A high-temperature integrated armor heater for green, high-energy, non-toxic thrusters for satellites

Abstract

The present invention discloses a high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite, and belongs to the technical field of armored heating devices. The integrated armored heater is an annular structure, and the inner wall size matches the size of the catalyst bed. The heater includes three parts: a working section, a transition section, and a lead-out section; the working section is the main heating and heat conduction part, and the working section includes a dual-path heating element, an armored shell, a heating element skeleton, and ceramic powder. The heating element material is a PtRh alloy, which is formed into a spiral heating element by dense winding. The integrated armored heater has two spiral heating elements, including one high-power heating element and one low-power heating element; the rated power of the high-power heating element can reach 30W, and the rated power of the low-power heating element is 3W. When the catalyst bed needs to heat up quickly, the two paths work simultaneously to ensure the bed temperature. When low temperature maintenance is required, only the low-power device works to save energy on the satellite.

Description

Technical Field

[0001] The present invention relates to the technical field of armored heating devices, and in particular to a high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite. Background Art

[0002] In satellites, green thrusters have gradually replaced hydrazine thrusters with their safety and non-toxic advantages. However, green thrusters also face many problems in the process of use. For example, the preheating temperature of green propellants (ammonium dinitramide and hydroxylamine nitrate) is relatively high, and the general preheating temperature of propellants must reach above 350°C; secondly, the combustion temperature of green propellants is above 1500°C. The increase in combustion temperature has changed the use conditions of other thruster components (thrust chamber, catalyst, armored heater, etc.). The thrust chamber and catalyst are single materials, and only need to change the shape and quality, while the armored heater is composed of complex components. The change in use conditions increases the difficulty of heater development. Limited by the heating efficiency and temperature resistance of the armored heater, the aerospace department can only reduce the ignition temperature of the thruster by adding water to the green propellant, in order to reduce the specific impulse in exchange for the possibility of using green propellants. In order to improve the working efficiency of green thrusters, the development of high-temperature armored heaters is imperative.

[0003] Heaters can be divided into two categories according to their structure, namely armored heaters and armored heating wires. The former has a higher device resistance and stable device heating, but the structure is relatively complex. The latter has a simple structure and can be twisted at will, but the heating wire is easy to contact the wall, causing the device to fail prematurely during operation. In terms of high-temperature heaters, armored heating wires are mainly used. For example, the armored heaters involved in patent numbers 201420798031.1 and 201510153525.3 are high-power heating devices. The device resistance is small and there is no transition lead-out design. The lead-out part of the device will occupy the heating power of the device, making the heating power of the heater unconcentrated; at the same time, the heaters involved in the above patents use ceramic powder as filler inside. The powder has not been sintered, and the strength and density are low, and the heating wire is easy to contact the wall. France's THERMOCOAX company has also developed a heater that can withstand 1400°C using an armored heating wire structure. So far, high-temperature heaters have all adopted an armored heating wire structure, and there are fewer high-temperature devices with armored heater structures. Due to the low strength of platinum-rhodium alloy and the small elastic area in the tensile curve, the alloy wire is prone to plastic deformation under low stress, and multiple plastic bending will cause the heating wire to break. Therefore, there are few reports on armored heaters using platinum-rhodium alloy as the heating wire. Summary of the invention

[0004] In view of the shortcomings in the prior art, the purpose of the present invention is to provide a high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite. The heater has a compact structure and is easy to install. The optimized transition lead-out process makes the heating power more concentrated, ensuring stable operation of the device.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a star, which is an annular cylindrical structure, and the inner wall size matches the size of a catalyst bed; the heater comprises three parts: a working section, a transition section and a lead-out section; the working section is the main heating and heat conduction part, and the working section comprises a dual-path heating element, an armor shell, a heating element skeleton and ceramic powder, wherein: the dual-path heating element comprises a first-path heating element arranged on the inner side and a second-path heating element arranged on the outer side, the first-path heating element is continuously reciprocated on the outer peripheral surface of the catalyst bed along the axial direction of the catalyst bed, and the second-path heating element is continuously reciprocated on the outer peripheral surface of the first-path heating element along the axial direction of the catalyst bed; the transition section comprises a transition line, a thin-walled armor tube and a transition line skeleton; the lead-out section comprises an outer sleeve, a sealing material and a lead-out line.

