A method and device for analyzing the inflation time and buoyancy of a rapidly deployable aerostat

Abstract

The present invention discloses a method for analyzing the inflation time and buoyancy of a quickly deployable aerostat, belonging to the field of aerostat research. For the first time, this method uses the one-way fluid-structure coupling method to analyze the inflation time and the generated buoyancy under different gas source schemes and different working conditions, fully considering the external atmospheric conditions, the on-off characteristics of the check valve, the cylinder material, and the influence of the aerostat skin material on the inflation time and buoyancy. Compared with the existing test methods, it has the characteristics of high repeatability and high economy, and can also obtain the flow field characteristics inside the cylinder and at the nozzle, which are difficult to obtain by existing data acquisition equipment. Compared with the existing three-dimensional fluid-structure coupling, it has the characteristics of low required calculation, low difficulty, and high success rate. The method of the present invention can also be applied to the numerical research of other engineering fabrics, providing a new method for the gas source design of aerostats and other space inflatable deployment structures.

Description

Technical Field

[0001] The invention relates to a method and equipment for analyzing the inflation time and buoyancy of a rapid deployment aerostat, and belongs to the field of aerostat research. Background Art

[0002] The deployment process of conventional aerostats has many restrictions on launch conditions, high risks in the launch process, and long deployment time. In particular, ground launch requires a lot of preparation and operation, which can easily lead to missed opportunities. Therefore, rapid deployment of aerostats came into being.

[0003] The rapid deployment aerostat is loaded in the vehicle, and then the parachute is opened and the aerostat is pulled out. After the aerostat is completely pulled out, the inflation device is quickly inflated. After it is inflated, the parachute and the air source are discarded, and the rapid deployment aerostat is in the final working state (see: Cao Xu, Liao Hang, et al. A missile-borne floating balloon system. Invention patent number: 201610947550.3 and Luo Xiliu, Liu Juntao, Zhang Haiyan, et al. Research on the overall technology of rapid deployment aerostat. General Aerospace Technology, 2019, 3(5): 17-22). In this process, the rapid deployment aerostat must be inflated quickly to generate buoyancy. If the inflation time is too short, the buoyancy will be too small and unable to overcome the gravity of the payload; if the inflation time is too long, the pressure of the aerostat will be too high, and the air source system will not be discarded in time, resulting in a large deployment error. Therefore, the inflation time of the air source system of the rapid deployment aerostat and the buoyancy it generates are directly related to the success or failure of the entire mission.

[0004] However, the existing test methods are difficult to solve this key problem: on the one hand, ground tests cannot simulate the actual working conditions such as temperature, pressure and air density at the deployment altitude, and the existing data sensors are prone to failure due to low temperature during the helium inflation process; on the other hand, due to the diversity of deployment time, altitude and payload weight, direct airdrop tests are time-consuming and labor-intensive. Although the three-dimensional fluid-solid coupling method can be used to simulate the inflation and deployment process, the calculation model is relatively complex, involving complex contact and coupling algorithms, and requires large computing resources. The simpler theoretical method cannot be applied to the situation where the container volume changes and the airship is finally over-pressured and inflated.

[0005] In summary, the existing experimental methods and numerical methods cannot quickly and effectively estimate the inflation time and buoyancy of different deployment schemes and air source schemes. Therefore, the field of aerostat research urgently needs a simple calculation method for the buoyancy of rapidly deployed aerostats. Summary of the invention

[0006] In view of the above problems, the technical problem to be solved by the present invention is to provide a method and device for analyzing the inflation time and buoyancy of a rapid deployment aerostat.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] A method for calculating the inflation time of a rapidly deployable aerostat. The aerostat is inflated by a high-pressure gas cylinder through its nozzle. The calculation method includes the following specific steps:

[0009] Step 1: Establish a two-dimensional axisymmetric geometric model. The geometric model sequentially includes three regions along the axis of symmetry: a high-pressure gas cylinder area where the high-pressure gas cylinder is located, a nozzle area where the nozzle is located, and a deflation area where the aerostat is located;

[0010] Step 2: Divide the quadrilateral flow field grid according to the geometric model in Step 1 and form a connected computational domain for the three regions;

