Arm propulsion device for low-altitude single-person minimum flight system and design method thereof

Abstract

The application relates to a hand arm propulsion device for a low-altitude single-person minimum flight system and a design method thereof, and relates to the field of manned aircrafts. In order to solve the problems that the existing jet aircrafts have large self weight, inconvenient pose adjustment and are prone to causing harm to pilots, the left and right sides of an arm support are connected with an engine support through a plurality of multi-link assemblies, respectively, left and right engines are installed on the two engine supports, respectively, a handle is horizontally installed at the front end of the arm support, a trigger is installed at one end of the handle and close to the thumb holding position of the handle, the center line of the arm support and the axis of the top ends of the left and right engines intersect at a C point, the included angle between the left and right engines and the center line of the arm support is 15deg-25deg, and the distance R between the top ends of the left and right engines and the C point is 300mm-400mm. The application is used in a flight system.

Description

TECHNICAL FIELD

[0001] The present application relates to an arm propulsion device, in particular to an arm propulsion device for a low-altitude single-person minimum flight system and a design method thereof, and belongs to the field of manned aircraft and the field of aerospace. BACKGROUND

[0002] Future intelligent transportation systems require more flexible vehicles, the emergency rescue field needs mobile ways that can quickly reach disaster sites, the logistics industry needs more efficient transportation means, and in rescue environments, there is a need for a flight system that can quickly, stealthily and flexibly.

[0003] Taking a single-person aircraft powered by a turbojet engine as an example, the three most classic products in the history of research on single-person aircraft powered by a turbojet engine are jet suits, JB11, and flying boards. The design concepts of the three single-person aircrafts are completely different, but they all try to place a micro turbojet engine on a certain part of the human body to provide thrust. Jet suits are the aircraft with the best operating performance, and they use the human skeleton as a support to reduce external mechanical structures.

[0004] However, the current jet suit has a large weight, is inconvenient to wear, and because the pilot is operating the pose under the working state of the turbojet engine, there is a risk of loss of control during operation under the action of vibration and thrust. If not handled properly, the fluid ejected by the turbojet engine can also cause burns and other accidental injuries to the pilot.

[0005] In summary, the existing jet suit has the problems of large weight, inconvenient pose adjustment, and easy injury to the pilot. SUMMARY

[0006] The present application relates to an arm propulsion device, in particular to an arm propulsion device for a low-altitude single-person minimum flight system and a design method thereof, and belongs to the field of manned aircraft and the field of aerospace.

[0007] The technical scheme of the present application is: a hand arm propulsion device for a low-altitude single-person minimum flight system comprises an arm support, a left engine, a right engine, two engine supports, a handle, a trigger and two sets of multi-link assemblies, the left and right sides of the arm support are connected with an engine support through a set of multi-link assemblies respectively, the left engine and the right engine are installed on the two engine supports respectively, the handle is installed horizontally at the front end of the arm support, and the trigger is installed at one end of the handle and close to the thumb holding position of the handle; wherein, the center line of the arm support intersects with the axis of the top end of the left engine and the right engine at point C, and the included angle between the left engine, the right engine and the center line of the arm support is 15deg-25deg, and the distance R between the top end of the left engine and the right engine and point C is 300mm-400mm.

[0008] Further, the engine support is a cylindrical support, and the engine support comprises two semicircular arc-shaped pieces which are buckled and bolted relative to each other.

[0009] Further, the multi-link assembly comprises a first link, a second link, a third link and a fourth link, the second link and the third link are arranged in parallel, one end of the second link and the third link is connected with an engine support, and the other end of the second link and the third link is connected with the same side of the arm support; one end of the first link is connected with the second link, and one end of the first link and one end of the second link are located on the same side of the engine support, the other end of the first link is inclined to the handle side and connected with the arm support; one end of the fourth link is connected with the second link, and one end of the fourth link and one end of the third link are located on the same side of the engine support, the other end of the fourth link is inclined to the side away from the handle and connected with the arm support.

[0010] Further, a long strip-shaped hole is formed on one side surface of the arm support.

