CN116794151B - Experimental test method for electron density of propellant powder combustion product under normal pressure - Google Patents
Experimental test method for electron density of propellant powder combustion product under normal pressure Download PDFInfo
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 124
- 239000003380 propellant Substances 0.000 title claims abstract description 59
- 239000000843 powder Substances 0.000 title claims abstract description 28
- 238000010998 test method Methods 0.000 title claims abstract description 13
- 239000000523 sample Substances 0.000 claims abstract description 123
- 238000012360 testing method Methods 0.000 claims abstract description 29
- 238000002474 experimental method Methods 0.000 claims abstract description 28
- 238000004364 calculation method Methods 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 24
- 150000002500 ions Chemical class 0.000 claims description 13
- 238000004458 analytical method Methods 0.000 claims description 10
- 229920006395 saturated elastomer Polymers 0.000 claims description 9
- NLSCHDZTHVNDCP-UHFFFAOYSA-N caesium nitrate Chemical compound [Cs+].[O-][N+]([O-])=O NLSCHDZTHVNDCP-UHFFFAOYSA-N 0.000 claims description 8
- 230000007423 decrease Effects 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 239000003721 gunpowder Substances 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 229910001417 caesium ion Inorganic materials 0.000 claims description 3
- 238000010276 construction Methods 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 239000003814 drug Substances 0.000 claims 1
- 210000002381 plasma Anatomy 0.000 description 18
- 239000007789 gas Substances 0.000 description 12
- 230000009977 dual effect Effects 0.000 description 9
- 238000011160 research Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000002679 ablation Methods 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
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- 230000005593 dissociations Effects 0.000 description 1
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- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 description 1
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- 230000003595 spectral effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/626—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using heat to ionise a gas
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
- G01N25/22—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity on combustion or catalytic oxidation, e.g. of components of gas mixtures
Abstract
The invention relates to the technical field of electron density experimental tests, in particular to an experimental test method for electron density of propellant powder combustion products under normal pressure. According to the invention, a Langmuir double-probe-based propellant gas electron density test experiment system is constructed, electron density experiment values in combustion products under different combustion temperatures and different ionization seed contents are tested by adopting a Langmuir double-probe method, and electron density calculation values of the combustion products are calculated according to volt-ampere characteristic curves under different temperature intervals and different ionization seed contents, so that the electron density deviation values are analyzed, the reasons that deviation exists between the experiment results and the calculation results are further clarified, and meanwhile, the change of the electron temperature and the electron density deviation values of the combustion products under different ionization seed contents along with the temperature is analyzed, so that the change rule of the electron temperature and the electron density deviation values along with the temperature is reflected, and the method has important significance for designing and optimizing plasma application.
Description
Technical Field
The invention relates to the technical field of electron density experimental tests, in particular to an experimental test method for electron density of propellant powder combustion products under normal pressure.
Background
Related researches show that by adding ionization seeds into rocket propellant and gun propellant, combustion products can be thermally ionized to generate plasma, so that the ionization degree and the conductivity of the combustion products can be effectively improved, and the application of a magnetic field-controlled plasma/magnetic fluid technology is possible. The related derivative theory and technology have wide application prospects in the fields of magnetohydrodynamic power generation, rocket engine thrust vector control, hypersonic aircraft energy bypass, hypersonic aircraft magnetic control thermal protection, aerodynamics optimization of an aircraft and a high-speed train, ablation resistance of a barrel weapon and the like. In such applications, the ionization degree of the propellant/propellant combustion products containing the ionized seeds is critical for assessing the effect of magnetic field regulation, and therefore, accurate acquisition of the electron density of the propellant combustion products is of great importance.