[0011] Step 3: Set the wall thermal conductivity and specific heat capacity of the high-pressure gas cylinder area, the nozzle area, and the deflation area according to the materials of the high-pressure gas cylinder, the nozzle, and the aerostat skin;

[0012] Step 4: Initialize the pressure and temperature of the computational domain in Step 2 and set the marked time t check = 0;

[0013] Step 5: At the nth computational time step, perform a flow field calculation on the computational domain using the unsteady SIMPLE algorithm and proceed to Step 6;

[0014] Step 6: Calculate the average pressure p bottle in the high-pressure gas cylinder area and the average pressure p inflation in the deflation area, and calculate the first pressure difference Δp 1 = p bottle - p inflation . If Δp 1 ≥Δp checkvalve , then proceed to Step 7; otherwise, proceed to Step 16. Among them, Δp checkvalve is the one-way valve conduction pressure difference;

[0015] Step 7: Calculate the second pressure difference Δp 2 = p inflation - p air . If Δp 2 <Δp max , then proceed to Step 8; otherwise, proceed to Step 16. Among them, p air is the atmospheric pressure in the aerostat deployment area, and Δp max is the maximum pressure difference that the aerostat skin can withstand;

[0016] Step 8: If (l - l 0 )·π·h 2 ≥V balloon , then proceed to Step 9; otherwise, proceed to Step 11. Among them, l is the current deflation area length, and l 0is the initial length of the air release area, h is the height of the air release area, and V balloon is the designed volume of the aerostat;

[0017] Step Nine: If t check = 0, then go to Step Ten; otherwise, go to Step Fifteen;

[0018] Step Ten: Update the marked time t check = n·Δt, and go to Step Fifteen; where Δt is the calculation time step;

[0019] Step Eleven: Calculate the force on the moving boundary of the air release area and go to Step Twelve; where m is the number of grids of the moving boundary of the air release area, and p i is the static pressure on the i-th grid of the moving boundary, and A i is the area of the i-th grid of the moving boundary;

[0020] Step Twelve: Calculate the velocity change Δv = F·Δt / (π·h 2 ·ρ skin ), and go to Step Thirteen; where ρ skin is the skin surface density of the aerostat;

[0021] Step Thirteen: Calculate the moving velocity v of the moving boundary as v = Δv + v n-1 , and control the moving boundary to move along the symmetry axis. After moving, the updated length l of the air release area is l + v·Δt, and go to Step Fourteen; where v n-1 is the moving velocity of the moving boundary at the (n - 1)-th calculation time step,

[0022] Step Fourteen: Redivide the quadrilateral flow field grid of the air release area and update the flow field information, and go to Step Fifteen;

[0023] Step Fifteen: Let n = n + 1, and return to Step Five;

[0024] Step Sixteen: Calculate the final inflation time t final = n·Δt.

[0025] As a further technical solution of the present invention, the initialization step described in Step Four is as follows:

[0026] Step One: Set the initial pressure of half of the high-pressure gas cylinder area and the nozzle area connected thereto as the initial gas cylinder pressure and the initial temperature as the atmospheric temperature T of the aerostat deployment area air ;

[0027] Step Two: Set the initial pressure of the air release area and half of the nozzle area connected thereto as the atmospheric pressure p air of the aerostat deployment area, and the initial temperature as the atmospheric temperature T of the aerostat deployment areaair 。

[0028] As a further technical solution of the present invention, the ideal gas equation is adopted in the flow field calculation described in step five.

[0029] As a further technical solution of the present invention, the moving boundary described in step seven is the wall surface of the deflation area perpendicular to the axis of symmetry and not adjacent to the nozzle area.

[0030] As a further technical solution of the present invention, the re - division of the quadrilateral flow field grid described in step ten is realized by using the Layering dynamic grid technology.

[0031] As a further technical solution of the present invention, the skin material of the aerostat is polyethylene.

[0032] As a further technical solution of the present invention, the high - pressure gas cylinder and its nozzle are both made of alloy steel.

