An adjustable-angle droplet generator for spatial droplet radiative cooling

Abstract

The present invention discloses an adjustable-angle droplet generator for space droplet radiative heat dissipation, which includes a plurality of rotatable droplet generators, support connecting rods, rotating bearings, an intermediate liquid storage ring, and liquid delivery pipes. By adopting a design scheme that combines a droplet generator with a rotating mechanism and a controller, according to the power requirement of the heat rejection system, precise regulation of the start / stop number of the rotatable droplet generators and on-orbit loading can be achieved, greatly improving the heat rejection efficiency of the space droplet radiator and solving the problem of insufficient heat rejection capacity of traditional space radiators for high-power and high-heat-consumption spacecraft. In addition, compared with the traditional space droplet radiator with multiple parallel droplet layers arranged, the present invention solves the problem of the huge space structure weight caused by numerous liquid transport circuits and support structures. At the same time, the adjustable-angle droplet generator for space droplet radiative heat dissipation provided by the present invention is convenient and compact for on-orbit loading, small in volume and light in mass.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal control for high-power spacecraft in space, and specifically relates to an adjustable-angle droplet generator for space droplet radiation heat dissipation. Background Art

[0002] With the rapid development of space science and technology and the increasing tension of international space competition, many important space projects have been put on the agenda. For example, future space stations, lunar bases, Mars probes, etc. all require sufficient energy supply to make the system have a longer lifespan. However, high-power space power systems have higher requirements for heat rejection. Space radiators and heat pipes are currently advanced thermal control technologies that have received much attention. Among them, the space droplet radiation radiator is a very promising solution for the heat dissipation of large spacecraft. Compared with existing thermal control technologies, it is lighter and more compact during loading and is relatively less vulnerable to damage by micrometeoroids. The droplet layer serves as the effective heat transfer region of the space droplet radiation radiator. The droplet layer is ejected from the droplet generator and captured by the droplet collector. Since heat convection cannot function in space and the evaporative cooling effect of low-vapor-pressure working fluids is almost negligible, the heat rejection performance of the space droplet radiation radiator is only determined by the radiative heat transfer characteristics of the droplet layer.

[0003] Currently, most scholars have focused their research on the radiative heat transfer characteristics of a single droplet layer. However, with the increase in the heat rejection power level, the heat dissipation capacity of a single droplet layer often fails to meet the requirements. In particular, megawatt-level space power systems require space droplet radiation radiators with multiple droplet layers for heat rejection. At the same time, existing space droplet radiation radiators with multiple droplet layers usually arrange multiple droplet layers in series, parallel, or series-parallel on the same plane, which will result in an increase in more transport loops and support structures, thus greatly increasing the system weight. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide an adjustable-angle droplet generator for space droplet radiation heat dissipation, which can form multiple cross-shaped and uniformly arranged droplet layers in the circumferential space, and at the same time does not require a large number of liquid transport loops and support structures, which is of great significance for the lightweight and efficient heat rejection of spacecraft. To solve the problems that existing space thermal control technologies cannot efficiently meet the heat rejection requirements of high-power spacecraft and may cause a huge space structure weight.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An adjustable-angle droplet generator for space droplet radiative heat dissipation, the adjustable-angle droplet generator comprising a plurality of rotatable droplet generators 1, support connecting rods 2, rotary bearings 3, a controller 4, signal lines 5, an intermediate liquid storage ring 6 and a liquid delivery pipe 7; the plurality of rotatable droplet generators 1 are assembled with the support connecting rods 2 through the rotary bearings 3; the intermediate liquid storage ring 6 is also connected and assembled with the support connecting rods 2 through the rotary bearings 3, and the number and rotational movement of the intermediate liquid storage rings 6 are consistent with those of the rotatable droplet generators; when the adjustable-angle droplet generator is in orbit operation, the rotatable droplet generators 1 are manipulated by the controller 4 to rotate circumferentially around the support connecting rods 2 and unfold evenly, and the start and stop numbers of the rotatable droplet generators 1 are determined according to the power requirements of the heat dissipation system; the intermediate liquid storage ring 6 is connected to the rotatable droplet generators 1 through the liquid delivery pipe 7 and supplies liquid thereto, and a plurality of nozzle arrays 9 are provided on the rotatable droplet generators 1;