Most of the current researches on the electron density of the combustion products are theoretical calculation and numerical simulation, and in view of the high-temperature environment of the combustion process and the instability of the combustion process, few researches can accurately measure the electron density of the combustion products through an experimental method. The prior art builds an electron density experiment test system of the propellant powder combustion product based on a closed exploder, but the related research carried out by the system only obtains spectral lines of characteristic elements in the combustion product, and does not accurately diagnose the electron density of the propellant powder combustion product; in addition, the closed exploder works in an extremely high pressure environment, so that the experimental result has limited application scenes. For the application in hypersonic flight field, the fuel gas medium is generally under normal pressure or low pressure, so that the development of an experimental test system under normal pressure and the provision of an effective electron density test method are significant for the application of the technology in the related field.
Disclosure of Invention
The invention aims to provide an experimental test method for electron density of propellant powder combustion products under normal pressure, and solves the problems in the background technology.
The technical scheme adopted for solving the technical problems is as follows: the invention provides an experimental test method for electron density of a propellant powder combustion product under normal pressure, which comprises the following steps: step one, constructing a propellant gas electron density test experiment system based on Langmuir double probes.
And step two, testing electron density experimental values in combustion products at different combustion temperatures and different ionization seed contents by adopting a Langmuir double-probe method.
And thirdly, performing multiple ignition experiments by changing the contents of the propellant powder and the ionized seeds, and acquiring experimental data under the condition that the flame temperatures measured by the thermocouples are similar, so as to obtain volt-ampere characteristic curves under different temperature intervals and different ionized seed contents.
And step four, calculating an electron density calculation value of the combustion product according to volt-ampere characteristic curves under different temperature intervals and different ionization seed contents.
And fifthly, comparing the electron density experimental value in the combustion product with the electron density calculated value to obtain an electron density deviation value, and further analyzing the electron temperature of the combustion product under different ionization seed contents and the change of the electron density deviation value along with the temperature.
Preferably, the propellant gas electron density test experiment system based on Langmuir double probes consists of propellant containing ionized seeds, a combustion vessel, a laser igniter, langmuir double probes, a probe fixing and driving mechanism, a probe system control unit, a thermocouple and an upper computer. Wherein, the combustion vessel is made of high temperature resistant gun steel; the laser igniter is used for realizing remote ignition control of the propellant powder; the two Langmuir probes adopt identical structural parameters, and the non-test part of the probes is sealed by alumina ceramic; the probe fixing and driving mechanism consists of a supporting frame and a driving motor and is used for fixing the probe and realizing the movement of the probe in flame so as to acquire plasma parameters at different positions; the Langmuir probe is connected with the probe system control unit through a wire; the thermocouple is fixed at a position close to the probe head and used for measuring the macroscopic temperature of gunpowder gas at the probe.
Preferably, the experimental values of electron density in the combustion products under different combustion temperatures and different ionization seed contents are tested by using a Langmuir double-probe method, and specifically include: s1, after laser ignition, the flame to be emitted is basically stabilized, then testing is started, scanning voltage of Langmuir double probes and loading time of the scanning voltage are set, connection scanning is carried out according to the loading time of interval scanning voltage after each scanning is completed, voltage-current values corresponding to each test point are recorded, and an average value is calculated to construct a volt-ampere characteristic curve.
S2, by changing the mass fraction of cesium nitrate in the propellant powder and the dosage of the propellant powder and adjusting the position of the probe in flame, multiple laser ignition experiments are completed and the volt-ampere characteristic curves are synchronously recorded, so that multiple groups of electron density experiment values with different ionization seed contents and different temperatures are obtained.
Preferably, the third specific content includes: according to the volt-ampere characteristic curves of different temperature intervals and different ionization seed contents, the volt-ampere characteristic curves drawn by the average value of each experiment have good symmetry in a positive voltage section and a negative voltage section.
Further, it is known that, as the temperature increases, the standard deviation of the current value gradually increases, but the standard deviation coefficient gradually decreases, indicating that the ionization reaction in the combustion product becomes more stable as the temperature increases, and the deviation of the experimental data is also smaller.
