Spraying characteristic space-ground consistency simulation test system and method for liquid drop generator

Abstract

The invention discloses a heaven and earth consistency simulation test method and a heaven and earth consistency simulation test system for the spreading characteristics of a liquid drop generator, which are used for obtaining the spreading characteristics of the liquid drop generator in a vacuum environment. A ground test result can be equivalently converted into a space test result, and the problem of space-ground consistency equivalent measurement is solved. The working parameters of the jet spreader under the rated working condition are subjected to scale reduction design, so that the adverse effects caused by the fact that the jet spreader under the rated working condition is adopted to work due to limitation of ground test environment conditions, the thickness of liquid drops is too large, and the space environment real spreading effect is not met are overcome, and heaven and earth consistency equivalent measurement is achieved. A plurality of liquid drop collectors with the same surface area and material are placed at different positions, and the mass increment of the plurality of liquid drop collectors is measured, so that the thickness uniformity of the liquid film is measured.

Description

Technical Field

[0001] The present invention belongs to the field of space thermal control technology, and specifically relates to a method and system for simulating a test of the consistency of the spreading characteristics of a droplet generator between heaven and earth. Background Art

[0002] As a new type of space thermal control equipment, the droplet radiator is mainly composed of a droplet generator, a droplet collector, a circulation pump, a heat exchanger and a fluid pipeline. Its basic working principle is: the heat exchange medium flows through the space payload heat exchanger and is heated, and then supplied to the droplet generator. In the liquid collecting chamber of the droplet generator, the medium is stimulated by piezoelectric ceramics to produce pressure and flow oscillations of a certain frequency, and is ejected into the space environment through the nozzle to form a jet. Under the action of fluid oscillation, the initial surface wave of the jet is formed at the nozzle outlet and gradually develops, and finally breaks into a large number of droplets with uniform particle size, which radiate heat to the space environment through the large surface area characteristics of the droplet group. The cooled working medium droplets are collected and recycled by the liquid pump. Therefore, the droplet size, uniformity and number of droplet particles per unit area generated by the droplet generator will affect the heat dissipation of the droplet radiator, and the spreading range of the droplets generated by the droplet generator will affect the collection and reuse of the droplets. Therefore, the spreading characteristics of the droplet generator in the space environment are particularly important for the design of the droplet radiator. Summary of the invention

[0003] In order to solve the problem that the existing technology has limited ground test conditions and it is difficult to truly simulate the spreading characteristics of a droplet generator in a vacuum environment, the purpose of the present invention is to provide a method and system for simulating the consistency of the spreading characteristics of a droplet generator in the sky and in the earth, which are used to obtain the spreading characteristics of a droplet generator in a vacuum environment. The method and system for simulating the consistency of the spreading characteristics of a droplet generator in the sky and in the earth of the present invention can convert the ground test results into space test results, solving the problem of equivalent measurement of the consistency between the sky and the earth.

[0004] In order to achieve the above technical tasks, the present invention adopts the following technical solutions:

[0005] A method for simulating the consistency of the distribution characteristics of a droplet generator between heaven and earth, the method comprising the following steps:

[0006] Step 1: Calculate the rated working condition under the space environment according to the working parameters of the existing droplet generator and the structural parameters of the spray disc, that is, the motor speed n under the space environment, the droplet velocity ν under the space environment, and the spreading circle diameter D formed by the droplets under the space environment are known;

[0007] Step 2: According to the size of the vacuum chamber, the spray distance L under ground test conditions is given 0 , calculate the diameter D of the spreading circle formed by the droplets under ground test conditions 0 ;

[0008] Step 3: Under the condition that the maximum nozzle distribution circle radius R of the injection disk is consistent under the space environment and ground test conditions, the droplet velocity V under the given ground test conditions is 0 , calculate the motor speed n under ground test conditions 0 ;

[0009] Step 4: According to the principle of consistency of spreading characteristics between the sky and the earth, that is, the principle of consistency of the thickness of the liquid film formed, calculate the flow rate q of the working fluid required under the ground test conditions 0 ;

[0010] Step 5: Set the pre-spray pressure P under ground test conditions 0 According to the flow formula, the number of nozzles m of the equivalent injection disk is obtained, and the nozzle radius r of the equivalent injection disk is calculated, or the number of nozzles m of the equivalent injection disk is calculated according to the nozzle radius r of the equivalent injection disk.

