CN105756874A - Air suction type solar heat micro thruster - Google Patents

Abstract

The invention provides an air suction type solar heat micro thruster. The air suction type solar heat micro thruster mainly comprises a main body, an air intake channel, a diffuser pipe, a light collecting system, a heat exchange structure and a spraying pipe. The air suction type solar heat micro thruster has the advantages that the air suction type solar heat micro thruster can be applied to an ultra-low orbit satellite in an atmospheric layer which is 120-300km away from ground, air entering the micro thrust is heated by collected solar energy to obtain high-temperature air, the high-temperature air is sprayed out by the spraying pipe to produce about 0.02-2N thrust, and the thrust is very suitable for the attitude adjusting and drag compensation of the satellite; because a working medium of the micro thruster is mainly thin air, and the solar energy is used for heating, an aircraft only carries a small amount of propellant, thus the weight of the thruster is reduced, the maneuverability of an orbit is improved, the effective load of the aircraft is increased, and the on-orbit time of the aircraft is prolonged; by supplementing the propellant, the thrust produced by a thrusting system is increased, and the space application range of the aircraft is expanded.

Description

Air suction type solar heat microthruster

Technical field

The invention belongs to spacecraft propulsion system technical field, particularly to a kind of air suction type solar heat microthruster.

Background technology

It is more and more lower that Modern Satellite can run track, even occur in that and operate in the distance endoatmospheric ultralow orbiter of ground 120～300km, need during this kind of satellite transit to carry out attitude regulation and control and drag compensation, conventional chemical Push Technology passes through combusting propellant by conversion of heat into kinetic energy generation thrust propelling orbiter change rail, but the excessive attitude accuracy controlling that cannot meet satellite of thrust magnitude produced；The thrust magnitude of electric propulsion ranges between 0.1～0.005N, and thrust magnitude is too small, and during Satellite Orbit Maneuver, length consuming time needs to consume substantial amounts of electric energy.Run the track orbiter at 120～300km at present, the method of operation all adopts conventional chemical to advance, not yet adopt the novel propulsion mode of solar propulsion, the thrust range of solar thermal propulsion is identical with the frontal resistance scope that the orbiter of 120～300km is subject between 0.02～2N, during Satellite Orbit Maneuver, thrust is moderate does not need the too many time, is highly suitable for attitude regulation and control and the drag compensation of such satellite.

Summary of the invention

For overcoming deficiency of the prior art, air suction type Jet propulsion technology is combined by the present invention with solar thermal propulsion technology, design a kind of air suction type solar heat microthruster, incoming air through microthruster air intake duct compress after by convergence solar energy heating be high-temperature gas, after jet pipe sprays, produce thrust, be a kind of novel microthruster.

The present invention " air suction type solar energy microthruster ", including: main body 1, air intake duct 2, diffuser pipe 3, condenser system, heat exchange structure 4, jet pipe 5.Described main body 1 is cube configuration.The entrance of described air intake duct 2 is positioned at main body 1 side, and air intake duct 2, diffuser pipe 3, heat exchange structure 4 are airtight successively with jet pipe 5 to be connected, and the outlet of jet pipe 7 is positioned at the another side relative with the side, entrance place of air intake duct 2.

Described air intake duct 2 is rotation body structure, the bus of described rotary body is made up of two sections of curves 2.1,2.2, described curve 2.1,2.2 is by the 1/4 section of acquisition intercepting circumference, curve 2.1 concaves, the center of circle A of its place circumference is outside described rotary body, curve 2.2 convex, the center of circle B of its place circumference is at described a rotating body, curve 2.1 is positioned at the arrival end of air intake duct 4, curve 2.2 is positioned at the port of export of air intake duct 2, and the vertical dimension of the free end C distance rotation axes of symmetry 2.3 of curve 2.2 is equal with the radius of the entrance of diffuser pipe 3.Why air intake duct 2 adopts the recessed rear male structure of this elder generation, detached shock wave deceleration supercharging can be produced in air intake duct front end when being because air-flow by air intake duct and become subsonic airflow, and convex configuration clockwise is more readily formed whirlpool and blocks air intake duct, air inflow is made to greatly reduce, therefore, when air-flow has just enter into air intake duct, matrix arc structure should first be adopted.Described air intake duct surface can also adopt the coating of high temperature resistant more than 2000K, for instance SiC or Al₂O₃。