[0033] The present invention also provides a method for analyzing the buoyancy of a rapidly deployable aerostat. The analysis method includes the following specific steps:

[0034] Step 1: While calculating the final inflation time by using the calculation method described in any one of claims 1 to 7, calculate the length l of the final deflation area max = l;

[0035] Step 2: If t check = 0, then enter step 3, otherwise enter step 4;

[0036] Step 3: Calculate the buoyancy F of the aerostat float = (l max - l 0 )·π·h 2 ·ρ air ·g, where ρ air is the atmospheric density of the aerostat deployment area, and g is the acceleration of gravity in the aerostat deployment area;

[0037] Step 4: Calculate the buoyancy F of the aerostat float = V balloon ·ρ air ·g.

[0038] The present invention also provides a device for calculating the inflation time of a rapidly deployable aerostat, including one or more processors, one or more memories, and one or more programs. One or more programs are stored in the one or more memories and are configured to be executed by the one or more processors. The one or more programs include steps for executing the above - described calculation method.

[0039] The present invention also provides a buoyancy analysis device for a rapidly deployable aerostat, comprising one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include steps for performing the analysis method as described above.

[0040] Compared with the prior art, the present invention adopts the above technical solutions and has the following technical effects: The present invention first uses the unidirectional fluid-structure interaction method to calculate and analyze the inflation time and the generated buoyancy under different working conditions, fully considering the influence of the external atmospheric conditions, check valves, and the aerostat skin material on the inflation time and buoyancy. Compared with the existing test methods, it has the characteristics of high repeatability, easy data acquisition, and high economy; compared with the existing three-dimensional fluid-structure interaction, it has the characteristics of small required calculations, low difficulty, and high success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of the inflation of a rapidly deployable aerostat;

[0042] Figure 2 is a two-dimensional axisymmetric geometric model;

[0043] Figure 3 is a two-dimensional axisymmetric grid model;

[0044] Figure 4 is the initial temperature of the flow field under Working Condition 1;

[0045] Figure 5 is the initial pressure of the flow field under Working Condition 1;

[0046] Figure 6 is the pressure contour map at the moment of 2e-4 s under Working Condition 1;

[0047] Figure 7 is the temperature contour map at the moment of 2e-4 s under Working Condition 1;

[0048] Figure 8 is the density contour map at the moment of 2e-4 s under Working Condition 1;

[0049] Figure 9 is the velocity vector map at the moment of 2e-4 s under Working Condition 1;

[0050] Figure 10 is the variation diagram of the deflation zone length under Working Condition 1;

[0051] Figure 11 is the variation diagram of the average velocity of the nozzle under Working Condition 1;

[0052] Figure 12 is the pressure contour map at the moment of 1.579 s under Working Condition 2;

[0053] Figure 13It is the temperature contour map at 1.579 s in operating condition two;

[0054] Figure 14 It is the density contour map at 1.579 s in operating condition two;

[0055] Figure 15 It is the velocity vector map at 1.579 s in operating condition two;

[0056] Figure 16 It is the graph of the change in the length of the air release area in operating condition two;

[0057] Figure 17 It is the graph of the change in the average velocity of the nozzle in operating condition two;

[0058] In the figure, 1 is the axis of symmetry, 2 is the high-pressure gas cylinder area, 3 is the nozzle area, 4 is the air release area, 5 is the moving boundary of the air release area, 6 is the gas cylinder, 7 is the nozzle, and 8 is the aerostat. Detailed implementation mode

[0059] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be construed as a limitation to the present invention. At the same time, those skilled in the art of the present technology can understand that unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0060] The present invention provides a method for analyzing the inflation time and buoyancy of a quickly deployable aerostat, and the specific steps are as follows:

[0061] Step 1: Establish a two-dimensional axisymmetric geometric model, which sequentially includes three regions along the axis of symmetry: the high-pressure gas cylinder area where the high-pressure gas cylinder is located, the nozzle area where the nozzle is located, and the air release area where the aerostat is located. Among them, the high-pressure gas cylinder area and the nozzle area are established according to the actual geometric characteristics, and the height h of the air release area is 2.5 times the radius r of the high-pressure gas cylinder bottle and 5 times the initial length l of the air release area 0 ;

[0062] Step 2: Divide the quadrilateral flow field grid according to the geometric model in Step 1 and form a three-region connected computational domain;