[0011] Furthermore, the step 1 calculates the rated working condition in the space environment, that is, the motor speed n, the droplet velocity ν and the spreading circle diameter D formed by the droplets in the space environment are known. The expression of D is:

[0012]

[0013] Wherein L is the spray distance of droplets in space environment, unit: meter; ν is the droplet velocity ν in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; R is the radius of the maximum nozzle distribution circle of the injection disk, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter.

[0014] Furthermore, in step 2, according to the size of the vacuum chamber, the diameter D of the spreading circle formed by the droplets under the ground test conditions is calculated. 0 , D 0 The expression is:

[0015]

[0016] Where L is the spray distance of the droplets in the space environment, in meters; D is the diameter of the spreading circle formed by the droplets in the space environment, in meters; L 0 —D - the spray distance of the droplets under ground test conditions, unit: meter; 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

[0017] Furthermore, the step 3 calculates the motor speed n under the ground test conditions. 0 , to ensure that the maximum nozzle distribution circle radius R of the injection disk in the space environment is the same as that in the ground test conditions, given the droplet velocity V under the ground test conditions 0 , n 0The expression is:

[0018]

[0019] Where L is the spray distance of droplets in space environment, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter; V is the droplet velocity in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; L 0 —D - the spray distance of the droplets under ground test conditions, unit: meter; 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter; V 0 —Droplet velocity under ground test conditions, unit: m / s; n 0 —Motor speed under ground test conditions, unit: revolutions per minute.

[0020] Furthermore, the step 4: according to the principle of consistency of spreading characteristics between the sky and the earth, that is, the thickness of the liquid film formed is consistent, the flow rate q of the working fluid required under the ground test conditions is calculated. 0 ,q 0 The expression is:

[0021]

[0022] Where q is the flow rate of the working fluid in the space environment, unit: kg / s; D is the diameter of the spreading circle formed by the droplets in the space environment, unit: m; q 0 —Flow rate of working fluid under ground test conditions, unit: kg / s; D 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

[0023] The simulation experiment system constructed by the simulation experiment method of the present invention comprises at least a droplet generator test piece, a high-speed camera system, a vacuum system, a host computer, and a droplet collector. The droplet generator test piece is placed in the vacuum system. The droplet generator test piece comprises a storage tank, a spreader, and a controller connected in series in sequence. The spreader is connected to the droplet collector. The high-speed camera system comprises a high-speed camera, a high-speed camera collector, a light screen, and a light source. The high-speed camera is connected to a control trigger. The high-speed camera and the light screen are respectively arranged on two opposite sides of the vacuum chamber. The host computer is respectively connected to the controller and the control trigger.

[0024] Observation windows A and B are respectively provided on two opposite sides of the vacuum chamber, and the observation windows A and B correspond to the light screen and the high-speed camera respectively. The storage box is also connected to the gas source.

[0025] Compared with the prior art, the present invention has the following technical advantages:

[0026] 1. The present invention proposes a method and system for simulating the consistency of the spreading characteristics of a droplet generator between the ground and the sky, which can obtain the spreading characteristics of the droplet generator in a vacuum environment under ground test conditions.

[0027] 2. The present invention scales the working parameters of the spray spreader under rated conditions to overcome the adverse effects caused by the use of the spray spreader under rated conditions, which results in thick droplet thickness and does not conform to the actual spreading effect in the space environment, thereby achieving equivalent measurement of ground-to-earth consistency.

[0028] 3. The present invention places a plurality of droplet collectors with the same surface area and material at different positions, measures the increment of the mass of the plurality of droplet collectors, and thus realizes the measurement of the uniformity of the liquid film thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a method for simulating the sky-earth consistency of the droplet generator's spreading characteristics.

[0030] Figure 2 Schematic diagram of different spraying and spreading distances.

[0031] Figure 3 This is a structural principle diagram of the droplet generator spreading characteristics sky-ground consistency simulation test system of the present invention.