Described diffuser pipe 3 is axially symmetric structure, entrance point 3.1 is designed as circle, outlet with air intake duct 2 is airtight to be connected, the port of export 3.2 is designed as square structure, airtight with the entrance of heat exchange structure 4 it is connected, there is several aperture 3.3 along the uniformly arrangement of diffuser pipe circumference in the medium position at diffuser pipe 3 wall, as adding the entrance supplementing propellant；Incoming flow after air intake duct shock wave can regard subsonic continuous stream as, enters diffuser pipe 3 and carries out deceleration supercharging further.Before adopting, the advantage of circle rear structure design is: the configuration of expansion can alleviate the outlet pressure of air intake duct, it is prevented that backflow produces；Owing to adopting square structure heat exchange laminate that air-flow is heated, diffuser pipe exit design is that square being conducive to is connected with heat exchange structure, it is to avoid airflow leaks.

Described condenser system includes: reflecting mirror 6, main condenser 7, secondary condenser 8 and support bar 9,；Described main condenser 7 is made up of the concave surface being positioned at body upper surface, and described concave surface is paraboloid of revolution design；There is a circular hole 7.1 at paraboloidal geometric center place, and radius is R₄For placing the lens of secondary condenser 8, the area equation of the lens receiving plane of circular hole area and secondary condenser 8；Circular hole 7.1 surrounding is uniform-distribution with screwed hole 9.1, and support bar 9 one end is inserted in screwed hole 9.1, the mode stationary mirror being threaded connection and main condenser；The minute surface of reflecting mirror 6 is concave surface, and the also design in the paraboloid of revolution of described concave surface, the concave surface of reflecting mirror 6 is towards the concave surface of main condenser 7；The axis of symmetry of reflecting mirror 6 and main condenser 7 overlaps；Main condenser 7 overlaps with the paraboloid of revolution focus of both reflecting mirrors 6, makes the light beam being reflected and being formed convergence from main condenser 7 be reflected after mirror 6 reflects and become the directional light uniform irradiation lens surface to secondary condenser 8；The position of reflecting mirror 6 upper surface should lower than described microthruster upper surface to reduce frontal resistance simultaneously.

Sunray being focused in high speed rarefied gas flow environment owing to main condenser 7 is exposed, surface temperature is at about 2000K, so main body 1 adopts exotic material, for instance Molybdenum metal materials industry；Simultaneously in order to further increase effect of heat insulation, it is possible to scribble high-temperaure coating to overcome the high temperature of 1800～2000K on main condenser 7 surface, for instance can be selected for Al₂O₃As coating, melting temperature is 2322K, and surface is through polishing, it is possible to carry out effectively heat insulation.

Reflecting mirror 6 adopts resistance to 2000K high temperature above material equally, for instance molybdenum rolling forms, and the concave surface of reflecting mirror 6 adopts polishing to reduce diffuse-reflectance, is also coated with silver color high-temperaure coating, for instance Al simultaneously₂O₃, it is possible to it is thermally shielded, and prevents light therethrough reflecting mirror from causing energy loss.

Owing to aircraft runs at distance 130km place, ground, flight speed is close to the first universal speed, and No. one time condenser cannot calculate its anglec of rotation to adjust the angle of incidence of light according to position of sun in real time, thus certain ray-collecting can be caused to lose.Photo-thermal conversion efficiency in order to promote heat exchange structure needs to add secondary condensation technology.In existing secondary condensation technology, refractive secondary concentrator has efficiency of transmission greatly, absorbs the feature of little energy, and therefore the present invention chooses refractive secondary concentrator as described microthruster secondary condenser.

Described secondary condenser 8 mainly includes three parts: lens 8.1, energy extractor 8.3 and gripper shoe 8.2；Described secondary condenser 8 is placed in immediately below reflecting mirror 6, in the circular hole 7.1 at main condenser 7 center, the receiving plane of lens 8.1 is fixed by gripper shoe 8.2.The lens lower half of described secondary condenser 8 and energy extractor are inserted in the radiation heat transfer chamber 4.1 of heat exchange structure 4, energy extractor 8.3 is triangular pyramid structure, light is converged after entering lens 8.1 further, the light the converged conical surface outgoing by energy extractor 8.3, radiation heat transfer chamber 4.1 is transferred thermal energy to, it is possible to heating radiation heat exchanging chamber inwall by heat radiation effect；Heat convection is carried out again with the air-flow flow to by diffuser pipe 3.

