CN110569547B - Supersonic velocity spray pipe of plasma generator and design method thereof - Google Patents
Supersonic velocity spray pipe of plasma generator and design method thereof Download PDFInfo
- Publication number
- CN110569547B CN110569547B CN201910721491.1A CN201910721491A CN110569547B CN 110569547 B CN110569547 B CN 110569547B CN 201910721491 A CN201910721491 A CN 201910721491A CN 110569547 B CN110569547 B CN 110569547B
- Authority
- CN
- China
- Prior art keywords
- nozzle
- spray pipe
- point
- mach number
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Nozzles (AREA)
Abstract
The invention discloses a supersonic velocity spray pipe of a plasma generator, which comprises a pore plate arranged at the outlet end of a cavity of the plasma generator, wherein the lower end of the pore plate is fixedly connected with the inlet end of the spray pipe, and the outlet end of the spray pipe is fixedly connected with a test cavity; the spray pipe comprises an inner wall body of the spray pipe, an outer wall body is sleeved outside the inner wall body of the spray pipe, an interlayer is arranged between the outer wall body and the inner wall body of the spray pipe, and cooling liquid is filled between the inner wall body of the spray pipe and the interlayer. The supersonic velocity spray pipe can generate supersonic velocity plasma airflow with stability and high speed, and parameters can be adjusted according to user requirements, so that the supersonic velocity spray pipe is applied to other technical industries. The invention also discloses a design method of the supersonic velocity spray pipe of the plasma generator, which specifically comprises the following steps: (1) designing a contraction section of a spray pipe; (2) The design of the nozzle diffusion section solves the problem that the design algorithm of the supersonic nozzle in the prior art is complex.
Description
Technical Field
The invention belongs to the technical field of supersonic velocity spray pipes, relates to a supersonic velocity spray pipe of a plasma generator, and further relates to a design method of the supersonic velocity spray pipe.
Background
It is known that a large amount of gas is gathered around the earth surface to form an atmosphere of thousands of kilometers, when an aircraft returns to the earth after completing an outer space mission, the aircraft passes through the atmosphere on the earth surface, and due to the extremely high flight speed, after the aircraft comes into contact with the atmosphere, friction between the aircraft and the atmosphere gas generates a high-temperature and high-speed plasma gas flow, which, due to its extremely high temperature (up to ten thousand degrees centigrade), can cause serious ablation on the aircraft surface material, and if the aircraft surface material is not subjected to high-temperature ablation prevention treatment, the whole aircraft can be damaged. Therefore, in order to develop a high temperature resistant material for the surface of an aircraft, a great deal of research work has been done in various countries in the world in recent years. Many researchers have simulated the outer space environment by establishing Inductively Coupled Plasma (ICP) wind tunnels, have produced high temperature, high velocity Plasma airflows to test proposed aerospace vehicle surface materials, and have selected appropriate materials for fabricating aerospace vehicle shells to ensure that the vehicles can withstand the ablation of the high temperature airflows as they return to the earth and pass through the atmosphere. However, the flow velocity of the plasma generated by the conventional plasma generator is relatively low, so that it is very important to design a device capable of accelerating the plasma flow.
Supersonic nozzles are widely used in various industries, and are a very common component in the aspects of aircraft engines and rocket engines, because the aircraft engines and rocket engines have to have special power for flying, so that the requirement for obtaining the power is great for the exhaust structure, and the exhaust speed is very great. The supersonic nozzle is also applied to satellites, and the main function of the supersonic nozzle on the satellites is to adjust the orbit and the attitude of the satellites according to requirements. Supersonic nozzles are also of particularly common use in the industrial field.
However, in the prior art, when the nozzle tube is used to generate supersonic velocity airflow, the nozzle tube is usually installed at an outlet of a plasma torch in an ICP heater, and with such a structure, it is difficult to change subsonic plasma airflow into supersonic velocity plasma airflow and generate stable supersonic velocity plasma airflow, and the effect of increasing the flow rate of the plasma airflow is poor, so that experimental requirements cannot be met, and the design algorithm of the profile structure of the existing supersonic velocity nozzle tube is also complex.
Disclosure of Invention
The invention aims to provide a supersonic velocity spray pipe of a plasma generator, which solves the problems that stable supersonic velocity plasma airflow is difficult to generate and the effect of increasing the flow velocity of the plasma airflow is poor in the prior art.
The invention also aims to provide a design method of the supersonic velocity spray pipe, which solves the problem that the design algorithm of the supersonic velocity spray pipe is complex in the prior art.
