CN109670232B - Method for rapidly estimating size and weight of attitude control bipropellant thrust chamber - Google Patents

Method for rapidly estimating size and weight of attitude control bipropellant thrust chamber Download PDF

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CN109670232B
CN109670232B CN201811527811.1A CN201811527811A CN109670232B CN 109670232 B CN109670232 B CN 109670232B CN 201811527811 A CN201811527811 A CN 201811527811A CN 109670232 B CN109670232 B CN 109670232B
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thrust chamber
spray pipe
size
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胡海峰
李晓瑾
肖明杰
程奇峰
李亮
栾叶君
胡伟
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Xian Aerospace Propulsion Institute
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Abstract

The invention provides a method for rapidly estimating the size and weight of an attitude control bipropellant thrust chamber, which divides the attitude control bipropellant thrust chamber into three main parts, carries out quantitative description on design key size and performance parameters in the design process, obtains the geometric outline of the thrust chamber through parameter driving, determines the wall thickness of the thrust chamber according to a selected safety factor by adopting an intensity checking formula, and obtains the weight of the thrust chamber through statistical calculation in combination with the selected material density. The method helps researchers to quickly and effectively carry out thrust chamber design and performance estimation. The method realizes the rapid design and performance prediction of the attitude control two-component thrust chamber product in the demonstration stage of the power system, improves the design demonstration efficiency of the product to a great extent, shortens the demonstration period, and has a great application prospect in the design field of the attitude control system.

Description

Method for rapidly estimating size and weight of attitude control bipropellant thrust chamber
Technical Field
The invention relates to a method for rapidly estimating the size and weight of an attitude control two-component thrust chamber, which can be applied to the design of the two-component thrust chamber.
Background
The attitude and orbit control power system is an important actuating mechanism for realizing accurate target control and provides power for track and attitude adjustment of related systems. Wherein the two-component attitude and orbit control power system is the preferred scheme with high performance advantage.
At present, an attitude and orbit control power system has long demonstration time period, multiple rounds of iteration are carried out between the whole system and the component design, and the optimal system scheme is selected through the comparison of multiple schemes of the system. According to the existing mode, system demonstration needs component matching, if the system is designed in detail at the early stage of demonstration, the time period of demonstration of the whole component is long, and meanwhile, the scheme is likely to repeat after the demonstration of the feedback system, so that the component demonstration needs an adjustment scheme. Aiming at the problem, in order to meet the requirement of rapid convergence in the concept stage of the overall scheme, the method provides a method for rapidly estimating the size of the two-component thrust chamber.
Disclosure of Invention
The invention aims to provide a method for rapidly estimating the size and weight of an attitude control two-component thrust chamber, which aims to solve the problem of long demonstration time period of the existing attitude and orbit control power system.
The method divides the two-component thrust chamber into three main parts, quantitatively describes design key size and performance parameters in the design process, obtains the geometric outline of the thrust chamber through parameter driving, determines the wall thickness of the thrust chamber according to a selected safety coefficient by adopting an intensity checking formula, and obtains the quality of the thrust chamber through statistical calculation by combining the selected material density. The method helps researchers to quickly and effectively carry out thrust chamber design and performance estimation.
The technical scheme of the invention is to provide a method for rapidly estimating the size and weight of an attitude control two-component thrust chamber, which comprises the following steps:
s1: firstly, the attitude control two-component thrust chamber is decomposed into three large parts, namely a head part, a body part and a spray pipe. Respectively constructing the key structure sizes of the three parts, and realizing data association of the three parts through butt joint sizes;
s2: according to the general technical index requirements of propellant types, mixing ratios and thrust requirements, thermal calculation is carried out, the specific impulse change conditions under different pressures are calculated, the change relation between specific impulse and pressure is obtained, and the design chamber pressure is optimized;
s3: and then, calculating the structural sizes of the body part, the spray pipe and the head part according to the selected chamber pressure, the propellant type, the mixing ratio, the expansion ratio, the contraction ratio, the characteristic length, the contraction half angle, the expansion half angle, the combustion efficiency, the flow intensity correction coefficient and the heat re-immersion correction coefficient to obtain the size envelope of the inner molded surface of the thrust chamber.
