JPH0392585A - Arc jet propulsion apparatus - Google Patents

Abstract

PURPOSE: To improve efficiency and performance by providing a device for applying voltage to an anode and a cathode and a device for supplying a fuel gas mixture of high molecule fuel and low molecule fuel to an arc in an arc chamber. CONSTITUTION: A power controller 30 is electrically connected between an anode mainbody 12 and a cathode rod 14 to generate a potential difference between a plus on the anode mainbody 12 side and a minus on the cathode rod 14 side and generate an arc 32 traveling a gap 28. The arc 32 is forced along the surface 22 of a throttle 20 to the downstream with the spiral pressure flow of a fuel gas, as shown by an arrow mark 34, carried through the gap 28 outward of a nozzle 24 and stabilized on the surface 26 thereof. The fuel gas is heated in an area of the restriction 20 and an area of arc diffusion from the restriction 20 in a port 36 of the nozzle 24 in the downstream of an outlet to then exhaust superheated gas to the outside of the nozzle 24 and generate thrust.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates generally to small propulsion systems for spacecraft maneuvering, and more particularly to electrothermal arc jet thrust systems employing any one of a variety of performance-improving features. @Related to Europe.

[Prior Art and Problems] As is well known, an electrothermal arc jet thrust device converts electrical energy into thermal energy by flowing through an arc discharge (11) and converts it into thermal energy by heat transfer to the advancing fuel, and expands the heated fuel through a nozzle. It converts concentrated thermal energy into directional mechanical energy. For a description of historical aspects of the construction and operation of arcjet thrusters and the problems associated with this type of electrothermal propulsion, 1.
June 965, NASA Technical Note D-2868
ner) and J. Czi
ka, Jr. ) thrusters for space propulsion by Honorman (Hollman) Air Force! ijl! In March 11966, construction work 7-C
To>1-tsuhi (F.G. Per+yio) AD
671501 and HcGraw-t by R.G. John in 1968.
``Physics of Electric Propulsion'' by l i l i publisher
is referenced. Also cited is the US patent of G.L. CANN.

A common feature of most electrothermal arc jet thrust devices is an anode in the form of a nozzle body and a cathode in the form of a cylindrical rod with a conical tip. The nozzle body is provided with an arc chamber formed by a constriction in the rear part of the body and a nozzle in the front part. I! The i-pole rod is aligned along the longitudinal axis of the nozzle body, and its conical tip extends beyond the constriction to the upstream end of the arc chamber, forming a gap therebetween.

An electric arc first occurs between the cathode rod and the anode nozzle body at the entrance of the constriction. The arc is then directed downstream through the constriction by a pressurized swirling flow of propellant gas introduced into the arc chamber around the cathode rod. The electric arc becomes stable and adheres to the nozzle. The propellant gas is heated in the region of the constriction and in the region of arc diffusion at the mouth of the nozzle downstream of the outlet from the constriction. Superheated gas is discharged outside the nozzle and generates thrust.

Historically, pure propellant fuels have typically been ammonia (N
Hydrazine (N204) has been used as a propulsion fuel in an arc jet propulsion system developed by the assignee of the present invention. Propulsion fuels such as ammonia and hydrazine can be stored as liquids in space without freezing, but cryogenic fuels such as hydrogen and helium cannot be stored.

Fuel that can be easily stored in space (e.g. N3, N2
The impulse level that can be achieved with 114> is 800-10
00 (force/second bond per pawn bond) 1bf/sec
/Ibm, the maximum achievable with low temperature propulsion fuel (mouth 2, mouth e, etc.) is 1.500j! br・Sec/J b
However, it is considerably lower than the typical figure.

Silently, the performance advantages of cryogenic fuel's extremely low molecular weight are offset by the same properties that make storage of this burnt-off material difficult and expensive in space. Nevertheless, it would be desirable to be able to improve thrust performance to approach levels achievable with the use of low-volume propulsion fuels without incurring such fuel-related difficulties.

FEATURES OF THE INVENTION The present invention provides an improved performance arcjet thrust device constructed to meet the needs described above.

The basis of the present invention is that arcjet propulsion performance can be improved and enhanced through a clear formulation of the propulsion tIM utilization used in thrusters and a more sophisticated approach to the injection and circulation of the fuel flow within the arc chamber of the thruster. This is the idea.