[0007] By pressurizing the inside of the droplet generator, the pressurized liquid is forced to eject from the nozzle arrays 9 of the rotatable droplet generators 1 to form a continuous jet array, and a vibration device inside the rotatable droplet generator 1 applies a perturbation to cause the jet to break and form a continuous droplet flow array, and then the adjustable-angle droplet generator can generate a cross-shaped droplet layer 8 with good radiative heat dissipation performance.

[0008] The vibration device inside the rotatable droplet generator 1 is configured according to the working principle of using piezoelectric perturbation to cause the jet to break and form droplets, and includes a vibration piston 1-3 connected to an external signal generator 1-1 and a power amplifier 1-2.

[0009] The perturbation generated by the vibration piston 1-3 is a sine wave or square wave perturbation, which is provided by adjusting the signal generator 1-1 and the power amplifier 1-2. In order to obtain a uniform droplet flow, the perturbation wave number needs to be adjusted between 0.2 and 0.8.

[0010] The aperture diameter, hole pitch, number of holes and aspect ratio of the nozzle array 9 are determined according to the power requirements of the heat dissipation system, and directly determine the overall size of the droplet generator.

[0011] In order to obtain a high-quality nozzle array 9, advanced micro-hole manufacturing technologies such as laser drilling, electrochemical machining, and electrochemical machining can be used.

[0012] The pressurized liquid uses liquid metal tin, liquid metal lithium or silicone oil.

[0013] The radiative heat dissipation performance of the cross-shaped droplet layer 8 generated by the adjustable-angle droplet generator is numerically simulated and calculated using commercial CFD software.

[0014] After the cross-shaped droplet layer 8 generated by the adjustable-angle droplet generator is cooled by radiative heat dissipation, it will be captured by the corresponding droplet collector at the end of the rotatable droplet generator 1, and the collected liquid will be recycled.

[0015] The number of the rotatable droplet generators 1 does not exceed 24.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] An adjustable-angle droplet generator for space droplet radiative heat dissipation provided by the present invention includes a plurality of rotatable droplet generators, support connecting rods, rotating bearings, a controller, signal lines, an intermediate liquid storage ring, and liquid delivery pipes. Adopting a design scheme that combines a droplet generator with a rotating mechanism and a controller, according to the power requirement of the heat rejection system, it can achieve precise regulation of the start and stop numbers of the droplet generators and the on-orbit loading, greatly improving the heat rejection efficiency of the space droplet radiator and solving the problem of insufficient heat rejection capacity of traditional space radiators for high-power and high-heat-consumption spacecraft. In addition, compared with the traditional space droplet radiator with multiple droplet layers arranged in parallel, the present invention avoids the problem of huge space structure weight caused by numerous liquid transport circuits and support structures. At the same time, the adjustable-angle droplet generator for space droplet radiative heat dissipation provided by the present invention is convenient and compact for on-orbit loading, small in volume, and light in mass. Description of the Drawings

[0018] Figure 1 is a schematic diagram of the on-orbit operation of an adjustable-angle droplet generator for space droplet radiative heat dissipation according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of the connection and assembly details of a single rotatable droplet generator, an intermediate liquid storage ring and a rotating bearing provided by the present invention, and a schematic diagram of the nozzle array of the droplet generator;

[0020] Figure 3 is a schematic diagram of the nozzle array and the formation of droplet flow in the adjustable-angle droplet generator provided by the present invention.