Described heat exchange structure 4 includes: heat exchange laminate, radiation heat transfer chamber 4.1, thermal insulation board 4.4.Heat exchange laminate is heating working medium and realizes the critical component that energy converts.Described heat exchange laminate includes fin 4.3 and fin pipeline 4.2, and fin structure can improve heat exchange area, allows the flow to high efficient heat exchanging more；Fin 4.3 is attached to the outer wall of the main part of fin pipeline 4.2, the column structure that the main part of fin pipeline 4.2 adopts cross section to be ellipse, the long axis direction of this ellipse is set to parallel with diffuser pipe central axis direction, it is possible to reduce the resistance that air-flow runs into, and improves heat exchange efficiency；In order to place secondary condenser 8, being provided with cylindrical cavity as radiation heat transfer chamber 4.1 in fin pipeline 4.2, this cavity 4.1 is total to same axis with fin pipeline 4.2, and radiation heat transfer chamber 4.1 bottom design is coning to increase heat exchange area.The structure of every layer of heat exchange laminate is identical, it is possible to make gas flow temperature be evenly distributed, it is prevented that it is too high that air-flow produces local temperature after heat exchange.

The gripper shoe 8.2 of secondary condenser 8 being clamped between fixing plate 11 and fin pipeline 4.2 upper bottom surface, by screw 12, fixing plate 11, fin pipeline 4.2 upper bottom surface being fixed on thermal insulation board 4.4, thus locking the position of secondary condenser 8.

Owing to, in heat transfer process, the temperature range in radiation heat transfer chamber 4.1 is at 2200～2500K, and the material manufacturing radiation heat transfer chamber 4.1 necessarily requires have feature high temperature resistant, that specific heat is high, for instance BN pottery.

Described jet pipe 5 is designed as pyramidal structure, and this is relatively simple for structure, it is easy to manufacture.The pyramidal structure that half-angle can be adopted to be 15 ° (half-angle is generally 12 °～18 °) is as nozzle contour.

In sum, a kind of air suction type solar heat microthruster provided by the invention can be applicable on the distance endoatmospheric ultralow orbiter of ground 120～300km, the air being entered microthruster by the solar energy heating converged obtains high-temperature gas, after jet pipe sprays, produce the thrust being sized between 0.02～2N, be highly suitable for attitude regulation and control and the drag compensation of such satellite.Owing to the working medium of this microthruster mainly adopts rarefied atmosphere, and utilize solar energy to be heated, therefore aircraft only need to carry a small amount of propellant, thus alleviating thruster weight, strengthening orbit maneuver ability, increasing the payload of aircraft and extending the time in orbit of aircraft.Simultaneously because supplement the use of propellant, namely can improve thrust produced by propulsion system, the space range of application of aircraft can be expanded again.

Accompanying drawing explanation

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 microthruster sectional view of the present invention；

The geometric configuration schematic diagram of Fig. 2 air intake duct；

Fig. 3 diffuser pipe structural diagrams is intended to；

Fig. 4 condenser system close-up schematic view, wherein 10 represent to come flow path direction, and 6.1 represent light path；

Fig. 5 secondary condenser structural representation；

Fig. 6 secondary condenser top view；

Fig. 7 heat exchange structure front view；

Fig. 8 heat exchange structure side view；

Fig. 9 heat exchange structure cross sectional representation；

Figure 10 heat exchange structure top view；

Profilograph after Figure 11 secondary condenser and heat exchange structure assembling；

Schematic perspective view after Figure 12 secondary condenser and heat exchange structure assembling；

Figure 13 nozzle structure schematic diagram；

The undressed front top view of microthruster main body in Figure 14 embodiment；

In Figure 15 embodiment, microthruster body upper surface processes the top view after concave surface；

Microthruster top view in Figure 16 embodiment；

Microthruster front view in Figure 17 embodiment；

Microthruster left side view in Figure 18 embodiment；

Microthruster right side view in Figure 19 embodiment；

Radiation heat transfer cavity wall and secondary condenser Temperature Distribution cloud atlas locally in Figure 20 embodiment；

The Temperature Distribution cloud atlas that in Figure 21 embodiment, microthruster is overall.

Specific embodiments

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of protection of the invention.

The generally cube configuration of described microthruster, as shown in figure 14, it is of a size of 1.80m × 1.10m × 1.10m (long × wide × high) to its top view.First thereon bottom surface processes a spill paraboloid of revolution, as shown in figure 15, then along axis 1.2, cube is cut open into two parts of symmetry, two sections process the shape of air intake duct, diffuser pipe and jet pipe, and the installation site of secondary condenser and heat exchange structure, as shown in Figure 1.After heat exchange structure and secondary condenser are placed, two parts of main body are threadedly fastened, microthruster entirety top view, front view, left side view, right side view are such as shown in Figure 16～Figure 19, wherein 1.3 expressions are used for fixing the two-part screw of microthruster, and 2.4 represent the entrance of air intake ducts.Owing to overall bearing temperature is between 1500～2000K, choose molybdenum as microthruster material of main part.