The present invention incorporates several distinct features not present in the prior art, and which substantially overcomes the problems associated with the use of cryogenic fuels, makes arcjet thrusters economical for spacecraft operations. It also provides a promise to improve the performance of the arc jet thrust device in order to make it a reliable J(C) device.Most of the features can be suitably incorporated into the same arc jet thrust device and can be significantly improved. Although efficiency and performance are achieved, it is sometimes possible to separate the benefits of some of these features from others and enjoy them in different thrust gi nails.

Fundamentally, each of the above features provides a 4q improvement in the performance, efficiency and/or useful life of the arcjet thruster. One feature is the addition of a small second gas component, preferably a low gAffi agent, to the large storable propulsion fuel feed stream for specific impulse enhancement to the arc jet.

Another feature is that, first, the physical properties of the arc have been modified to reduce the amount of energy lost to refrigeration, and second, the thermal and chemical environment of the cathode surface has been modified. control and minimize thermal stress and chemical agitation.
In order to thereby extend the life of the cathode, the cabin M2 gaseous fuel, also preferably a low-temperature propulsion fuel, is injected into the region of the arc chamber surrounding the cathode of the propulsion AM.

Yet another characteristic point is the tI in the boundary layer of the constriction part.
NSL! : Implementation of small propulsion M slope recirculation in which the significant pressure difference between the injection point near the cathode and the injection point is used as a preheating device for the fuel feed to the central arc region, increasing thrust efficiency and specific impulse. be.

The last feature to be mentioned is that the feed gas in the reactor/regenerator is
One point is the production of JFF advanced fuel gas mixtures for improved arc jet performance through JIII decomposition.

These and other advantages and achievements of the present invention will be apparent to those skilled in the art from the following detailed description, which is given in conjunction with the accompanying drawings which illustrate embodiments of the invention. 1, Q is applied to the same or corresponding parts throughout the drawings. In different embodiments of the propeller incorporating the features of the invention, the same parts are applied to the same parts as in standard or prior art propellers. Reference numbers also use different characters.

In FIG. 1, a schematic diagram of a standard constricted arc geometry electrothermal arc jet propeller 10 according to the prior art is shown. As is well known, the arcjet propulsion device 10 is
There is provided an anode 12 in the form of a cylindrical body essentially made of conductive metal and a cathode 14 in the form of a II1% rod made of conductive metal with a conical tip 16. The anode body 12 has a constriction 20 in the form of a cylindrical surface 22 at the rear part of the body and a conical surface 26 at the front part. An arc chamber 18 formed by a nozzle 24 is provided. The cathode rod 14 is provided with its tip 16 extending to the upper i end of the arc chamber 18 and extending beyond the constriction part 20 to form a gap gA28 therebetween.

The power controller 30 connects the cathode wood body 12 and the anode rod 14.
The anode body side 1 is electrically connected between the
2 plus the cathode rod side 14 minus and act to generate a potential difference therebetween to generate an arc 32 across the gap Fjl 28. Is the configuration of the power controller 1 and roller 30 within the skill of the art? P''C--is well known and is therefore shown in block diagrams lv--and its detailed description merely adds complexity to the description of the arcjet propulsion device 10 without adding to its simplicity. It merely increases the

An arc 32 is first generated at the entrance to the constriction 20 between the tip 16 of the cathode rod 14 and the anode body 12. Next, this arc 32 is along the surface 22 of the constriction part 20, and the arrow 34
As shown in the figure, the pressurized spiral flow of fuel gas drives it downstream and passes through fi128 and is throttled. JS2
0 to the outside of the nozzle of the W advancer 10. The arc 32 is stabilized at the surface 26 of the nozzle 24 of the anode body 12.

Standard aperture arc geometry above arcjet propulsion!
10, the electric arc 32 is connected to the flat t of the cylindrical surface of the constriction part.
Due to the electrode shape and the dynamic force of the radial gas in the induced swirl generated by the tangential injection of the propellant fuel, the fuel gas is "throttled" in the region of the throttling section 20 and the nozzle 24 downstream of the exit from the throttling section. The superheated gas is then heated in the region of the arm diffusion at the mouth 36 of the nozzle 24.
is discharged to the outside and generates thrust. The electrical circuit of the arc jet propulsion III is completed between the cathode rod 14 and the anode body 12 with arc deposition occurring in the area of the nozzle rod 36. The location of the arc attachment on the anode body 12 is determined by the flow rate of the bulk charge which forces the arc diffusion area down the nozzle 24 and the conductive area Wt for arc attachment.
Depends on the availability/cost of the 5III3-pole main body.

