A hydrogen peroxide decomposition chamber and a pressure drop design method for the decomposition chamber

Abstract

The present invention discloses a hydrogen peroxide decomposition chamber and a method for designing a pressure drop of the decomposition chamber. A hydrogen peroxide decomposition chamber comprises a shell, wherein the axial front end of the shell is provided with a liquid inlet, and the axial rear end of the shell is fixedly provided with a flange; the interior of the shell is provided with an injector disc and a support plate in sequence along the axial direction, wherein the injector disc and the support plate divide the inner cavity of the shell into a liquid cavity, a catalyst cavity and a gas cavity, and a catalyst bed is provided in the catalyst cavity; the axial rear end of the support plate is provided with an adjustment ring, and the axial rear end of the adjustment ring is in close contact with the flange. In the present invention, by providing an injector disc, the flow decomposition of the decomposition chamber is ensured to be uniform, and the service life is increased by more than one time. In addition, the working life can reach 10,000 seconds, the installation and replacement structure is flexible, and the reusability is good, which solves the technical problem of shortened service life caused by uneven local decomposition of the catalyst bed in the prior art.

Description

Technical Field

[0001] The invention belongs to the field of aerospace, and relates to a method for calculating the pressure drop of a decomposition chamber, in particular to a hydrogen peroxide decomposition chamber and a method for designing the pressure drop of the decomposition chamber. Background Art

[0002] Hydrogen peroxide is widely used in rocket propulsion and civilian applications. As a non-toxic and environmentally friendly aerospace propellant, high-concentration hydrogen peroxide usually has a concentration of 80% to 98%. The decomposition products are high-temperature oxygen and water vapor, which are non-toxic and environmentally friendly. Currently, many countries are actively researching hydrogen peroxide catalytic decomposition technology and advanced gas generator design, which can be used for spacecraft propulsion fuel and other civilian hot gas sources, and can also be used in manned spacecraft life support systems.

[0003] In the design of hydrogen peroxide decomposition, the decomposition process is complex, including catalytic decomposition, thermal decomposition, etc., especially the thermal decomposition process is complex, involving liquid phase heating and decomposition, evaporation, gas phase decomposition, etc. At present, particulate catalysts are rarely used in hydrogen peroxide catalytic decomposition, and the maximum bed load is generally no more than 10g / (cm 2 ·s), while mesh-based catalysts have high activity and high permeability, which can achieve high bed load, long life and high decomposition pressure, and are therefore widely used. The bed load of mesh-based catalysts is usually higher than 20g / (cm 2 ·s), which also makes the pressure drop of the decomposition chamber higher, which is greatly affected by the bed load, working pressure, bed length, etc. The pressure drop of the decomposition chamber is an important design indicator. The present application discloses a hydrogen peroxide decomposition chamber and a pressure drop design method of the decomposition chamber, which can be used for the design and evaluation of catalytic decomposition chambers such as hydrogen peroxide thrust chambers and gas generators. Summary of the invention

[0004] In view of the shortcomings of the prior art, the object of the present invention is to provide a hydrogen peroxide decomposition chamber and a pressure drop design method for the decomposition chamber, so as to solve the technical problems of unreasonable pressure drop design of the decomposition chamber and short life of the catalyst bed in the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A hydrogen peroxide decomposition chamber comprises a shell, wherein the axial front end of the shell is provided with a liquid inlet, and the axial rear end of the shell is fixedly provided with a flange; an injector disc and a support plate are sequentially provided inside the shell along the axial direction, and the injector disc and the support plate divide the inner cavity of the shell into a liquid cavity, a catalyst cavity and a gas cavity, and a catalyst bed is provided in the catalyst cavity;

[0007] An adjusting ring is arranged at the axial rear end of the supporting plate, and the axial rear end of the adjusting ring is in close contact with the flange.

[0008] The present invention also includes the following technical features:

[0009] The catalyst bed comprises multiple layers of mesh sheets arranged along the axial direction, and multiple flow-stopping rings are arranged at intervals among all the mesh sheets.

[0010] The thickness of the stop ring is 0.8-1 mm.

[0011] The flange is fixed to the rear end surface of the shell by bolts, and a sealing ring is arranged between the flange and the rear end surface of the shell.

[0012] The multi-layer meshes have different mesh sizes.

[0013] The injector disk is provided with a plurality of spray holes, and the spray holes located on the same radius have the same aperture and are evenly distributed along the circumference.