[0011] Further, the trigger is internally provided with two slot holes.

[0012] Further, it further comprises two electronic displacement sensors, the upper parts of the two electronic displacement sensors are inserted into the two slot holes of the trigger, and the lower parts of the two electronic displacement sensors are inserted and fixed in the handle.

[0013] Preferably, the upper parts of the two electronic displacement sensors are in interference fit with the two slot holes of the trigger.

[0014] The present application also provides a design method of a hand arm propulsion device for a low-altitude single-person minimum flight system, which comprises the following steps:

[0015] Step one: design the included angle β between the left engine, the right engine and the center line of the arm support, the distance R from the top end of the left engine and the right engine to point C, and the position of the handle on the axis;

[0016] Step one: using SCDM software to establish the outer fluid domain and fluid domain of the left engine and the right engine, and create a BOI area on the centerline of the arm support as the key observation area;

[0017] Wherein, the position of the BOI area is selected as: the intersection between the distance between the left engine and the right engine and the centerline of the arm support is taken back 100*100*100 volume area, and the centerline of the volume area in the horizontal position is the position of the handle;

[0018] Step two: import the established fluid model into FLUENT Meshing for meshing;

[0019] Step three: after meshing, import into the solver to solve the model, and select the input and output parameters of the left engine and the right engine according to the actual boundary conditions: the total pressure of the output and input of the fluid model is 1 atm, the inlet total temperature is 288 K, the turbine speed is 98000 rpm, the fuel is RP-3 aviation kerosene, and the fuel flow is 0.0118 kg / s; Under the above parameters, the final solution is obtained under different R and β of the jet gas velocity, temperature distribution;

[0020] Step four: analyze the BOI area of the model under different R and β, and take the average value of the temperature and velocity on the BOI area interface as the simulation result of the model under the corresponding distance R and angle β;

[0021] Step five: all results are counted and analyzed to obtain the temperature and velocity distribution graph of different R and β;

[0022] Step six: test the distance R and angle β with low temperature in the simulation result, and the test result and simulation error are within 5%;

[0023] Step seven: through the experimental test, it is known that: the larger the angle β, the smaller the thrust generated by the left engine and the right engine, therefore, it is necessary to trade off between temperature and thrust, and finally determine R=400mm, β=25deg;

[0024] Step two: topological optimization design of multi-link assembly;

[0025] Step two: connect the engine support and the arm support with a whole aluminum plate;

[0026] Step two: static analysis: fix the arm support, apply a force of 300N to the left and right engine supports respectively, and retain 10% of the volume on the aluminum plate, and the most important structure part will be automatically retained during the topological optimization process, so as to achieve the effect of bearing the maximum force with the minimum volume, that is, the rough topological optimization structure can be obtained;

[0027] Step two three: the multi-link assembly is obtained after the topological optimization structure is shaped, and thus the design of the arm propulsion device is completed

[0028] Compared with the prior art, the present application has the following effects:

[0029] 1. The present application is a portable manned aircraft, which is suitable for use in a low-altitude single-person minimum flight system. The pilot can quickly reach any position and adjust the pilot's posture by changing the included angle between the arm and the body and the size of the throttle at the grip.

[0030] 2. The left engine A and the right engine B of the present application are micro turbojet engines, which have a very high thrust-to-weight ratio. When the aircraft is in use, the pilot has two arm propulsion devices and one backpack propulsion device, all of which use micro turbojet engines as the main power source. The single-person aircraft body has a total of six micro turbojet engines, two 30KG-level engines for each arm propulsion device, and two 40KG-level engines for the backpack propulsion device. The backpack is equipped with a fuel system and an electronic control system. The pilot can adjust the thrust at the arm by the trigger in the arm propulsion device, and the thrust at the backpack is obtained by the controller, which allows the pilot to focus on adjusting the arm thrust and the body posture to change the direction and height, while the controller ensures the stability of the pilot.