The suboptimal performance of standard arcjet propulsion machine 10 in quasi-arc jets is due, at least in part, to two deficiencies. The first drawback, as mentioned above, is that propellant fuels such as ammonia and drazine, which are most commonly considered for use in 7-jet jets advancing into space, are also relatively easy to store in the darkness of space. The point is that the level of specific impulse that can be achieved is limited.

Therefore, as expected, its use only results in suboptimal performance of the propulsion machine. Other important fuels, such as cold gas hydrogen and helium, can achieve much higher specific impulse levels but pose storageability problems that make them unsuitable candidates for missions requiring large propellant fuels.

The second drawback is that in the R life test that exceeds 8 hours, it is 4! ! The quasi-arcjet thrust IfA10 is applied to the extremely reactive species formed by the minute impurities in the grades of ammonia and hydrazine used in the fuel. The cathode 14 is at a point where it corrodes considerably due to exposure to the etchant. To explain this second drawback in more detail, in the Muku quasi-arcjet propulsion device 10, the fuel gas is
It is introduced into the portion of the arc chamber 1 around the cathode 14 so as to give the anode body 12 and the axis 11A of the aperture group 20 a significant circumferential velocity vector in addition to the velocity component directed downstream. As a result, a t4 winding flow is formed concentrically with the axis MA and substantially parallel to the cylindrical body 22 of the throttle section 20 toward the expansion nozzle 24. The morphological characteristic of the forceful swirl flow is the formation of a low moon in the central core surrounded by high pressure in the outer flow region near the constriction wall or surface 22. The resulting large gradient in the radial direction causes an electric arc to fly in the direction of the axial force between the cathode 14 and the anode 12? - It functions to stabilize the arc 32 and confine the arc to the central low core as shown in FIG. This initial mechanical confinement of the gas facilitates operation of the arc 32 at temperatures well above the melting point of the anode body 12 material, which is typically a refractory material such as tungsten. An extremely large radial temperature gradient occurs at the constriction section 20.
and generated in the nozzle 24, the temperature near the center of the plasma arc 32 exceeds 10,000 degrees absolute degree, and the overall average wetness is 3500' to 5000 degrees K.

Arc operation and therefore propulsion performance is governed by a complex balance of heat generation, heat transfer, chemical and ionic reactions, and radiation processes that are strongly influenced by the properties of the propellant gas.

The following features of the invention are characterized by different propulsion fuel mixtures or brightness for arc jet propulsion machines. The standard arc jet propulsion 8110 described above is directly related to the systematic configuration and improvement of fuel production and circulation within the arc chamber.
I recommend reducing the disadvantages of y! 8! improve the performance of

A first feature of the present invention is the provision of different fuel mixtures containing high specific impulse additives in ordinary bulk propulsion fuel for the arcjet thruster 3i aircraft. It is aimed at improving bamboo ability. A mixture of a small fraction of a secondary low molecular weight gas component such as low aqueous gas hydrogen with a bulk storage propellant gas such as ammonia has a much higher arc than predicted by the large hanging load average of the pure component performance parameters. It has been proven that jet propulsion aircraft performance can be achieved.

This improvement in propulsion performance is illustrated by the graph in Figure 2, which shows data obtained from tests with a 30KllI class Arcjet propulsion machine. The data are plotted as specific impulse (Iso) as a function of the propulsion input power P versus the ratio of total flow bed rate (m>) for different W1 propulsion fuel mixtures.
120 and pure ammonia N. Experimental data for the feed gas as well as various N:H2 mixtures are shown. Thus, a large admixture of 20% hydrogen and 80% ammonia per ff2ffi can produce specific impulse values in the arcjet thrust device that are close to the average of the pure component specific impulses.