[0021] Figure 4 is a schematic diagram of a numerical simulation scheme for the radiative heat dissipation performance of a cross-shaped droplet layer generated by an adjustable-angle droplet generator for space droplet radiative heat dissipation according to an embodiment of the present invention;

[0022] Fig. 5(a) is a radiation power curve graph of a cross-shaped droplet layer with three rotatable droplet generators under different uniform arrangements, Fig. 5(b) is the radiation power of the cross-shaped droplet layer at different angles under uniform arrangement, and Fig. 5(c) is the radiation power per unit mass of the cross-shaped droplet layer at different angles under uniform arrangement.

[0023] Icon: 1 - Rotatable droplet generator; 1-1 - External signal generator; 1-2 - Power amplifier; 1-3 - Vibration piston; 2 - Support link; 3 - Rotating bearing; 4 - Controller; 5 - Signal line; 6 - Intermediate liquid storage ring; 7 - Liquid delivery pipe; 8 - Cross-shaped droplet layer; 9 - Orifice array. Detailed implementation mode

[0024] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] As Figure 1 and Figure 2 shown, the present invention provides an adjustable-angle droplet generator for space droplet radiative heat dissipation. The adjustable-angle droplet generator includes a plurality of rotatable droplet generators 1, support links 2, rotating bearings 3, a controller 4, signal lines 5, an intermediate liquid storage ring 6, and liquid delivery pipes 7. The rotatable droplet generators 1 are all assembled with the support links 2 through the rotating bearings 3. The intermediate liquid storage ring 6 is also connected and assembled with the support links 2 through the rotating bearings 3, and the number and rotational movement of the intermediate liquid storage ring 6 are consistent with those of the rotatable droplet generators 1.

[0026] When the angle-controllable droplet generator is in orbit operation, the rotatable droplet generator 1 is manipulated by the controller to rotate circumferentially and evenly expand around the support link 2, and the start and stop numbers of the rotatable droplet generator 1 are determined according to the power requirements of the heat dissipation system. The intermediate liquid storage ring 6 is connected to the rotatable droplet generator 1 through the liquid delivery pipe 7 and supplies liquid. By pressurizing the inside of the rotatable liquid supply droplet generator, the liquid is forced to eject from the orifice array 9 of the rotatable droplet generator to form a continuous jet array, and the internal vibration device applies perturbations to cause the jet to break and form a continuous droplet flow array. Then, the adjustable-angle droplet generator can generate a cross-shaped droplet layer 8 with good radiative heat dissipation performance.

[0027] The vibration device inside the rotatable droplet generator 1 is configured according to the working principle of using piezoelectric perturbation to cause the jet to break and form droplets disclosed in the Chinese patent CN111695218A, titled "Method for Determining Parameters of a Droplet Generator in a Space Radiation Heat Exchange System", and includes a vibration piston 1-3 connected to an external signal generator 1-1 and a power amplifier 1-2. Here, in combination with Figure 3 , it can be more clearly described. Referring to Figure 3 the schematic diagram of the orifice array and the formation of multiple droplet flows in the droplet generator in the embodiment of the present invention shown. Figure 3 In it, ① is the pressurized liquid stably and continuously provided by the intermediate liquid storage ring, which fills the inside of the droplet generator to make the liquid chamber pressure reach P1, thereby squeezing the liquid to flow out from the distance of s nThe jet holes of the jet hole array 9 eject outwards. Since the external pressure of the droplet generator is P0, there is an internal and external pressure difference ΔP = P1 - P0 between the two, thus forming a continuous liquid jet ② with a certain velocity U. The disturbance signal with a frequency of f emitted by the external signal generator 1-1 causes the vibration piston 1-3 to generate a small deformation with an amplitude of A through the power amplifier 1-2, thereby applying a small disturbance to the circumferential direction of the continuous liquid jet ②, promoting its fracture to form a continuous droplet flow ③ with a droplet spacing of s. d The above measures ensure that the droplet flow formed by each jet hole can achieve the required kinetic characteristics, and finally the jet hole array can form the required droplet layer.