Preferably, the calculating the electron density calculation value of the combustion product specifically includes: obtaining saturated ion currents of the probe 1 and the probe 2 according to volt-ampere characteristic curves under different temperature ranges and different ionization seed contents, wherein the saturated ion currents are respectively I 1+ And I 2+ When the two probes are identical in structure, there is generally I + ＝I 1+ ＝-I 2+ Analysis of electron temperature T e The calculation formula is that The slope of the voltammetric characteristic curve when the potential difference between the two probes is 0 is represented by e, which is the electron charge, and k, which is the Boltzmann constant.
Calculation of the electron Density calculation value N of Combustion products e-calculated value The calculation formula is thatA p ＝πd p L p In which A p For the surface area of the probe, pi is the circumference ratio, M i Is the mass of Cs ion, d p For the diameter of the probe head of the probe, L p Is the probe length.
Preferably, the electron density deviation value analysis mode is thatWherein N is e-experimental values Is an electron density experimental value of the combustion product.
Preferably, the analysis of the electron temperature and the variation of the electron density deviation value with temperature of the combustion products under different ionization seed contents comprises: when ionizing seed content alpha Cs When=2%, the calculated plasma parameters at different combustion temperatures, it can be known that the electron temperature of the combustion product measured by Langmuir double probe is higher than the temperature of the neutral particle measured by thermocouple, i.e. the combustion product is not completely in thermodynamic equilibrium state under normal pressure; however, unlike the non-equilibrium plasma generated by the discharge reaction, the difference in temperature is not significant, and therefore the combustion products containing ionized seed propellants at normal pressure are weak non-isothermal plasmas.
In addition, when the combustion product temperature is low, N e The experimental value and the calculated value have larger deviation; meanwhile, the electron density measuring range and the measuring precision are limited by the Langmuir probe method, and the electron density measuring result has larger accidental error at low temperature; as the temperature increases, the deviation between the electron density experimental value and the calculated value gradually decreases.
Preferably, the analysis of the electron temperature and the variation of the electron density deviation value with temperature of the combustion products under different ionization seed contents further comprises: statistics to obtain T of combustion products under different ionization seed contents e Values ofValue variation with temperature, construction of T of combustion products at different ionized seed contents e Value +.>A graph of the value versus temperature, from which it can be seen that for a particular ionised seed content, T e The value increases with the rise of the temperature of the combustion products, and T is within the set temperature range e The value of (2) and the value of T approximately form a linear corresponding relation; t when the temperature is similar and the content of ionized seeds is different e The change in value of (2) is not significant.
The deviation between the electron density experimental value and the calculated value is reduced with the increase of the temperature of the combustion products at different temperatures of the combustion products; it is further known that the electron density experimental result and the calculation result tend to be more consistent with further temperature rise.
Compared with the prior art, the experimental test method for the electron density of the propellant powder combustion product under the normal pressure condition has the following beneficial effects: (1) According to the invention, by constructing the propellant gas electron density test experiment system based on Langmuir double probes, the application scene guided by the experiment result can be expanded, and the method has great significance in technical application in the technical field of electron density experiment test.
(2) According to the invention, the Langmuir double-probe method is adopted to test the electron density experimental values in the combustion products under different combustion temperatures and different ionization seed contents, and the electron density calculated values of the combustion products are calculated according to the volt-ampere characteristic curves under different temperature intervals and different ionization seed contents, so that the electron density of the propellant combustion products is accurately diagnosed, the accuracy and the reliability of the electron density experimental result of the propellant combustion products are improved, the electron density deviation values are further analyzed, the reasons for deviation between the experimental result and the calculated result are further clarified, the change of the electron temperature and the electron density deviation values of the combustion products under different ionization seed contents along with the temperature is analyzed, the change rule of the electron temperature and the electron density deviation values along with the temperature is reflected, and the method has important significance for designing and optimizing plasma application.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic flow chart of the method of the present invention.
FIG. 2 is a schematic diagram of a propellant gas electron density test experimental system based on Langmuir dual probes.
Fig. 3 is a graph of langmuir dual probe voltammetric characteristics.
Fig. 4 is a graph of voltammetric characteristics at different temperature intervals and different ionized seed content.
FIG. 5 is a T of combustion products at different ionized seed levels e Values ofGraph of the value versus temperature.
Description of the drawings: in FIG. 4, (a) is a temperature range of 1100 to 1250K, (b) is a temperature range of 1350 to 1500K, (c) is a temperature range of 1600 to 1700K, and (d) is a temperature range of 2000 to 2150K; FIG. 5 (a) shows T at various ionized seed levels e A graph of the value as a function of temperature, (b) at different ionized seed contentsGraph of the value as a function of temperature.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, the invention provides an experimental test method for electron density of propellant powder combustion products under normal pressure, comprising the following steps: step one, constructing a propellant gas electron density test experiment system based on Langmuir double probes, as shown in figure 2.
In a preferred embodiment, the propellant gas electron density test experiment system based on Langmuir dual probes consists of propellant containing ionized seeds, a combustion vessel, a laser igniter, langmuir dual probes, a probe fixing and driving mechanism, a probe system control unit, a thermocouple and an upper computer. Wherein, the combustion vessel is made of high temperature resistant gun steel, and can resist the high temperature of about 2500K in a short time; the laser igniter is used for realizing remote ignition control of the propellant powder; for data processing, the two Langmuir probes adopt identical structural parameters, and the probe diameter d of the probes p Length L of probe is 0.4mm p Is 10mm, the distance DeltaL between the two probes p For 2mm, the non-test portion of the probe was sealed with alumina ceramic to support and protect the probe; the probe fixing and driving mechanism consists of a supporting frame and a driving motor and is used for fixing the probe and realizing the movement of the probe in flame so as to acquire plasma parameters at different positions; the Langmuir probe is connected with a probe system control unit through a wire, the model of the control unit is ALP-150, a voltage scanning range of-150V can be provided for the probe, and potential and current data of the probe can be obtained in real time, so that a volt-ampere characteristic curve is obtained for analyzing plasma parameters; the method comprises the steps of carrying out a first treatment on the surface of the The double platinum rhodium type B thermocouple is fixed at a position close to the head of the probe, is about 5mm away from the axis position of the double probe, and is used for measuring the macroscopic temperature of gunpowder gas at the probe. The propellant powder is a double-base flat bulb powder, cesium nitrate seeds with certain mass are weighed by a high-precision balance and are fully mixed with the propellant powder, so that plasma parameters in combustion flame under the conditions that the mass fractions of ionized seeds are 1%, 2%, 4% and 6% respectively are tested.
The invention can expand the application scene guided by the experimental result by constructing the propellant gas electron density test experimental system based on Langmuir double probes, thereby having great significance to the technical application in the technical field of electron density test.
And step two, testing electron density experimental values in combustion products at different combustion temperatures and different ionization seed contents by adopting a Langmuir double-probe method.
In a preferred embodiment, the experimental values of electron density in the combustion products under different combustion temperatures and different ionization seed contents are tested by using a Langmuir double probe method, and specifically include: s1, after laser ignition, the flame to be emitted is basically stabilized, then testing is started, scanning voltage of Langmuir double probes and loading time of the scanning voltage are set, connection scanning is carried out according to the loading time of interval scanning voltage after each scanning is completed, voltage-current values corresponding to each test point are recorded, and an average value is calculated to construct a volt-ampere characteristic curve. Thereby avoiding the effects of accidental errors. In addition, abnormal data with larger deviation from the average value in the experimental data are removed.
S2, by changing the mass fraction of cesium nitrate in the propellant powder and the dosage of the propellant powder and adjusting the position of the probe in flame, multiple laser ignition experiments are completed and the volt-ampere characteristic curves are synchronously recorded, so that multiple groups of electron density experiment values with different ionization seed contents and different temperatures are obtained.
In a specific embodiment, the scanning voltage of the Langmuir dual probe is set to be-5V, the interval of the scanning voltage is 0.2V, the loading time of the scanning voltage is 20ms, and continuous scanning is performed at intervals of 20ms after each scanning is completed.
In general, a voltammetric characteristic curve as shown in fig. 3 is formed between probes of Langmuir dual probes by applying a scan voltage. In FIG. 3, I 1+ And I 2+ For the saturation ion currents of probe 1 and probe 2, respectively, when the two probe structures are identical, there is generally I + ＝I 1+ ＝-I 2+ ；The slope of the volt-ampere characteristic curve when the potential difference between the two probes is 0;saturation of potential between two probesSlope of the ampere characteristic curve.
It should be explained that the Langmuir dual probe method obtains the voltammetric characteristic curve of the dual probe, i.e., the operating current I, by applying a scan voltage between two probes inserted into the plasma D And a scan voltage V D And thus the electron temperature and ion density in the plasma are calculated using the parameters contained in the curve. Compared with Langmuir single probe, the double probes do not need to measure the suspension potential of the probes, so that the double probes are simpler and more convenient to use; in addition, the potential of the double probes does not use the discharge electrode as a reference point, so that the damage of the probes caused by overlarge current of the probes can be effectively avoided. It should be noted that, although the Langmuir dual probe can measure the electron temperature in the gunpowder gas, the flame generally does not completely satisfy the local thermodynamic equilibrium state because the collision frequency between particles in the flame is not high under low pressure and normal pressure, i.e. the electron temperature is slightly higher than the temperature of heavy particles or may reach several times of the temperature of heavy particles, so in order to obtain the electron density data at different flame temperatures, the temperature of the gas needs to be synchronously tested.
And thirdly, performing a plurality of ignition experiments by changing the contents of the propellant powder and the ionized seeds, and acquiring experimental data under the condition that the flame temperatures measured by the thermocouples are similar, so as to obtain volt-ampere characteristic curves under different temperature intervals and different ionized seed contents, as shown in figure 4.
As can be seen from fig. 4, the volt-ampere characteristic curve drawn by the average value of each experiment has good symmetry in the positive voltage section and the negative voltage section; although there is some deviation in the saturated ion currents of probe 1 and probe 2, the deviation is small, indicating that it is feasible to measure plasma parameters in the propellant flames using the Langmuir double probe method. As can be seen from FIGS. 4 (a), (b) and (d), the saturated ion currentThe value of (2) increases with increasing temperature; as can be seen from FIG. 4 (c), at different ionized seed contents, the morphology of the voltammetric characteristic curve is substantially uniform when the temperature of the propellant gas is close, indicating the temperature versus plasmaThe influence of the parameters is most remarkable, and the change of the temperature in a smaller range can lead to obvious change of the electron number density, which also proves the change rule of the electron density calculated by the minimum Gibbs free energy method in the related numerical simulation research.
Further, as can be seen from comparison of fig. 4, as the temperature increases, the standard deviation of the current value gradually increases, but the standard deviation coefficient gradually decreases, indicating that the ionization reaction in the combustion product becomes more stable as the temperature increases, and the deviation of the experimental data is also smaller.
And step four, calculating an electron density calculation value of the combustion product according to volt-ampere characteristic curves under different temperature intervals and different ionization seed contents.
In a preferred embodiment, said calculating the electron density calculation of the combustion products comprises in particular: obtaining saturated ion currents of the probe 1 and the probe 2 according to volt-ampere characteristic curves under different temperature ranges and different ionization seed contents, wherein the saturated ion currents are respectively I 1+ And I 2+ When the two probes are identical in structure, there is generally I + ＝I 1+ ＝-I 2+ Analysis of electron temperature T e The calculation formula is that The slope of the voltammetric characteristic curve when the potential difference between the two probes is 0 is represented by e, which is the electron charge, and k, which is the Boltzmann constant.
Calculation of the electron Density calculation value N of Combustion products e-calculated value The calculation formula is thatA p ＝πd p L p In which A p For the surface area of the probe, pi is the circumference ratio, M i Is the mass of Cs ion, d p For the diameter of the probe head of the probe, L p Is the probe length.
And fifthly, comparing the electron density experimental value in the combustion product with the electron density calculated value to obtain an electron density deviation value, and further analyzing the electron temperature of the combustion product under different ionization seed contents and the change of the electron density deviation value along with the temperature.
In a preferred embodiment, the electron density deviation value is analyzed byWherein N is e-experimental values Is an electron density experimental value of the combustion product.
In addition, for the problem of deviation of the ionization of saturated ions of two probes due to factors such as combustion stability or accidental errors, the average value of the saturated ion currents measured by the two probes is used as the final value, I + ＝(I 1+ -I 2+ )/2。
Further, the analysis of the variation of the electron temperature and the electron density deviation value of the combustion products with the temperature under the different ionization seed contents comprises the following steps: when ionizing seed content alpha Cs At=2%, plasma parameters at different combustion temperatures were calculated as shown in table 1.
TABLE 1 plasma parameters at different combustion temperatures at 2% ionized seed content
It is known that the electron temperature of the combustion products measured by the Langmuir double probe is higher than the temperature of the neutral particles measured by the thermocouple, i.e., the combustion products are not completely in thermodynamic equilibrium at normal pressure; however, unlike the non-equilibrium plasma generated by the discharge reaction, the difference in temperature is not significant, and therefore the combustion products containing ionized seed propellants at normal pressure are weak non-isothermal plasmas.
In addition, when the combustion product temperature is low, N e The experimental value and the calculated value of (2) have larger deviation, even several times, because the electron density in the combustion product is very low at low temperature, and the result obtained by the least Gibbs free energy method has larger deviation. Meanwhile, the electron density measuring range and the measuring precision are limited by the Langmuir probe method, and the electron density measuring result has larger accidental error at low temperature; as the temperature increases, the deviation between the electron density experimental value and the calculated value gradually decreases. When the combustion product temperature exceeds 1500K, the deviation remains substantially within 30%. The reasons for the deviation between the experimental result and the calculated result include the difference between the components of the combustion products of the propellant in the air and the airtight condition, the failure of complete combustion to reach the thermal equilibrium state, the combustion reaction, the instability of ionization seeds in dissociation and ionization, etc.
Based on the above, T of combustion products under different ionization seed contents is counted e Values ofValue variation with temperature, construction of T of combustion products at different ionized seed contents e Value +.>A graph of the value versus temperature is shown in fig. 5.
As can be seen from FIG. 5 (a), T is for a particular ionized seed content e The value increases with the rise of the temperature of the combustion products, and T is within the set temperature range e The value of (2) and the value of T approximately form a linear corresponding relation; t when the temperature is similar and the content of ionized seeds is different e The change in value of (2) is not significant.
As can be seen from fig. 5 (b), the deviation between the electron density experimental value and the calculated value decreases with the increase of the combustion product temperature at different combustion product temperatures; as the highest temperature reached by the propellant powder under normal pressure and the highest measured temperature of the thermocouple are about 2000K, the electron density experimental result and the calculation result tend to be more consistent with the further increase of the temperature.
The invention adopts Langmuir double-probe method to test the electron density experimental values in the combustion products under different combustion temperatures and different ionization seed contents, and calculates the electron density calculation values of the combustion products according to the volt-ampere characteristic curves under different temperature intervals and different ionization seed contents, thereby realizing accurate diagnosis of the electron density of the propellant combustion products, improving the accuracy and reliability of the electron density experimental results of the propellant combustion products, further analyzing the electron density deviation values, further determining the reasons for deviation between the experimental results and the calculation results, and simultaneously analyzing the electron temperature of the combustion products under different ionization seed contents and the change of the electron density deviation values along with the temperature, further reflecting the change rule of the electron temperature and the electron density deviation values along with the temperature, and having important significance for designing and optimizing plasma application.
The foregoing is merely illustrative and explanatory of the principles of this invention, as various modifications and additions may be made to the specific embodiments described, or similar arrangements may be substituted by those skilled in the art, without departing from the principles of this invention or beyond the scope of this invention as defined in the claims.
Claims (6)
1. The experimental test method for electron density of propellant powder combustion products under normal pressure is characterized by comprising the following steps:
step one, constructing a baseThe propellant gas electron density test experiment system of the double probes;
the base is based onThe dual-probe propellant gas electron density test experiment system consists of propellant containing ionized seeds, a combustion vessel, a laser igniter and +.>Double-probe and probe fixationThe positioning and driving mechanism, the probe system control unit, the thermocouple and the upper computer are combined; wherein, the combustion vessel is made of high temperature resistant gun steel; the laser igniter is used for realizing remote ignition control of the propellant powder; two->The probe adopts the identical structural parameters, and the non-test part of the probe is sealed by alumina ceramic; the probe fixing and driving mechanism consists of a supporting frame and a driving motor and is used for fixing the probe and realizing the movement of the probe in flame so as to acquire plasma parameters at different positions; />The probe is connected with the probe system control unit through a wire; fixing a thermocouple at a position close to the head of the probe for measuring the macroscopic temperature of gunpowder gas at the probe;
step two, adoptingThe electron density experimental values in the combustion products under different combustion temperatures and different ionization seed contents are tested by a double-probe method;
the adoption ofThe electron density experimental values in the combustion products under different combustion temperatures and different ionization seed contents are tested by a double-probe method, and specifically comprise the following steps:
s1, after the laser ignition, the flame of the medicine to be emitted is basically stabilized, testing is started, and setting is carried outThe method comprises the steps of carrying out connection scanning according to the scanning voltage and the loading time of the scanning voltage of the double probes, recording the voltage-current values of each test point corresponding to each time after each scanning is completed, and calculating an average value to construct a volt-ampere characteristic curve;
s2, completing multiple laser ignition experiments and synchronously recording volt-ampere characteristic curves by changing the mass fraction of cesium nitrate in the propellant and the dosage of the propellant and adjusting the position of a probe in flame, so as to obtain a plurality of groups of electron density experiment values with different ionization seed contents and different temperatures;
step three, performing multiple ignition experiments by changing the contents of the propellant powder and the ionized seeds, and acquiring experimental data under the condition that the flame temperatures measured by the thermocouples are similar, so as to obtain volt-ampere characteristic curves under different temperature intervals and different ionized seed contents;
step four, calculating an electron density calculation value of a combustion product according to volt-ampere characteristic curves under different temperature intervals and different ionization seed contents;
and fifthly, comparing the electron density experimental value in the combustion product with the electron density calculated value to obtain an electron density deviation value, and further analyzing the electron temperature of the combustion product under different ionization seed contents and the change of the electron density deviation value along with the temperature.
2. The experimental test method for electron density of propellant powder combustion products under normal pressure condition according to claim 1, wherein: the third specific content of the step comprises:
according to the volt-ampere characteristic curves of different temperature intervals and different ionization seed contents, the volt-ampere characteristic curves drawn by the average value of each experiment have good symmetry in a positive voltage section and a negative voltage section;
further, it is known that, as the temperature increases, the standard deviation of the current value gradually increases, but the standard deviation coefficient gradually decreases, indicating that the ionization reaction in the combustion product becomes more stable as the temperature increases, and the deviation of the experimental data is also smaller.
3. The experimental test method for electron density of propellant powder combustion products under normal pressure condition according to claim 1, wherein: the method for calculating the electron density calculation value of the combustion product specifically comprises the following steps:
obtaining saturated ions of the probe 1 and the probe 2 according to volt-ampere characteristic curves under different temperature ranges and different ionization seed contentsThe currents are respectivelyAnd->When the two probe structures are identical, there is generally +.>Analysis of electron temperature->The calculation formula is ∈>，/>Slope of volt-ampere characteristic curve when potential difference between two probes is 0, < >>For electron charge +.>Is the Boltzmann constant;
calculating an electron density calculation of combustion productsThe calculation formula is that，/>In the formula->For the surface area of the probe>Is of circumference rate>Is the mass of Cs ion, +.>For the probe diameter of the probe +.>Is the probe length.
4. The experimental test method for electron density of propellant powder combustion products under normal pressure condition according to claim 3, wherein: the electron density deviation value analysis mode is thatWherein->Is an electron density experimental value of the combustion product.
5. The experimental method for determining the electron density of a propellant charge combustion product under atmospheric conditions according to claim 4, wherein: the analysis content of the change of the electron temperature and the electron density deviation value of the combustion products with the temperature under the different ionization seed contents comprises the following steps:
when the seed content is ionizedIn this case, the plasma parameters at the different combustion temperatures are calculated, from which it is known that +.>The electron temperature of the combustion products measured by the double probe is higher than the temperature of the neutral particles measured by the thermocouple, i.e. the combustion products are not completely in thermodynamic equilibrium at normal pressure; but in an unbalanced state due to discharge reactionThe difference of the temperature of the ion body and the temperature of the ion body is not obvious, so that the combustion product containing ionized seed propellant is weak non-isothermal plasma at normal pressure;
in addition, when the temperature of the combustion products is low,the experimental value and the calculated value have larger deviation; at the same time, is limited byThe electron density measuring range and measuring precision of the probe method have larger accidental errors in the electron density measuring result at low temperature; as the temperature increases, the deviation between the electron density experimental value and the calculated value gradually decreases.
6. The experimental method for determining the electron density of a propellant charge combustion product under atmospheric conditions according to claim 5, wherein: the analysis content of the change of the electron temperature and the electron density deviation value of the combustion products with the temperature under the different ionization seed contents further comprises the following steps:
statistics to obtain combustion products under different ionization seed contentsValue +.>Value as a function of temperature, construction of combustion products at different ionization seed contents +.>Value +.>The graph of the value as a function of temperature shows that for a particular ionised seed content,/->Value increases with combustion product temperatureHigh and increased, and within a set temperature range, < > and>the value of (2) and->Is approximately in a linear correspondence; when the temperature is similar and the ionized seed content is different, the method comprises the steps of->The value of (2) is not significantly changed;
the deviation between the electron density experimental value and the calculated value is reduced with the increase of the temperature of the combustion products at different temperatures of the combustion products; it is further known that the electron density experimental result and the calculation result tend to be more consistent with further temperature rise.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0737817A (en) * | 1993-06-28 | 1995-02-07 | Sony Corp | Plasma measuring probe and plasma measuring method using same |
| CN107025325A (en) * | 2017-01-03 | 2017-08-08 | 中国人民解放军装甲兵工程学院 | A kind of ionization seed optimization method for making powder gas generate plasma |
| CN110289053A (en) * | 2019-06-26 | 2019-09-27 | 中国人民解放军陆军装甲兵学院 | Gun propellant combustion generates plasma law study method |
| CN110287599A (en) * | 2019-06-26 | 2019-09-27 | 中国人民解放军陆军装甲兵学院 | A kind of propellant powder generates the construction method of plasma rule model |
-
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0737817A (en) * | 1993-06-28 | 1995-02-07 | Sony Corp | Plasma measuring probe and plasma measuring method using same |
| CN107025325A (en) * | 2017-01-03 | 2017-08-08 | 中国人民解放军装甲兵工程学院 | A kind of ionization seed optimization method for making powder gas generate plasma |
| CN110289053A (en) * | 2019-06-26 | 2019-09-27 | 中国人民解放军陆军装甲兵学院 | Gun propellant combustion generates plasma law study method |
| CN110287599A (en) * | 2019-06-26 | 2019-09-27 | 中国人民解放军陆军装甲兵学院 | A kind of propellant powder generates the construction method of plasma rule model |
Non-Patent Citations (1)
| Title |
|---|
| 等离子体综合实验仪;李明;王叶;耿在斌;;物理实验(第11期);12-14页 * |
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