S4: on the basis, pressure intensity and temperature distribution parameters of different positions of the thrust chamber along the axis direction are obtained through thermopneumatic calculation; and (4) predicting the wall thickness of the thrust chamber according to a strength checking formula, selecting the material density of different parts in a rotation mode, and calculating to obtain the weight of the thrust chamber.
Further, in step S3, the body structure size is calculated by the following procedure:
s31: a cylindrical structure representation body structure form is adopted, and the throat radius Rt of the spray pipe is calculated according to the thermal performance parameter data obtained in the step S2 and the total technical index requirement;
At＝C*·η c ·F/Is/Pc，Rt＝sqrt(At/π)；
wherein At is the throat area, C is the characteristic velocity, η c For combustion efficiency, F Is thrust (total required input value), is specific impulse, and Pc Is preferred chamber pressure;
s32: according to a selected contraction ratio epsilon c Determining the radius R of the body c ；
Rc＝sqrt(ε c )·Rt；
Calculating the length of the body part through the selected contraction half angle beta and the characteristic length, wherein the length comprises a contraction section length Lc2 and a cylinder section length Lc1;
Lc2＝(Rc-Rt)/tanβ
Figure BDA0001904898970000031
where Vc is the volume of the thrust chamber, V c ＝L * ·A t L is the characteristic length, rc is the radius of the body, and Rt is the radius of the throat part of the spray pipe;
or when the gas stays for a long time or is considered to be completely combusted without reaching a critical surface, calculating the length Lc1 of the front section cylindrical section by the following formula;
Figure BDA0001904898970000032
further, in step S3, the structural size of the nozzle is calculated by the following process, including the nozzle convergent section and the nozzle divergent section:
nozzle convergent section:
the molded surface of the nozzle convergent section consists of an inlet circular arc with the radius of Rcc, a throat upstream circular arc with the radius of Rc1 and a straight line section; wherein Rcc =5 × rt; rc1= (1.5 to 2) × Rt; the straight line section adopts a drawing method, and a straight line is tangent to the two arcs after the upstream arc and the downstream arc are determined, so that the straight line section can be obtained;
a nozzle expansion section:
a) Conical spray pipe:
nozzle outlet diameter Re
Re＝sqrt(ε)·Rt；
Length Ln of the dilated segment:
Ln＝(Re-Rt)/tanα；
wherein alpha is the diffusion half angle of the spray pipe;
b) Double-arc spray pipe:
the arc equation of two arcs forming the double-arc nozzle is set as follows:
Figure BDA0001904898970000033
wherein, X 0 ＝Ln+R 0 sinφ；
Figure BDA0001904898970000034
Wherein
Figure BDA0001904898970000035
Wherein phi is the half angle of the outlet of the spray pipe,
Figure BDA0001904898970000041
Figure BDA0001904898970000042
the relative length of the spray pipe;
c) Maximum thrust spray pipe:
determining the approximate equation of the maximum thrust nozzle profile as a parabolic equation by a geometric method: x = aY 2 + bY + c, wherein
Figure BDA0001904898970000043
Figure BDA0001904898970000044
c＝X1-aY1 2 -bY1；
Wherein, X1= R td sinα，Y1＝R td (1-cosα)+R t ，R td For the downstream arc radius of the nozzle throat (design choice value, generally R) td ＝Rt)；X2＝L n ；Y2＝Re，
Figure BDA0001904898970000045
Further, in step S3, the head is characterized by using a solid cylinder structure, and the head structure size is calculated by the following process:
l head part ＝f(F,Pc,η c ,η h )
V Head part ＝l Head part ·π·Rc 2
In the formula I Head part Indicating the axial length of the head;
η c representing a flow intensity correction factor;
η h representing a flow intensity correction factor;
V head part Representing the volume of the head;
R c representing the radius of the body.