[0014] The outlet of the spray hole is provided with a chamfer.

[0015] The support plate is provided with a plurality of air holes, and the air holes on the same radius have the same aperture and are evenly distributed along the circumference.

[0016] The injector disc is provided with a first rib plate, and the support plate is provided with a second rib plate.

[0017] A pressure drop design method for designing a hydrogen peroxide decomposition chamber as claimed in the claims, specifically comprising the following steps:

[0018] Step 1, preliminarily selecting the total pressure drop of the initial decomposition chamber, the chamber pressure of the decomposition chamber, the bed load of the catalyst bed and the bed length of the catalyst bed according to the system inlet pressure and flow rate required by the product;

[0019] Step 2, calculating the diameter of the catalyst bed according to the flow rate selected in step 1 and the bed load of the catalyst bed; setting the diameter of the injector disk to be equal to the diameter of the catalyst bed;

[0020] Step 3, determining the injection pressure drop p1 according to the system inlet pressure, and designing the injector disc according to the injection pressure drop p1 and the flow rate;

[0021] The injection pressure drop p1 ranges from 0.2MPa to 0.3MPa;

[0022] The design of the injector disk according to the injection pressure drop p1 and flow rate specifically includes the following operations:

[0023] The total area of ​​the spray holes is calculated based on the flow rate and the injection pressure drop p1, and then the number of holes and the average hole diameter are obtained based on the total area of ​​the spray holes;

[0024] The spray holes are distributed in a plurality of concentric circles, and the number of spray holes on different circles is 6, 12, 18, 24 ... 6n, where n is the number of concentric circles;

[0025] The flow distribution of the nozzles in the center area is 15%; the flow distribution in the main area is 60%; the flow distribution in the side area is 25%;

[0026] The central area is the area within the 1 / 3 diameter range on the injector disk; the main area is the area within the 1 / 3 to 2 / 3 diameter range on the injector disk; the edge area is the area between the 2 / 3 diameter on the injector disk and the edge of the injector disk;

[0027] Step 4, select the support plate;

[0028] The pores on the support plate are distributed in multiple concentric circles, and the number of pores on different circles is 3, 9, 15...{3+6(m-1)}, m is the number of concentric circles, and the pore pressure drop p2 is 0.1MPa.

[0029] Step 5, calculate the catalyst bed pressure drop ΔPcat using the following formula;

[0030] ΔPcat=a*Gb b *Pc c

[0031] Where:

[0032] Gb represents the bed loading of the catalyst bed, g / cm 2 .s;

[0033] Pc represents the pressure of the decomposition chamber, MPa;

[0034] a=0.000552, b=2.604, c=-1.016;

[0035] Step 6, calculating the total pressure drop P of the decomposition chamber;

[0036] P=p1+p2+ΔPcat

[0037] Step 7, judging whether the sum of the total pressure drop P of the decomposition chamber obtained in step 6 and the chamber pressure of the decomposition chamber selected in step 1 exceeds the system inlet pressure required by the product, if not, proceeding to step 8; if exceeding, reducing the value of the bed load of the catalyst bed or increasing the chamber pressure of the decomposition chamber, executing step 5 to calculate the corrected catalyst bed pressure drop, or calculating the corrected catalyst bed pressure drop by adjusting the bed length, until the sum of the total pressure drop P of the decomposition chamber and the chamber pressure of the decomposition chamber is less than or equal to the system inlet pressure required by the product, proceeding to step 8;

[0038] The calculation formula for the corrected catalyst bed pressure drop calculated by adjusting the bed length is as follows:

[0039] ΔPcat'=ΔPcat*Lb / 70

[0040] Where:

[0041] Lb represents the bed length of the catalyst, ranging from 50 mm to 100 mm;

[0042] ΔPcat' represents the corrected catalyst bed pressure drop;

[0043] Step 8, select the mesh packing compaction force according to the catalyst bed pressure drop, and the value range is 15MPa to 20MPa.

[0044] Step 9, obtaining a hydrogen peroxide decomposition chamber.

[0045] Compared with the prior art, the present invention has the following beneficial technical effects:

[0046] (I) The present invention ensures uniform flow decomposition in the decomposition chamber by providing an injector disk, thereby achieving a lifespan increase of more than double. In addition, the working life can reach 10,000 seconds, the installation and replacement structure is flexible, and the reusability is good, thus solving the technical problem of shortened lifespan caused by uneven local decomposition of the catalyst bed in the prior art.