[0028] The number of the rotatable droplet generators 1 does not exceed 24. The parameters of its jet hole array 9, such as the aperture, hole pitch, number of holes, and the aspect ratio of the jet hole array, can be designed according to the method disclosed in the Chinese patent CN111695218A, titled "A Method for Determining the Parameters of a Droplet Generator in a Spatial Radiation Heat Transfer System". In order to obtain high-quality jet holes, advanced micro-hole manufacturing technologies such as laser drilling, electrochemical machining, and electrochemical processing can be adopted.

[0029] The pressurized liquid uses liquid metal tin, liquid metal lithium, or silicone oil. The vapor pressures of these liquids are very low, thus greatly reducing the mass loss of the liquid caused by evaporation.

[0030] The disturbance generated by the vibration piston 1-3 uses a sine wave or square wave disturbance, which can be provided by adjusting the signal generator 1-1 and the power amplifier 1-2. In order to obtain a uniform droplet flow, the disturbance wave number needs to be adjusted between 0.2 and 0.8.

[0031] As Figure 4 As shown, the radiative heat dissipation performance of the cross-shaped droplet layer (8) generated by the adjustable-angle droplet generator is numerically simulated using commercial CFD software. The geometric model of the cross-shaped droplet layer is geometrically modeled using Solidworks software and a geometric file is generated; then it is imported into ICEM CFD software for mesh generation of the physical model, using high-quality hexahedral structured meshes and generating a mesh file; finally, the mesh file is imported into Fluent software for numerical simulation calculation. The numerical simulation calculation of the radiative heat dissipation performance of the cross-shaped droplet layer is carried out using the DO radiation model. After the calculation converges, the temperature distribution of the cross-shaped droplet layer is obtained through post-processing, and the radiative energy, radiative power, and radiative power per unit mass of the cross-shaped droplet layer are calculated according to the radiative heat transfer theory formula.

[0032] As shown in Fig. 5(a), Fig. 5(b), and Fig. 5(c), the radiative performance curve diagram of the cross-shaped droplet layer (8) generated by the adjustable-angle droplet generator provided by the present invention.

[0033] Example 1:

[0034] The present invention provides an adjustable-angle droplet generator for space droplet radiative cooling. Taking a device equipped with three rotatable droplet generators as an example:

[0035] The selected liquid is DC 705 silicone oil, the initial temperature is 320K, the pressure difference inside and outside the droplet generator is 0.1MPa, and the pressure perturbation frequency is 5kHz.

[0036] The FLUENT software is used to perform numerical simulation calculations on the cross-shaped droplet layer of three rotatable droplet generators under uniform arrangement and non-uniform arrangement conditions.

[0037] Taking the uniform arrangement as a reference, different degrees of non-uniform arrangement are achieved by rotating one of the rotatable droplet generators, and the rotation angle is used to represent the non-uniformity of the arrangement of the rotatable droplet generators. Δθ = 0 indicates a uniform arrangement of the droplet sheets, and the larger its value, the more uneven the arrangement of the droplet sheets.

[0038] Figure 5(a) shows the radiation power curve of the cross-shaped droplet layer with three rotatable droplet generators under different degrees of uniform arrangement. It can be seen that the radiation power of the cross-shaped droplet layer is the largest when the rotatable droplet generators are uniformly arranged, which proves the design requirement of the present invention, that is, the adjustable-angle droplet generator needs to be evenly deployed in orbit when it is turned on.

[0039] Example 2:

[0040] The selected liquid is liquid metal tin, the initial temperature is 750K, the pressure difference inside and outside the droplet generator is 3.77MPa, and the pressure perturbation frequency is 5kHz.

[0041] The FLUENT software is used to perform numerical simulation calculations on the cross-shaped droplet layer at different angles under uniform arrangement conditions. The present invention defines the droplet layer angle θ, that is, the included angle when adjacent droplet generators are deployed in orbit. Since the adjustable-angle droplet generator is evenly deployed in the circumferential direction, the droplet layer angle and the number of rotatable droplet generators are in one-to-one correspondence, that is, the number of droplet generators n is a positive integer.