[0007] The first heating element and the second heating element are both spiral heating elements formed by densely winding PtRh alloy wires. The first heating element is a high-power heating element, and the second heating element is a low-power heating element. The rated power of the high-power heating element can reach 30W, and the rated power of the low-power heating element is 3W. When the catalytic bed needs to heat up quickly, the two heating elements work simultaneously to ensure the bed temperature. When low temperature needs to be maintained, only low-power devices work to save on-board energy.

[0008] The first heating element and the second heating element are respectively installed in the heating element frame, and the heating element frame of the dual-path heating element is protected by an armor shell arranged outside it; the gaps between the heating element, the heating element frame and the armor shell are filled with ceramic powder to ensure that the relative positions between the components are fixed.

[0009] The armor shell material is PtRh alloy, which is used to protect the components inside the device in the space environment; the heating element skeleton material is α-Al 2 O 3 , providing necessary support and insulation for the heating element; the ceramic powder is composed of Al 2 O 3 With SiO 2 The powders are mixed in a weight ratio of 1:1.

[0010] In the transition section, the transition line is installed in the transition line frame, and the transition line frame is sheathed with a thin-walled armored tube; the lead-out end of the heating element is connected to the transition line by spot welding.

[0011] The first heating element and the second heating element each have two lead-out ends, and the two lead-out ends of each heating element are respectively connected to two transition wires. The two transition wires connected to each heating element are installed in a transition wire skeleton and then protected by a thin-walled armor tube.

[0012] The transition wire is a metal Pt wire, and the wire diameter is 1.5 times the wire diameter of the connected heating element, ensuring that the power is concentrated in the working section; the wall thickness of the thin-walled armored tube is 0.1-0.15mm, which can reduce the conduction of heat to the power supply and valve body end while maintaining a certain strength.

[0013] In the lead-out section, the two transition lines connected to each heating element are respectively connected to an external lead, and an outer sleeve is sheathed outside the two connection points for protection; the gap inside the outer sleeve is filled with a sealing material.

[0014] The outer sleeve is made of Ni80Cr20 alloy, and the sealing material is epoxy resin, both of which are used to ensure the relative positions of the internal components of the device; the lead wires are used to connect the power part and the power supply part to ensure stable operation of the device.

[0015] In the absence of a coating, the heater of the present invention can preheat the catalyst bed in a low-temperature background environment to above 400°C, and can withstand the propellant combustion temperature of 1500°C when the thruster is ignited.

[0016] Compared with the existing patented technology, the present invention has the following beneficial effects:

[0017] (1) The heating element of the device is a platinum-rhodium spiral structure, which has a higher resistance per unit length;

[0018] (2) The integrated armored heater has a more compact structure and is easier to install;

[0019] (3) The transition lead-out process is adopted to make the heating power more concentrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall structure of high-temperature integrated armored heater for green, high-energy and non-toxic thrusters for satellites;

[0021] Figure 2 This is a schematic diagram of the assembly structure of the armored heater and the catalyst bed of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the working section of the armored heater of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the lead-out section of the armored heater of the present invention.

[0024] In the figure: 100-working section; 101-armored shell; 102-heating element frame (α-Al 2 O 3 ); 103-ceramic powder; 104-heating element; 200-transition section; 201-transition line; 202-transition line skeleton (α-Al 2 O 3 ); 203-thin-wall armored tube; 300-lead-out section; 301-outer sleeve; 302-epoxy resin; 303-external lead; 4-catalytic bed. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are further described below in conjunction with the accompanying drawings. The implementation methods of the present invention include but are not limited to the following embodiments.

[0026] Example 1

[0027] like Figure 1-4 The figure shows a high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite according to the present invention, which is an annular cylindrical structure, and the inner wall size matches the size of the catalyst bed 4; the heater includes three parts: a working section 100, a transition section 200 and a lead-out section 300.