The technical scheme adopted by the invention is that the supersonic velocity spray pipe of the plasma generator comprises a pore plate arranged at the outlet end of a plasma cavity of the plasma generator, wherein the lower end of the pore plate is fixedly connected with the inlet end of the spray pipe, and the outlet end of the spray pipe is fixedly connected with a test cavity; the spray pipe comprises an inner wall body of the spray pipe, an outer wall body is sleeved outside the inner wall body of the spray pipe, an interlayer is arranged between the outer wall body and the inner wall body of the spray pipe, and cooling liquid is filled between the inner wall body of the spray pipe and the interlayer.
The invention is also characterized in that:
the outer wall body comprises an upper outer wall body of the spray pipe and a lower outer wall body of the spray pipe, the upper outer wall body of the spray pipe is sleeved outside the contraction section of the inner wall body of the spray pipe, the lower outer wall body of the spray pipe is sleeved outside the diffusion section of the inner wall body of the spray pipe, an external connecting element is fixedly installed at the joint of the upper outer wall body of the spray pipe and the lower outer wall body of the spray pipe, and the spray pipe is fixedly connected with the test cavity through the external connecting element.
And a plurality of bolt holes are formed in the external connecting element along the direction vertical to the flowing direction of the plasma airflow, and bolts are screwed into the bolt holes to connect the spray pipe with the test cavity in a threaded manner.
The orifice plate is provided with a through hole with the diameter of 50mm, the diameter of the throat of the spray pipe is 15mm, the diameter of the outlet of the diffusion section of the spray pipe is 36mm, the inclination of the contraction section of the spray pipe is 45 degrees, the inclination of the diffusion section of the spray pipe is 30 degrees, and the length of the spray pipe is 35mm.
The material of the spray pipe is stainless steel.
A design method of a supersonic velocity spray pipe of a plasma generator specifically comprises the following steps:
(1) Design of nozzle constriction
The contraction section is the part between the inlet of the spray pipe and the throat, the length of the contraction section is L, and L is approximately equal to 0.5-1.0D 1 ，D 1 The section diameter at the inlet of the contraction section of the supersonic nozzle is shown;
x represents the relative distance from the inlet of the spray pipe to any position, x is 0 to 1, and the gradient of the axial Mach number of the spray pipe is set as dM/dx = Ksin 2 Pi x, M is the Mach number of any position on the contraction section of the nozzle, the Mach number of the air flow at the throat is 1,K as a coefficient, and the value of K is the Mach number increment of the air flow flowing through the contraction section; dM/dx =0 when x =0 and x =1, indicating that the acceleration of the gas flow at the inlet of the convergent section is 0,M 1 The Mach number of the gas flow at the inlet is obtained by the integral formula:
the relation between the Mach number of any position on the contraction section of the spray pipe and the Mach number at the inlet can be obtained:
when x =1, M =1, and thus K =2 (1-M) 1 ) The formula of the substitute (1) is as follows:
then, the Mach number M of the spray pipe at any position x can be obtained according to the formula (2), and then according to the area ratio formula:
in the formula, A i Is the cross-sectional area of the nozzle at any position, M i The cross section area of the contraction section of the spray pipe is A i Mach number of (A) 2 Is the sectional area of the throat at the outlet of the jet pipe, and k is the specific heat ratio of the fluid;
wherein, firstly, the sectional area A at the inlet of the spray pipe is determined 1 Cross-sectional area A of throat of nozzle 2 Substituting the formula (3) to obtain the Mach number M of the airflow at the inlet 1 Then M is added 1 Substituting the equation (2) to obtain a Mach number M curve at any position X of the spray pipe, and obtaining a sectional area curve at any position of the spray pipe according to the equation (3) to obtain a spray pipe contraction section curve and further obtain the shape of the spray pipe contraction section;
(2) Design of nozzle diffuser
The diffuser section is the part between the throat and the outlet of the nozzle, and the airflow in the nozzle is divided into three different places in the diffuser section according to the Freund's method: the gas spring flow emitted from the coordinate zero point is an area I, the area II is a region III for rectifying the gas spring flow, and the air flow in the area III is uniform and has the same speed; A. b, C, D, E represents the different positions of the diffuser, respectively, in zone i, the flow takes the origin O as the center, and takes the form of a radial spring flow, r = r indicates the flow at the throat, r > r indicates the flow at supersonic velocity, and the relationship between the velocity, mach number and r at each point is:
wherein A represents a cross-sectional area at an arbitrary position, and A * Representing the cross-sectional area at the throat, v representing the velocity at each point, gamma being the specific heat ratio, a * Representing the speed of sound of the throat, r is the radius of any position of the diffuser, r * Is the numerical value of the throat radius of the outlet of the diffusion section: r/r * ＝R，v/a * = W, given
Assuming an ideal gas, γ =1.4, so α =6, (4) is formulated as:
after finishing, the relation between the Mach number M and the speed ratio W can be obtained:
knowing the Mach number of point B, W can be obtained from equation (6) B Then substituting the formula (5) to obtain the section radius R at the point B B The difference between the Mach number of the point B and the Mach number of the point C is 0.2;
theta is an included angle between any point on the BA line and OB, and theta' is an angle AOB, then:
when W = W B When θ =0, so:
the position of the point A and the maximum expansion angle theta A There is a certain relation between the maximum expansion angle theta A The values at different operating band mach numbers are shown in table 1:
TABLE 1 values of maximum expansion angle at different operating band Mach numbers
| M | 1.5～2 | 3～4 |
| θ A (゜) | 3～5 | 8 |
Will theta A Dividing by N, and obtaining R values at different points on the BA line according to the formulas (5) and (7), so that coordinate values of all the points on the BA line and parameters of air flow existing at all the points can be obtained;
on the central line, the speed change from the coordinate zero point to the point B can be known according to the formula (5), the speed of the point C is the designed final speed, and the speed relationship between the point B and the point C is expressed by the following cubic expression:
wherein
x C Is the distance, x, from the zero point of the coordinate to point C B Is the distance from the zero point of the coordinate to point B, x is the distance from the zero point of the coordinate to any point in segment BC, a 0 、a 1 、a 2 、a 3 For coefficients, the cubic polynomial satisfies the boundary conditions:
And is represented by the formula:
select x C Substituting these boundary conditions into equation (8) simplifies to the following:
the position coordinate values of the point B and the point C can be obtained, the characteristic line passing through the left side of the point C is a straight line, the Mach number on the characteristic line is the Mach number to be designed, the characteristic line end point E can be determined according to the same method, the AB, BC and CE are used as boundary conditions, the whole characteristic line network formed by the AB, BC and CE can be obtained by using a ternary characteristic line theory, and the shape of the diffusion section of the spray pipe is further obtained.
The invention has the beneficial effects that: the supersonic velocity spray pipe has the advantages of simple structure, light weight, small thickness and the like, the orifice plate is additionally arranged in front of the spray pipe, the nozzle is changed into a gradually-reduced section jet flow type from a linear type, so that airflow is directly blocked at the inlet of the spray pipe to generate large pressure at the inlet, then the airflow speed at the outlet of the spray pipe can be greatly increased by utilizing the aerodynamic principle that the pressure difference is larger and the outlet speed is higher, the Mach number of the nozzle reaches more than 1.1, the supersonic velocity plasma airflow with stable and high flow velocity can be generated and used for testing the surface material of an aerospace craft, the subsonic velocity plasma airflow can be changed into the supersonic velocity plasma airflow, the gas flow velocity is increased, the experimental requirement can be met, and the spray pipe can be popularized in the same line and has high economic value and practical value.
Drawings
FIG. 1 is a schematic structural view of a supersonic nozzle of a plasma generator according to the present invention;
FIG. 2 is a schematic view of a nozzle structure in a supersonic nozzle of a plasma generator according to the present invention;
FIG. 3 is a design view of a nozzle constriction in a supersonic nozzle of a plasma generator of the present invention;
FIG. 4 is a design diagram of a nozzle diffuser in a supersonic nozzle of a plasma generator of the present invention.
In the figure, 1, quartz tube, 2, induction coil, 3, plasma chamber, 4, orifice plate, 5, nozzle, 6, test chamber, 7, upper outer wall of nozzle, 8, inner wall of nozzle, 9, interlayer, 10, external connecting element, 11, lower outer wall of nozzle, 12, bolt hole.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention relates to a supersonic velocity spray pipe of a plasma generator, which comprises a pore plate 4 arranged at the outlet end of a plasma chamber 3 of the plasma generator, wherein the plasma generator is an induction coupling plasma generator and consists of a quartz tube 1 and three induction coils 2, the lower end of the pore plate 4 is fixedly connected with the inlet end of a spray pipe 5, and the outlet end of the spray pipe 5 is fixedly connected with a test cavity 6; the spray pipe 5 comprises a spray pipe inner wall body 8, an outer wall body is sleeved outside the spray pipe inner wall body 8, an interlayer 9 is arranged between the outer wall body and the spray pipe inner wall body 8, and cooling liquid is filled between the spray pipe inner wall body 8 and the interlayer 9.