The air-breathing of air suction type solar energy microthruster, diffusion, optically focused, heat exchange, jet five part primary structure are combined closely, and are organic wholes.From the gas of collection orbit altitude to finally producing thrust, it it is a more complicated process.The designing and calculating that design calculation result often a part of in this course is all next part provides initial condition.Describe the work process of whole system by the examples below in detail.

1, air intake duct

The working environment of air suction type solar heat microthruster is the track high from ground 130km.With this understanding, the flowing of air intake duct is rarefied atmosphere flowing.The configuration of air intake duct 2 is made up of two quarter circular arc, and orthodrome 2.1 is positioned at air intake duct leading portion, and radius is R₁, small arc-shaped 2.2 is connected with air intake port, and radius is R₂.The present embodiment is selected R₁=0.35m, R₂=0.15m.According to designing requirement, air intake duct front face area is given as 1m², owing to air intake duct is axisymmetry structure, can calculate and obtain inlet mouth radius L₄=0.56m.Air intake duct length L₂It is two arc radius sums, L₂=R₁+R₂=0.5m, air intake port radius L₃=L₄-R₁-R₂=0.06m.Air intake duct leading portion is compressed with overlapped way, and most high density area is distributed between 0.4m～0.5m, keeps a segment distance with outlet, so that gas has had certain expansion distance by compression afterwards, it is easier to high density gas is discharged.Air velocity is 7500m/s near inlet mouth, drops to about 500m/s in exit.This process experienced by a shock-wave effect, and after shock wave, stream pressure and density raise, and speed reduces.Incoming flow is in air intake duct after overcompression, and density becomes 4 × 10^-5kg/m³, mass flow is 0.105g/s, is a kind of more satisfactory Design of Inlet.The surface of air intake duct 4 can also adopt SiC as coating material, and melting temperature is 2818K, it is possible to bear the high temperature of 1800K.

2, diffuser pipe

Gas has met continuity hypothesis condition after being entered diffuser pipe 3 by air intake duct 2, incoming flow is relatively big due to Entropy Changes, need to add supplementary propellant, adopts water working medium as a supplement in the present embodiment.The equivalent diameter d at diffuser pipe square outlet 3.2 place is calculated by formula (1),

$d=\sqrt{\frac{4S}{\mathrm{\π}}}---\left(1\right)$

Wherein S is diffuser pipe exit cross-section area.

The exit condition of air intake duct 2 is as the entry condition of diffuser pipe 3, and input static pressure is 35Pa, and stagnation pressure is 45Pa, and temperature is 1600K；The outlet of diffuser pipe 5 is pressure export, and pressure is 40Pa；The inlet pressure supplementing propellant steam is 45Pa, and initial velocity is 0m/s, and temperature is 700K, and mass flow is 0.08g/s, is 0.76 times that carrys out current mass collected.

After compression flows into diffuser pipe 5, mix with the supplementary propellant steam flowed into by propellant entrance 5.3, owing to the temperature of water is relatively low, therefore reduce at supplementary propellant inlet temperature, mix the latter two temperature reach balance time, the temperature of mixed working fluid is 1100K.Before mixing, incoming-flow pressure is gradually reduced, and in steam mixing place position, pressure has part to jump, and this is owing to steam enters the static pressure that the pressure of air intake duct needs is greater than in fluid, is increased to 45Pa from 43Pa, and then as flowing, air flow pressure is reduced to 43Pa.

After flowing into diffuser pipe, speed is gradually reduced by 500m/s, through mixed zone, adding steam working medium, after mixing according to both momentum theorems, speed moment diminishes to 200m/s, afterwards owing to viscosity and flow area become the factor such as big, speed gradually decreases to 80m/s.

Current density of coming after air intake duct is 4 × 10^-5kg/m³, through mixed zone, owing to adding steam, density increases to 1.25 × 10^-4Kg/m³, afterwards along with flowing, density tends to uniform gradually, finally stable 9.8 × 10^-5kg/m³。

The design parameter size of diffuser pipe is in Table 1.