[0031] 3. In the single-person aircraft, the arm propulsion device can provide a maximum thrust of 54KG; the multi-link structure is simple and reliable; the angle design fully ensures the safety of the pilot, and the self-weight is only 2.2KG (excluding engines); the grip is firm, and the linear sensor makes the pilot's operation more comfortable, and the more the pilot presses, the more force is generated; the design method combining simulation and experiment greatly shortens the design cycle of the arm propulsion device.

[0032] The present application focuses on the design, simulation and optimization of the arm propulsion device of the single-person aircraft. Through numerical simulation and experimental verification, we prove the effectiveness of the design method and optimize the arrangement of the engines at the arm, making the device more safe and reliable. Each component of the arm propulsion device is designed in its entirety, and the connecting rod is designed using topological optimization technology, ensuring that the weight is reduced while meeting the needs of force transmission and protecting the pilot. The overall research provides an important reference for the future design of single-person aircraft and demonstrates its good performance and commercial potential in practical applications. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a model schematic diagram of the arm propulsion device of the present application worn on the pilot; wherein the arrows represent the force schematic diagram;

[0034] Figure 2 This is a schematic diagram of the overall structure of the arm propulsion device of the present invention;

[0035] Figure 3 yes Figure 2 The main view;

[0036] Figure 4 This is a schematic diagram of the structure of the semi-circular arc-shaped sheet 6;

[0037] Figure 5 This is a schematic diagram of the arm support 3;

[0038] Figure 6 This is a schematic diagram of the assembly of the grip 4 and the trigger 5.

[0039] Figure 7 yes Figure 6 A sectional view;

[0040] Figure 8 This is a schematic diagram of the included angle β, the distance R from the top of the left engine A and the right engine B to point C in step one;

[0041] Figure 9 This is a physical image of the experimental test conducted on the experimental bench in step one seven.

[0042] Figure 10 This is a schematic diagram of the multi-link assembly designed using topology optimization in step two;

[0043] Figure 11 This is a schematic diagram of using SCDM software to establish the external fluid domain 8 and fluid domain 9 of the two engines, and creating BOI region 10 on the axis as the key observation area;

[0044] Figure 12 This is a schematic diagram showing the velocity and temperature distribution of the ejected gas at different distances R and angles β obtained in step one.

[0045] Figure 13 The BOI region of the model is analyzed under different distances R and included angles β, and the average values ​​of temperature and velocity on the BOI interface are taken as the simulation results of the model under the corresponding distances R and included angles β.

[0046] Figure 14 yes Figure 1 Force analysis diagram;

[0047] Figure 15 yes Figure 8 It is a force analysis diagram;

[0048] Figure 16 It is F A1 The relationship between θ and θ;

[0049] Figure 17 is the relationship between G and a;

[0050] Fig. 18(a) is the distribution of 8 thermocouples on the aluminum alloy small platform;

[0051] Fig. 18(b) is the placement of the aluminum alloy small platform on the test bench;

[0052] Figure 19 is the temperature distribution and data processing when R = 300 mm and β = 15 degrees; (a) temperature change with engine running time (working condition) on the symmetry axis, (b) processing of the first group of sampling data, and (c) processing of the second group of sampling data. DETAILED DESCRIPTION

[0053] The technical solutions of the present application are not limited to the following specific embodiments, but also include any reasonable combination of the specific embodiments.

[0054] Specific embodiment one: in combination with Figures 1-8 To illustrate this embodiment, the embodiment includes an arm support 3, a left engine A, a right engine B, two engine supports 1, a handle 4, a trigger 5, and two sets of multi-link assemblies 2. The left and right sides of the arm support 3 are connected to one engine support 1 through one set of multi-link assemblies 2, respectively. The left engine A and the right engine B are installed on the two engine supports 1, respectively. The handle 4 is horizontally installed at the front end of the arm support 3, and the trigger 5 is installed at one end of the handle 4 and close to the thumb holding position of the handle 4. The center line of the arm support 3 intersects with the axis of the top end of the left engine A and the right engine B at point C, and the included angle between the left engine A and the right engine B and the center line of the arm support 3 is 15 deg-25 deg. The distance R between the top end of the left engine A and the right engine B and point C is 300 mm-400 mm.