As shown in FIG. 2, the outer wall body comprises an upper nozzle outer wall body 7 and a lower nozzle outer wall body 11, the upper nozzle outer wall body 7 is sleeved outside the contraction section of the inner nozzle wall body 8, the lower nozzle outer wall body 11 is sleeved outside the diffusion section of the inner nozzle wall body 8, an external connecting element 10 is fixedly installed at the joint of the upper nozzle outer wall body 7 and the lower nozzle outer wall body 11, and the nozzle 5 is fixedly connected with the test cavity 6 through the external connecting element 10.
The external connecting element 10 is provided with a plurality of bolt holes 12 along the direction vertical to the flowing direction of the plasma airflow, and bolts are screwed into the bolt holes 12 to connect the spray pipe 5 and the test cavity 6 in a threaded manner.
The orifice plate 4 is provided with a through hole with the diameter of 50mm, the diameter of the throat of the nozzle 5 is 15mm, the diameter of the outlet of the diffusion section of the nozzle 5 is 36mm, the inclination of the contraction section of the nozzle 5 is 45 degrees, the inclination of the diffusion section of the nozzle 5 is 30 degrees, and the length of the nozzle 5 is 35mm.
The material of the nozzle 5 is stainless steel.
A design method of a supersonic velocity spray pipe of a plasma generator specifically comprises the following steps:
(1) Design of nozzle constriction
The contraction section is a part between the inlet of the nozzle and the throat, and the contraction section is used for enabling the airflow to be uniformly accelerated and enabling the flow velocity of the airflow to be accelerated to supersonic velocity at the throat of the nozzle. When studying the constriction, the property that must be met for the gas flow to pass through the throat is that its velocity is uniform. According to the previous experimental results, if the speed of the airflow passing through the throat meets the condition of uniformity, the design of the contraction section becomes very simple, so that the contraction section capable of meeting the design requirement can be designed more easily, and the final function of the whole spray pipe is influenced by the design of the contraction section.
In the design process of the contraction section, under the condition of realizing all functions of the contraction section, as shown in FIG. 3, the length of the contraction section is L, and L is approximately equal to 0.5-1.0D 1 ，D 1 Shown in the supersonic nozzle constrictionThe cross-sectional diameter at the mouth;
x represents the relative distance from the inlet of the nozzle to any position, x is 0 to 1, and the gradient of the axial Mach number of the nozzle is dM/dx = Ksin 2 Pi x, M is the Mach number of any position on the contraction section of the nozzle, the Mach number of the air flow at the throat is 1,K as a coefficient, and the value of K is the Mach number increment of the air flow flowing through the contraction section; dM/dx =0 when x =0 and x =1, indicating that the acceleration of the gas flow at the inlet of the convergent section is 0,M 1 The Mach number of the gas flow at the inlet is obtained by the integral formula:
the relation between the Mach number of any position on the contraction section of the spray pipe and the Mach number of the inlet can be obtained:
when x =1, M =1, and thus K =2 (1-M) 1 ) The formula of the substitute (1) is as follows:
then, the Mach number M of the spray pipe at any position x can be obtained according to the formula (2), and then according to the area ratio formula:
in the formula, A i Is the cross-sectional area of the nozzle at any position, M i The cross section area of the contraction section of the spray pipe is A i Mach number of (A) 2 Is the sectional area of the throat at the outlet of the jet pipe, and k is the specific heat ratio of the fluid;
wherein, firstly, the sectional area A at the inlet of the spray pipe is determined 1 Cross-sectional area A of throat of nozzle 2 Substituting the Mach number M of the air flow at the inlet into the formula (3) 1 Then M is added 1 Substituting the equation (2) to obtain Mach number M curve of any position X of the spray pipe, and obtaining the Mach number M curve according to the equation (A)3) The sectional area curve of any position of the spray pipe is obtained, so that the curve of the contraction section of the spray pipe can be obtained, and the shape of the contraction section of the spray pipe can be further obtained;
(2) Design of nozzle diffuser
The diffuser section is a part between the throat and the outlet of the nozzle, and can ensure that the airflow uniformly flows through the diffuser section and obtain the previously designed Mach number, and when the airflow flows to the outlet of the nozzle, the speed of the diffuser section can reach the designed Mach number. The ratio of the area at the nozzle exit to the area of the throat determines the designed velocity of the gas flow to be achieved, and the uniformity of the gas flow is determined by the profile of the nozzle.