[0047] (II) The pressure drop of the catalyst bed in the decomposition chamber of the present invention can be comprehensively coordinated based on parameters such as the decomposition chamber pressure, bed load, bed length and clamping force, thereby achieving adjustable pressure drop of the catalyst bed in the decomposition chamber. In addition, the catalyst bed has strong rigidity under the thermal structure, thereby achieving stable operation of the decomposition chamber under high and low flow rates (above the 5:1 ratio range).

[0048] (III) By adopting the decomposition chamber pressure drop design method of the present invention, under the condition that the pressure drop meets the system requirements, the designed bed length is achieved with a reasonable pressing force, the decomposition uniformity is improved, the flow rate that can be fully decomposed is large, and the bed load is high, so that the bed load of the catalyst bed in the decomposition chamber is doubled to 40g / (cm 2 ·s), the diameter of the decomposition chamber is reduced by 40%, achieving the goal of miniaturization of the catalyst bed. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of the hydrogen peroxide decomposition chamber of the present invention;

[0050] Figure 2 for Figure 1 A schematic diagram of the structure of the injector disk;

[0051] Figure 3 for Figure 2 The middle BB section is a schematic diagram;

[0052] Figure 4 for Figure 3 A partial enlarged view of the

[0053] Figure 5 for Figure 1A schematic diagram of the structure of the support plate;

[0054] Figure 6 for Figure 5 The AA section in the middle is a schematic diagram;

[0055] Figure 7 for Figure 1 Schematic diagram of the structure of the stop ring.

[0056] The meanings of the numbers in the figure are: 1-shell, 2-liquid inlet, 3-flange, 4-injector plate, 5-support plate, 6-inner cavity, 7-catalyst bed, 8-adjusting ring, 9-bolt, 10-sealing ring;

[0057] 401-spray hole, 402-chamfer, 403-first rib;

[0058] 501-air hole, 502-second rib;

[0059] 601-liquid chamber, 602-catalyst chamber, 603-gas chamber;

[0060] 701-mesh, 702-stop ring.

[0061] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0062] It should be noted that, unless otherwise specified, all components in the present invention are components known in the art.

[0063] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0064] The present invention provides a hydrogen peroxide decomposition chamber, comprising a shell 1, wherein a liquid inlet 2 is provided at the axial front end of the shell 1, and a flange 3 is fixedly provided at the axial rear end of the shell 1; an injector disc 4 and a support plate 5 are sequentially provided inside the shell 1 along the axial direction, and the injector disc 4 and the support plate 5 divide the inner cavity 6 of the shell 1 into a liquid cavity 601, a catalyst cavity 602 and a gas cavity 603, and a catalyst bed 7 is provided in the catalyst cavity 602;

[0065] An adjusting ring 8 is provided at the axial rear end of the supporting plate 5 , and the axial rear end of the adjusting ring 8 is in close contact with the flange 3 .

[0066] Specifically, the catalyst bed 7 includes multiple layers of mesh sheets 701 arranged along the axial direction, multiple stop rings 702 are arranged at intervals between all the mesh sheets 701, and a stop ring 702 is arranged for each layer or multiple layers of mesh sheets 701.

[0067] Specifically, the thickness of the stop ring 702 is 0.8-1 mm.

[0068] Specifically, the flange 3 is fixed to the rear end surface of the shell 1 by bolts 9, and a sealing ring 10 is arranged between the flange 3 and the rear end surface of the shell 1 to ensure the sealing inside the decomposition chamber.

[0069] Specifically, the multi-layer mesh 701 uses different mesh sizes. The front mesh is similar to a distribution mesh with low activity; the mesh size of the middle and rear mesh is larger and the activity is high.

[0070] Specifically, the injector disk 4 is provided with a plurality of spray holes 401 . The spray holes 401 located on the same radius have the same aperture and are evenly distributed along the circumference, thereby ensuring even flow distribution in the entire cross section.

[0071] Specifically, the outlet of the spray hole 401 is provided with a chamfer 402 to increase the contact area between the sprayed liquid and the mesh.

[0072] Specifically, a plurality of air holes 501 are provided on the support plate 5 . The air holes 501 located on the same radius have the same aperture and are evenly distributed along the circumference, thereby ensuring even flow distribution in the entire cross section.

[0073] Specifically, the injector disk 4 is provided with a first rib 403, and the support plate 5 is provided with a second rib 502, so as to improve the rigidity of the injector disk and the support plate.