Further, step S5 specifically includes:
s51) according to the geometric parameters of the inner molded surface of the thrust chamber calculated in the step S3, the total gas temperature parameters obtained by combining chamber pressure and thermodynamic calculation are combined, meanwhile, cooling efficiency modification parameters are introduced, and pressure and temperature distribution parameters of the inner wall surface of the thrust chamber at different positions along the axial direction are calculated;
the main input variables are specific heat ratio k and speed coefficient lambda value of the fuel gas, and a necessary pneumatic function is calculated according to the values;
Figure BDA0001904898970000051
Figure BDA0001904898970000052
Figure BDA0001904898970000053
solving a speed coefficient lambda according to the aerodynamic relationship, solving other necessary parameters according to the speed coefficient, and back-calculating the pressure P and the temperature T of the basic aerodynamic parameter in the thrust chamber;
ideally A cr Namely the throat area;
Figure BDA0001904898970000054
calculating the corresponding specific Ma number of different sections A in the spray pipe according to an iteration method, calculating lambda reversely, and obtaining parameters such as temperature, pressure and the like under different sectional areas according to pneumatic calculation;
s52) according to the selected safety coefficient of the thrust chamber and the material attribute information of different parts of the thrust chamber, combining the temperature and pressure distribution parameters of different axial positions of the thrust chamber calculated in the step S51), and calculating the wall thickness h of different positions of the body part of the thrust chamber and the spray pipe along the axial direction by adopting an engineering strength checking empirical formula based on the physical property parameters of the material at the temperature;
Figure BDA0001904898970000055
wherein P is c.max Local static pressure at a given axial position;
σ 0.2 is the yield limit of the material;
r is the radius for a given axial position;
Figure BDA0001904898970000056
for safety of selectionA coefficient;
according to the inner profile parameters, the wall thickness of the individual position and the design size of the head, the size envelope parameters of the full thrust chamber can be obtained;
s53) according to the size envelope parameters of the full thrust chamber and the wall thicknesses of the body part and the spray pipe at different positions obtained through calculation, the volume V of the body part and the volume V of the spray pipe are counted in a revolving body mode;
V＝∑dx·2·R·π
wherein dx is the size change of the attitude control thrust chamber in the axial direction;
r is the radius for a given axial position;
s54) respectively calculating the mass of the three parts by combining the selected material attribute and the head volume, the body volume and the spray pipe volume obtained in the step S53), and summarizing the three parts to obtain the estimated mass of the thrust chamber;
m thrust chamber ＝m Head part +m Body part +m Spray pipe
m Thrust chamber The estimated weight of the thrust chamber;
m head part Is the estimated head weight;
m body part The estimated weight of the body part;
m spray pipe Is the estimated weight of the nozzle.
Compared with the prior art, the invention has the beneficial effects that:
1. in the initial stage of the design of the attitude control two-component system, the method for quickly and accurately estimating the size and the weight of the attitude control two-component thrust chamber can be used for realizing the quick design and performance prediction of a thrust chamber product, improving the design demonstration efficiency of the product to a great extent, shortening the demonstration period, and supporting the quick closure of the overall design and the system parameter design of the attitude control power system.
2. The approximate geometric model is adopted to represent the size of the thrust chamber, the performance of the thrust chamber is estimated according to the volume and the material selected by combining the structure of the thrust chamber, and the rapid iterative convergence of the overall scheme stage is met. In the model construction process, the data information of the actual product of the existing attitude control two-component thrust chamber is fully considered, the cooling correction coefficient and the heat return immersion correction coefficient are comprehensively considered in the aspect of the integrity of the model, meanwhile, the change conditions of gas aerodynamic pressure and temperature parameters along the axis direction of the engine are comprehensively considered for the estimation of the wall thickness of the engine, and the temperature influence is fully considered for the selection of the yield limit of the material, so that the whole model has high engineering prediction precision, the obtained weight and size have little deviation with the actual design product under the condition of ensuring the precision, but the demonstration efficiency is shortened to several minutes of attitude from the traditional several days, and the quick iteration of the system scheme in the overall scheme design stage of the orbit control power system can be quickly supported.
3. Compared with an attitude control two-component thrust chamber, the attitude control two-component thrust chamber is finely designed by adopting a numerical simulation means, and the demonstration design efficiency in the earlier stage of the scheme can be obviously improved.