Table 1 diffuser pipe parameter size

3, main condenser

The present embodiment being assumed, solar radiation area is S_Too=1.3m², by S_Too=π R₃ ²Obtain the maximum radius R of main condenser 7 paraboloid of revolution₃=0.643m.Main condenser 7 is with parabola y=x²/ 4f is the rotation profile of bus, and wherein f is parabolical focal length, and f must is fulfilled for R₃ ²/ 4f > f, the present embodiment takes f=0.25m.

Sunray being focused in high speed rarefied gas flow environment owing to main condenser is exposed, surface temperature is at about 2000K, and in order to further increase effect of heat insulation, main concentrator surface is coated with Al₂O₃, melting temperature is 2322K, and the high temperature of 2000K, through polishing, therefore can be born without deforming in surface.The physical dimension parameter of condenser and material are in Table 2.

The main condenser material of table 2 and parameters of structural dimension

4, reflecting mirror

The reflecting surface of reflecting mirror 6 is also designed to paraboloid of revolution type, and the sunray making convergence that overlapped with the focus of reflecting mirror 6 by main condenser 7 becomes directional light by the focus of reflecting mirror and is irradiated in secondary condensation system.

Reflecting mirror 6 adopts metal molybdenum rolling to form equally, is fixed with microthruster main body 1 by support bar 9, and mirror reflection surface adopts polishing to reduce diffuse-reflectance, it is prevented that light therethrough reflecting mirror causes energy loss.

Owing to the radius of the sun is 6.96 × 10⁵Km, earth radius is 6371km, ground day track operating radius be 1.496 × 10⁸Km, from the earth, the sun is spheroid, it is impossible to regards the sun as particle and is calculated, and therefore reflecting mirror area should be greater than the projected area of the sun.

The light of sun injection arrives terrestrial time and has only small angle, i.e. sun subtended angle 2 θ.

Try to achieve θ=16 ', sunray is irradiated to the earth with sun subtended angle 32 ', assumes that sunray is parallel radiation to simplify to calculate before, and therefore all light all converge in focus, due to the impact of sun subtended angle and incident ray angle, all light form little sun picture near focal point.

Along with the change (being not more than sun subtended angle) of solar radiation angle, sunray gets to different positions, forms small sun picture.Reflecting mirror area have to be larger than the minimum sun image planes of incident ray formation and amasss, to guarantee all to be reflexed to by light source in birefringence condenser, due to the complexity of optical path analysis, here do not do labor, obtain the sun imaging radius r of theory through inspection information_TooWith collection solar radiation panel radius R₃Relational expression:

r_Too=0.005 λ R₃(3)

Wherein R₃=0.643m, λ are safety coefficient, and Practical Project technology and reflecting mirror material bear the restriction of maximum temperature, and safety coefficient is more big, and the reflecting surface temperature of reflecting mirror is more low, owing to reflecting mirror cannot be made too little by the impact of sun angle, take λ=5. and obtain r_Too=0.0126m, the light-receiving area of reflecting mirror is π r_Too ²=4.987 × 10^-4m², the geometric concentrating ratio of main condenser is:

C_g1=π R₃ ²/πr_Too ²=1600 (4)

Table 3 is mirror structure size.

Table 3 reflecting mirror material and parameters of structural dimension

The installation site of reflecting mirror 6 should not exceed the upper bottom surface of microthruster main body 1, otherwise can produce unnecessary frontal resistance；The bottom surface of reflecting mirror 6 can be analyzed by being given above size (so-called middle section refers to bottom surface in main body apart from equal with main body middle section 1.1, and the plane parallel with upper bottom surface) vertical dimension h=0.31m, this distance is less than the half H=0.55m of body height, thus without producing frontal resistance.

5, secondary condenser

Secondary condenser 8 is to convert solar energy into the core component of heat energy, the main heat exchange mode of secondary condenser 8 and laminate inwall is radiation heat transfer, it is divided into two parts: a part is the penetrating component of environment projection radiation, and another part is the reflected radiation at side medium interface.

By the Temperature Distribution cloud atlas (Figure 20) of radiation heat transfer cavity wall and secondary condenser local it can be seen that, in the present embodiment, the temperature of energy extractor 8.3 is up to 2400K, radiation heat transfer chamber 4.1 internal face bottom temp is made to rise to 2315K by radiation heat transfer, internal heat conduction makes whole radiation heat transfer chamber 4.1 internal face temperature maintain about 2200K, heat exchange laminate outside wall surface temperature difference is up to 122K, between heat exchange laminate, surface temperature is more or less the same, it is ensured that the stability of the air-flow after heating.