These dramatic effects are generally attributable to the reduction in 1l state, particularly freezing 11 loss, that low molecular weight additives such as hydrogen have on arc operating physics. Freeze flow network loss, including ionization, dissociation, and energization of molecules into excited molecular states, occurs when the fuel gas is heated to a very high temperature in contact with the electric arc and exhausted to the outside of the nozzle.

An insufficient V# interval is allowed in the high pressure region to allow ions and dissociated molecules to recombine or to relax the excited state.

Therefore, these puot? Energy locked into the base is lost and cannot be used for thrust.

Peasant farmers can add additives or "seed" ingredients to the largest fuel FIPR in any of several ways. One method is to mix the separately stored components into a homogeneous mixture prior to their introduction into the arc chamber at the cathode. Another method is to store and then use the gas as a homogeneous mixture. Yet another method is to separately store additives within the region surrounding the cathode, preferably at the center of the flow, where changes in arc operation can be much more dramatic than large mixing of the components upstream from the force device. Arc f! This is a method of injecting into four areas. (A device for such injection is related to the second and third features of the present invention described below). Yet another method is to use a large trough in the reactor/regenerator to utilize the waste heat from the W1 fsFl pole body. 11611 production of the desired additive by partial chemical decomposition of the fuel feed stream (apparatus for such additive generation is related to the fifth aspect of the invention described below).

Fuel Drop in the Cathode Tip Region The second and third features of the present invention are two methods for discharging separately stored quantities of fuel and additives into the region around the cathode.
It involves two different devices. FIGS. 3 and 4 show improved performance arc jet propulsion systems lflOA and 1 according to the first and second embodiments that utilize these respective characteristics.
Indicates 0B. Thrust device ff10A. The basic design and construction of 10B is generally similar to standard propulsion 8110 of FIG. 1, and therefore only the differences will be discussed in detail below.

In both the first and second embodiments, thrust device 10A. 10
In B, bulk fuel FiPR is attached to the cathode tips 18A, 16.
Each of the upstream arc chambers 18A. 18B for injection into each anode body 12A. A port 38 formed through 12B is included. Anode body 12A for each port. 12B relative to the axis 11A, the angle of the injected bulk fuel to each chamber 1
8A, 18B and the throttle portions 20A, 20B are selected so that a swirling flow is generated within and along the axes thereof.

The port 38 is connected to a line (not shown) to an appropriate fuel gas source (not shown), such as that provided in conventional arc jet thrusters.
connected via.

Furthermore, in the first propulsion unit Saneura example shown in FIG.
A device is shown for indexing propellant fuel additive through A into the region of arc chamber i8A at its tip 16A and further into the central region of arc 32A. The injection device is implemented in the form of a central large diameter cylindrical passage 40 with a plurality of small diameter end channels 42 extending longitudinally through the cathode rod 14A of the thruster 10A.

The pant channel 42 flares outwardly and extends from the downstream end of the passage 2840. Channel 42 has cathode tip 16
An outlet 44 is located near but sufficiently upstream of the downstream n portion of A and sufficiently upstream from the initial arc attachment area to allow the anode 12A to cross the intermediate gap 28A to surround and form the channel 42. This prevents deformation of the cathode tip 16A in the portion of the cathode caused by high temperatures. Also, channel 42
The edges of the cathode rod forming the outlet 44 must be smoothly rounded to a suitable radius to prevent arc buildup at the outlet 44.

In the second propulsion embodiment shown in FIG. 4, fuel additive is injected along the outer surface of the cathode rod 14B to the cathode tip 16B into the area of the arc chamber 18B and into the central area of the arc 32B. An apparatus according to another embodiment is shown. The ejection device is in the form of a hollow cylindrical sleeve or shield 48 extending along the cathode rod 16B and placed concentrically around the rod, with an annular flow conduit therebetween. is forming. The upstream end of the shield 48 is closed by an insulating ring 52, which insulates the shield 48 from the cathode rod 16B. The sheath 48 is provided with a series of circumferentially spaced M-spaced openings 54 extending therethrough near the downstream side of the ring 52 so that a suitable supply source (not shown) can be accessed via an annular 8I tube 50. The downstream end of the cladding 48 is open to receive the propellant additive gas.The cladding 48 is suitably rounded to prevent arc deposition and to prevent rA pole tip 16B.
be placed sufficiently upstream from the arc to avoid the severe heat of the arc attachment area
We must prevent damage from occurring.