Drawings
FIG. 1 is a schematic of the system of the present invention;
FIG. 2 is a schematic head design;
FIG. 3 is a schematic diagram of an attitude control two-component thrust chamber;
FIG. 4 is a schematic diagram of an attitude control bipropellant thrust chamber interior profile structure parameter identification;
FIG. 5 is a schematic view of a bi-arc nozzle configuration of the present invention;
FIG. 6 is a schematic view of a maximum thrust nozzle configuration of the present invention.
Detailed Description
The invention is further described with reference to the following figures and specific embodiments.
1) Scheme design
1.1 The attitude control two-component thrust chamber is divided into three main parts, namely a head part, a body part and a spray pipe.
1.2 According to the general technical index requirements of propellant type, mixing ratio, thrust, weight and space size envelope, thermal calculation is carried out, the change condition of specific impulse under different pressures is calculated, the direct change relation of specific impulse and pressure is obtained, and the design chamber pressure is optimized; and correspondingly obtaining the thermal performance parameter data under the chamber pressure.
2) Size determination
The geometric parameters which need to be input or selected by a designer through an interface in the body design stage mainly comprise: throat radius, characteristic length, throat upstream arc radius, throat downstream arc radius, expansion ratio and nozzle type. A half cone angle is required to be input for the conical spray pipe; for a double-arc-shaped spray pipe, in order to determine the geometric parameters of the expansion section, an outlet half angle of an equivalent conical spray pipe, the relative length of the spray pipe and an outlet angle of the arc-shaped expansion section need to be input; for the maximum thrust nozzle, the diffusion half angle, the outlet half angle and the relative length of the nozzle of the equivalent conical nozzle are required to be input. The specific parameters are shown in table 1, and the parameters of the thrust chamber are shown in fig. 4.
Table 1 description of the input parameters
Figure BDA0001904898970000071
Figure BDA0001904898970000081
2.1 According to the thermodynamic calculation result parameters and the overall parameter requirements, calculating the throat diameter Rt of the spray pipe;
At＝C*·η c ·F/Is/Pc (1)
Rt＝sqrt(At/π) (2)
2.2 Adopting a cylindrical structure to represent the structural form of the body part, determining the diameter of the body part according to the selected contraction ratio, and calculating the length of the body part through the selected characteristic length; specific feature length selections are shown in table 1.
TABLE 1 characteristic lengths of different propellants
Serial number Propellant Characteristic length L (m)
1 Liquid hydrogen/liquid oxygen (gas hydrogen injection) 0.60～0.70
2 Liquid hydrogen/liquid oxygen (liquid hydrogen injection) 0.76～1.00
3 Liquid oxygen/kerosene 1.00～1.40
4 Dinitrogen tetroxide/hydrazines 0.76～1.20
5 Nitric acids/hydrazines 0.76～1.20
6 Liquid fluorine/liquid hydrogen 0.60～0.75
7 Liquid fluorine/hydrazine 0.60～0.75
8 Liquid oxygen/ammonium 0.75～1.00
Shrinkage ratio epsilon c The ratio of the body cross-sectional area to the throat cross-sectional area of the thrust chamber is defined as:
Figure BDA0001904898970000091
according to a given shrinkage ratio epsilon c Calculating the radius Rc of the body of the thrust chamber
Rc＝sqrt(ε c )·Rt (4)
Given the contraction half angle β, the contraction section length Lc2 is calculated:
Lc2＝(Rc-Rt)/tanβ (5)
after the propellant is selected, the characteristic length of the thrust chamber can be determined according to experience or reference to the existing engine, and the volume of the thrust chamber is calculated according to the characteristic length:
V c ＝L * ·A t (6)
the length Lc1 of the front cylindrical section is obtained from the volume:
Figure BDA0001904898970000092
when the gas stays for a long time or when it is considered that complete combustion is achieved without reaching the critical plane, vc calculated from the characteristic length can be considered as a 2/3 convergence section and a cylinder section, where the length Lc1 of the front cylinder section:
Figure BDA0001904898970000093
2.3 According to the main form of the current bipropellant thrust chamber spray pipe, three structural forms of a conical spray pipe, a double-arc spray pipe and a maximum thrust spray pipe are determined, and different spray pipe types are selected according to calculation; calculating according to a theoretical formula and the selected parameters to obtain structural parameters of the spray pipe and obtain parameters of the inner profile of the spray pipe; calculating to obtain key geometric parameters of the length Ln and the outlet radius Re of the spray pipe;
at present, a circular laval nozzle is widely used, which is composed of a subsonic convergent section and a supersonic divergent section, and converts the heat energy of the gas into kinetic energy. The spray pipe profile design mainly comprises the following contents:
a convergence section
The converging section profile generally consists of three sections, an inlet arc with radius Rcc, a throat upstream arc with radius Rc1, and a straight section.