[0074] Furthermore, the present invention also provides a pressure drop design method for designing a hydrogen peroxide decomposition chamber, which specifically includes the following steps:

[0075] Step 1, preliminarily selecting the total pressure drop of the initial decomposition chamber, the chamber pressure of the decomposition chamber, the bed load of the catalyst bed and the bed length of the catalyst bed according to the system inlet pressure and flow rate required by the product;

[0076] Step 2, calculating the diameter of the catalyst bed according to the flow rate selected in step 1 and the bed load of the catalyst bed; setting the diameter of the injector disk to be equal to the diameter of the catalyst bed;

[0077] Step 3, determining the injection pressure drop p1 according to the system inlet pressure, and designing the injector disc according to the injection pressure drop p1 and the flow rate;

[0078] The injection pressure drop p1 range is 0.2MPa~0.3MPa;

[0079] Designing the injector disc according to the injection pressure drop p1 and flow rate specifically includes the following operations:

[0080] The total area of ​​the spray holes is calculated based on the flow rate and the injection pressure drop p1, and then the number of holes and the average hole diameter are obtained based on the total area of ​​the spray holes;

[0081] The nozzles are distributed in multiple concentric circles, and the number of nozzles on different circles is 6, 12, 18, 24...6n, where n is the number of concentric circles;

[0082] The flow distribution of the nozzles in the center area is 15%; the flow distribution in the main area is 60%; the flow distribution in the side area is 25%;

[0083] The central area is the area within the 1 / 3 diameter range on the injector disk; the main area is the area within the 1 / 3 to 2 / 3 diameter range on the injector disk; the edge area is the area between the 2 / 3 diameter on the injector disk and the edge of the injector disk;

[0084] Step 4, select the support plate;

[0085] The pores on the support plate are distributed in multiple concentric circles. The number of pores on different circles is 3, 9, 15...{3+6(m-1)}, m is the number of concentric circles, and the pore pressure drop p2 is 0.1MPa.

[0086] Step 5, calculate the catalyst bed pressure drop ΔPcat using the following formula;

[0087] ΔPcat=a*Gb b *Pc c

[0088] Where:

[0089] Gb represents the bed loading of the catalyst bed, g / cm 2 .s;

[0090] Pc represents the pressure of the decomposition chamber, MPa;

[0091] a=0.000552, b=2.604, c=-1.016;

[0092] Step 6, calculating the total pressure drop P of the decomposition chamber;

[0093] P=p1+p2+ΔPcat

[0094] Step 7, judging whether the sum of the total pressure drop P of the decomposition chamber obtained in step 6 and the chamber pressure of the decomposition chamber selected in step 1 exceeds the system inlet pressure required by the product, if not, proceeding to step 8; if exceeding, reducing the value of the bed load of the catalyst bed or increasing the chamber pressure of the decomposition chamber, executing step 5 to calculate the corrected catalyst bed pressure drop, or calculating the corrected catalyst bed pressure drop by adjusting the bed length, until the sum of the total pressure drop P of the decomposition chamber and the chamber pressure of the decomposition chamber is less than or equal to the system inlet pressure required by the product, proceeding to step 8;

[0095] The calculation formula for the corrected catalyst bed pressure drop calculated by adjusting the bed length is as follows:

[0096] ΔPcat'=ΔPcat*Lb / 70

[0097] Where:

[0098] Lb represents the bed length of the catalyst, ranging from 50 mm to 100 mm;

[0099] ΔPcat' represents the corrected catalyst bed pressure drop;

[0100] Step 8, select the mesh packing compaction force according to the catalyst bed pressure drop, and the value range is 15MPa to 20MPa.

[0101] Step 9, obtaining a hydrogen peroxide decomposition chamber.