[0063] Step 3: Set the wall thermal conductivity and specific heat capacity of the high-pressure gas cylinder area, the nozzle area, and the air release area according to the materials of the high-pressure gas cylinder, the nozzle, and the aerostat skin;

[0064] Step 4: Initialize the pressure and temperature of the computational domain described in Step 2, and set the marked time t check = 0;

[0065] Step 5: At the current nth time step, perform a transient SIMPLE algorithm for the flow field calculation of the computational domain; where n = 1, 2, 3.....;

[0066] Step 6: At the current nth time step, calculate the average pressure p bottle in the high-pressure gas cylinder area and the average pressure p inflation in the gas release area, and calculate the first pressure difference Δp 1 = p bottle - p inflation . If Δp 1 ≥ Δp checkvalve , then go to Step 7, otherwise go to Step 16; where Δp checkvalve is the one-way valve conduction pressure difference;

[0067] Step 7: At the current nth time step, calculate the second pressure difference Δp 2 = p inflation - p air . If Δp 2 <Δp max , then go to Step 8, otherwise go to Step 16; where p air is the atmospheric pressure in the aerostat deployment area, and Δp max is the maximum pressure difference that the aerostat skin can withstand;

[0068] Step 8: At the current nth time step, if (l - l 0 )·π·h 2 ≥ V balloon , then go to Step 9, otherwise go to Step 11; where l is the current length of the gas release area, l 0 is the initial length of the gas release area, h is the height of the gas release area, and V balloon is the designed volume of the aerostat;

[0069] Step 9: If t check = 0, then go to Step 10, otherwise go to Step 15;

[0070] Step 10: Update the marked time t check to the time corresponding to the current nth time step, that is, t check = n·Δt, and go to Step 15; where Δt is the computational time step;

[0071] Step 11: At the current nth time step, calculate the force on the moving boundary of the gas release area where m is the number of moving boundary grids in the gas release area, p iThe static pressure on the $i$-th grid of the moving boundary, $A$ i is the area of the $i$-th grid of the moving boundary;

[0072] Step Twelve: At the current $n$-th time step, calculate the velocity change $\Delta v = F\cdot\Delta t / (\pi h$ 2 $\cdot\rho$ skin ), $\rho$ skin is the skin surface density of the aerostat;

[0073] Step Thirteen: At the current $n$-th time step, calculate the moving velocity $v$ of the moving boundary as $v=\Delta v + v$ n-1 , where $v$ n-1 is the moving velocity of the moving boundary at the previous time step, and control the moving boundary to move along the symmetry axis. After moving, the updated length $l$ of the deflation area is $l + v\cdot\Delta t$;

[0074] Step Fourteen: Redivide the quadrilateral flow field grid in the deflation area and update the flow field information;

[0075] Step Fifteen: Return to Step Five and enter the calculation of the $(n + 1)$-th time step;

[0076] Step Sixteen: End the flow field calculation, record the time $t$ corresponding to the current $n$-th time step as the final inflation time $t$ final $=n\cdot\Delta t$, and record the final deflation area length $l$ max $=l$;

[0077] Step Seventeen: If $t$ check $ = 0$, then enter Step Eighteen, otherwise enter Step Nineteen;

[0078] Step Eighteen: Calculate the buoyancy $F$ of the aerostat float $=(l$ max $-l$ 0 )$\cdot\pi\cdot h$ 2 $\cdot\rho$ air $\cdot g$, where $\rho$ air is the atmospheric density in the deployment area of the aerostat, and $g$ is the gravitational acceleration in the deployment area of the aerostat;

[0079] Step Nineteen: Calculate the buoyancy $F$ of the aerostat float $=V$ balloon $\cdot\rho$ air $\cdot g$.

[0080] Among them, the initialization step described in Step Four is:

[0081] Step One: Set the initial cylinder pressure of the high-pressure gas cylinder area and half of the nozzle area connected to it The temperature is the atmospheric temperature $T$ of the deployment area air ;

[0082] Step 2: Set the initial pressure of the deflation area and half of the nozzle area connected to it to the atmospheric pressure p of the deployment area air , and the temperature to the atmospheric temperature T of the deployment area air .