The wi shroud 48 is connected to the output controller 30B to maintain the controller at a slightly greater potential than the cathode 14B to retard further arcing between the shroud 48 and the cathode body 12l3. However, the potential of the coating 4
8i! which promotes lightning arc formation between 8 and the cathode rod 14B! It can't be expensive.

In both the embodiments of FIGS. 3 and 4, a second stream of additive gas is injected into the arc chambers 18A, 18B. The swirling flow pattern created by the bulk fuel injection causes each constriction 2OA. 20B into the axially arcuate area.

The l@pole tip J1 facilitates significant cooling of the cathodes 14A, 14B, thereby extending the life of the cathodes. Furthermore, using both cathode tip designs i! Conditions can be imposed on the chemical environment of the iitjA cathodes to prevent or significantly reduce chemical reactions between the respective cathodes 14A, 14B and propellant gases or derivative gaseous impurities.

Finally, both cathode tip designs are used to promote boundary layer re-W ringing as described below.

Boundary Layer Recirculation A fourth feature of the present invention is to redirect a portion of the annular outer spiral flow of fuel gas from the constriction through one of the cathode tip designs of FIGS. 3 and 4. It involves a device for recirculating the gas to the central arc area. In FIG. 5, an improved performance arc jet propulsion machine according to a third embodiment utilizing this feature is shown at 1QC. This propulsion device 1110
The basic design and component parts of C are roughly as shown in Figure 1 in Figure 3.
is the same as propulsion device example 10A, and therefore only the differences between the two will be described in detail below.

The re-WJ ring arrangement is in the form of at least one pair of return passages 56 that are generally U-shaped. A base portion of each passage 56 is formed within the anode body 12C so as to extend parallel to the axis 11A. The leg portions 60 are connected to the respective upstream and downstream ends of each passage 56 (the constriction portion 20C and the cathode rod 1).
4G) in the anode body 12C, and extends generally in the radial direction with respect to the axis MA. , an upstream one of the leg portions 60 is formed with an inner part 62 and an outer part 7II64, and the inner part has an axis I! A
In contrast, it is tilted toward the nozzle 24G of the anode main body 12C. Recirculation of the propellant fuel through the return passage 56 is achieved through the constriction 2.
Driven by the sharp radial pressure gradient of the swirling flow at 0c. The wall-to-center pressure ratio at a given axial location in the constriction can be as high as 2:1.

Thus, in the case of the boundary layer recirculation design of third propulsion device example 10C, the skewer's tIA stripped gas from the cold outer stream is passed through opening 66 upstream of the return passage formed in the cylindrical wall or surface 22c of the constriction. The inner S portion 62 of the leg portion 60 is removed.

This removed gas flow is connected to a return passage 56 within the anode body 12c.
It is then sent to the cathode rod 14C and injected into the central arc region. FIG. 5 shows the return path 56 of the boundary layer recirculation design that has reached the cathode extraction design of FIG. Although utilized as in machine embodiment 10A, it should be understood that the return path 56 of the recirculating ffi design of FIG. No.

In order to delay the adhesion of the electric arc to the opening 62 to the return path leg portion 60, the annular portion 68 of the anode main hole 12c of the propulsion device 10c, including the opening 66, is connected to the anode and cathode by an annular dielectric spacer 70. It is electrically insulated from the potential and independently connected to the power controller 30C to maintain the portion E at a certain intermediate potential.

A tS temperature dielectric is suitable for use as the insulation spacer 70. Alternatively, the anode body portion 68 can be made from a high temperature dielectric material as shown in FIG. Subesa 70
The material of the annular anode body portion 68 may be boron nitride, alumina, quartz, or other suitable high temperature insulating material.

During passage through the constriction 20G, the outward swirling flow primarily serves to stabilize and confine the arc 32G, protecting the constriction surface 22c. When the gas in the swirling flow also passes through the constriction section 20C, it comes into contact with the arc 32G and the constriction surface 2.
Contact with 2G causes considerable heating. In the boundary layer recirculation design J3, when the feed to the center arc region first passes through the constriction section 20C it effectively preheats and stabilizes the arc 32C. The use of a preheat feed to the central arc region allows higher temperatures to be achieved in the arc, thus facilitating higher specific impulse thrusters.