[0055] Specific embodiment two: in combination with Figure 1 and Figure 4 To illustrate this embodiment, the engine support 1 of the embodiment is a cylindrical support, which includes two semicircular arc-shaped pieces 6 that are buckled and bolted relative to each other. In this way, it is convenient to install and disassemble. The other components and connection relationships are the same as those of specific embodiment one.

[0056] Specific embodiment three: in combination with Figure 2In this embodiment, the multi-link assembly 2 comprises a first link 2-1, a second link 2-2, a third link 2-3, and a fourth link 2-4. The second link 2-2 and the third link 2-3 are arranged in parallel, and one end of each of the second link 2-2 and the third link 2-3 is connected to an engine support 1, and the other end of each of the second link 2-2 and the third link 2-3 is connected to the same side of an arm support 3. One end of the first link 2-1 is connected to the second link 2-2, and the one end of the first link 2-1 and the one end of the second link 2-2 are located on the same side of the engine support 1, and the other end of the first link 2-1 is inclined to the side of a handle 4 and connected to the arm support 3. One end of the fourth link 2-4 is connected to the second link 2-2, and the one end of the fourth link 2-4 and the one end of the third link 2-3 are located on the same side of the engine support 1, and the other end of the fourth link 2-4 is inclined to the side away from the handle 4 and connected to the arm support 3. In this way, the 3D printed nylon material is light in weight and has high connection rigidity, and the deformation under maximum thrust is only 6.9e-5 meters. This facilitates to ensure the safety and reliability of the entire arm propulsion device during operation. The other components and connection relationships are the same as those in Embodiment One or Two.

[0057] Embodiment Four: Combination Figure 2 and Figure 5 In this embodiment, one side of the arm support 3 is provided with a long strip-shaped hole 21. In this way, the weight of the entire arm propulsion device is reduced, and the driver's arm is also easily worn. The other components and connection relationships are the same as those in any one of Embodiments One to Three.

[0058] Embodiment Five: Combination Figure 6 and Figure 7 In this embodiment, two slots 20 are arranged in the interior of the trigger 5. In this way, the electronic displacement sensor 7 is easily installed. The other components and connection relationships are the same as those in any one of Embodiments One to Four.

[0059] Embodiment Six: Combination Figure 6 and Figure 7 In this embodiment, the trigger 5 further comprises two electronic displacement sensors 7, the upper parts of the two electronic displacement sensors 7 are inserted into the two slots 20 of the trigger 5, and the lower parts of the two electronic displacement sensors 7 are inserted and fixed in the handle 4.

[0060] In this way, the displacement of the driver's arm is easily detected, and the accuracy of the flight pose is ensured. The other components and connection relationships are the same as those in any one of Embodiments One to Five.

[0061] Embodiment Seven: Combination Figure 6 and Figure 7The upper part of the two electronic displacement sensors 7 of the embodiment is in interference fit with the two slot holes 20 of the trigger 5.

[0062] In this way, the connection is more reliable. The other components and connection relationship are the same as any one of embodiments one to six.

[0063] Embodiment eight: combination Figures 1-13 The embodiment includes the following steps:

[0064] Step one: design the included angle β between the left engine A and the right engine B and the center line of the arm support 3, the distance R from the top of the left engine A and the right engine B to the C point, and the position of the handle 4 on the axis;

[0065] Step one: use SCDM software to establish the outer fluid domain 8 and the fluid domain 9 of the left engine A and the right engine B, and create a BOI area 10 on the center line of the arm support 3 as the key observation area;

[0066] The position of the BOI area 10 is selected as follows: the intersection point between the distance between the left engine A and the right engine B and the center line of the arm support 3 is taken back to a volume area of 100*100*100, and the center line of the volume area in the horizontal position is the position of the handle 4;

[0067] Step two: import the established fluid model into FLUENT Meshing for meshing;