[0083] The following takes a certain rapidly deployable aerostat as an example for illustration:

[0084] The volume of the high-pressure gas cylinder is 0.008 m 3 , the gas type is helium, and the radius r of the high-pressure gas cylinder bottle is 0.1 m; the radius of the nozzle is 0.0035 m, the length of the nozzle is 0.03 m, and the conduction pressure difference Δp of the check valve in the nozzle area checkvalve is 0.258 MPa; both the high-pressure gas cylinder and the nozzle are made of alloy steel, with a thermal conductivity of 16.27 W / (m·K) and a specific heat capacity of 502.48 J / (kg·K); the skin of the aerostat is polyethylene, with a surface density ρ skin of 0.13 kg / m 2 , a thermal conductivity of 0.42 W / (m·K), a specific heat capacity of 2300 J / (kg·K), and the maximum pressure difference Δp it can withstand max is 200 Pa, and the designed volume V of the aerostat balloon is 2.45 m 3 .

[0085] As Figure 1 shown, if an actual three-dimensional calculation model is to be established, it is necessary to establish a folded-state aerostat model. At the same time, a contact algorithm needs to be added during the calculation process. At the same time, the aerostat structure grid and the internal and external flow field grids may be distorted, resulting in the termination of the calculation. To improve the calculation efficiency, the present invention approximates and simplifies the aerostat coupling domain, simplifies the full-skin coupling algorithm of the aerostat to a local-skin coupling algorithm, thereby avoiding complex contact algorithms and two-way fluid-structure coupling algorithms.

[0086] As Figure 2 shown, first establish a two-dimensional axisymmetric geometric model. The entire geometric model is successively the high-pressure gas cylinder area, the nozzle area, and the deflation area along the axis of symmetry. Among them, the moving boundary is the wall surface of the deflation area perpendicular to the axis of symmetry and not adjacent to the nozzle area. The high-pressure gas cylinder area and the nozzle area are established according to the above actual geometric characteristics. Among them, the height h of the deflation area is 2.5 times the radius r of the high-pressure gas cylinder bottle , that is, 0.25 m; the initial length l of the deflation area 0 is 0.05 m. As Figure 3 shown, according to the above geometric model, divide the flow field domain grid, with a total of 4043 quadrilateral grids, and form a three-zone connected calculation domain.

[0087] The following is illustrated with two different working conditions:

[0088] · Condition 1: Initial high-pressure gas cylinder pressure is 5 MPa, the atmospheric temperature T in the planned deployment area air is 293.15 K, the atmospheric pressure p in the deployment area air is 0.1 MPa, the atmospheric density ρ in the deployment area air is 1.2 kg / m 3 , and the local gravitational acceleration g is 9.81 m / s 2 .

[0089] Assign the thermal conductivity and specific heat capacity of alloy steel to the boundaries of the high-pressure gas cylinder area and the nozzle area, while assign the thermal conductivity and specific heat capacity of polyethylene to the boundary of the gas release area. As Figure 4 and Figure 5 shown, initialize the pressure and temperature of the flow field. Among them, set the initial gas cylinder pressure i.e., 5 MPa, and the temperature is the atmospheric temperature T in the deployment area air , i.e., 293.15 K, in the high-pressure gas cylinder area and half of the nozzle area connected to it; while set the initial pressure as the atmospheric pressure p in the deployment area air , i.e., 0.1 MPa, and the temperature is the atmospheric temperature T in the deployment area air , i.e., 293.15 K, in the gas release area and half of the nozzle area connected to it. Finally, set the marked time t check = 0.

[0090] Start the flow field calculation for the computational domain using the unsteady SIMPLE algorithm. During the calculation process, the time step Δt is 1e-6 s. In addition to solving the mass conservation equation, momentum conservation equation, and energy conservation equation involved in the conventional CFD calculation, the ideal gas state equation is used for the helium gas state equation.