The focusing ratio of secondary condenser 8 is less than 10², mirror body selects monocrystal sapphire material, does not result in too much energy loss to the absorption efficiency of sunray is very low, carries out secondary convergence to once converging the sunray obtained, the diameter d of reflecting mirror bottom surface in embodiment_InsteadIt is designed as 0.024m, the relational expression of its radiation heat transfer chamber 4.1 internal temperature and geometric concentrating ratio:

$T_s={\{\frac{(1-\mathrm{\η}){\mathrm{\ρ\αC}}_g{\sin }^2{\mathrm{\ζT}}_{sun}^4}{\mathrm{\ϵ}}+T_{amb}^4\}}^{\frac{1}{4}}---\left(5\right)$

T in formula_sFor radiation heat transfer chamber internal temperature；C_g=4960 is geometric concentrating ratio；η=0.96 is the proportion of energy loss shared by heat conduction and convection current；α=0.98 is the absorption efficiency of heat exchanger；ρ=0.95 is the surface reflectivity of condenser；ζ=32 ' are sun subtended angle；ε=0.3 is the emissivity of absorber；T_sun=5780K is solar temperature；T_amb=360K is ambient temperature；It is about 5000 that rough estimate to maintain the total focusing ratio of geometry that radiation heat transfer chamber internal temperature is 2400K needs.

The total focusing ratio of geometry of condenser system is equal to the geometric concentrating ratio of main condenser 7 and the geometric concentrating ratio product of secondary condenser 8,

C_g=C_g1×C_g2(6)

C in the present embodiment_g1=1600, C_g2=3.1, so the total focusing ratio C of the geometry of condenser_g=4960, it is possible to meeting maintenance radiation heat transfer chamber internal temperature is the demand of 2400K.

The cross-sectional diameter of energy extractor is designed as 0.017m, owing to light says row total reflection, sapphire refractive index n=1.76, refraction angle in refractive secondary concentratorAs long as the cone angle 10.4 when therefore lens are to axle body transition is less than 34.62 °.In the present embodiment, the angle at axle body inclination angle is 10 °, can calculate that to obtain lens entire length be 0.088m.

The physical dimension parameter of secondary condenser is in Table 4.

Table 4 secondary condenser parameters of structural dimension

6, heat exchange laminate

Heat exchange laminate is heating working medium and realizes the critical component that energy converts.Light is converged by secondary condenser 8, transfers thermal energy to radiation heat transfer chamber 4.1 by heat radiation effect, then carries out heat exchange with the air-flow flow to by diffuser pipe 3.

Embodiment adopts the heat exchange structure of fin shape.Generally cube configuration, wherein comprises 20 fins 4.3, and every fin clearance is 5.29mm, and the cross section of fin pipeline 4.2 is oval (as shown in Figure 9), and its short-axis direction is with to carry out flow path direction vertical.Fin pipeline more than 4.2 is square fixing plate 11, and fixing board size is 120mm × 120mm × 10.31mm (long × wide × high).Owing to, in heat transfer process, the temperature in radiation heat transfer chamber 4.1 is significantly high, the present embodiment selects BN pottery as the material in radiation heat transfer chamber 4.1.The diameter in radiation heat transfer chamber 4.1 is 40mm, and length is 118mm, and the angle of bottom element of cone and its axis of symmetry is 37.23 °.The relevant parameter of heat exchange laminate is in Table 5.

Table 5 heat exchange layer board parameter

Incoming flow is heated by heat convection through out-of-date by heat exchange laminate at compression incoming flow so that gas flow temperature raises.Analysis process is ignored the thermal contact resistance between fluid and solid, between solid and solid；And assume convection transfer rate uniformity in flowing, not with distance change.The discharge state parameter of diffuser pipe 3 is as the inlet condition parameter of heat exchange laminate, input static pressure 45Pa, and stagnation pressure is 55Pa, and air velocity is 80m/s, and temperature is 1100K.Heat exchange laminate adopts BN material, and heat conductivity is 52W/ (m K), and thermal source is set in heat exchange laminate internal face, and fixed temperature is 2300K.

Air-flow reduces through fin plate flow section so that speed raises as 300m/s, then cross section of fluid channel increase so that air-flow is decelerated to 160m/s through fin afterbody, and pressure is then gradually lowered to 30.5Pa, and excursion is less.The state equation P=ρ RT selecting ideal gas analyzes, if pressure change is little, then when temperature is raised, current density can reduce.In fin, temperature rises acutely, the therefore decrease in density of air-flow after fin heat exchange.