[0068] Step three: after meshing, import into the solver for solving the model, and select the input and output parameters of the left engine A and the right engine B according to the actual boundary conditions: the total pressure of the output port and the input port of the fluid model is 1 atm, the inlet total temperature is 288 K, the turbine speed is 98000 rpm, the fuel selected is RP-3 aviation kerosene, and the fuel flow is 0.0118 kg / s; under the above parameters, the final solution is obtained under different R and β The speed and temperature distribution of the ejected gas;

[0069] Step four: analyze the BOI area 10 of the model under different R and β, and take the average value of the temperature and speed on the interface of the BOI area 10 as the simulation result of the model under the corresponding distance R and angle β;

[0070] Step five: all results are counted and analyzed to obtain the temperature and speed distribution graph of different R and β;

[0071] Step six: test the distance R and angle β with low temperature in the simulation result, and the test result and simulation error are within 5%;

[0072] Step one seven: Through experimental tests, it is known that the greater the included angle β, the smaller the thrust generated by the left engine A and the right engine B, therefore, the temperature and the thrust need to be traded off, and finally R = 400 mm and β = 25 deg are determined;

[0073] Step two: Topology optimization design of multi-link assembly;

[0074] Step two one: connecting the engine support 1 and the arm support 3 with an aluminum plate 11;

[0075] Step two two: static force analysis: fixing the arm support 3, applying a force of 300 N to the left and right engine supports 1 respectively, retaining 10% of the volume on the aluminum plate 11, and automatically retaining the most important structure part in the topology optimization process to achieve the effect of bearing the maximum force with the minimum volume, that is, the rough topology optimization structure 12 can be obtained;

[0076] Step two three: shaping the topology optimization structure 12 to obtain a multi-link assembly 2, thus completing the design of the arm propulsion device.

[0077] The process of Step one five in the embodiment for statistical analysis of all results is as follows: when the flight system is balanced, the generated thrust will be balanced with the total gravity, that is, the resultant force of the three thrusts is equal in magnitude and opposite in direction to the gravity, and the force diagram of the flight system and the force analysis when balanced are shown in Figure 1 and Figure 14 .

[0078] For convenience of analysis, we assume that F A1 = F A2 , it can be found from Figure 1 that the maximum thrust required by the engine is actually only related to two included angles: the included angle theta between the two arms and the included angle alpha between the resultant force F A of the thrusts generated by the two single-arm propulsion devices and the thrust F B obtained from the back.

[0079] Through Figure 14 . Force diagram and force analysis diagram, it can be seen from the force analysis diagram that when balanced, the thrust and the two included angles have the following relationship:

[0080]

[0081] In fact, F B is a known quantity. When selecting a micro turbojet engine, choosing a domestic manufacturer can save time in purchasing and research and development. We selected Xuanyun Power through research, which has a micro turbojet engine with a maximum thrust of 80 kg per single engine. As can be seen from formula (1.1), when F BThe greater the take-off, the greater the gravity can be carried. Therefore we choose 80KG as the maximum thrust of the back, and set the safety factor of 1.25. At this time, the rated thrust of the back is: F B =64KG, into equation (1.1) can be obtained F A1 and the relationship between θ, G and α. Details see Figure 16 and Figure 17 .

[0082] If take θ greater than 80 °, then need to be placed on both sides of the arm engine to provide a larger thrust. For most normal adult males, a single arm to bear close to 40 kg of thrust is already very large, but for safety reasons, the thrust of the single arm propulsion device still needs to meet the value, so that when a certain engine fails, there is still enough thrust to support the pilot to land safely. From Figure 17 we can know that the smaller α, the greater G. Take α for 35 °, G is 122KG, then the rated total weight of the aircraft is 122KG.

[0083] After determining that the maximum θ is 80 °, F A1 the maximum is 41.8KG, we further need to design the specific parameters required by the structure of the single arm propulsion device. The structure parameters and force analysis of the single arm propulsion device are shown in Figure 8 and Figure 15 .

[0084] According to the force analysis in Figure 15 , F A1 and F T should meet: F A1 =2F T ·cosβ.