[0091] As Figure 6 , Figure 7 , Figure 8 and Figure 9 shown, during the calculation of each time step, judge whether the following inequality holds:

[0092] (l - l 0 )·π·h 2 ≥ V balloon (1)

[0093] Δp 1 ≥ Δp checkvalve (2)

[0094] Δp 2 <Δp max (3)

[0095] Among them, l is the current length of the gas release area, Δp 1 = p bottle - pinflation is the first pressure difference, p bottle is the average pressure of the current high-pressure gas cylinder area, p inflation is the average pressure of the current gas release area, Δp 2 = p inflation - p air is the second pressure difference.

[0096] If the inequality (1) holds, update the marking time t check is the time corresponding to the current nth time step, i.e., t check = n·Δt. In the subsequent time step calculations, the moving boundary no longer moves, and the grids in the gas release area are no longer re-divided; in the next step calculation, if t check ≠0, the marking time t check is no longer updated, that is, the marking time only records the first time when the inequality (1) holds. The marking time t check ≠0 indicates that the aerostat is full, and the internal pressure of the aerostat begins to be greater than the external atmospheric pressure.

[0097] If either of the inequalities (2) or (3) does not hold, stop the calculation of the next time step, record the time t corresponding to the current nth time step as the final inflation time t final = n·Δt, record the final length l of the gas release area max = l, and the flow field calculation ends.

[0098] As described above, after the calculation starts, the high-pressure helium gas in the high-pressure gas cylinder area enters the gas release area through the nozzle area. To ensure the internal and external pressure balance, the moving boundary in the gas release area moves along the symmetry axis direction within each time step. Before the aerostat is full, the movement of the moving boundary is achieved through the following methods:

[0099] (1) First, calculate the force on the moving boundary of the gas release area where m is the number of grids of the moving boundary in the gas release area, p i is the static pressure on the i-th grid of the moving boundary, A i is the area of the i-th grid of the moving boundary;

[0100] (2) Calculate the velocity change Δv = F·Δt / (π·h 2 ·ρ skin );

[0101] (3) Calculate the moving velocity v of the moving boundary in the current nth time step as v = Δv + v n-1 , where v n-1 is the moving velocity of the previous time step, and control the moving boundary to move along the symmetry axis direction. After the movement, the updated length l of the gas release area is l + v·Δt;

[0102] While implementing the movement of the moving boundary, to ensure the grid quality, the grid in the deflation area is re-divided and the flow field information is updated. The grid re-division is implemented using the Layering dynamic grid technology, where the grid splitting coefficient is 0.4 and the collapse coefficient is 0.2.

[0103] As Figure 10 shown, under this working condition, the inequality (1) never holds, and the moving boundary in the deflation area always moves according to the above steps. Similarly, the grid in the deflation area is re-divided. However, at the 4041000th time step, the inequality (2) no longer holds, indicating that the pressure in the high-pressure gas cylinder is insufficient to make the one-way valve conduct. At this time, the final inflation time t final = 4.041 s, and the final length l of the deflation area max = 1.848 m, and the calculation ends.

[0104] Finally, check whether t check = 0 holds. If it holds, calculate the buoyancy F float through Equation (4), otherwise calculate the buoyancy F float :

[0105] F float = (l max - l 0 )·π·h 2 ·ρ air ·g (4)

[0106] F float = V balloon ·ρ air ·g (5)

[0107] After the calculation is completed, the marked time t check = 0 in Case 1, and the aerostat is not fully inflated. Under this working condition, the buoyancy F of the aerostat float is calculated to be 4.15 N through Equation (4).

[0108] As Figure 11 shown, it can be found from the calculation results that for this gas source scheme, the inflation volume is significantly insufficient, the inflation efficiency is not high, and the effective inflation time is mainly the first 2 s.

[0109] · Case 2: The initial pressure of the high-pressure gas cylinder is 20 MPa, the atmospheric temperature T air in the planned deployment area is 223.15 K, the atmospheric pressure p air in the deployment area is 0.052 MPa, the atmospheric density ρ air in the deployment area is 0.813 kg / m 3 , and the local acceleration of gravity g is 9.81 m / s 2 .

[0110] Perform calculations using the grid model described in operating condition 1, initialize the flow field grid using operating condition 2, and start the calculations using the above steps.