[0028] The working section is the main heating and heat conduction part, and the working section includes the main heating components, the dual-path heating element 104, the armored shell 101, the heating element frame 102 and the ceramic powder 103, wherein: the dual-path heating element includes a first-path heating element arranged on the inner side and a second-path heating element arranged on the outer side, the first-path heating element is continuously reciprocated on the outer peripheral surface of the catalytic bed along the axial direction of the catalytic bed, and the second-path heating element is continuously reciprocated on the outer peripheral surface of the first-path heating element along the axial direction of the catalytic bed; the first-path heating element and the second-path heating element are both made of PtRh alloy, and the PtRh alloy wire is processed into a spiral heating element after winding and decontamination. The spiral heating element has the characteristics of high resistance density, concentrated heat, and large heat capacity, and is the most ideal heating element structure. The first heating element is a high-power heating element (wire diameter 0.18mm), with a working resistance of 39Ω and a rated power of 30W; the second heating element is a low-power heating element (wire diameter 0.13mm), with a working resistance of 98Ω and a rated power of 3W; the high-power heating element and the low-power heating element can work simultaneously or be used separately. When the catalytic bed needs to heat up quickly, the two heating elements work simultaneously to ensure the bed temperature. When low temperature needs to be maintained, only the low-power device works to save on-board energy.

[0029] The first heating element and the second heating element are respectively installed on α-Al 2 O 3 The heating element skeleton provides necessary support and insulation for the heating element. 2 O 3For high temperature sintering of Al at 1300℃~1350℃ 2 O 3 It is formed by powder and has excellent temperature resistance, strength and thermal shock resistance. Especially in a high temperature environment of 1500°C, it still has high dielectric properties, thus ensuring good electrical performance of the device. The heating element skeleton of the dual-path heating element is installed in a PtRh alloy armored shell. The armored shell is used to protect the internal components of the device in the space environment to prevent the internal components from being affected by space radiation, oxygen atoms (AO) impact and space debris impact while the satellite is in orbit. The gaps between the heating element, the heating element skeleton and the armored shell are filled with ceramic powder to ensure that the relative positions of the components are fixed, improve the overall seismic resistance of the device, and fix the relative positions of the three. The ceramic powder is made of Al 2 O 3 With SiO 2 The powders are mixed in a weight ratio of 1:1.

[0030] The transition section includes a transition line 201, a thin-walled armored tube 203 and a transition line skeleton 202; the thin-walled armored tube is welded to the rear end of the armored shell of the working section. In the transition section, the transition line is installed in the transition line skeleton, and the thin-walled armored tube is installed outside the transition line skeleton; the lead-out end of the heating element is connected to the transition line by spot welding.

[0031] The first heating element and the second heating element each have two lead-out terminals, and the two lead-out terminals of each heating element are respectively connected to two transition wires. The two transition wires connected to each heating element are installed in a transition wire skeleton, and then protected by a thin-walled armor tube. The transition wire is a metal Pt wire, and the wire diameter is 1.5 times the wire diameter of the connected heating element to ensure that the power is concentrated in the working section; the thin-walled armor tube is α-Al 2 O 3 The wall thickness of the thin-walled armored tube is 0.1-0.15 mm. The wall thickness of the thin-walled armored tube is preferably about 15% of the wall thickness of the armored shell. On the basis of maintaining a certain strength, it can reduce the conduction of heat to the power supply and the valve body end. The gaps between the transition line, the transition line skeleton and the thin-walled armored tube are filled with ceramic powder. The ceramic powder is Al 2 O 3 With SiO 2 The powders are mixed in a weight ratio of 1:1.

[0032] The lead-out section includes an outer sleeve 301, a sealing material and an external lead 303; in the lead-out section, the two transition lines connected to each heating element are each connected to an external lead, and an outer sleeve 301 is sheathed outside the two connection points for protection; the gap inside the outer sleeve is filled with a sealing material.

[0033] The outer sleeve is made of Ni80Cr20 alloy, and the sealing material is epoxy resin 302, both of which are used to ensure the relative position of the internal components of the device and prevent stress concentration at the solder joints; the lead wires are used to connect the power part and the power supply part, and the heater is a four-wire lead-out, so that the two spiral heating elements are connected to the power supply to ensure stable operation of the device.

