A hybrid ultra-high enthalpy arc heater

Abstract

A hybrid ultra-high enthalpy 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 is attached to the electrode of the rear electrode group. The contraction section is mainly used to compress the arc column, completing the first plasma acceleration. The compression channel is used to compress and elongate the arc column, fully heating and ionizing the working gas. The airflow is concentrated to high pressure at the throat, completing the second plasma acceleration. The airflow completes the third plasma acceleration in the expansion section. The arc cathode is attached to the electrode terminal of the front electrode group, where the plasma is subjected to the Lorentz force, achieving the fourth acceleration and ultimately forming an ultra-high enthalpy flow field. This invention can be applied to the field of aerodynamic thermal ground simulation technology research, mainly providing medium and low pressure ultra-high enthalpy uniform flow fields.

Description

Technical Field

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

[0002] With the advancement of aero-thermal ground simulation technology, various types of arc heaters have been developed. Each type of arc heater has a specific simulation range. For example, laminated arc heaters can simulate medium- and low-pressure, high-enthalpy heating environments, while MPD arc heaters can simulate low-pressure, ultra-high-enthalpy heating environments. Currently, no heater can simulate both medium- and low-pressure, ultra-high-enthalpy heating environments. Against this backdrop, there is an urgent need to develop a new type of arc heater that combines the advantages of both laminated and MPD arc heaters, 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-mentioned 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; 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;

[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 airflow 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 the anode to receive electrons. The positive arc root of the arc is evenly distributed on the 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, causing the gas flow to form 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 seals.

[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 several second contraction sheets and second insulating sheets; several second contraction sheets and second insulating sheets 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 and blow away the arc between the plates to prevent the current from propagating along the third compression plate.

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

[0020] Furthermore, in the above heater, the front electrode group further 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 operated in parallel through the arc-dividing resistor.

[0021] Furthermore, in the above heater, the 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 uses aerodynamic acceleration and magnetic field acceleration superposition, and after four accelerations, obtains a high-speed and high-temperature airflow, providing an ultra-high enthalpy flow field, and has the highest enthalpy value simulation upper limit 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 is not available in 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 This 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 This is a schematic diagram of the expansion section and front electrode group structure of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be described in further 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 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 airflow 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 airflow and completes the third acceleration of the plasma;

[0038] The front electrode group 6 includes several electrode terminals 61, which act as anodes to receive electrons. The positive arc roots of the arc are evenly distributed on the several electrode terminals, forming a self-magnetic field. The plasma is accelerated by the Lorentz force in the magnetic field, causing the airflow to form 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°; 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 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; 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 several second contraction sheets 21 and second insulating sheets 22; several second contraction sheets 21 and second insulating 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 the arc between the sheets to prevent the current from propagating along the second contraction sheet 21.

[0045] Preferably, the compression channel 3 includes several third compression plates 31 and third insulating plates 32; several third compression plates 31 and 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 arc current; an air intake ring is provided on the third compression plate 31 to introduce air, blow away the arc between the plates, and prevent the current from propagating along the third compression plate 31.

[0046] Preferably, the expansion section 5 includes several expansion sheets 51 and a fourth insulating sheet 52; the several expansion sheets 51 and the fourth insulating sheet 52 are alternately arranged to form a trumpet shape; an air intake ring is provided on the expansion sheet 51 to introduce air, 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 number of electrode terminals 61 and the fifth insulating member 62 are alternately arranged to form a circular ring, all electrode terminals 61 are operated in parallel through the arc-dividing resistor, 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. The negative arc root of the arc is evenly distributed on several electrode sheets, which helps to reduce electrode sheet burnout, provide a clean flow field and extend the life of the arc heater. The number of electrode sheets depends on the arc current and 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. The airflow after contraction and acceleration forms the speed of sound here. The aspect 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. The airflow gathers to high pressure here, completing the second acceleration of the plasma. The cross-section of the throat entrance section is arc-shaped. The acceleration effect is better when the arc diameter is 8 times the throat diameter. The throat exit section is conical, and the cone angle is 50° to 60°.

[0055] The expansion section 5 is located downstream of the throat 4. The airflow expands rapidly here, completing the third acceleration. The expansion angle is consistent with the throat cone angle.

[0056] The front electrode group 6, located downstream of the expansion section 5, acts as an anode to receive electrons. The positive arc root is evenly distributed across several electrode terminals. The arc forms a self-magnetic field here, where the plasma is accelerated by the Lorentz force, creating an ultra-high enthalpy flow field. The number of electrode terminals is approximately 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 plates 12, annular electrode plates 13, insulating plates 14, and an intake ring 15 arranged alternately. The function of the protective plates is to appropriately increase the distance between adjacent annular electrode plates to avoid arc root concentration. All annular electrode plates operate in parallel through arc-dividing resistors. Adjacent protective plates and annular electrode plates are insulated by insulating plates, and argon gas is injected through the intake ring to prevent arcing between the plates.

[0058] The contraction section 2 is formed of a plurality of contraction sheets 21 and insulation sheets 22 arranged alternately in a conical shape. An air intake ring is provided on the contraction sheet to introduce air, blow away arcs between the sheets, and 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 plates 31 and insulating plates 32 arranged alternately in a cylindrical shape. The inner diameter of the cylinder is approximately equal to one-five hundredth of the maximum arc current. An air intake ring 33 is provided on the compression plate to introduce air, blow away the arc between the plates, and prevent the current from propagating along the compression plate. The compression channel has a solid wall compression effect on the arc column, and the injected airflow disturbs the arc column, which is conducive to increasing the temperature of the arc column. In this embodiment, the aspect ratio of the compression channel is 32, and every 16 compression plates form a compression unit. The airtight connection between the various parts in the compression unit is achieved by 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 design standards of a Laval nozzle. The airflow is concentrated to a high pressure here, completing the second plasma acceleration. 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 entrance section has an arc-shaped cross-section, with the arc diameter R being 8 times the throat diameter r. The throat exit section is conical, with a cone angle b of 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 the fastening device 54.

[0063] The expansion section is formed by alternating a number of expansion plates 51 and a fourth insulating plate 52 in a trumpet-shaped arrangement. An air intake ring 53 is provided on the expansion plates to introduce air and blow away arcs between the plates, thereby preventing current from propagating along the expansion plates. The expansion angle c is consistent with the throat cone angle b, and in this embodiment is 55°.

[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. All electrode terminals are connected in parallel through arc-dividing resistors. 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 3000 A, 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 connections 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 above, they are not limited to the applications listed in the description and implementation methods. 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 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) 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; The contraction section (2) is connected to the rear electrode group (1) upstream and to the compression channel (3) downstream, for compressing and accelerating 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 and complete the second acceleration of the plasma; The expansion section (5) is connected to the throat (4) upstream and to the front electrode group (6) downstream, and rapidly expands the airflow to complete the third acceleration of the plasma; The front electrode group (6) includes a plurality of electrode terminals (61); it serves as an anode to receive electrons, and the positive arc roots of the arc are 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. The 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. The 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 aspect ratio of the compression channel (3) is 20 to 40.

4. The 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 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).

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 sheet are alternately arranged and superimposed; and all the annular electrode sheets are connected in parallel via the arc-dividing resistor.

6. The 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 the sheets, thereby preventing current from propagating along the second contraction sheet (21).

7. The 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 arc current; an air intake ring is provided on the third compression plate (31) to introduce air, 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 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, and all electrode terminals (61) are operated in parallel 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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