[0032] The symbols and numbers in the figure represent the following meanings: 1—droplet generator test piece; 2—storage tank; 3—dispenser; 4—controller; 5—vacuum system; 6—droplet collector; 7—host computer; 8—gas source; 9—manual valve; 10—LED light source; 11—light screen; 12—high-speed camera; 13—high-speed camera acquisition; 14—control trigger; 15—cable; 16—pipeline; 20—vacuum chamber; 21—observation window A; 22—observation window B; 23—chamber opening. DETAILED DESCRIPTION

[0033] In the ground test, the entire spraying process needs to be placed in a vacuum chamber to simulate the vacuum environment of space. Therefore, due to the size of the vacuum chamber, the spraying distance is much shorter than the actual spraying distance in vacuum. If the spraying is carried out according to standard working conditions, the number of droplet particles per unit area under the shorter spraying distance under ground test conditions is much larger than the number of droplet particles per unit area when spraying in vacuum. Assuming that the sprayed and spread particles are evenly distributed, the consistency of the number of droplet particles per unit area can be converted into the evaluation of the consistency of the liquid film thickness. The number of droplet particles per unit area directly affects the efficiency of radiation heat dissipation, and the spread range of droplets is directly related to the design of the droplet collector. Therefore, the test conditions of the spraying process and the number of spray holes of the spray disk need to be redesigned to ensure that the spraying effect is the same as the effect in the space environment under the rated working conditions, so as to achieve the equivalent measurement of the sky and the earth consistency. How to determine the structural parameters and working parameters of the equivalent injection disk is what the equivalent measurement method of the sky and the earth consistency needs to solve.

[0034] At the same time, whether the uniformity of the thickness of the liquid film formed by the working fluid is consistent seriously affects the efficiency of radiative heat dissipation. It is possible to place multiple droplet collectors with the same surface area and material at different positions within the effective range of the same distance and spraying and spreading, and evaluate the uniformity of the liquid film thickness by measuring the mass increment of multiple droplet collectors. When the droplet generator product works in a space environment, it is necessary to form a certain number of droplet particle groups at a certain spraying distance. The design of the equivalent spray disk is mainly to achieve equivalent measurement of the consistency between the sky and the earth, to overcome the limitations of the ground test environment conditions (mainly caused by different spraying distances), which leads to the use of the spray spreader under rated conditions to work, resulting in a large density of liquid particle groups, which does not meet the adverse effects of the actual spreading effect in the space environment.

[0035] See also Figure 1-Figure 2 The present invention is a method for simulating the consistency of the spreading characteristics of a droplet generator between heaven and earth. First, based on the working parameters of the existing droplet generator and the structural parameters of the spray disc, the rated working conditions in the space environment are calculated (the motor speed n in the space environment, the droplet velocity ν in the space environment and the spreading circle diameter D formed by the droplets in the space environment are known);

[0036] The second step is to give the ejection distance L under ground test conditions according to the size of the vacuum chamber. 0 , calculate the diameter D of the droplet spreading circle under ground test conditions 0 ;

[0037] The third step is to ensure that the maximum nozzle distribution circle radius R of the injection disk is consistent under the space environment and the ground test conditions, and the droplet velocity V under the given ground test conditions is 0 , calculate the electrode speed n under ground test conditions 0 .

[0038] The fourth step is to calculate the required working fluid flow rate q under ground test conditions based on the principle of consistency of spreading characteristics between the sky and the earth, that is, the principle of consistency of the thickness of the liquid film formed. 0 ;

[0039] Step 5: Given the pre-spray pressure P under ground test conditions 0 According to the flow formula, the number of nozzles m of the equivalent injection disk is given to calculate the nozzle radius r of the equivalent injection disk, or the nozzle radius r of the equivalent injection disk is given to calculate the number of nozzles m of the equivalent injection disk.

[0040] In particular, step 1, according to the working parameters of the existing droplet generator and the structural parameters of the spray disc, the rated working condition in the space environment is calculated. The motor speed n in the space environment, the droplet velocity ν in the space environment and the spreading circle diameter D formed by the droplets in the space environment are known. The expression of D is:

[0041]

[0042] Where L is the spray distance of droplets in space environment, unit: meter; ν is the droplet velocity in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; R is the radius of the maximum nozzle distribution circle of the injection disk, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter.