[0034] The integrated armored heater of the present invention adopts a transition lead-out design between the heating element and the external lead, so that the heating power of the device is concentrated on the working part. The external leads of the device are respectively led out from two thin-walled armored tubes, and the device is connected to the star power supply by four external leads.

[0035] In the absence of a coating, the heater of the present invention can preheat the catalyst bed in a low-temperature background environment to above 400°C, and can withstand the propellant combustion temperature of 1500°C when the thruster is ignited.

[0036] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any changes made by adopting the design principles of the present invention and performing non-creative work on this basis should fall within the protection scope of the present invention.

Claims

1. A high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a star, characterized by: The integrated armored heater is an annular cylindrical structure, and the inner wall size matches the size of the catalyst bed; the heater includes three parts: a working section, a transition section and a lead-out section; the working section is the main heating and heat conduction part, and the working section includes a double-path heating element, an armor shell, a heating element skeleton and ceramic powder, wherein: the double-path heating element includes a first-path heating element arranged on the inner side and a second-path heating element arranged on the outer side, the first-path heating element is continuously reciprocated on the outer peripheral surface of the catalyst bed along the axial direction of the catalyst bed, and the second-path heating element is continuously reciprocated on the outer peripheral surface of the first-path heating element along the axial direction of the catalyst bed; the transition section includes a transition line, a thin-walled armor tube and a transition line skeleton; the lead-out section includes an outer sleeve, a sealing material and a lead-out line; The first heating element and the second heating element are both spiral heating elements formed by densely winding PtRh alloy wires. The first heating element is a high-power heating element, and the second heating element is a low-power heating element. The rated power of the high-power heating element can reach 30W, and the rated power of the low-power heating element is 3W. When the catalytic bed needs to heat up quickly, the two heating elements work at the same time to ensure the bed temperature. When the low temperature needs to be maintained, only the low-power device works to save on-board energy. The first heating element and the second heating element are respectively installed in the heating element frame, and the heating element frame of the double-channel heating element is protected by an armor shell arranged outside the heating element; the gaps between the heating element, the heating element frame and the armor shell are filled with ceramic powder to ensure that the relative positions between the components are fixed; The armor shell material is PtRh alloy, which is used to protect the internal components of the device in a space environment; the heating element skeleton material is α-Al2O3, which provides necessary support and insulation for the heating element; the ceramic powder is a mixture of Al2O3 and SiO2 powder in a weight ratio of 1:

1.

2. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 1, characterized in that: In the transition section, the transition line is installed in the transition line frame, and the transition line frame is sheathed with a thin-walled armored tube; the lead-out end of the heating element is connected to the transition line by spot welding.

3. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 2 is characterized by: The first heating element and the second heating element each have two lead-out ends, and the two lead-out ends of each heating element are respectively connected to two transition wires. The two transition wires connected to each heating element are installed in a transition wire skeleton and then protected by a thin-walled armor tube.

4. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 2 or 3, characterized in that: The transition wire is a metal Pt wire, and the wire diameter is 1.5 times the wire diameter of the connected heating element, ensuring that the power is concentrated in the working section; the wall thickness of the thin-walled armored tube is 0.1-0.15mm, which can reduce the conduction of heat to the power supply and valve body end while maintaining a certain strength.

5. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 1, characterized in that: In the lead-out section, the two transition lines connected to each heating element are each connected to an external lead wire, and an outer sleeve is sheathed outside the two connection points for protection; the gap inside the outer sleeve is filled with insulating sealing material.

6. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 5, characterized in that: The outer sleeve is made of Ni80Cr20 alloy, and the insulating sealing material is epoxy resin, both of which are used to ensure the relative positions of the internal components of the device; the lead wires are used to connect the power part and the power supply part to ensure stable operation of the device.

7. The high-temperature integrated armored heater for a green, high-energy, non-toxic thruster for a satellite as claimed in claim 1, characterized in that: Without a coating, the heater can preheat the catalyst bed in a low-temperature background environment to over 400°C, while being able to withstand the propellant combustion temperature of 1500°C during thruster ignition.

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