CN114483373A - Engine grain forming and demolding method based on deformable core mold standard test - Google Patents
Engine grain forming and demolding method based on deformable core mold standard test Download PDFInfo
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- CN114483373A CN114483373A CN202111579533.6A CN202111579533A CN114483373A CN 114483373 A CN114483373 A CN 114483373A CN 202111579533 A CN202111579533 A CN 202111579533A CN 114483373 A CN114483373 A CN 114483373A
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- standard test
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/24—Charging rocket engines with solid propellants; Methods or apparatus specially adapted for working solid propellant charges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/10—Shape or structure of solid propellant charges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/32—Constructional parts; Details not otherwise provided for
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
The invention provides a method for forming and demoulding engine grain based on a deformable core mould standard test, which comprises the following steps: preparing an initial straight pipe of a deformable core mold by adopting a thermally-driven shape memory polymer; preparing a deformable core mould according to the shape structure of the standard test engine grain; assembling the deformable core mold with a standard test engine shell, and pouring and curing the solid propellant; and (3) placing the cured standard test engine in an oven at a preset temperature, heating and deforming a deformable core mold to restore the deformed core mold to an initial straight pipe, and separating and extracting the core mold from the solid propellant grain to finish the forming of the standard test engine grain. The invention adopts the deformable core die based on thermal drive, can realize safe and rapid demoulding, effectively shortens the charging period, and simultaneously replaces the metal core die to eliminate potential safety hazard generated by friction in the demoulding process of the metal core die.
Description
Technical Field
The invention relates to the field of solid rocket engine charging, in particular to an engine grain forming and demolding method based on a deformable core model standard test.
Background
The integral metal core mold is a key part for forming a standard test engine grain structure. The monolithic structural core is a single structural member and is typically of a solid design to ensure its shape. In the process of charging and demolding, the integral core mold is demolded by adopting single-end strong traction, the core mold and the solid propellant are easy to rub with each other in the operation process, the deflagration of the solid propellant occurs, and the danger is extremely high.
Shape Memory Polymer (SMP for short) is a new type of functional Polymer material. Under certain conditions, the material is given a certain shape (initial state) and when the external conditions change, it can change shape accordingly and fix it (morphed). If the external environment changes again in a specific way and law, the material can be restored to the initial state reversibly, and a cycle of 'memory initial state-fixed deformation state-restored initial state' is formed. Shape memory polymers can be classified, driven by external conditions: thermally driven shape memory polymers, electrically driven shape memory polymers, optically driven shape memory polymers, magnetic field driven shape memory polymers, solution driven shape memory polymers, and the like. The driving method of the thermal driving shape memory polymer is simple, direct and effective, and generally consists of a fixed phase for memorizing the original shape of a forming component and a reversible phase for softening and hardening along with temperature change, so that the forming requirement can be met, and meanwhile, the structural stability can be kept for a long time. Compared with the traditional metal core mold, the deformable core mold made of the thermally-driven shape memory polymer has the advantages of light weight, convenience in operation, difficulty in friction during demolding, high safety and the like. A plurality of experts in China have made deformable core moulds by adopting a thermally-driven shape memory polymer, for example, patent CN201610247810.6 discloses a preparation and safe and rapid demoulding process of inner hole combustion grains of a solid rocket engine, and the patent proposes that the deformable core moulds required by the formation of the inner hole combustion grains are prepared by adopting the thermally-driven shape memory polymer, and is characterized in that: the deformable core mold can maintain the deformation state at 40-48 ℃ and recover to the initial state at 52-60 ℃, the deformation capacity is not less than 50%, and the wall thickness of the deformable core mold is between 2-10 mm. The demolding process mainly comprises the steps of heating and stimulating the deformable core mold, and when the temperature rises to (52-60) DEG C, recovering the deformable core mold from a deformation state to an initial state and separating the deformable core mold from a solid propellant grain, so that the core mold is rapidly demolded.
The traditional metal core mold has certain potential safety hazard in the charging and demolding process of a standard test engine. With the development of shape memory polymer material technology, deformable mandrel applications have evolved. The deformable core mold based on thermal driving is made of thermal driving shape memory polymer, has the characteristics of shape memory and variable rigidity, and can change the shape under the stimulation of external temperature change so as to achieve the aim of safely and quickly demolding. The rigidity of the thermal driving deformable core mold is obviously changed along with the temperature, and when the temperature is higher than the glass transition temperature of the shape memory polymer, the rigidity of the core mold is lower, the blow molding deformation is easy, and the deformation form can be designed; when the temperature is lower than the glass transition temperature of the shape memory polymer, the rigidity of the core mold is higher, and the deformation state required by the operation of the core mold can be effectively kept. The patent CN201610247810.6 discloses a preparation and safe and rapid demoulding process of an inner hole combustion explosive column of a solid rocket engine, on one hand, the research of the charging and demoulding process of the solid rocket engine is only carried out on a deformable core mould which is deformed into a straight pipe, and the research of the charging and demoulding process is not carried out on the deformable core mould with a large end and a small end and different deformation rates; on the other hand, the deformable core die disclosed in the patent can keep the deformation state at the temperature of (40-48 ℃), and the temperature range does not meet the requirements of standard engine charging tests.