The portion of the total flow that is recycled in this way can be as high as 20% on a vlm basis, depending on thruster design and power level. Such a level of recirculation can provide a complete supply of preheated propellant to the arc portion of the flow. In conjunction with the first aspect of the invention, a recycle stream may be combined with the additive gas as previously described.

Fuel Decomposition Reactor/Regenerator A fifth feature of the present invention relates to an apparatus for regenerating a seedling by circulating fuel into an arc chamber at a cathode position by reacting with a part of the seedling. A fourth embodiment of an improved performance arcjet propulsion device implementing this feature is shown in FIGS. 6 and 7.

The reaction and regeneration device is in the form of a plurality of regeneration passages 72 formed within the anode body 12D to extend generally parallel to the axis A. These regeneration passages 72 are separated from each other in the circumferential direction as shown in FIG. Regeneration return passage 7 radially from ilA
It is located further away than 2r. The feed passageway 72f connects its downstream end to the upstream end of the return passageway 72''. Such connection connects the anode body 12D near the forward end of the nozzle 24D.
Located within. As previously mentioned, a portion of the total fuel supply to propulsion system 100 is directed into these passageways prior to injection into arc chamber 18D.

The propulsion fuel is supplied from the inner return passage 72 to the anode main body 1.
2D, extending parallel to cathode rod 14D and connected at its upstream end to a return passageway. The fuel supply is supplied via flow path 74 at its downstream end and ll! It is sent to an outlet port 76 located near the pole tip 16D.

When passing through the passage 72, the fuel feed gas has an absolute temperature of 160
It can be heated to temperatures down to 0 degrees.

Regeneration passage 72 is used in conjunction with any one of the cathode indexing designs of FIGS. 3 and 4 to index the partially disassembled fuel supply into the central arc region where its effectiveness is greatest. can be used.

In such applications, it is not necessarily necessary to pass the entire flow of the fuel supply through the regeneration passage 72, and the option is provided to pass only the full flow directed to the inner cathode injection.

There are three advantages in passing the fuel supply through the regeneration passage 72 before being injected into the arc chamber 18D. First, controlled decomposition of the fuel feed gas to form low molecular weight components is promoted. Although the residence time in the regeneration passageway 72 is typically too short for equilibrium dissociation to occur, sufficient parent small molecules are present as discussed above under the heading "Fuel Mixing with High Specific Impulse Additives". Generated to cause dramatic thruster performance improvements.

The special case of pure ammonia feed gas helps explain the effect. N port at an absolute temperature of 1600 degrees K and a pressure of 1 to 2 atmospheres (typical feed pressure for arc jet propulsion machines). Equilibrium dissociation of is completed, but such complete dissociation is unlikely due to the υ1 limit on the regeneration path residence time. Silently, the dissociation of ammonia with partial endotherms in the arcjet propulsion engine reduces propulsion performance to pure NH.
It is possible to create sufficient amounts of diatomic and monatomic hydrogen (H2 and H2) to dramatically improve the feed rate. Such dissociation is a homogeneous gas reciprocal action or can be promoted by a catalytic agent applied to the regeneration channel walls or to the substrate packed in the channel. As is well known, the N-port 3 dissociation causes a catalytic reaction with rhenium, which is a refractory metal suitable for manufacturing the anode body. Propulsion 1!5Fl degree of dissociation U arcjet operating conditions (7s8i mold rate, power, current), anode and regeneration passage morphology (and therefore R residence time in the passages) and judicious design of catalyst and substrate usage can be quickly controlled.

Second, preheating of the fuel feed gas promotes a higher overall average temperature and therefore a higher specific power level at the throttle. Third, cooling the anode body reduces thermal stress on the propulsion material and thus extends the life of the propulsion device. Cooling the anode body reduces heat dissipation from the anode's outer surface, simplifying thermal management of the thrust loading and the entire spacecraft.

Bulk fuel flow a typical for arcjet propulsion machines
The propulsion fuel gas flowing through the regeneration passage 72 has an arc 3 in the arc attachment area of the nozzle 24d.
2D allows only a part of the waste heat accumulated in the anode main hole 12D to be removed.

Therefore, in designing the passage configuration, care must be taken to ensure that the radial conduction path between the passages is wide enough to allow sufficient heat transfer to the rJJ pole outer surface where the FJA pole body is radially cooled. No. Improper conduction paths through passageway 72 can cause temperatures at surfaces 22D and 26D of constriction 200 and nozzle 24D, respectively, that approach or even exceed the melting temperature of tungsten.

4. The present invention and its many advantages may be understood from the foregoing description, and various changes may be made in the form, structure, and structure without departing from the spirit and scope of the invention or detracting from all of its substantial advantages. It is obvious that additions can be made to the configuration of the parts, and the configurations described herein are merely preferred or representative embodiments thereof.

[Brief explanation of drawings]

FIG. 1 is a schematic axial sectional view showing the cathode rod and anode nozzle body of a standard prior art arc jet propulsion machine; FIG.
FIG. 3 is a graph showing the relationship of specific impulse as a function of the ratio of propulsion input power to total suspended flow M rate for a mixture; FIG. FIG. 4 is a schematic axial cross-sectional view showing a first practical example of an arc jet propulsion machine having improved performance, and FIG. 4 is an improved t! ! FIG. 5 is a schematic cross-sectional view in the vertical direction showing a second embodiment of an arc jet propulsion device according to the present invention; FIG. FIG. 6 is a schematic axial cross-sectional view of a third embodiment of the machine; FIG. Schematic axial sectional view showing the embodiment. FIG. 7 is a sectional view showing the fourth embodiment of the propulsion device taken along line 116-6 in FIG. 16. 10... Arc jet propulsion device, 12...
...Anode, 14...Cathode, 16...
Conical end, 18...Arc chamber, 20...
Throttle part, 22...Cylindrical surface, 24...Nozzle, 30...Power controller, 32...
Arc, 34...'spiral flow of fuel gas, A...
...Axis line, 38...Port, 40...
...Large diameter center passage, 42...Small diameter end channel V channel, 48
. . . Hollow cylindrical sleeve, 50 . . . Annular conduit, 56 . . . Pair of return passages, 58 .
・・・Base part, 60... Leg part, 68...
...Annular portion, 66...Opening, 70...
...Annular smoother, 72...Regeneration passage.

Claims (21)

[Claims] (1) An arc jet propulsion device, comprising (a) an annular constriction portion and an annular nozzle arranged in series, each having a surface forming an arc chamber, and at least the nozzle is electrically (b) a gap extending in substantially the same plane as the arc chamber; (c) generating an electric arc from the cathode to the anode in the arc chamber by the heat of the propulsion fuel gas flowing through the chamber; (d) a high molecular weight fuel having a first specific impulse and a second specific impulse greater than the first specific impulse; an apparatus for supplying a fuel gas mixture comprising a low molecular weight fuel having a specific impulse to the arc within the arc chamber. (2) The arc jet propulsion device according to claim 1, wherein the low molecular weight fuel is a low temperature propulsion fuel gas. (3) (a) An annular constriction portion and an annular nozzle arranged in series are provided, each having a surface that together forms an arc chamber, and at least the nozzle has an anode formed of an electrically conductive material. (b) an anode having a distal end located near the constriction and separated upstream from the constriction, and separated from the anode by a gap extending substantially in the same plane as the arc chamber; (c) generating an electric arc from the cathode to the anode in the arc chamber, heating the propellant gas flowing through the chamber through the nozzle; (d) a bulk charge of propulsion fuel having a separately supplied first specific impulse and a first specific impulse greater than the first specific impulse; an arc jet propulsion device comprising: a propellant fuel additive having a specific impulse of 2; and a device for separately injecting a propellant fuel additive into the arc chamber in the region of the tip of the cathode. (4) The arc jet propulsion system according to claim 3, wherein the bulk propulsion fuel is a high molecular weight fuel and the fuel additive is a low molecular weight fuel. (5) at least one injection device extending through the body and opening into the arc chamber upstream of the tip of the cathode for injecting a bulk charge of fuel into the arc chamber in the region of the cathode tip; 4. An arc jet propulsion device according to claim 3, including a device for forming a port. 6. An arc jet propulsion system according to claim 5, wherein the port extends at an oblique angle to the central axis of the body so that the injected bulk fuel creates a swirling flow within the arc chamber. (7) (a) An annular constriction portion and an annular nozzle arranged in series are provided, each having a surface that together forms an arc chamber, and at least the nozzle has an anode formed of an electrically conductive material. (b) a cathode having a distal end disposed near the constriction portion and extending upstream from the constriction portion, and separated from the anode by a gap extending substantially in the same plane as the arc chamber; (c) generating an electric arc from the cathode to the anode in the arc chamber, heating the propulsion fuel gas flowing through the chamber with heat and the fuel passing through the nozzle; (d) applying a separately supplied bulk charge of propellant fuel and propellant additive to said anode and cathode in the region of said tip of said cathode; (e) The injection device includes a device for forming a passage through the cathode and the tip of the cathode, and the injection device includes a device for forming a passage through the cathode and the tip of the cathode, and injects the propellant fuel additive into the cathode through the cathode. An arc jet propulsion device for injecting into the arc chamber in the region of the tip and further into the central region of the arc formed between the cathode and the anode. (8) The passageway includes an elongated central portion formed longitudinally through the cathode and a plurality of outwardly flared central portions connected to the central portion and formed through the cathode and upstream of the tip and near the cathode. 8. An arc jet propulsion device according to claim 7, having a rounded end. (9) (a) A device for forming an annular constriction portion and an annular nozzle arranged in series and each having a surface that together form an arc chamber are provided, and at least the nozzle constitutes an anode and is electrically connected to the anode. (b) has a tip extending upstream from the constriction portion and placed near the constriction portion, and is electrically conductive and has the same extent as the arc chamber as a whole; (c) applying a voltage to the anode and the cathode to generate an electric arc that heats the propellant gas flowing through the chamber and expands the gas passing through the nozzle; a device for generating gas from the cathode in the chamber toward the anode; an arc jet propulsion device having a device for recirculating into the central region of the electric arc formed therebetween. 10. The arc jet propulsion device according to claim 9, wherein the recirculation device includes at least one return passageway extending between the constriction portion of the body and the cathode. (11) The passageway is generally U-shaped and includes a base portion and a pair of leg portions located at respective upstream and downstream ends of the base portion. arcjet propulsion device. 12. The arc jet propulsion device according to claim 11, wherein the body includes a device for electrically isolating an annular portion of the body containing the upstream leg portion of the passage from the potentials of the anode and cathode. (13) The arc jet propulsion device according to claim 12, wherein the isolation device is a pair of annular dielectric spacers placed on opposite upstream and downstream ends of the annular portion of the body. . (14) The arc jet propulsion device according to claim 11, wherein the annular portion of the main body is made of a dielectric material to electrically isolate the portion from the potentials of the anode and cathode. (15) Apparatus for separately injecting separately supplied bulk charges of propellant fuel and propellant additive into the arc chamber in the region of the tip of the cathode. arcjet propulsion device. (16) The arc jet propulsion system according to claim 15, wherein the bulk propulsion fuel is a high molecular weight fuel and the propulsion fuel additive is a low molecular weight fuel. (17) the injection device extends through the body and opens into the arc chamber near upstream of the tip of the cathode, and injects a bulk charge of propellant fuel into the arc chamber in the region of the cathode tip; 16. An arc jet propulsion device according to claim 15, including means for forming at least one port for. (18) The port extends at an angle relative to the central axis of the body so that the injected bulk fuel creates a swirling flow within the arc chamber.
Arcjet propulsion device according to section. (19) The injection device includes a device for forming a passage through the cathode and its tip, through which the propellant fuel additive is introduced into the arc chamber in the region of the cathode tip and between the cathode and the anode. 16. The arc jet propulsion device according to claim 15, wherein the arc jet propulsion device injects light into the central region of an arc formed in the arc jet. (20) The injection device includes a device for injecting a propellant fuel additive along the outer surface of the cathode into a region at the tip of the cathode and into a central region of an arc formed between the cathode and the anode. An arc jet propulsion device according to claim 15. (21) The propellant fuel additive injection device includes a hollow cladding disposed concentrically around the cathode, extending outward from the cathode and extending along the cathode, and connecting the cladding with the cathode. Claim 20, wherein an annular flow conduit is formed between the
Arcjet propulsion device according to section.