[0042] Figure 5(b) shows the radiation power curve of the cross-shaped droplet layer with different rotatable droplet generators under uniform arrangement conditions. It can be seen that when the droplet layer angle θ = 15°, that is, the number of droplet generators The radiation power of the cross-shaped droplet layer is the largest.

[0043] Figure 5(c) is a graph of the radiation power per unit mass of a cross-type droplet layer with different rotatable droplet generators under uniform arrangement conditions. It can be seen that when the droplet layer angle θ = 15°, that is, the number of droplet generators when, the radiation power per unit mass of the cross-type droplet layer begins to reach the maximum and then remains almost unchanged. The above proves the design requirement of the present invention, that is, the number of rotatable droplet generators does not exceed 24.

Claims

1. An adjustable-angle droplet generator for space droplet radiative heat dissipation, characterized in that, The adjustable-angle droplet generator includes a plurality of rotatable droplet generators (1), support connecting rods (2), rotating bearings (3), a controller (4), signal lines (5), an intermediate liquid storage ring (6), and a liquid delivery pipe (7); the plurality of rotatable droplet generators (1) are assembled with the support connecting rods (2) through the rotating bearings (3); the intermediate liquid storage ring (6) is also connected and assembled with the support connecting rods (2) through the rotating bearings (3), and the number and rotational movement of the intermediate liquid storage rings (6) are consistent with those of the rotatable droplet generators; when the adjustable-angle droplet generator operates in orbit, the rotatable droplet generators (1) are manipulated by the controller (4) to rotate circumferentially and expand evenly around the support connecting rods (2), and the start and stop numbers of the rotatable droplet generators (1) are determined according to the power requirements of the heat rejection system; the intermediate liquid storage ring (6) is connected to the rotatable droplet generators (1) through the liquid delivery pipe (7) to supply liquid, and a plurality of spray hole arrays (9) are provided on the rotatable droplet generators (1). By pressurizing the inside of the droplet generator, the pressurized liquid is forced to eject from the spray hole arrays (9) of the rotatable droplet generator to form a continuous jet array, and a vibration device inside the rotatable droplet generator (1) applies perturbations to cause the jet to break and form a continuous droplet flow array, and then the adjustable-angle droplet generator can generate a cross-shaped droplet layer (8) with good radiative heat dissipation performance.

2. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, The vibration device inside the rotatable droplet generator (1) is configured based on the working principle of using piezoelectric perturbations to cause the jet to break and form droplets, and includes a vibration piston (1-3) connected to an external signal generator (1-1) and a power amplifier (1-2).

3. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 2, characterized in that, The perturbations generated by the vibration piston (1-3) are sine wave or square wave perturbations, which are provided by adjusting the signal generator (1-1) and the power amplifier (1-2). In order to obtain a uniform droplet flow, the perturbation wave number needs to be adjusted between 0.2 and 0.

8.

4. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, The aperture, hole pitch, number of holes, and aspect ratio of the spray hole array (9) are determined according to the power requirements of the heat rejection system, and directly determine the overall size of the droplet generator.

5. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 4, characterized in that, In order to obtain a high-quality spray hole array (9), laser drilling, electrochemical machining, or electrochemical processing is used.

6. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, The pressurized liquid uses liquid metal tin, liquid metal lithium, or silicone oil.

7. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, The radiative heat dissipation performance of the cross-shaped droplet layer (8) generated by the adjustable-angle droplet generator is numerically simulated and calculated using commercial CFD software.

8. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, After the cross-shaped droplet layer (8) generated by the adjustable-angle droplet generator radiatively dissipates heat and cools, it will be captured by the corresponding droplet collector at the end of the rotatable droplet generator (1), and the collected liquid is recycled.

9. The adjustable-angle droplet generator for space droplet radiative heat dissipation according to claim 1, characterized in that, The number of the rotatable droplet generators (1) does not exceed 24.

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