(1) Radius of inlet arc
The inlet arc radius rcc has a great influence on the pressure distribution and the heat flow density distribution of the convergent section. Empirically, rcc =5 × rt was taken.
(2) Radius of arc at upstream of throat
The ratio of the arc radius upstream of the throat to the throat radius, rc1, has an effect on the flow coefficient and flow field of the nozzle. Rc1= (1.5 to 2) × Rt is usually taken.
(3) Straight line segment
And the straight line section adopts a drawing method, and the straight line is tangent to the two arcs after the upstream arc and the downstream arc are determined, so that the straight line section can be obtained.
b expansion section
The molded surface of the expansion section consists of a throat downstream circular arc section with the radius of Rc2 and a contour line given by a certain molding method. According to different expansion profiles, the spray pipe mainly comprises a conical spray pipe, a double-arc spray pipe and a conical spray pipe.
(1) Downstream arc radius of throat
The throat outlet radius is connected with the arc of the inlet radius Rc1 by adopting the arc of Rc2 to form a throat. Rc2 < Re, generally Rc2= (0.45 to 1.0) × Rt.
(2) Conical spray pipe
The expanding section of the conical nozzle is conical, is tangent to the Rc2 arc of the throat outlet, and forms an included angle a = 10-15 degrees with the axis.
2a conical nozzle design
The design process is as follows: firstly, selecting a nozzle diffusion half angle alpha (generally 15-18 degrees), an outlet half angle and the like and a diffusion half angle, and obtaining the following parameters according to an expansion ratio epsilon:
nozzle outlet diameter Re
Re＝sqrt(ε)·Rt； (9)
Length Ln of the dilated segment:
Ln＝(Re-Rt)/tanα； (10)
2b double-arc nozzle design
The double-arc method has simple modeling, difficult manufacture and particularly good performance, and is commonly used for designing the molded surface of the spray pipe. The double-arc method is a method that the molded surface of the transonic section and the supersonic section of the spray pipe is composed of two arcs. The nozzle throat profile is R t ＝d t The expansion section is also a circular arc, and the two circular arcs are tangent at a point M, as shown in FIG. 4, the radius of the circular arc of the expansion section and the coordinate of the circle center can have a geometric relationship to obtain:
circle center coordinates:
X 0 ＝Ln+R 0 sinφ； (11)
Y 0 ＝R 0 cosφ-Re； (12)
in the formula L n = dilated segment length;
phi = nozzle outlet half angle;
obtaining by solution:
Figure BDA0001904898970000111
L n the length of the nozzle extension, when the extension ratio is known, the relative length of the nozzle is determined according to the selected outlet angle
Figure BDA0001904898970000112
Figure BDA0001904898970000113
The geometrical parameters of the double-arc nozzle can be obtained through simultaneous calculation.
Let the arc equation be:
Figure BDA0001904898970000121
and substituting the parameters to obtain an arc equation.
2c maximum thrust spray pipe
The maximum thrust jet pipe is designed according to the maximum thrust principle under the given jet pipe length and the external pressure, so that the jet pipe has the best performance.
And determining a profile approximation equation, namely a parabolic equation, by a geometric method under the condition of the given nozzle expansion section length Ln, the diffusion half angle alpha and the outlet half angle phi. See fig. 6.