Disclosure of Invention
The invention provides a method for forming and demoulding engine grain based on deformable core mould standard test, which can realize safe and rapid demoulding by adopting a deformable core mould based on thermal drive, effectively shorten the charging period, and simultaneously replace a metal core mould to eliminate potential safety hazard generated by friction in the demoulding process of the metal core mould.
In order to solve the technical problem, the invention provides a method for forming and demoulding a charge of an engine based on a deformable core mould standard test, which comprises the following steps:
s1: preparing an initial straight pipe of a deformable core mold by adopting a thermally-driven shape memory polymer;
s2: preparing a deformable core mould according to the shape structure of the standard test engine grain;
s3: assembling the deformable core mold with a standard test engine shell, and pouring and curing the solid propellant;
s4: and (3) placing the cured standard test engine in a baking oven at a preset temperature, enabling the deformable core mold to be heated and deformed to recover to an initial straight pipe, and separating and extracting the core mold from the solid propellant grain to finish the forming of the standard test engine grain.
Furthermore, the length of the initial S1 straight pipe is 155 mm-300 mm, the outer diameter is 54 mm-60 mm, and the wall thickness is 2mm-5 mm.
Further, in the S2, in the environment with the temperature of 75-100 ℃, the blow molding pressure of 0.02-0.1 MPa is applied to the initial straight pipe, so that the initial straight pipe is deformed into the deformable core mold required by the standard test engine charging, the deformation rate of one end of the straight pipe is 0-10%, and the deformation rate of the other section is 80-100%.
Further, the deformable core die in the step S3 is assembled with the standard test engine shell through an auxiliary tool, and the auxiliary tool comprises a deformable core die tray, bolts and a connecting flange; the deformable core mould tray is provided with a circular groove with the depth of 2mm-5mm, the width of 2mm-6mm and the diameter of 108mm-114mm, and one end of the deformable core mould is embedded into the circular groove to prevent the core mould from displacing in the solid propellant pouring process.
Further, the assembling sequence of the deformable core die and the standard test engine shell in the step S3 is as follows:
s31: connecting and fixing the deformable core mould tray and the connecting flange through 4 sets of bolts;
s32: assembling and screwing the standard test engine shell and the connecting flange through threads;
s33: embedding the deformable core mold into a circular groove on a deformable core mold tray, and sealing a gap between the circular groove and the deformable core mold by adopting an O-shaped sealing ring to prevent solid propellant slurry from permeating into the circular groove during charging;
s34: after the standard test engine and the deformable core die are assembled, the assembly is placed in an oven with the temperature of 50 +/-2 ℃ for preheating.
S35: and placing the preheated standard test engine in a casting cylinder for casting a solid propellant, curing in an environment with the temperature of 50-70 ℃ for 168-360 h, and cooling the temperature of the standard test engine to room temperature after curing is finished.
Further, the standard test engine which is cured in the step S4 is heated to 75-80 ℃ from room temperature, the heating rate is 2.5-10 ℃/min, the standard test engine is placed in an oven at the temperature of 75-80 ℃ for 0.5-2 h, and the deformable core mold can be drawn out after being separated from the inner wall of the drug column of the standard test engine, so that the drug column demoulding of the standard test engine is completed.
One or more technical solutions of the present invention at least have one or more of the following technical effects:
the invention provides a method for forming and demoulding engine grain based on deformable core mould standard test, which can realize safe and rapid demoulding by adopting a deformable core mould based on thermal drive, effectively shorten the charging period, and simultaneously replace a metal core mould to eliminate potential safety hazard generated by friction in the demoulding process of the metal core mould. The invention has simple manufacturing process, can be repeatedly used, has safe and quick demolding process, and can effectively shorten the charging period and reduce the production cost.
Drawings
FIG. 1 is a process flow of a method for forming and demolding a charge of an engine based on a deformable core standard test;
figure 2, the initial straight tube shape of the deformable core;
FIG. 3 is a schematic diagram of a deformable mandrel for a standard test engine;
FIG. 4 is a front view of the auxiliary fixture for assembling the deformable core mold;
FIG. 5 is a plan view of the deformable core mold assembly auxiliary tool;
wherein: 1. a deformable core tray; 2. four sets of bolts; 3. a connecting flange; 4. a circular groove; 5. a housing; a deformable mandrel.