[0043] Step 2: Calculate the diameter D of the droplet spreading circle under ground test conditions according to the size of the vacuum chamber. 0 , D 0 The expression is:

[0044]

[0045] Where L is the spray distance of the droplets in the space environment, in meters; D is the diameter of the spreading circle formed by the droplets in the space environment, in meters; L 0 —D - the spray distance of the droplets under ground test conditions, unit: meter; 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

[0046] Step 3: Calculate the motor speed n under ground test conditions 0 , to ensure that the maximum nozzle distribution circle radius R of the injection disk in the space environment is the same as that in the ground test conditions, given the droplet velocity V under the ground test conditions 0 , n 0 The expression is:

[0047]

[0048] Where L is the spray distance of droplets in space environment, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter; V is the droplet velocity in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; L 0 —D - the spray distance of the droplets under ground test conditions, unit: meter; 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter; V 0 —Droplet velocity under ground test conditions, unit: m / s; n 0 —Motor speed under ground test conditions, unit: revolutions per minute.

[0049] Step 4: According to the principle of consistency of spreading characteristics between the sky and the earth, that is, the principle of consistency of the thickness of the liquid film formed, calculate the flow rate q of the working fluid required under the ground test conditions 0 ,q 0 The expression is:

[0050]

[0051] Where q is the flow rate of the working fluid in the space environment, unit: kg / s; D is the diameter of the spreading circle formed by the droplets in the space environment, unit: m; q 0 —Flow rate of working fluid under ground test conditions, unit: kg / s; D 0 —Diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

[0052] Step 5: Given the pre-spray pressure P under ground test conditions 0 According to the flow formula, the number of nozzles m of the equivalent injection disk is given to calculate the nozzle radius r of the equivalent injection disk, or the nozzle radius r of the equivalent injection disk is given to calculate the number of nozzles m of the equivalent injection disk.

[0053] See also Figure 3 , the droplet generator spreading characteristic earth-sky consistency simulation test system refers to a test system that completes the droplet generator spreading. The simulation test system built using the simulation test method described in the present invention at least includes a droplet generator test piece 1, a high-speed camera system, a vacuum system 5, a host computer 7, and a droplet collector 6. The high-speed camera system 17 mainly includes a high-speed camera 12, a high-speed camera acquisition 13, a light screen 11 and an LED light source 10. Its main function is to shoot the spraying and spreading of droplets when the droplet generator test piece is working, and to measure parameters such as droplet particle size and speed. The vacuum system 5 is a VTM-3000 thermal vacuum chamber system, and its main function is to create a vacuum environment for simulating a space working environment. The main functions of the host computer 7 are to control the operation of the controller, receive controller telemetry data, and trigger high-speed photography.

[0054] The droplet generator test piece 1 is placed in the vacuum system 5. The droplet generator test piece 1 includes a tank 2, a spreader 3 and a controller 4 connected in series in sequence. The tank 2 is also connected to the gas source 8. The spreader 3 is connected to the droplet collector 6. The high-speed camera 12 is connected to the control trigger 14. The high-speed camera 12 and the light screen 11 are respectively deployed on the two opposite sides of the vacuum chamber 20. The host computer 7 is respectively connected to the controller 4 and the control trigger 14. The two opposite sides of the vacuum chamber 20 are respectively provided with an observation window A21 and an observation window B22. The observation window A21 and the observation window B22 correspond to the light screen 11 and the high-speed camera 12 respectively.

Claims

1. A method for simulating the consistency of the distribution characteristics of a droplet generator between heaven and earth, characterized in that: The method comprises the following steps: Step 1: Calculate the rated working condition under the space environment according to the working parameters of the existing droplet generator and the structural parameters of the spray disc, that is, the motor speed n under the space environment, the droplet velocity ν under the space environment, and the spreading circle diameter D formed by the droplets under the space environment are known; Step 2: According to the size of the vacuum chamber, the spray distance L0 under the ground test condition is given, and the diameter D0 of the spreading circle formed by the droplets under the ground test condition is calculated; Step 3: Under the condition that the maximum nozzle distribution circle radius R of the injection disk is consistent under the space environment and ground test conditions, given the droplet velocity V0 under the ground test conditions, calculate the motor speed n0 under the ground test conditions; Step 4: Based on the principle of consistency between the spreading characteristics and the ground, i.e. the principle of consistency in the thickness of the liquid film formed, calculate the flow rate q0 of the required working fluid under the ground test conditions; Step 5: Set the pre-spray pressure P0 under ground test conditions, and calculate the spray hole radius r of the equivalent injection disk by obtaining the number of spray holes m of the equivalent injection disk according to the flow formula, or calculate the number of spray holes m of the equivalent injection disk according to the spray hole radius r of the equivalent injection disk.