Air-flow temperature before experience fin remains unchanged as 1100K, and fin plate temperature is 2400K.When flowing through fin plate, air-flow is gradually heated to 2200K, flows out fin afterwards, flows into the changeover portion of heat exchange structure and jet pipe 5.

Owing to the material of thermal insulation board 4.4 is polymeric foam, effect of heat insulation is good, Figure 21 is the Temperature Distribution cloud atlas that microthruster is overall, can be seen that heat exchange laminate can be maintained at the temperature that temperature is more than 2000K and remain unchanged by thermal insulation board, and making thruster bulk temperature maintain about 1700K, main condenser place temperature is minimum for 1600K；The variations in temperature of heat exchange structure is mainly distributed on diffuser pipe near exit and nozzle inlet vicinity.

7, jet pipe

Jet pipe 5 is accepted with heat exchange layer plate exit, so nozzle entry state parameter is consistent with heat exchange layer plate exit, inlet pressure is 30.5Pa, speed 160m/s is negligible compared to the speed 7.8km/s of free incoming flow, temperature is 2200K, exports as ambient pressure, and pressure is 1.2 × 10^-5Pa。

After air-flow enters the heat exchange structure changeover portion with jet pipe 5, owing to flow section becomes big, air velocity increases, and causes that gas flow temperature declines, therefore air-flow density of air-flow when jet pipe is detained has certain rising compared with the density in heat exchange structure so that the total body density of air-flow remains as 1.0 × 10^-4kg/m³Left and right.

Air-flow expansion process in jet pipe 5 is one and flows the mixed process to thin stream from continuous.Air-flow is accelerated by jet pipe, makes density sharply decline, and declines the most violent in throat position.Along with the reduction of current density, when distance nozzle throat position x=0.36m, density is reduced to ρ=3.073 × 10^-7kg/m³, reached the critical point of seriality air-flow.Second half section air-flow cannot regard seriality gas as.Air-flow is in outside nozzle, and jet pipe flow isSpeed is v₂=3200m/s, outlet pressure p₂=1.2 × 10^-3Pa, density p=1.16 × 10^-7kg/m³More than surrounding density p_o=2.22 × 10^-8kg/m³, jet pipe is in overexpansion state, and the air-flow namely sprayed also may proceed to expand

Little nozzle-divergence angle α makes the momentum direction of most air-flow axially, then obtains higher specific impulse, but long jet pipe adds the dry mass of propulsion system and the complexity of design.Comprehensive factors above, the conical nozzle that the present embodiment adopts half-angle to be 15 °.

The dimensional parameters of jet pipe 5 is in Table 6.

Table 6 jet pipe dimensional parameters

8, thrust calculates

The momentum of gas flow jet produces thrust in solar heat thruster structure.Owing to flowing is supersonic speed, nozzle exit pressure is more than ambient pressure, and the thrustmeter that therefore jet produces is shown as:

$F=\mathrm{\β}\stackrel{\·}{m}{v}_2+(p_2-p_3)A_2---\left(7\right)$

β is theoretical correction coefficient, β=0.983；Outlet pressure p₂=1.2 × 10^-3Pa；p₁For ambient pressure；A₂For nozzle exit area.

(7) Section 2 in formula is ignored.The mass flow of high temperature mixing incoming flow is 0.1857g/s, and speed is 3200m/s, obtains generation thrust through calculating and is:

$F=\mathrm{\β}\stackrel{\·}{m}{v}_2=0.983\×0.1857\×{10}^{-3}\×3200=0.582N---\left(8\right)$

And frontal resistance is 0.4N, the thrust that therefore thruster produces after adding the supplementary propellant that mass flow is 0.08g/s can maintain aircraft in orbit.

The above; being only the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, any those familiar with the art is in the technical scope that the invention discloses; the change that can readily occur in or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.

Claims (8)

1. an air suction type solar energy microthruster, including main body (1), air intake duct (2), diffuser pipe (3), condenser system, heat exchange structure (4), jet pipe (5)；

Described main body (1) is cube configuration；The entrance of described air intake duct (2) is positioned at main body (1) side, air intake duct (2), diffuser pipe (3), heat exchange structure (4) are airtight successively with jet pipe (5) to be connected, and the outlet of jet pipe (5) is positioned at the another side relative with the side, entrance place of air intake duct (2)；