Claims

1. A pressure drop design method, characterized in that: Used for designing a hydrogen peroxide decomposition chamber, the hydrogen peroxide decomposition chamber comprising a shell (1), the axial front end of the shell (1) being provided with a liquid inlet (2), and the axial rear end of the shell (1) being fixedly provided with a flange (3); characterized in that an injector disc (4) and a support plate (5) are sequentially arranged inside the shell (1) along the axial direction, the injector disc (4) and the support plate (5) dividing the inner cavity (6) of the shell (1) into a liquid cavity (601), a catalyst cavity (602) and a gas cavity (603), and a catalyst bed (7) is arranged in the catalyst cavity (602); An adjustment ring (8) is provided at the axial rear end of the support plate (5), and the axial rear end of the adjustment ring (8) is in close contact with the flange (3); The catalyst bed (7) comprises a plurality of mesh sheets (701) arranged along the axial direction, and a plurality of flow-stopping rings (702) are arranged at intervals between all the mesh sheets (701); The method specifically comprises the following steps: Step 1, preliminarily selecting the total pressure drop of the initial decomposition chamber, the chamber pressure of the decomposition chamber, the bed load of the catalyst bed and the bed length of the catalyst bed according to the system inlet pressure and flow rate required by the product; Step 2, calculating the diameter of the catalyst bed according to the flow rate selected in step 1 and the bed load of the catalyst bed; setting the diameter of the injector disk to be equal to the diameter of the catalyst bed; Step 3: Determine the injection pressure drop based on the system inlet pressure , and according to the injection pressure drop and flow design injector disc; The injection pressure drop The range is 0.2MPa~0.3MPa; The injection pressure drop The specific operations of injector plate design and flow rate design include the following: According to the flow rate, injection pressure drop The total area of ​​the spray holes is calculated, and then the number of holes and the average hole diameter are obtained according to the total area of ​​the spray holes; The spray holes are distributed in a plurality of concentric circles, and the number of spray holes on different circles is 6, 12, 18, 24 ... 6n, where n is the number of concentric circles; The flow distribution of the nozzles in the central area is 15%; the flow distribution in the main area is 60%; the flow distribution in the side area is 25%; The central area is the area within the 1 / 3 diameter range on the injector disk; the main area is the area within the 1 / 3 to 2 / 3 diameter range on the injector disk; the edge area is the area between the 2 / 3 diameter on the injector disk and the edge of the injector disk; Step 4, select the support plate; The pores on the support plate are distributed in multiple concentric circles, and the number of pores on different circles is 3, 9, 15... {3+6 (m-1)}, m is the number of concentric circles, and the pore pressure drop is Both are 0.1 MPa, Step 5, calculate the catalyst bed pressure drop using the following formula: ; Where: Indicates the bed loading of the catalyst bed, g / cm 2 .s; Indicates the pressure of the decomposition chamber, MPa; a=0.000552, b=2.604, c=-1.016; Step 6: Calculate the total pressure drop in the decomposition chamber ; Step 7, determine the total pressure drop of the decomposition chamber obtained in step 6 Whether the sum of the pressure of the decomposition chamber selected in step 1 exceeds the system inlet pressure required by the product, if not, proceed to step 8; if exceeded, reduce the value of the bed load of the catalyst bed or increase the decomposition chamber pressure, execute step 5 to calculate the corrected catalyst bed pressure drop, or calculate the corrected catalyst bed pressure drop by adjusting the bed length, until the total pressure drop of the decomposition chamber is The sum of the pressure of the decomposition chamber and the pressure of the decomposition chamber is less than or equal to the system inlet pressure required by the product, and the process goes to step 8; The calculation formula for the corrected catalyst bed pressure drop calculated by adjusting the bed length is as follows: Where: Indicates the bed length of the catalyst, ranging from 50mm to 100mm; represents the corrected catalyst bed pressure drop; Step 8, selecting the mesh packing pressure according to the catalyst bed pressure drop, the value range is 15 MPa ~ 20 MPa; Step 9, obtaining a hydrogen peroxide decomposition chamber.

2. The pressure drop design method according to claim 1, characterized in that: The flow-stop ring (702) has a thickness of 0.8 to 1 mm.

3. The pressure drop design method according to claim 1, characterized in that: The flange (3) is fixed to the rear end surface of the housing (1) by means of bolts (9), and a sealing ring (10) is provided between the flange (3) and the rear end surface of the housing (1).

4. The pressure drop design method according to claim 1, characterized in that: The multi-layer mesh (701) has different mesh sizes.

5. The pressure drop design method according to claim 1, characterized in that: The injector disk (4) is provided with a plurality of spray holes (401), and the spray holes (401) located on the same radius have the same aperture and are evenly distributed along the circumference.

6. The pressure drop design method according to claim 1, characterized in that: The outlet of the spray hole (401) is provided with a chamfer (402).

7. The pressure drop design method according to claim 1, characterized in that: The support plate (5) is provided with a plurality of air holes (501), and the air holes (501) located on the same radius have the same aperture and are evenly distributed along the circumferential direction.

8. The pressure drop design method according to claim 7, characterized in that: The injector disc (4) is provided with a first rib (403), and the support plate (5) is provided with a second rib (502).

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