The design of the diffuser section is essentially based on the eigen-line theory. Physically, a physical disturbance propagation track is defined as a characteristic line, and the disturbance propagates along the mach number of the airflow in the supersonic flow field, and the mach line is actually the characteristic line in the supersonic flow field. Strictly from a mathematical point of view, a characteristic line is defined as a curve along which a partial differential equation can be converted into a full differential equation, by means of which the derivative of the physical parameter can be discontinuous, while the physical parameter itself remains continuous, and the flow zones can be connected together along the characteristic line, even if in each flow zone the derivatives of the parameter and of the characteristic parameter are continuous, while at the interface they are discontinuous. As shown in fig. 4, the flow in the nozzle is divided into three different places in the divergent section according to fleshy's method: the gas spring flow emitted from the coordinate zero point is an area I, the area II is a region III for rectifying the gas spring flow, and the air flow in the area III is uniform and has the same speed; A. b, C, D, E represents the different positions of the diffuser, respectively, in zone i, the flow takes the origin O as the center, and takes the form of a radial spring flow, r = r indicates the flow at the throat, r > r indicates the flow at supersonic velocity, and the relationship between the velocity, mach number and r at each point is:
wherein A represents a cross-sectional area at an arbitrary position, and A * Representing the cross-sectional area at the throat, v representing the velocity at each point, gamma being the specific heat ratio, a * Representing the speed of sound of the throat, r is the radius of any position of the diffuser, r * Is the numerical value of the throat radius of the outlet of the diffusion section: r/r * ＝R，v/a * = W, given
Assuming an ideal gas, γ =1.4, so α =6, (4) is formulated as:
after finishing, the relation between the Mach number M and the speed ratio W can be obtained:
knowing the Mach number of point B, W can be obtained from equation (6) B Then substituting the formula (5) to obtain the section radius R at the point B B A great number of experiments show that the difference between the Mach number of the point B and the Mach number of the point C is 0.2;
theta is an included angle between any point on the BA line and OB, and theta' is an angle AOB, then:
when W = W B When, θ =0, so:
the position of the point A and the maximum expansion angle theta A There is a certain relation between the maximum expansion angle theta A The values at different operating band mach numbers are shown in table 1:
TABLE 1 values of maximum expansion angle at different operating band Mach numbers
| M | 1.5～2 | 3～4 |
| θ A (゜) | 3～5 | 8 |
Will theta A Dividing by N, and obtaining R values at different points on the BA line according to the formulas (5) and (7), so that coordinate values of all the points on the BA line and parameters of air flow existing at all the points can be obtained;
on the central line, the speed change from the coordinate zero point to the point B can be known according to the formula (5), the speed of the point C is the designed final speed, and the speed relationship between the point B and the point C is expressed by the following cubic expression:
wherein
x C Is the distance, x, from the zero point of the coordinate to point C B Is the distance from the zero point of the coordinate to point B, x is the distance from the zero point of the coordinate to any point in segment BC, a 0 、a 1 、a 2 、a 3 For coefficients, the cubic polynomial satisfies the boundary conditions:
And is represented by the formula:
select x C Substituting these boundary conditions into equation (8) simplifies to the following:
the position coordinate values of the point B and the point C can be obtained, the characteristic line passing through the left side of the point C is a straight line, the Mach number on the characteristic line is the Mach number to be designed, the characteristic line end point E can be determined according to the same method, the AB, BC and CE are used as boundary conditions, the whole characteristic line network consisting of the AB, BC and CE can be obtained by using a ternary characteristic line theory, and the shape of the nozzle diffusion section is further obtained.
The invention relates to a supersonic velocity spray pipe of a plasma generator, which comprises the following working processes: the inductively coupled plasma generator is formed by a quartz tube 1 and three additional induction coils 2, the entering gas is broken down through an electromagnetic field generated by applying high-frequency alternating current, conductive gas forms an eddy current layer concentric with the induction coils under the action of the electromagnetic field, joule heat generated by large current heats the gas entering a plasma torch in a heat transfer and heat conduction mode, so that subsonic plasma airflow is formed, the subsonic plasma airflow passes through a plasma chamber 3 and then forms a block after passing through an orifice plate 4, the air pressure is increased, then supersonic plasma airflow is generated through a nozzle 5 and enters a test cavity 6, and then a test piece is placed on a test bed for testing. The upper and lower nozzle outer walls 7, 11 are the outer walls of the nozzle, and a layer of coolant is provided between the inner nozzle wall 8 and the interlayer 9 to reduce the temperature of the plasma gas stream, and the nozzle 5 is bolted to the test chamber 6 by means of external connection elements 10 and bolt holes 12.