[0085] In fact, β should be greater than 15 ° and less than 40 °, too small will have no space to place the arm on the axis, too large will make the size too large, and the maximum thrust requirement of the engine will be higher. When β is not greater than 40 °, F T at least needs 27.3KG of thrust. We choose the largest thrust of 30KG engine under the flag of Xuanyun Power to meet the demand.

[0086] The turbojet engine will emit a large amount of high-temperature high-speed gas when running, in order to ensure that the pilot's hands are not burned, we need to further design R and β, the two important parameters, to find the right position to place the hand on the symmetry axis of the arm propulsion device.

[0087] In addition, there are many combinations of R-β, if every group is tested by experiment, it will consume a lot of time and fuel. Through simulation technology, we can quickly obtain the temperature distribution under different R-β, which will greatly save manpower and material resources when designing and optimizing the hand propulsion device of the single person aircraft.

[0088] Specific implementation nine: combination Figures 1-13 In this implementation, the third step of assembling each component is also included;

[0089] Step three one: install the handle 4 in the arm support 3;

[0090] Step three two: insert the upper part of the two electronic displacement sensors 7 into the two slot holes 20 of the trigger 5, and insert and fix the lower part of the two electronic displacement sensors 7 in the handle 4;

[0091] Step three three: pre-install the left engine A in one of the semicircular arc-shaped pieces 6, and then buckle the other semicircular arc-shaped piece 6 on the one semicircular arc-shaped piece 6 to complete the installation of the left engine A. The right engine B is installed in the same way.

[0092] The arm propulsion device in the single-person aircraft of the present application needs to consider safety and portability. By using the method of combining simulation and experiment, the design cycle is greatly shortened, and at the same time, the influence of different designs on temperature and speed can be seen intuitively. The arm support is designed according to the Chinese adult body size standard GB / T 10000-2023, and is suitable for most 18-30 year old adult males. At the same time, the 3D metal printing integrated technology is used to make it, which provides great safety guarantee for the pilot. The engine support is customized according to the SW300B turbojet engine, which is light in quality and reliable in clamping. The multi-link is designed by using topology optimization, which is light in quality and large in connection rigidity, and the deformation under maximum thrust is only 6.9e-5 meters. The handle is designed by ergonomics, and the grip force is uniform. The 3D printed nylon material is light in quality. The electronic displacement sensor is a linear sensor, which can also output linear thrust. As the arm propulsion device of the single-person aircraft, the mechanism is safe and reliable enough and powerful enough.

[0093] The experimental test process in step one six of the present application is as follows:

[0094] Place the engine on the force table, and then process 24 groups of hole positions on the desktop of the test bench according to the combination of R and β for fixing the two force tables. In order to measure the temperature distribution of the ejected gas on the symmetry axis, an 8-channel K-type thermocouple temperature measuring instrument produced by large gallium sensor is used. The temperature measuring instrument is sensitive to temperature and the sampling frequency can reach 15HZ, and the temperature range is -200-1360℃, which fully meets our experimental requirements. As shown in FIGS. 18(a) and 18(b), we combine 8 thermocouples in pairs, place them on an aluminum alloy small platform (use 3M double-sided tape for heat insulation) with an interval of 5cm, and place the aluminum alloy small platform on the symmetry axis of the two engines, which has the same height as the axis of the two engines.

[0095] In the experiment, we found that the temperature distribution on the symmetry axis of the two engines is different during the start-up acceleration and running, as shown in the simulation. During the start-up acceleration, high-temperature and low-speed gas is generated by deflagration, which makes the temperature on the symmetry axis higher. During the running, the aviation kerosene is fully combusted in the combustion chamber, and the generated high-temperature and high-speed gas is only distributed on the engine axis, so the temperature on the symmetry axis is close to the atmospheric temperature (not considering heat radiation), as shown in (a). Therefore, we focused more on the start-up stage of the two engines and made more detailed experiments. Each R-β combination was sampled at least three times during the start-up stage, and two close data were taken as the true value. At the same time, the remote T1 and T2 were excluded during data processing, and the other temperature values were averaged (as shown in (b) and (c)). The average value of the two data was taken again, and the final result was obtained. We can consider that the actual temperature of the observation area is the final result. Figure 19 Figure 19