[0111] As Figure 12 , Figure 13 , Figure 14 , Figure 15 and Figure 16 shown, at the 1,579,000th time step after the start of the calculation, inequality (1) holds for the first time, so the marked time t check = 1.579 s is updated. The moving boundary in subsequent time step calculations no longer moves, and the grid in the deflation area is no longer re-divided. When the calculation proceeds to the 1,582,000th time step, inequality (3) no longer holds, indicating that the pressure difference inside and outside the aerostat has reached the maximum pressure difference that the skin material can withstand. At this time, the final inflation time t final = 1.582 s, and the final length l of the deflation area max = 12.528 m, and the calculation ends.

[0112] After the calculation is completed, the marked time t check in operating condition 2 = 1.579 s, and the aerostat is full. Under this operating condition, the buoyancy F of the aerostat float is calculated by equation (5) to be 19.54 N.

[0113] As Figure 17 shown, it can be found from the calculation results that this gas source scheme has a relatively high inflation efficiency. However, inequality (2) still holds until the last moment, indicating that there is still a large amount of helium in the high-pressure gas cylinder that cannot generate buoyancy, which is not conducive to the lightweight design of the rapid deployment of the aerostat.

[0114] A method for analyzing the inflation time and buoyancy of a rapid deployment aerostat designed by the present invention first uses the one-way fluid-structure interaction method to analyze the inflation time and the generated buoyancy under different gas source schemes and different operating conditions, fully considering the external atmospheric conditions, the on-off characteristics of the one-way valve, the gas cylinder material, and the influence of the aerostat skin material on the inflation time and buoyancy. Compared with the existing test methods, it has the characteristics of high repeatability and high economy, and can also obtain the flow field characteristics inside the gas cylinder and at the nozzle, which are difficult to obtain by existing data acquisition equipment. Compared with the existing three-dimensional fluid-structure interaction, it has the characteristics of small required calculations, low difficulty, and high success rate. The method of the present invention can also be applied to the numerical research of other engineering fabrics, providing a new method for the gas source design of aerostats and other space inflatable deployment structures.

[0115] Based on the same technical solution, the present invention further provides a rapid deployment aerostat inflation time calculation device, including one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include steps for executing the inflation time calculation method.

[0116] Based on the same technical solution, the present invention further provides a rapid deployment aerostat buoyancy analysis device, including one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include steps for executing the buoyancy analysis method.

[0117] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program code.

[0118] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be realized by computer program instructions. These computer program instructions can be provided to the processors of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate means for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0119] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means realizes the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable apparatus to generate a computer-implemented process, thereby providing instructions for implementing the process Figure 1 a process or processes and / or blocks Figure 1 steps for the functions specified in a block or blocks.