The invention relates to a supersonic velocity spray pipe of a plasma generator and a design method thereof, which has the beneficial effects that: the supersonic velocity spray pipe solves the problems that stable supersonic velocity plasma air flow is difficult to generate and the effect of increasing the flow velocity of the plasma air flow is poor in the prior art, has the advantages of being simple in structure, light in weight and small in thickness, can generate stable supersonic velocity plasma air flow with large flow velocity, and can be used for testing the surface material of a spacecraft; the design method of the supersonic velocity spray pipe solves the problem that the design algorithm of the supersonic velocity spray pipe is complex in the prior art, simplifies the design algorithm and has high design efficiency.
Claims (6)
1. A design method of a supersonic velocity spray pipe of a plasma generator is characterized by comprising the following steps:
(1) Design of nozzle constriction
The contraction section is the part between the inlet of the spray pipe and the throat, the length of the contraction section is L, and L is approximately equal to 0.5-1.0D 1 ，D 1 The section diameter at the inlet of the contraction section of the supersonic nozzle is shown;
x represents the relative distance from the inlet of the nozzle to any position, x is 0 to 1, and the gradient of the axial Mach number of the nozzle is dM/dx = Ksin 2 Pi x, M is the Mach number of any position on the contraction section of the nozzle, the Mach number of the air flow at the throat is 1,K as a coefficient, and the value of K is the Mach number increment of the air flow flowing through the contraction section; dM/dx =0 when x =0 and x =1, indicating that the acceleration of the gas flow at the inlet of the convergent section is 0,M 1 The mach number of the gas flow at the inlet is integrated by the following formula:
the relation between the Mach number of any position on the contraction section of the spray pipe and the Mach number at the inlet can be obtained:
when x =1, M =1, and thus K =2 (1-M) 1 ) The formula of the substitute (1) is as follows:
then, the mach number M of the nozzle at any position x can be obtained according to the formula (2), and then according to the area ratio formula:
in the formula, A i Is the cross-sectional area of the nozzle at any position, M i The cross section area of the contraction section of the spray pipe is A i Mach number of (A) 2 Is the sectional area of the throat at the outlet of the jet pipe, and k is the specific heat ratio of the fluid;
wherein, firstly, the sectional area A at the inlet of the spray pipe is determined 1 And the sectional area A of the throat of the nozzle 2 Substituting the formula (3) to obtain the Mach number M of the airflow at the inlet 1 Then M is added 1 Substituting the equation (2) to obtain a Mach number M curve at any position X of the spray pipe, and obtaining a sectional area curve at any position of the spray pipe according to the equation (3) to obtain a spray pipe contraction section curve and further obtain the shape of the spray pipe contraction section;
(2) Design of nozzle diffuser
The diffuser section is the part between the throat and the outlet of the nozzle, and the airflow in the nozzle is divided into three different places in the diffuser section according to the Freund's method: the gas spring flow radiated from the coordinate zero point is an area I, the area II is a region III for rectifying the gas spring flow, and the air flow of the area III is uniform and the speed is the same; A. b, C, D, E represents the different positions of the diffuser, respectively, in zone i, the flow takes the origin O as the center, and takes the form of a radial spring flow, r = r indicates the flow at the throat, r > r indicates the flow at supersonic velocity, and the relationship between the velocity, mach number and r at each point is:
wherein A represents a cross-sectional area at an arbitrary position, and A * Represents the cross-sectional area at the throat, v represents the velocity at each point, γ is the specific heat ratio, a * Representing the speed of sound of the throat, r is the radius of any position of the diffuser, r * Is the numerical value of the throat radius of the outlet of the diffusion section: r/r * ＝R，v/a * = W, given
Assuming an ideal gas, γ =1.4, so α =6, (4) is formulated as:
after finishing, the relation between the Mach number M and the speed ratio W can be obtained:
knowing the Mach number of point B, W can be obtained from equation (6) B Then substituting the formula (5) to obtain the section radius R at the point B B The difference between the Mach number of the point B and the Mach number of the point C is 0.2;
theta is an included angle between any point on the BA line and OB, and theta' is an angle AOB, then:
when W = W B When, θ =0, so:
the place where the point A is located is the maximum expansion angle theta A There is a certain relation between the maximum expansion angle theta A The values under different working section Mach numbers are as follows: when M is 1.5-2, theta A Is 3 to 5; when M is 3 to 4, theta A Is 8;
will theta A Dividing by N, and obtaining R values at different points on the BA line according to the formulas (5) and (7), so that coordinate values of all the points on the BA line and parameters of air flow existing at all the points can be obtained;
on the central line, the speed change from the coordinate zero point to the point B can be known according to the formula (5), the speed of the point C is the designed final speed, and the speed relationship between the point B and the point C is expressed by the following cubic expression:
wherein
x C Is the distance, x, from the zero point of the coordinate to point C B Is the distance from the zero point of the coordinate to point B, x is the distance from the zero point of the coordinate to any point in segment BC, a 0 、a 1 、a 2 、a 3 For coefficients, the cubic polynomial satisfies the boundary conditions:
And is composed of
Select x C Substituting these boundary conditions into equation (8) simplifies to the following:
the position coordinate values of the point B and the point C can be obtained, the characteristic line passing through the left side of the point C is a straight line, the Mach number on the characteristic line is the Mach number to be designed, the characteristic line end point E can be determined according to the same method, the AB, BC and CE are used as boundary conditions, the whole characteristic line network formed by the AB, BC and CE can be obtained by using a ternary characteristic line theory, and the shape of the diffusion section of the spray pipe is further obtained.
2. The supersonic velocity spray pipe of the plasma generator of the design method of claim 1, characterized by comprising a pore plate (4) arranged at the outlet end of a plasma chamber (3) of the plasma generator, wherein the lower end of the pore plate (4) is fixedly connected with the inlet end of a spray pipe (5), and the outlet end of the spray pipe (5) is fixedly connected with a test cavity (6); the spray pipe (5) comprises a spray pipe inner wall body (8), an outer wall body is sleeved outside the spray pipe inner wall body (8), an interlayer (9) is arranged between the outer wall body and the spray pipe inner wall body (8), and cooling liquid is filled between the spray pipe inner wall body (8) and the interlayer (9).
3. The supersonic nozzle of plasma generator according to claim 2, wherein the outer wall comprises an upper nozzle outer wall (7) and a lower nozzle outer wall (11), the upper nozzle outer wall (7) is sleeved outside the contraction section of the inner nozzle wall (8), the lower nozzle outer wall (11) is sleeved outside the expansion section of the inner nozzle wall (8), an external connecting element (10) is fixedly installed at the joint of the upper nozzle outer wall (7) and the lower nozzle outer wall (11), and the nozzle (5) is fixedly connected with the test cavity (6) through the external connecting element (10).
4. Supersonic nozzle of a plasma generator according to claim 3, characterized in that the external connection element (10) has a plurality of bolt holes (12) along the direction perpendicular to the flow direction of the plasma gas flow, and bolts are screwed into the bolt holes (12) to connect the nozzle (5) and the test chamber (6) by screw thread.
5. Supersonic nozzle of a plasma generator according to claim 3, characterized in that the orifice plate (4) is provided with a through hole with a diameter of 50mm, the diameter at the throat of the nozzle (5) is 15mm, the diameter at the outlet of the diffuser section of the nozzle (5) is 36mm, the slope of the convergent section of the nozzle (5) is 45 °, the slope of the diffuser section of the nozzle (5) is 30 °, and the length of the nozzle (5) is 35mm.