Described air intake duct (2) is rotation body structure, the bus of described rotary body is by two sections of curves (2.1), (2.2) constitute, described curve (2.1), (2.2) by the 1/4 section of acquisition intercepting circumference, curve (2.1) concaves, the center of circle A of its place circumference is outside described rotary body, curve (2.2) convex, the center of circle B of its place circumference is at described a rotating body, curve (2.1) is positioned at the arrival end of air intake duct (2), curve (2.2) is positioned at the port of export of air intake duct (2), the vertical dimension of free end C distance rotation axes of symmetry (2.3) of curve (2.2) is equal with the radius of the entrance of diffuser pipe (3)；

Described diffuser pipe (3) is axially symmetric structure, entrance point (3.1) is designed as circle, outlet with air intake duct (2) is airtight to be connected, the port of export (3.2) is designed as square structure, airtight with the entrance of heat exchange structure (4) it is connected, there is several aperture (3.3) along the uniformly arrangement of diffuser pipe circumference in the medium position at diffuser pipe (2) wall, as adding the entrance supplementing propellant；

Described condenser system includes: reflecting mirror (6), main condenser (7), secondary condenser (8) and support bar (9)；Described main condenser (7) is made up of the concave surface being positioned at main body (1) upper surface, and described concave surface is paraboloid of revolution design；There is a circular hole (7.1) at described paraboloidal geometric center place, is used for placing the area equation of the lens receiving plane of the lens (8.1) of secondary condenser (8), circular hole (7.1) area and secondary condenser 8；Circular hole (7.1) surrounding is uniform-distribution with screwed hole (9.1), support bar (9) one end is inserted in screwed hole (9.1), and reflecting mirror (6) is fixed on main condenser (7) by the mode being threaded connection；The minute surface of reflecting mirror (6) is concave surface, and the also design in the paraboloid of revolution of described concave surface, the concave surface of reflecting mirror 8 is towards the concave surface of main condenser (7)；The axis of symmetry of reflecting mirror (6) and main condenser (7) overlaps；The two the focus of the paraboloid of revolution of main condenser (7) and reflecting mirror (6) overlaps；

Described secondary condenser (8) is refractive secondary concentrator, mainly includes three parts: lens (8.1), energy extractor (8.3) and gripper shoe (8.2)；Described secondary condenser (8) is placed in the circular hole at reflecting mirror (6) underface, main condenser (7) center；The lens lower half of described secondary condenser (8) and energy extractor (8.3) are inserted in the radiation heat transfer chamber (4.1) of heat exchange structure (4), and energy extractor (8.3) is triangular pyramid structure；

Described heat exchange structure (4) including: heat exchange laminate, radiation heat transfer chamber (4.1), thermal insulation board (4.4)；Described heat exchange laminate includes fin (4.3) and fin pipeline (4.2)；Fin (4.3) is attached to the outer wall of the main part of fin pipeline (4.2), the column structure that the main part of fin pipeline (4.2) adopts cross section to be ellipse, the long axis direction of this ellipse is set to parallel with diffuser pipe central axis direction；In order to place secondary condenser (8), fin pipeline (4.2) is provided with cylindrical cavity as radiation heat transfer chamber (4.1), this cavity (4.1) and fin pipeline (4.2) same axis altogether, radiation heat transfer chamber (4.1) bottom design is coning；The gripper shoe (8.2) of secondary condenser (8) is clamped between the upper bottom surface of fixing plate (11) and fin pipeline (4.2), by screw (12), fixing plate (11), fin pipeline (4.2) upper bottom surface is fixed on thermal insulation board (4.4)；

Described jet pipe (5) is designed as pyramidal structure.

2. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that described main body (1) adopts the material of resistance to 2000K high temperature above, it is preferable that molybdenum.

3. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that the surface of described air intake duct (2) can also be coated with the material of resistance to 2000K high temperature above, it is preferable that SiC or Al₂O₃。

4. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that the position of described reflecting mirror (4) upper surface should lower than the upper surface of described microthruster.

5. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that the material of resistance to 1800～2000K high temperature can be coated with on main condenser (7) surface, it is preferable that Al₂O₃, and through polishing.

6. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that reflecting mirror (6) adopts the material of resistance to 2000K high temperature above, it is preferable that molybdenum；The concave surface of reflecting mirror (6) adopts polishing, it is also possible to be coated with the resistance to 2000K high temperature above high temperature coating of silver color, it is preferable that Al₂O₃。

7. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that radiation heat transfer chamber (4.1) adopt the material of resistance to 2200～2500K high temperature, it is preferable that BN pottery.

8. air suction type solar energy microthruster as claimed in claim 1, it is characterised in that the pyramidal structure that jet pipe (5) can adopt half-angle to be 15 ° is as nozzle contour.