that, The pressurized gas supply pipe (4) is inserted into the bottom of the diffuser housing (1) and contacts the base plate (11).

5. The cryogenic tank gas diffuser according to claim 4, characterized in that, The side of the end of the pressurized gas pipe (4) that extends into the diffuser housing (1) has a plurality of ventilation slots (41) parallel to the axis of the pressurized gas pipe (4).

6. The cryogenic tank gas diffuser according to claim 5, characterized in that, The ventilation slot (41) is located between two adjacent reinforcing plates (3).

7. The cryogenic tank gas diffuser according to claim 5 or 6, characterized in that, The ventilation slot 41 has a length of 150mm and a width of 6mm.

8. The cryogenic tank gas diffuser according to claim 1, characterized in that, The diffuser housing (1) has multiple annular layers that are equally spaced and parallel on its side wall, and each annular layer is uniformly provided with multiple air outlet holes (2).

9. The cryogenic tank gas diffuser according to claim 8, characterized in that, The diffuser housing (1) has four annular layers on its sidewall, and the number of air outlets (2) on the annular layers gradually increases along the direction from the top to the bottom of the sidewall of the diffuser housing (1).

10. The cryogenic tank gas diffuser according to claim 1, characterized in that, The inclination angle of the air outlet (2) is between 30° and 60°.

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