6. Supersonic nozzle of a plasma generator according to claim 2, characterized in that the material of the nozzle (5) is stainless steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910721491.1A CN110569547B (en) | 2019-08-06 | 2019-08-06 | Supersonic velocity spray pipe of plasma generator and design method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910721491.1A CN110569547B (en) | 2019-08-06 | 2019-08-06 | Supersonic velocity spray pipe of plasma generator and design method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110569547A CN110569547A (en) | 2019-12-13 |
| CN110569547B true CN110569547B (en) | 2022-10-14 |
Family
ID=68774748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910721491.1A Active CN110569547B (en) | 2019-08-06 | 2019-08-06 | Supersonic velocity spray pipe of plasma generator and design method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110569547B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114280220B (en) * | 2021-12-30 | 2022-10-21 | 西安交通大学 | Design method of opposed flame spray pipe capable of forming uniform velocity field |
| CN115358101B (en) * | 2022-10-21 | 2022-12-20 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Jet pipe design method based on sound velocity solution and characteristic line reverse thrust |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102323961A (en) * | 2011-05-18 | 2012-01-18 | 中国人民解放军国防科学技术大学 | Asymmetric supersonic velocity spray pipe and design method thereof |
| JP2018141208A (en) * | 2017-02-28 | 2018-09-13 | 学校法人 芝浦工業大学 | Supersonic nozzle used for supersonic free jet physical vapor deposition device, method for manufacturing the same, method for designing supersonic nozzle used for supersonic free jet physical vapor deposition device, and computer program |
| CN109655226A (en) * | 2018-12-07 | 2019-04-19 | 中国航天空气动力技术研究院 | Macker type arc heater working characteristics diagnostic system and diagnostic method |
-
2019
- 2019-08-06 CN CN201910721491.1A patent/CN110569547B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102323961A (en) * | 2011-05-18 | 2012-01-18 | 中国人民解放军国防科学技术大学 | Asymmetric supersonic velocity spray pipe and design method thereof |
| JP2018141208A (en) * | 2017-02-28 | 2018-09-13 | 学校法人 芝浦工業大学 | Supersonic nozzle used for supersonic free jet physical vapor deposition device, method for manufacturing the same, method for designing supersonic nozzle used for supersonic free jet physical vapor deposition device, and computer program |
| CN109655226A (en) * | 2018-12-07 | 2019-04-19 | 中国航天空气动力技术研究院 | Macker type arc heater working characteristics diagnostic system and diagnostic method |
Non-Patent Citations (2)
| Title |
|---|
| 用于气流粉碎机的超音速喷管设计研究;王海涛等;《西北工业大学学报》;20040430(第02期);全文 * |
| 高稳定性电弧等离子体超声速喷管流动装置;岳斌等;《流体力学实验与测量》;20050615(第02期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110569547A (en) | 2019-12-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102323961B (en) | Asymmetric supersonic velocity spray pipe and design method thereof | |
| CN108168832B (en) | A kind of throat structure improving tube wind tunnel test Reynolds number | |
| CN110569547B (en) | Supersonic velocity spray pipe of plasma generator and design method thereof | |
| CN102218378B (en) | Ultrasonic nonuniform flow nozzle and design method thereof | |
| CN108195544B (en) | A kind of impulse type wind-tunnel tandem jet pipe | |
| CN108421649B (en) | Rectangular supersonic nozzle and design method thereof | |
| CN102302989A (en) | Supersonic velocity spray pipe with shared throat part and design method of supersonic velocity spray pipe | |
| CN108345714B (en) | Numerical simulation method for parameter design of inner annular jet flow pressure stabilizing cavity | |
| CN107741313A (en) | A kind of low wide Mach number wind-tunnel laminar flow double venturi of disturbance | |
| WO2023213196A1 (en) | Forward jet drag reduction and heat shielding method for hypersonic pointed-cone aircraft | |
| CN106596038B (en) | The calculation method of the mute wind tunnel nozzle suction flow of supersonic and hypersonic | |
| CN107891970A (en) | The active thermal protection system of hypersonic aircraft gaseous film control | |
| CN108263638B (en) | High-temperature low-consumption special-shaped spray pipe | |
| CN105781790B (en) | A kind of curved two end number mixing exhaust systems of double S of segmentation reducing-pitch thread | |
| Nicoll et al. | Performance of conical diffusers with annular injection at inlet | |
| CN112240831A (en) | Design method of aero-engine intake temperature distortion generator | |
| CN103742296B (en) | A kind of gaseous film control jet pipe | |
| CN108534981A (en) | A kind of high-temperature tunnel collection port spraying temperature lowering apparatus | |
| Georgiadis et al. | Computational investigations of high-speed dual stream jets | |
| Srinivasarao et al. | Characteristics of co-flow jets from orifices | |
| CN109815549B (en) | Design method of single-pair supersonic flow direction vortex generating device | |
| CN110889180A (en) | Design method for fan ring rotating rectangular isolation section | |
| Sokolov et al. | Optimization of micronozzle performance at zero ambient pressure | |
| CN214132251U (en) | Controllable isothermal wall rectangular spray pipe structure | |
| CN110454961A (en) | It is a kind of to disappear the uneven annular water conservancy diversion orifice fitting in whirlpool for jet stream restricted clearance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |