Hybrid ultrahigh-enthalpy electric arc heater

Abstract

A hybrid ultrahigh-enthalpy electric arc heater comprises a rear electrode group, a contraction section, a compression channel, a throat, an expansion section and a front electrode group, the arc cathode arc root is attached to the electrode of the rear electrode group; the contraction section is mainly used for compressing an electric arc column to finish first acceleration of plasma; the compression channel is used for compressing and lengthening the electric arc column, so that the working gas is fully heated and ionized; the airflow gathers to high pressure at the throat, and second acceleration of the plasma is completed; the airflow completes the third acceleration of the plasma in the expansion section; an electric arc positive electrode is attached to an electrode terminal of the front electrode set, the plasma is subjected to Lorentz force at the position, fourth acceleration is achieved, and an ultrahigh enthalpy flow field is finally formed. The device can be applied to the field of aerodynamic heat ground simulation technology research, and mainly provides a medium-low pressure ultrahigh enthalpy uniform flow field.

Description

Technical Field

[0001] The invention relates to a hybrid ultra-high enthalpy electric arc heater, in particular to a high-power medium-low pressure ultra-high enthalpy electric arc uniform heating device, belonging to the research field of aerodynamic thermal ground simulation equipment. Background Art

[0002] With the development of aerodynamic thermal ground simulation technology, various types of arc heaters have been developed. Various arc heaters have their specific simulation ranges. For example, laminated arc heaters can simulate medium and low pressure high enthalpy heating environments, and MPD arc heaters can simulate low pressure ultra-high enthalpy heating environments. Currently, there is no heater that can simulate medium and low pressure ultra-high enthalpy thermal environments at the same time. In this context, it is urgent to develop a new type of arc heater that couples the advantages of the two laminated and MPD types, overcomes their shortcomings, and develops a hybrid ultra-high enthalpy arc heater. Summary of the invention

[0003] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a hybrid ultra-high enthalpy arc heater that provides an ultra-high enthalpy flow field under medium and low pressure environments.

[0004] The above object of the present invention is achieved through the following technical solutions:

[0005] The present invention discloses a hybrid ultra-high enthalpy arc heater, comprising a rear electrode group, a contraction section, a compression channel, a throat, an expansion section and a front electrode group; wherein:

[0006] The rear electrode group includes a plurality of annular electrode sheets; the cathode emits electrons as a hot cathode, and the negative arc roots of the arc are evenly distributed on the plurality of annular electrode sheets;

[0007] The contraction section is connected to the rear electrode group upstream and the compression channel downstream to compress and accelerate the airflow;

[0008] The compression channel is connected to the throat at the downstream, and the compressed and accelerated airflow forms the speed of sound in the compression channel;

[0009] The throat is used to gather the gas flow to a high pressure state and complete the second acceleration of the plasma;

[0010] The expansion section is connected to the throat upstream and the front electrode group downstream, which rapidly expands the airflow and completes the third acceleration of the plasma;

[0011] The front electrode group includes several electrode terminals; it serves as an anode to receive electrons, and the positive arc roots of the arc are evenly distributed on several electrode terminals. The arc bends in the expansion section and the front electrode to generate a self-magnetic field. The plasma is accelerated by the Lorentz force in the magnetic field, so that the airflow forms an ultra-high enthalpy flow field;

[0012] The rear electrode group, the contraction section, the compression channel, the throat, the expansion section and the front electrode group are connected by insulating sealing.

[0013] Furthermore, in the above heater, the number of the electrode sheets is 1 / 1000 to 1 / 900 of the arc current; and the number of the electrode terminals is 1 / 100 to 1 / 90 of the arc current.

[0014] Furthermore, in the above heater, the contraction angle of the contraction section is 40° to 60°; and the aspect ratio of the compression channel is 20 to 40.

[0015] Furthermore, in the above-mentioned heater, the longitudinal section of the inlet section of the throat is arc-shaped, and the arc diameter is 7 to 9 times the throat diameter; the throat outlet section is conical, and the cone angle is 50° to 60°; the expansion angle of the expansion section is consistent with the cone angle of the throat.

[0016] Furthermore, in the above heater, the rear electrode group further includes an arc-dividing resistor and a first insulating sheet; wherein the annular electrode sheets and the first insulating sheet are alternately arranged and stacked; and all the annular electrode sheets are connected in parallel via the arc-dividing resistor.

[0017] Furthermore, in the above-mentioned heater, the contraction section includes a plurality of second contraction sheets and a second insulating sheet; the plurality of second contraction sheets and the second insulating sheet are alternately arranged to form a conical structure; an air intake ring is provided on the second contraction sheet to introduce air and blow away the arc between the sheets to prevent the current from propagating along the second contraction sheet.

[0018] Furthermore, in the above-mentioned heater, the compression channel includes a plurality of third compression plates and a third insulating plate; the plurality of third compression plates and the third insulating plates are alternately arranged to form a cylindrical structure, and the inner diameter of the cylindrical structure is 1 / 500 to 1 / 400 of the maximum current of the arc; an air intake ring is provided on the third compression plate to introduce air to blow away the arc between the plates and prevent the current from propagating along the third compression plate.

[0019] Furthermore, in the above-mentioned heater, the expansion section includes a plurality of expansion sheets and a fourth insulating sheet; the plurality of expansion sheets and the fourth insulating sheet are alternately arranged to form a bell-mouth shape; an air intake ring is provided on the expansion sheet to introduce air, blow away the arc between the sheets, and prevent the current from propagating along the expansion sheet.

[0020] Furthermore, in the above heater, the front electrode group also includes a fifth insulating member and an arc-dividing resistor; a plurality of electrode terminals and the fifth insulating member are alternately arranged to form a circular ring, and all electrode terminals are connected in parallel through the arc-dividing resistor.

[0021] Furthermore, in the above heater, metal parts in contact with the hot air flow in the rear electrode group, the contraction section, the compression channel, the throat, the expansion section and the front electrode group all adopt a water cooling structure.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention adopts the superposition of pneumatic acceleration and magnetic field acceleration, and obtains high-speed and high-temperature airflow after four accelerations, providing an ultra-high enthalpy flow field, and has the highest upper limit of enthalpy simulation among medium and low pressure arc heaters;

[0024] (2) The present invention uses contraction and compression technology to increase the total pressure of the airflow, and has the highest upper limit of pressure simulation among ultra-high enthalpy arc heaters;

[0025] (3) The medium-low pressure and ultra-high enthalpy flow field provided by the present invention cannot be provided by other types of arc heaters; BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural principle diagram of a hybrid ultra-high enthalpy arc heater of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the rear electrode group and the contraction section of the present invention;

[0028] Figure 3 This is a schematic diagram of the compression channel structure of the present invention;

[0029] Figure 4 This is a schematic diagram of the throat pneumatic structure of the present invention;

[0030] Figure 5 It is a schematic diagram of the expansion section and the front electrode group structure of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0032] The present invention discloses a hybrid ultra-high enthalpy arc heater, comprising a rear electrode group 1, a contraction section 2, a compression channel 3, a throat 4, an expansion section 5 and a front electrode group 6; wherein:

[0033] The rear electrode group 1 includes a plurality of annular electrode sheets; it acts as a hot cathode to emit electrons, and the negative arc roots of the arc are evenly distributed on the plurality of annular electrode sheets;

[0034] The contraction section 2 is connected to the rear electrode group 1 upstream and to the compression channel 3 downstream to compress and accelerate the airflow;

[0035] The compression channel 3 is connected to the throat 4 at the downstream, and the compressed and accelerated airflow forms the speed of sound in the compression channel 3;

[0036] Throat 4 is used to gather the gas flow to a high pressure state and complete the second acceleration of the plasma;

[0037] The expansion section 5 is connected to the throat 4 upstream and the front electrode group 6 downstream, which rapidly expands the gas flow and completes the third acceleration of the plasma;

[0038] The front electrode group 6 includes a plurality of electrode terminals 61, which serves as an anode to receive electrons. The positive arc roots of the arc are evenly distributed on the plurality of electrode terminals, forming a self-magnetic field. The plasma is accelerated by the Lorentz force in the magnetic field, so that the airflow forms an ultra-high enthalpy flow field.

[0039] The rear electrode group 1, the contraction section 2, the compression channel 3, the throat 4, the expansion section 5 and the front electrode group 6 are connected by insulating sealing.

[0040] Preferably, the number of the electrode sheets is 1 / 1000 to 1 / 900 of the arc current; the number of the electrode terminals is 1 / 100 to 1 / 90 of the arc current.

[0041] Preferably, the contraction angle of the contraction section 2 is 40° to 60°; and the aspect ratio of the compression channel 3 is 20 to 40.

[0042] Preferably, the longitudinal section of the inlet section of the throat 4 is arc-shaped, and the arc diameter is 7 to 9 times the diameter of the throat 4; the throat outlet section is conical, and the cone angle is 50° to 60°; the expansion angle of the expansion section 5 is consistent with the cone angle of the throat 4.

[0043] Preferably, the rear electrode group 1 also includes an arc-dividing resistor and a first insulating sheet; wherein the annular electrode sheets and the first insulating sheet are alternately arranged and stacked; all the annular electrode sheets are connected in parallel through the arc-dividing resistor, and argon gas is injected between two adjacent annular electrode sheets to prevent arcing between the sheets. The arc-dividing resistor is composed of a number of resistors, one end of all the resistors is connected to the power cable, and the other end of each resistor is connected to an electrode sheet. This parallel connection method can force the arc to be distributed on these electrode sheets. If the resistance values ​​of the resistors are the same, they are evenly distributed, and if the resistance values ​​are different, they are unevenly distributed. Figure 1 shown.

[0044] Preferably, the contraction section 2 includes a plurality of second contraction sheets 21 and a second insulating sheet 22; the plurality of second contraction sheets 21 and the second insulating sheet 22 are alternately arranged to form a conical structure; an air intake ring is provided on the second contraction sheet 21 to introduce air and blow away the arc between the sheets to prevent the current from propagating along the second contraction sheet 21.

[0045] Preferably, the compression channel 3 includes a plurality of third compression plates 31 and a third insulating plate 32; the plurality of third compression plates 31 and the third insulating plates 32 are alternately arranged to form a cylindrical structure, and the inner diameter of the cylindrical structure is 1 / 500 to 1 / 400 of the maximum current of the arc; an air intake ring is provided on the third compression plate 31 to introduce air and blow away the arc between the plates to prevent the current from propagating along the third compression plate 31.

[0046] Preferably, the expansion section 5 includes a plurality of expansion sheets 51 and a fourth insulating sheet 52; the plurality of expansion sheets 51 and the fourth insulating sheet 52 are alternately arranged to form a bell-mouth shape; an air intake ring is provided on the expansion sheet 51 to introduce air to blow away the arc between the sheets and prevent the current from propagating along the expansion sheet 51.

[0047] Preferably, the front electrode group 6 also includes a fifth insulating member 62 and an arc-dividing resistor; a plurality of electrode terminals 61 and the fifth insulating member 62 are alternately arranged to form a circular ring, all electrode terminals 61 are connected in parallel through arc-dividing resistors, and argon gas is injected between two adjacent electrode terminals 61 to prevent arcing between the electrode terminals 61.

[0048] Preferably, the metal parts in contact with the hot air flow in the rear electrode group 1, the contraction section 2, the compression channel 3, the throat 4, the expansion section 5 and the front electrode group 6 all adopt a water cooling structure.

[0049] Example

[0050] Depend on Figure 1 It can be seen that a hybrid ultra-high enthalpy arc heater is characterized by comprising a rear electrode group 1, a contraction section 2, a compression channel 3, a throat 4, an expansion section 5 and a front electrode group 6.

[0051] Among them, the rear electrode group 1 acts as a hot cathode to emit electrons, and the negative arc roots of the arc are evenly distributed on several electrode sheets, which is beneficial to reduce the burning of the electrode sheets, provide a clean flow field and extend the life of the arc heater. The number of electrode sheets depends on the arc current, which is approximately equal to one thousandth of the current;

[0052] The contraction section 2 is located downstream of the rear electrode group 1, where the airflow is compressed and accelerated. The acceleration effect is better when the contraction angle is between 40° and 60°.

[0053] The compression channel 3 is located downstream of the contraction section 2, where the airflow after contraction and acceleration forms the speed of sound. The length-to-diameter ratio of the compression channel is in the range of 20 to 40, which is conducive to the full mixing of the airflow and the arc column.

[0054] The throat 4 is located downstream of the compression channel 3, where the airflow gathers to high pressure to complete the second acceleration of the plasma. The throat inlet section has an arc-shaped cross section. When the arc diameter is 8 times the throat diameter, the acceleration effect is better. The throat outlet section is conical, and the cone angle is 50° to 60°.

[0055] The expansion section 5 is located downstream of the throat 4, where the airflow expands rapidly and completes the third acceleration, and the expansion angle is consistent with the throat cone angle;

[0056] The front electrode group 6 is located downstream of the expansion section 5, and serves as an anode to receive electrons. The positive arc roots of the arc are evenly distributed on a number of electrode terminals, where the arc forms a self-magnetic field. The plasma is accelerated by the Lorentz force in the magnetic field, so that the airflow forms an ultra-high enthalpy flow field. The number of electrode terminals is approximately equal to one percent of the current.

[0057] Depend on Figure 2 It can be seen that the rear electrode group 1 and the contraction section 2 of a hybrid ultra-high enthalpy arc heater are assembled into a structural unit, wherein the tail of the rear electrode group 1 is an end cap 11, which is provided with a pressure measuring hole and a cooling channel. Downstream of the end cap are a number of protective sheets 12, annular electrode sheets 13, insulating sheets 14 and an intake ring 15 arranged alternately. The function of the protective sheet is to appropriately increase the distance between adjacent annular electrode sheets to avoid arc root concentration. All annular electrode sheets are connected in parallel through arc dividing resistors. Adjacent protective sheets and annular electrode sheets are insulated by insulating sheets, and argon is injected through the intake ring to prevent arcing between sheets.

[0058] The contraction section 2 is composed of a plurality of contraction sheets 21 and insulation sheets 22 arranged alternately in a cone shape, and an air intake ring is arranged on the contraction sheet to introduce air and blow away arcs between sheets to prevent current from propagating along the contraction sheet. In this embodiment, the contraction angle a=50°.

[0059] The rear electrode group 1 and the contraction section 2 are connected in an airtight manner by means of a fastening device 23 .

[0060] Depend on Figure 3 It can be seen that the compression channel 3 of a hybrid ultra-high enthalpy arc heater is composed of a number of compression sheets 31 and insulating sheets 32 arranged alternately in a cylindrical shape. The inner diameter of the cylinder is approximately equal to one five hundredth of the maximum current of the arc. An air intake ring 33 is arranged on the compression sheet to introduce air and blow away the arc between the sheets to prevent the current from propagating along the compression sheet. The compression channel has a wall compression effect on the arc column, and the injected airflow disturbs the arc column, which is beneficial to increase the temperature of the arc column. In this embodiment, the aspect ratio of the compression channel is 32, and every 16 compression sheets form a compression unit. The airtight connection between the various parts in the compression unit is achieved through fasteners 34.

[0061] Depend on Figure 4 It can be seen that the inner profile of the throat 4 of a hybrid ultra-high enthalpy arc heater meets the Laval nozzle design standard, where the airflow gathers to high pressure to complete the second acceleration of the plasma. The minimum inner diameter of the throat 4 is determined by the input gas flow rate and the required arc chamber pressure. In this embodiment, the throat inlet section is an arc-shaped section, the arc diameter R is 8 times the throat diameter r, and the throat outlet section is conical, and the cone angle b is 55°.

[0062] Depend on Figure 5 It can be seen that the expansion section 5 and the front electrode group 6 of a hybrid ultra-high enthalpy arc heater are assembled into a structural unit and are airtightly connected by a fastening device 54.

[0063] The expansion section is formed by a plurality of expansion sheets 51 and a fourth insulating sheet 52 arranged alternately in a bell-mouth shape. An air intake ring 53 is provided on the expansion sheet to introduce air and blow away the arc between the sheets to prevent the current from propagating along the expansion sheet. The expansion angle c is consistent with the throat cone angle b, which is 55° in this embodiment.

[0064] The front electrode group 6 is composed of a plurality of electrode terminals 61 and fifth insulating members 62 alternately arranged in a circular ring shape. All electrode terminals are connected in parallel through arc-dividing resistors, and argon gas is injected between two adjacent electrode terminals to prevent arcing between the terminals.

[0065] It should be noted that the resistance of all insulating plates in this embodiment reaches 100 kΩ.

[0066] It should be noted that, in this embodiment, the maximum arc current is 3000A, the number of electrode sheets in the rear electrode group is 3, and the number of electrode terminals in the front electrode group is 30.

[0067] It should be noted that all metal parts in this embodiment adopt a water cooling structure.

[0068] It should be noted that, in this embodiment, sealing rings and fastening devices are used to achieve insulating and sealed connection between the rear electrode group, the contraction section, the compression channel, the throat, the expansion section and the front electrode group.

[0069] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applicable to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

[0070] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A hybrid ultra-high enthalpy arc heater, characterized in that: It comprises a rear electrode group (1), a contraction section (2), a compression channel (3), a throat (4), an expansion section (5) and a front electrode group (6); wherein, The rear electrode group (1) comprises a plurality of annular electrode sheets; as a hot cathode to emit electrons, the negative arc roots of the arc are evenly distributed on the plurality of annular electrode sheets; The contraction section (2) is connected to the rear electrode group (1) upstream and to the compression channel (3) downstream to compress and accelerate the airflow; The compression channel (3) is connected to the throat channel (4) at its downstream, and the compressed and accelerated airflow forms a sonic velocity in the compression channel (3); The throat (4) is used to gather the gas flow to a high pressure state to complete the second acceleration of the plasma; The expansion section (5) is connected to the throat (4) at the upstream and to the front electrode group (6) at the downstream, and rapidly expands the gas flow to complete the third acceleration of the plasma; The front electrode group (6) includes a plurality of electrode terminals (61); the anode receives electrons, and the positive arc root of the arc is evenly distributed on the plurality of electrode terminals. The arc bends in the expansion section and the front electrode to generate a self-magnetic field. The plasma is accelerated by the Lorentz force in the magnetic field, so that the airflow forms an ultra-high enthalpy flow field; The rear electrode group (1), the contraction section (2), the compression channel (3), the throat (4), the expansion section (5) and the front electrode group (6) are connected in an insulating and sealed manner.

2. A hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The number of the electrode sheets is 1 / 1000 to 1 / 900 of the arc current; the number of the electrode terminals is 1 / 100 to 1 / 90 of the arc current.

3. A hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The contraction angle of the contraction section (2) is 40° to 60°; the length-to-diameter ratio of the compression channel (3) is 20 to 40.

4. A hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The longitudinal section of the inlet section of the throat (4) is in the shape of an arc, and the diameter of the arc is 7 to 9 times the diameter of the throat (4); the outlet section of the throat is in the shape of a cone, and the cone angle is 50° to 60°; the expansion angle of the expansion section (5) is consistent with the cone angle of the throat (4).

5. The hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The rear electrode group (1) further comprises an arc-dividing resistor and a first insulating sheet; wherein the annular electrode sheets and the first insulating sheets are alternately arranged and superimposed; and all the annular electrode sheets are connected in parallel via the arc-dividing resistor.

6. A hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The contraction section (2) comprises a plurality of second contraction sheets (21) and second insulation sheets (22); the plurality of second contraction sheets (21) and second insulation sheets (22) are alternately arranged to form a conical structure; an air intake ring is provided on the second contraction sheet (21) to introduce air and blow away arcs between sheets, thereby preventing current from propagating along the second contraction sheet (21).

7. A hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The compression channel (3) comprises a plurality of third compression plates (31) and a third insulating plate (32); the plurality of third compression plates (31) and the third insulating plates (32) are alternately arranged to form a cylindrical structure, and the inner diameter of the cylindrical structure is 1 / 500 to 1 / 400 of the maximum current of the arc; an air intake ring is arranged on the third compression plate (31) to introduce air to blow away the arc between the plates and prevent the current from propagating along the third compression plate (31).

8. The hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The expansion section (5) comprises a plurality of expansion sheets (51) and a fourth insulating sheet (52); the plurality of expansion sheets (51) and the fourth insulating sheet (52) are alternately arranged to form a bell-mouth shape; an air intake ring is provided on the expansion sheet (51) to introduce air, blow away arcs between the sheets, and prevent current from propagating along the expansion sheet (51).

9. The hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: The front electrode group (6) further comprises a fifth insulating member (62) and an arc-dividing resistor; a plurality of electrode terminals (61) and the fifth insulating member (62) are alternately arranged to form a circular ring, and all electrode terminals (61) are connected in parallel and operated via the arc-dividing resistor.

10. The hybrid ultra-high enthalpy arc heater according to claim 1, characterized in that: Metal parts in contact with the hot air flow in the rear electrode group (1), the contraction section (2), the compression channel (3), the throat (4), the expansion section (5) and the front electrode group (6) all adopt a water cooling structure.

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