Detailed Description
The embodiment of the invention provides a method for forming and demoulding an engine grain based on a deformable core mould standard test.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the obtained embodiments. All other embodiments that can be derived from the embodiments of the present invention by one of ordinary skill in the art are within the scope of the present invention.
Example one
The invention provides a method for forming and demoulding engine grain based on a deformable core mould standard test, which is used for replacing materials with a certain type of solid propellant. As shown in fig. 1, the specific steps are as follows:
s1: deformable core die design and preparation
(1) A deformable straight tube of 170mm length, 60mm outer diameter and 2mm wall thickness was prepared using a heat-activated shape memory polymer, as shown in FIG. 2.
(2) One end of the deformable straight pipe is completely sealed, the other end of the deformable straight pipe is provided with an air duct, the deformable straight pipe is placed into a high-temperature drying oven, the temperature is increased to 100 ℃, and the deformable straight pipe is kept for 30min to achieve heat balance. And taking out the deformable straight pipe, putting the deformable straight pipe into an auxiliary steel die, and deforming the deformable straight pipe by adopting blow molding air pressure of 0.02MPa until the deformable straight pipe is completely attached to the inner wall of the steel die. And then keeping the blow molding air pressure unchanged, cooling to room temperature, removing the blow molding air pressure, and removing the steel mold to obtain the deformable core mold, as shown in figure 3.
S2: standard test engine and deformable core mold assembly
(1) Assembly auxiliary tool assembly
In combination with the structural characteristics of the standard test engine and the deformable core mold, the invention designs an auxiliary tool for assembling the standard test engine and the deformable core mold, as shown in fig. 4-5. The assembly auxiliary tool comprises a deformable core die tray 1, four sets of bolts 2 and a connecting flange 3. Wherein, the deformable core mould tray 1 is designed and processed with a circular groove 4 with the depth of 2mm, the width of 4mm and the outer diameter of 112mm, one end of the deformable core mould 6 is embedded into the circular groove 4, thereby preventing the core mould from displacement in the process of pouring the solid propellant.
(2) Assembling step
The assembly sequence for the standard test engine was as follows:
(1) connecting and fixing the deformable core mould tray 1 and the connecting flange 3 through four sets of bolts 2;
(2) assembling and screwing the standard test engine shell 5 and the connecting flange 3 through threads;
(3) the deformable core mould 6 is embedded into the circular groove 4 on the deformable core mould tray, and the O-shaped sealing ring is adopted to seal the gap between the circular groove 4 and the deformable core mould 6, so that the solid propellant slurry is prevented from permeating into the circular groove during charging.
After the standard test engine is assembled with the deformable core mold, the standard test engine is placed in an oven at a temperature of (50 +/-2) DEG C for preheating.
S3: standard test engine charge
And (3) placing the preheated standard test engine in a casting cylinder for casting the solid propellant, wherein the casting temperature is 50 ℃. After the pouring is finished, a non-integral ring is covered on a front machine opening of a standard test engine. The standard test engine was then cured in an environment at a temperature of 50 ℃ for a curing time of 240 h.
S4: standard test engine demold
After the standard test engine is solidified, when the temperature is reduced to the room temperature, the auxiliary tool is disassembled, and redundant solid propellant is cleaned. Then the standard test engine is placed in an oven to be heated from room temperature to 75 ℃, and the heating rate is 5 ℃/min. After the standard test engine is placed in an oven with the temperature of 75 ℃ for 1.5 hours, the deformable core mold is separated from the inner wall of the standard test engine grain. The oven was closed and the temperature was allowed to drop to room temperature, and the deformable plug was then removed and the recovery of the deformable plug was calculated to be 96.37%. The core mold removal of the standard test engine can be completed through the process. And (5) detecting the demoulded standard test engine, wherein the forming precision of the explosive column meets the requirement of a design index.
Claims (6)
1. A method for forming and demoulding engine grain based on a deformable core mould standard test is characterized by comprising the following steps:
s1: preparing an initial straight pipe of a deformable core mold by adopting a thermally-driven shape memory polymer;
s2: preparing a deformable core mould according to the shape structure of the standard test engine grain;
s3: assembling the deformable core mold with a standard test engine shell, and pouring and curing the solid propellant;
s4: and (3) placing the cured standard test engine in a baking oven with a preset temperature, heating the deformable core mold to deform and restore to the initial straight pipe, separating the core mold from the solid propellant grain, and extracting to finish the molding of the standard test engine grain.
2. The method for forming and demolding engine grains based on the deformable core mold standard test according to claim 1, wherein the method comprises the following steps: the length of the S1 initial straight pipe is 155 mm-300 mm, the outer diameter is 54 mm-60 mm, and the wall thickness is 2mm-5 mm.
3. The method for forming and demolding engine grains based on the deformable core mold standard test according to claim 1, wherein the method comprises the following steps: in the S2, in the environment with the temperature of 75-100 ℃, blow molding pressure of 0.02-0.1 MPa is applied to the initial straight pipe to deform the initial straight pipe into a deformable core mold required by the charging of a standard test engine, the deformation rate of one end of the straight pipe is 0-10%, and the deformation rate of the other section is 80-100%.
4. The method for forming and demolding engine grains based on the deformable core mold standard test according to claim 1, wherein the method comprises the following steps: the deformable core die in the S3 is assembled with the standard test engine shell through an auxiliary tool, and the auxiliary tool comprises a deformable core die tray, bolts and a connecting flange; the deformable core mould tray is provided with a circular groove with the depth of 2mm-5mm, the width of 2mm-6mm and the diameter of 108mm-114mm, and one end of the deformable core mould is embedded into the circular groove to prevent the core mould from displacing in the casting process of the solid propellant.
5. The method for forming and demolding a deformable core mold standard test engine grain-based engine according to claim 4, wherein the assembling sequence of the deformable core mold and the standard test engine shell in the step S3 is as follows:
s31: connecting and fixing the deformable core mould tray and the connecting flange through 4 sets of bolts;
s32: assembling and screwing the standard test engine shell and the connecting flange through threads;
s33: embedding the deformable core mold into a circular groove on a deformable core mold tray, and sealing a gap between the circular groove and the deformable core mold by adopting an O-shaped sealing ring to prevent solid propellant slurry from permeating into the circular groove during charging;
s34: after the standard test engine and the deformable core die are assembled, the assembly is placed in an oven with the temperature of 50 +/-2 ℃ for preheating.
S35: and placing the preheated standard test engine in a casting cylinder for casting a solid propellant, curing in an environment with the temperature of 50-70 ℃ for 168-360 h, and cooling the temperature of the standard test engine to room temperature after the curing is finished.
6. The method for forming and demolding engine grains based on the deformable core mold standard test according to claim 1, wherein the method comprises the following steps: and in the step S4, the standard test engine which is cured is heated to 75-80 ℃ from room temperature, the heating rate is 2.5-10 ℃/min, the standard test engine is placed in an oven at the temperature of 75-80 ℃ for 0.5-2 h, and the deformable core mold can be drawn out after being separated from the inner wall of the grain column of the standard test engine, so that the grain column demoulding of the standard test engine is completed.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111579533.6A CN114483373A (en) | 2021-12-22 | 2021-12-22 | Engine grain forming and demolding method based on deformable core mold standard test |
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| CN202111579533.6A CN114483373A (en) | 2021-12-22 | 2021-12-22 | Engine grain forming and demolding method based on deformable core mold standard test |
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| CN114483373A true CN114483373A (en) | 2022-05-13 |
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| CN202111579533.6A Pending CN114483373A (en) | 2021-12-22 | 2021-12-22 | Engine grain forming and demolding method based on deformable core mold standard test |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105840344A (en) * | 2016-04-20 | 2016-08-10 | 哈尔滨工业大学 | Preparation and safe quick demolding process for solid rocket engine inner hole burning grain |
| CN107187008A (en) * | 2017-07-06 | 2017-09-22 | 哈尔滨工业大学 | One kind is used for shape-memory polymer plastic uptake mould |
| US20200094491A1 (en) * | 2018-09-26 | 2020-03-26 | The Boeing Company | System and method for manufacturing composite structures |
-
2021
- 2021-12-22 CN CN202111579533.6A patent/CN114483373A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105840344A (en) * | 2016-04-20 | 2016-08-10 | 哈尔滨工业大学 | Preparation and safe quick demolding process for solid rocket engine inner hole burning grain |
| CN107187008A (en) * | 2017-07-06 | 2017-09-22 | 哈尔滨工业大学 | One kind is used for shape-memory polymer plastic uptake mould |
| US20200094491A1 (en) * | 2018-09-26 | 2020-03-26 | The Boeing Company | System and method for manufacturing composite structures |
Non-Patent Citations (1)
| Title |
|---|
| 王蓬勃 等: "基于形状记忆聚合物固体火箭发动机装药芯模试验研究", 《固体火箭技术》, vol. 45, no. 1, pages 109 - 114 * |
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