X1＝R td sinα (15)
Y1＝R td (1-cosα)+R t (16)
X2＝L n (17)
Y2＝Re (18)
Figure BDA0001904898970000122
Figure BDA0001904898970000123
Let the parabolic equation be: x = aY 2 +bY+c
Figure BDA0001904898970000124
Figure BDA0001904898970000125
c＝X1-aY1 2 -bY1 (23)
R td Is the downstream arc radius of the throat part of the spray pipe; r is td Taking R as a design choice value td And (= Rt). The equations are solved simultaneously, so that a parabolic equation can be obtained, and the geometrical parameter relation of different positions of the expansion section of the spray pipe is obtained.
2.4 The head is characterized by a solid cylindrical structure, with the nozzle head and body diameters being the same. Estimating the length of the head of a newly designed thrust chamber according to an empirical analogy formula of the head parameters of the existing thrust chamber of the same type, and calculating to obtain the volume of the head by considering a flow intensity correction coefficient and a heat back immersion correction coefficient;
l head part ＝f(F,Pc,η c ,η h ) (24)
V Head part ＝l Head part ·π·Rc 2 (25)
In the formula I Head part Indicating the axial length of the head;
η c representing a flow intensity correction factor;
η h representing a flow intensity correction factor;
V head part Representing the volume of the head;
R c represents the radius of the body;
the function f is a category calculation formula obtained according to existing product library statistics, size information in existing products of the attitude control two-component engine is comprehensively considered, and thrust magnitude, room pressure, flow intensity correction coefficients and hot back immersion correction coefficients are considered through a difference mode.
2.5 Step 2.1), step 2.2) and step 2.3) to obtain the geometric parameter data of the inner molded surface of the thrust chamber.
3) Weight estimation
3.1 According to the 2.5 steps, the geometric parameters of the inner molded surface of the existing thrust chamber are obtained through calculation, the total gas temperature parameters obtained through chamber pressure and thermodynamic calculation are combined, meanwhile, cooling efficiency modification parameters are introduced, the gas temperature change condition in the design process of adopting a cooling structure is comprehensively considered, and the pressure and temperature distribution parameters of the inner wall surface of the thrust chamber at different positions along the axial direction are obtained through calculation;
the main input variables include the specific heat ratio k (obtained by thermodynamic calculation) of the fuel gas and the speed coefficient lambda value, and the necessary pneumatic function is calculated according to the values.
Figure BDA0001904898970000131
Figure BDA0001904898970000132
Figure BDA0001904898970000133
And solving the speed coefficient lambda according to the aerodynamic relation, solving other necessary parameters according to the speed coefficient, and back-calculating the basic aerodynamic parameter pressure P and the temperature T in the thrust chamber.
Ideally Acr is the throat area.
Figure BDA0001904898970000141
And calculating the corresponding specific Ma number of different sections A in the spray pipe according to an iteration method, calculating lambda back, and obtaining parameters such as temperature, pressure and the like under different sectional areas according to pneumatic calculation.
3.2 According to the selected safety coefficient of the thrust chamber and the material attribute information of different parts of the thrust chamber, combining the temperature and pressure distribution parameters of different axial positions of the thrust chamber calculated in the step 3.1, calculating by adopting an engineering strength checking empirical formula to obtain the wall thickness of different positions of the body part of the thrust chamber and the spray pipe along the axial direction based on the physical property parameters of the material at the temperature;
Figure BDA0001904898970000142
wherein h calculates the wall thickness;
P c.max local static pressure at a given axial position;
σ 0.2 is the yield limit of the material;
r is the radius of a given axial position;
Figure BDA0001904898970000143
a selected safety factor.
Combining the inner profile parameters after the step 2.5) with the wall thickness of the individual position and adding the design size of the head to obtain the size envelope parameters of the full thrust chamber.
3.3 According to the profile data of the thrust chamber obtained in the step 2.5) and the wall thicknesses of different positions of the body part and the spray pipe obtained by calculation, the volumes of the body part and the spray pipe are counted in a revolving body mode;
V＝∑dx·2·R·π (31)
wherein V is the calculated volume of the body or the nozzle;
dx is the size change of the attitude control thrust chamber in the axial direction;
σ 0.2 is the yield limit of the material and,
r is the radius for a given axial position.
3.4 And) respectively calculating the mass of the three parts by combining the head volume obtained in the step 2.4), the body volume obtained in the step 3.2) and the spray pipe volume, and summarizing the three parts to obtain the estimated mass of the thrust chamber.
m Thrust chamber ＝m Head part +m Body part +m Spray pipe (32)
m Thrust chamber To estimate the thrust chamber weight;
m head part Is the estimated head weight;
m body part The estimated weight of the body part;
m spray pipe The estimated weight of the spray pipe is obtained;
those skilled in the art will appreciate that the invention has not been described in detail in this specification.

Claims (5)

1. A method for rapidly estimating the size and the weight of an attitude control two-component thrust chamber is characterized by comprising the following steps:
s1: decomposing the attitude control two-component thrust chamber into a head part, a body part and a spray pipe;
s2: acquiring thermodynamic performance parameter data under the optimal room pressure according to the overall technical index requirements;
s3: calculating the structural sizes of the body part, the spray pipe and the head part according to the selected chamber pressure, the overall technical index requirement, the thermal performance parameter, the flow intensity correction coefficient and the heat return leaching correction coefficient to obtain the size envelope of the inner molded surface of the thrust chamber;
s4: obtaining pressure and temperature distribution parameters of different positions of the thrust chamber along the axis direction according to thermopneumatic calculation; and (4) predicting the wall thickness of the thrust chamber according to a strength checking formula, selecting the material density of different parts in a rotation mode, and calculating to obtain the weight of the thrust chamber.
2. The method for rapidly estimating the size and the weight of the attitude control two-component thrust chamber according to claim 1, wherein in the step S3, the body structure size is calculated through the following process:
s31: calculating the throat radius Rt of the spray pipe according to the thermal performance parameter data acquired in the step S2 and the total technical index requirement;
At＝C*·η c ·F/Is/Pc Rt＝sqrt(At/π)；
wherein At is the throat area, C is the characteristic velocity, η c For combustion efficiency, F Is thrust, is specific impulse, and Pc Is the preferred chamber pressure;
s32: according to a selected shrinkage ratio epsilon c Determining the radius Rc of the body;
Rc＝sqrt(ε c )·Rt；
calculating the length of the body part through the selected contraction half angle beta and the characteristic length, wherein the length comprises a contraction section length Lc2 and a cylinder section length Lc1;
Lc2＝(Rc-Rt)/tanβ
Figure FDA0001904898960000021
where Vc is the volume of the thrust chamber, V c ＝L * ·A t L is the characteristic length, rc is the radius of the body, and Rt is the radius of the throat part of the spray pipe;
or, when the gas stays for a long time or the gas is completely combusted without reaching a critical surface, calculating the length Lc1 of the front section cylindrical section by the following formula;
Figure FDA0001904898960000022
3. the method for rapidly estimating the size and the weight of the attitude control two-component thrust chamber according to claim 1, wherein in the step S3, the structural size of the nozzle is calculated by the following process, including the nozzle converging section and the nozzle expanding section:
nozzle convergent section:
the molding surface of the convergent section of the spray pipe consists of an inlet circular arc with the radius of Rcc, a throat upstream circular arc with the radius of Rc1 and a straight line section; wherein Rcc =5 × Rt; rc1= (1.5 to 2) × Rt; the straight line section adopts a drawing method, and a straight line is tangent to the two arcs after the upstream arc and the downstream arc are determined, so that the straight line section can be obtained;
a nozzle expansion section:
a) Conical spray pipe:
nozzle outlet diameter Re
Re＝sqrt(ε)·Rt；
Length Ln of the dilated segment:
Ln＝(Re-Rt)/tanα；
wherein alpha is the diffusion half angle of the spray pipe;
b) Double-arc spray pipe:
the arc equation of the two arcs forming the double-arc nozzle is set as follows:
Figure FDA0001904898960000023
wherein, the first and the second end of the pipe are connected with each other,
X 0 ＝Ln+R 0 sinφ；
Figure FDA0001904898960000037
wherein:
Figure FDA0001904898960000031
wherein phi is the half angle of the outlet of the spray pipe,
Figure FDA0001904898960000032
Figure FDA0001904898960000033
the relative length of the spray pipe;
c) Maximum thrust spray pipe:
determining the approximate equation of the maximum thrust nozzle profile as a parabolic equation by a geometric method:
X＝aY 2 +bY+c，
wherein:
Figure FDA0001904898960000034
Figure FDA0001904898960000035
c＝X1-aY1 2 -bY1；
wherein: x1= R td sinα，Y1＝R td (1-cosα)+R t ，R td Is the downstream arc radius of the throat part of the spray pipe; x2= L n ；Y2＝Re，
Figure FDA0001904898960000036
4. The method for rapidly estimating the size and the weight of the attitude control two-component thrust chamber according to claim 1, wherein in the step S3, the head is represented by a solid cylinder structure, and the size of the head structure is calculated by the following process:
l head part ＝f(F,Pc,η c ,η h )
V Head part ＝l Head part ·π·Rc 2
In the formula I Head part Indicating the axial length of the head;
η c representing a flow intensity correction factor;
η h representing a flow intensity correction factor;
V head part Representing the volume of the head.
5. The method for rapidly estimating the size and the weight of the attitude control two-component thrust chamber according to claim 1, wherein the step S5 is specifically as follows:
s51) according to the geometric parameters of the inner molded surface of the thrust chamber calculated in the step S3, the total gas temperature parameters obtained by combining chamber pressure and thermodynamic calculation are combined, meanwhile, cooling efficiency modification parameters are introduced, and temperature and pressure distribution parameters along the axial direction and at different axial positions are calculated;
s52) according to the selected safety coefficient of the thrust chamber and the material attribute information of different parts of the thrust chamber, combining the temperature and pressure distribution parameters of different axial positions of the thrust chamber calculated in the step S51), and calculating the wall thickness h of different positions of the body part of the thrust chamber and the spray pipe along the axial direction by adopting an engineering strength checking empirical formula based on the physical property parameters of the material at the temperature;
Figure FDA0001904898960000041
wherein P is c.max Local static pressure at a given axial position;
σ 0.2 is the yield limit of the material;
r is the radius for a given axial position;
Figure FDA0001904898960000042
a selected safety factor;
according to the inner profile parameters, the wall thickness of the individual position and the design size of the head, the size envelope parameters of the full thrust chamber can be obtained;
s53) according to the size envelope parameters of the full thrust chamber and the wall thicknesses of the body part and the spray pipe at different positions obtained through calculation, the volume V of the body part and the volume V of the spray pipe are counted in a revolving body mode;
V＝∑dx·2·R·π
wherein dx is the size change of the attitude control thrust chamber in the axial direction;
r is the radius for a given axial position;
s54) respectively calculating the mass of the three parts by combining the selected material attribute and the head volume, the body volume and the spray pipe volume obtained in the step S53), and summarizing the three parts to obtain the estimated mass of the thrust chamber;
m thrust chamber ＝m Head part +m Body part +m Spray pipe
m Thrust chamber The estimated weight of the thrust chamber;
m head part Is the estimated head weight;
m body part The estimated weight of the body part;
m spray pipe Is the estimated weight of the nozzle.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996025595A1 (en) * 1995-02-16 1996-08-22 Royal Ordnance Plc Thrust chambers
CN108763747A (en) * 2018-05-28 2018-11-06 北京航空航天大学 Carrier rocket dimensional parameters evaluation method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996025595A1 (en) * 1995-02-16 1996-08-22 Royal Ordnance Plc Thrust chambers
CN108763747A (en) * 2018-05-28 2018-11-06 北京航空航天大学 Carrier rocket dimensional parameters evaluation method

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* Cited by examiner, † Cited by third party
Title
200N LOX/MMH推力系统方案论证;张忠利;《火箭推进》;20090615(第03期);全文 *

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