[0121] As described above, only the specific embodiments of the present invention are shown, but the protection scope of the present invention is not limited thereto. Any person familiar with the technology can think of the transformations or substitutions within the scope of the technology disclosed in the present invention, and they should all be covered within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for calculating the inflation time of a rapidly deployable aerostat, where the aerostat is inflated by a high-pressure gas cylinder through its nozzle. Characterized in that, The calculation method includes the following specific steps: Step 1: Establish a two-dimensional axisymmetric geometric model, which sequentially includes three regions along the axis of symmetry: the high-pressure gas cylinder region where the high-pressure gas cylinder is located, the nozzle region where the nozzle is located, and the deflation region where the aerostat is located. Step 2: Divide the quadrilateral flow field grid according to the geometric model in Step 1 and form a connected computational domain for the three regions. Step 3: Set the wall thermal conductivity and specific heat capacity of the high-pressure gas cylinder region, the nozzle region, and the deflation region according to the high-pressure gas cylinder material, the nozzle material, and the aerostat skin material. Step 4: Initialize the pressure and temperature of the computational domain described in Step 2, and set the marked time t check = 0; Step 5: At the nth computational time step, perform a flow field calculation on the computational domain using the unsteady SIMPLE algorithm, and proceed to Step 6. Step Six: Calculate the average pressure p of the high-pressure gas cylinder area bottle and the average pressure p of the air release area inflation , and calculate the first pressure difference Δp 1 = p bottle - p inflation . If Δp 1 ≥Δp checkvalve , then go to Step Seven; otherwise, go to Step Sixteen. Wherein, Δp checkvalve is the on-pressure difference of the one-way valve; Step Seven: Calculate the second pressure difference Δp 2 = p inflation - p air ; if Δp 2 < Δp max , then proceed to Step Eight; otherwise, proceed to Step Sixteen. Here, p air is the atmospheric pressure in the deployment area of the aerostat, and Δp max is the maximum pressure difference that the aerostat skin can withstand. Step Eight: If (l - l 0 )·π·h 2 ≥V balloon , then go to Step Nine; otherwise, go to Step Eleven. Here, l is the length of the current air release area, l 0 is the initial length of the air release area, h is the height of the air release area, and V balloon is the designed volume of the aerostat. Step Nine: If t check = 0, then proceed to Step Ten; otherwise, proceed to Step Fifteen. Step Ten: Update the marking time t check = n·Δt, and proceed to Step Fifteen; where Δt is the computational time step. Step Eleven: Calculate the force on the moving boundary of the gas release area Proceed to Step Twelve; where m is the number of grids of the moving boundary of the gas release area, and p i is the static pressure on the i-th grid of the moving boundary, and A i is the area of the i-th grid of the moving boundary; Step Twelve: Calculate the velocity change Δv = F·Δt / (π·h 2 ·ρ skin ), and proceed to Step Thirteen; where ρ skin is the skin areal density of the aerostat. Step 13: Calculate the moving speed v of the moving boundary as v = Δv + v n-1 , and control the moving boundary to move along the symmetry axis. After the movement, the updated length l of the air release area is l + v·Δt, and proceed to Step 14; where v n-1 is the moving speed of the moving boundary at the (n - 1)-th calculation time step Step 14: Re-divide the quadrilateral flow field grid in the deflation region and update the flow field information, and proceed to Step 15. Step 15: Let n = n + 1, and return to Step 5. Step Sixteen: Calculate the final inflation time t final = n·Δt.

2. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The initialization step in Step 4 is: Step 1: Set the initial pressure in the high-pressure gas cylinder area and half of the nozzle area connected thereto as the initial gas cylinder pressure The initial temperature is the atmospheric temperature T in the aerostat deployment area air ; Step 2: Set the initial pressure of the deflation area and half of the nozzle area connected thereto to the atmospheric pressure p of the aerostat deployment area air , and the initial temperature to the atmospheric temperature T of the aerostat deployment area air .

3. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The ideal gas equation is adopted in the flow field calculation in Step 5.

4. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The moving boundary in Step 7 is the wall of the deflation region perpendicular to the axis of symmetry and not adjacent to the nozzle region.

5. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The re-division of the quadrilateral flow field grid in Step 10 is realized by using the Layering dynamic mesh technology.

6. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The aerostat skin material is polyethylene.

7. A method for calculating the inflation time of a rapidly deployable aerostat according to claim 1, Characterized in that, The high-pressure gas cylinder and its nozzle are both made of alloy steel.

8. A method for analyzing the buoyancy of a rapidly deployable aerostat, Characterized in that, This analysis method includes the following specific steps: Step 1, while calculating the final inflation time using the calculation method described in any one of claims 1 to 7, calculate the length l of the final deflation zone max = l; Step 2, if t check = 0, then proceed to Step 3; otherwise, proceed to Step 4; Step 3: Calculate the buoyancy F of the aerostat float =(l max -l 0 )·π·h 2 ·ρ air ·g, where ρ air is the atmospheric density of the aerostat deployment area, and g is the acceleration due to gravity of the aerostat deployment area; Step 4: Calculate the buoyancy F of the aerostat float = V balloon · ρ air · g 9. A device for calculating the inflation time of a rapidly deployable aerostat, Characterized in that, It includes one or more processors, one or more memories, and one or more programs, where one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs include steps for executing the calculation method according to any one of claims 1 to 7.

10. A device for analyzing the buoyancy of a rapidly deployable aerostat, Characterized in that, It includes one or more processors, one or more memories, and one or more programs, where one or more programs are stored in the one or more memories and are configured to be executed by the one or more processors, and the one or more programs include steps for executing the analysis method according to any one of claim 8.

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