2. The method for simulating the consistency of the droplet generator's spreading characteristics between heaven and earth as claimed in claim 1, characterized in that: The step 1 calculates the rated working condition in the space environment, that is, when the motor speed n, the droplet velocity ν in the space environment and the diameter D of the spreading circle formed by the droplets in the space environment are known, the expression of D is: Where L is the spray distance of droplets in space environment, unit: meter; ν is the droplet velocity in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; R is the radius of the maximum nozzle distribution circle of the injection disk, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter.

3. The method for simulating the consistency of the droplet generator's spreading characteristics between heaven and earth as claimed in claim 1, characterized in that: Step 2: Calculate the diameter D0 of the droplet spreading circle under ground test conditions according to the size of the vacuum chamber. The expression of D0 is: Where L is the spray distance of the droplets in the space environment, unit: meter; D—the diameter of the spreading circle formed by the droplets in the space environment, unit: meter; L0—droplet spray distance under ground test conditions, unit: meter; D0—The diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

4. The method for simulating the consistency of the droplet generator's spreading characteristics between heaven and earth as claimed in claim 1, characterized in that: Step 3: Calculate the motor speed n0 under ground test conditions to ensure that the maximum nozzle distribution circle radius R of the injection disk under space environment and ground test conditions is the same. Given the droplet velocity V0 under ground test conditions, the expression of n0 is: Where L is the spray distance of droplets in space environment, unit: meter; D is the diameter of the spreading circle formed by droplets in space environment, unit: meter; V is the velocity of droplets in space environment, unit: meter / second; n is the motor speed in space environment, unit: revolution / minute; L0 is the spray distance of droplets under ground test conditions, unit: meter; D0—the diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter; V0—droplet velocity under ground test conditions, unit: m / s; n0—motor speed under ground test conditions, unit: rpm.

5. The method for simulating the consistency of the droplet generator's spreading characteristics between heaven and earth as claimed in claim 1, characterized in that: Step 4: According to the principle of consistency between the spreading characteristics and the ground, that is, the thickness of the formed liquid film is consistent, the flow rate q0 of the required working fluid under the ground test conditions is calculated. The expression of q0 is: Where q is the flow rate of the working fluid in the space environment, unit: kg / s; D is the diameter of the spreading circle formed by the droplets in the space environment, unit: meter; q0—flow rate of working fluid under ground test conditions, unit: kg / s; D0—The diameter of the spreading circle formed by the droplets under ground test conditions, unit: meter.

6. A simulation experiment system constructed by using the simulation experiment method according to any one of claims 1 to 5, characterized in that: The simulation experiment system at least comprises a droplet generator test piece (1), a high-speed camera system, a vacuum system (5), a host computer (7), and a droplet collector (6). The droplet generator test piece (1) is placed in the vacuum system (5). The droplet generator test piece (1) comprises a storage tank (2), a spreader (3), and a controller (4) which are sequentially connected in series. The spreader (3) is connected to the droplet collector (6). The high-speed camera system comprises a high-speed camera (12), a high-speed camera collector (13), a light screen (11), and a light source (10). The high-speed camera (12) is connected to a control trigger (14). The high-speed camera (12) and the light screen (11) are respectively arranged on two opposite sides of a vacuum chamber (20). The host computer (7) is respectively connected to the controller (4) and the control trigger (14).

7. The simulation experiment system constructed by the simulation experiment method according to claim 6 is characterized in that: An observation window A (21) and an observation window B (22) are respectively provided on two opposite sides of the vacuum chamber (20), and the observation window A (21) and the observation window B (22) correspond to the light screen (11) and the high-speed camera (12) respectively.

8. The simulation experiment system constructed by the simulation experiment method according to claim 6 is characterized in that: The storage tank (2) is also connected to a gas source (8).

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