[0096] After the above processing, the temperature data of each R-β combination is shown in Table 1. The experiment was divided into two times. The first time, the R=300mm group was measured, but the environmental temperature was relatively high (about 25℃) at that time, and the measured data was also around the environmental temperature, which led to the failure to measure the true value of β=40degree. The second time, the R=350, 400, 450mm groups were experimented, and the environmental temperature was about 17℃. NaN in the table represents that the measured temperature is near the environmental temperature and cannot reflect the true temperature.

[0097] Table 1. Temperature distribution of different R-β combinations obtained in the experiment

[0098] R / β 15 20 25 30 35 40 300 46.01121 35.84805 30.46588 31.57834 29.52475 NaN 350 38.08079 35.33153 24.3879 NaN NaN NaN 400 31.35575 21.80423 NaN NaN NaN NaN 450 25.86344 NaN NaN NaN NaN NaN

[0099] From the above table, it can be clearly found that the true temperature of the measured R-β combination is basically consistent with the simulation temperature. The temperature that cannot be normally measured can be predicted according to the temperature distribution of the simulation (c). Figure 19

[0100] The temperature of human skin temperature sensation is between 20-47℃. When the temperature is around 35℃, the human skin produces a warm feeling. When the temperature exceeds 45℃, it produces a hot or scalding feeling. When the temperature reaches 47℃, there is a scalding pain. When the temperature is greater than 50℃, it will cause a blister. If the human skin is contacted with 60℃ for one minute, it will cause a third-degree burn. In fact, we also need to consider that being too close to the engine nozzle shell will greatly increase the heat radiation temperature. The nozzle shell can reach 170℃ during high-speed running, so we need to maintain a certain distance from it. At the same time, the larger the R-β, the larger the overall size of the hand propeller. Considering the above, we selected R=400mm and β=20degree as the design size.​​​

[0101] While the application has been described by way of example with reference to preferred embodiments, it is to be understood that persons skilled in the art can make other changes and modifications to the application without departing from the spirit and scope thereof, and that such changes and modifications are intended to be encompassed by the appended claims.

Claims

1. A design method for an arm propulsion device for a low-altitude single-person minimum flight system, the arm propulsion device for a low-altitude single-person minimum flight system includes an arm support (3), a left engine (A), a right engine (B), two engine mounts (1), a grip (4), a trigger (5) and two sets of multi-link assemblies (2), the left and right sides of the arm support (3) are respectively connected to an engine mount (1) through a set of multi-link assemblies (2), the left engine (A) and the right engine (B) are respectively mounted on the two engine mounts (1), the grip (4) is horizontally mounted at the front end of the arm support (3), and the trigger (5) is mounted at one end of the grip (4) and close to the thumb grip of the grip (4); in, The centerline of the arm support (3) intersects the axis of the top of the left engine (A) and the right engine (B) at point C, and the angle between the left engine (A) and the right engine (B) and the centerline of the arm support (3) is 15deg-25deg. The distance R between the top of the left engine (A) and the right engine (B) and point C is 300mm-400mm. Its characteristic is that the design method includes the following steps: Step 1: Design the angle β between the center line of the left engine (A) and the right engine (B) and the arm support (3), the distance R from the top of the left engine (A) and the right engine (B) to point C, and the position of the handle (4) on the axis; Step 11: Use SCDM software to establish the external fluid domain (8) and fluid domain (9) of the left engine (A) and the right engine (B), and create a BOI region (10) on the center line of the arm support (3) as the key observation area; The position of the BOI region (10) is selected as follows: a volume area of ​​100*100*100 is taken behind the intersection of the distance between the left engine (A) and the right engine (B) and the center line of the arm support (3). The center line of this volume area in the horizontal position is the position of the handle (4). Steps 1 and 2: Import the established fluid model into FLUENT Meshing for mesh generation; Step 13: After meshing, import the model into the solver and select the input and output parameters of the left engine (A) and right engine (B) according to the actual boundary conditions: the total pressure at both the output and input ports of the fluid model is 1 atm, the total inlet temperature is 288 K, the turbine speed is 98000 rpm, the fuel used is RP-3 aviation kerosene, and the fuel flow rate is 0.0118 kg / s; under the above parameters, the velocity and temperature distribution of the ejected gas under different R and β values ​​are finally obtained. Step 14: Analyze the BOI region (10) of the model under different R and β, and take the average value of temperature and velocity on the interface of the BOI region (10) as the simulation result of the model under the corresponding distance R and angle β; Step 15: Statistically analyze all results to obtain temperature and velocity distribution maps for different R and β values; Step 16: Conduct experimental tests on the distance R and the included angle β of the low temperature in the simulation results, and obtain test results with an error of less than 5% compared with the simulation results; Step 17: Experimental tests show that the larger the included angle β, the smaller the thrust generated by the left engine (A) and the right engine (B). Therefore, a trade-off needs to be made between temperature and thrust, and R = 400 mm and β = 25 degrees are finally determined. Step 2: Use topology optimization to design multi-link components; Step 21: Connect the engine bracket 1 and the arm bracket (3) with a single piece of aluminum plate (11); Step 22: Static analysis: Fix the arm bracket (3), apply a force of 300N to the engine brackets (1) on the left and right sides respectively, and retain 10% of the volume on the aluminum plate (11). During the topology optimization process, the most important structural parts will be automatically retained to achieve the effect of bearing the maximum force with the smallest volume, and a rough topology optimization structure (12) can be obtained. Steps 2 and 3: After shaping the topology optimization structure (12), the multi-link assembly (2) is obtained. Thus, the design of the arm propulsion device is completed.

2. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 1, characterized in that: The engine bracket (1) is a cylindrical bracket, which includes two semi-circular arc-shaped pieces (6) that are fastened and bolted together.

3. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 2, characterized in that: The multi-link assembly (2) includes a first link (2-1), a second link (2-2), a third link (2-3), and a fourth link (2-4). The second link (2-2) and the third link (2-3) are arranged in parallel, and one end of the second link (2-2) and the third link (2-3) are connected to an engine bracket (1), and the other end of the second link (2-2) and the third link (2-3) are connected to the same side of the arm bracket (3); One end of the first link (2-1) is connected to the second link (2-2), and one end of the first link (2-1) and one end of the second link (2-2) are located on the same side of the engine bracket (1). The other end of the first link (2-1) is tilted toward the handle (4) and connected to the arm bracket (3). One end of the fourth link (2-4) is connected to the second link (2-2), and one end of the fourth link (2-4) and one end of the third link (2-3) are located on the same side of the engine bracket (1). The other end of the fourth link (2-4) is tilted away from the grip (4) and connected to the arm bracket (3).

4. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 1 or 3, characterized in that: The arm support (3) has an elongated hole (21) on one side.

5. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 4, characterized in that: The trigger (5) has two slots (20) inside.

6. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 5, characterized in that: It also includes two electronic displacement sensors (7), the upper parts of which are inserted into the two slots (20) of the trigger (5), and the lower parts of which are inserted into and fixed in the grip (4).

7. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 6, characterized in that: The upper parts of the two electronic displacement sensors (7) are interference-fitted with the two slots (20) of the trigger (5).

8. The design method of an arm propulsion device for a low-altitude single-person minimum flight system according to claim 7, characterized in that: It also includes step three: assembling the components; Step 31: Install the grip (4) inside the arm support (3); Step 32: Insert the upper parts of the two electronic displacement sensors (7) into the two slots (20) of the trigger (5), and insert and fix the lower parts of the two electronic displacement sensors (7) into the handle (4); Step 33: Pre-install the left engine (A) inside one of the semi-circular arc-shaped pieces (6), and then fasten the other semi-circular arc-shaped piece (6) onto one of the semi-circular arc-shaped pieces (6) to complete the installation of the left engine (A). The right engine (B) is installed in the same way.

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