阅读说明：本技术 一种燃烧室壁面实时热流密度测量装置及测量方法 (Device and method for measuring real-time heat flux density of wall surface of combustion chamber ) 是由 刘昭宇 薛帅杰 李悦 王焕燃 熊剑 房喜荣 肖虹 于 2021-09-10 设计创作，主要内容包括：本发明涉及热流密度测量技术,尤其涉及一种燃烧室壁面实时热流密度测量装置及测量方法,主要解决了现有技术测量燃烧室壁面的热响应时间久、测量精度低且无法实时测量的技术问题。本发明装置包括燃烧室壁、测量孔、测量组件以及固定限位组件；燃烧室壁上设置测量孔；测量孔内放置热电偶；热电偶与测量孔底部接触；固定套筒套在热电偶上,热电偶固定板上设置有限位孔；热电偶固定板与燃烧室壁固连,将固定套筒压紧固定在燃烧室外壁面和热电偶固定板之间,将弹簧压缩在挡块和热电偶固定板之间。固定套筒、弹簧、挡块以及热电偶固定板组合形成一种弹簧补偿式热电偶固定法。同时,本发明还提供了一种燃烧室壁面实时热流密度的测量方法。(The invention relates to a heat flux density measurement technology, in particular to a real-time heat flux density measurement device and a measurement method for a wall surface of a combustion chamber, and mainly solves the technical problems that in the prior art, the measurement time for measuring the heat response of the wall surface of the combustion chamber is long, the measurement precision is low, and real-time measurement cannot be carried out. The device comprises a combustion chamber wall, a measuring hole, a measuring component and a fixed limiting component; the wall of the combustion chamber is provided with a measuring hole; a thermocouple is placed in the measuring hole; the thermocouple is contacted with the bottom of the measuring hole; the fixed sleeve is sleeved on the thermocouple, and a limit hole is formed in the thermocouple fixing plate; the thermocouple fixing plate is fixedly connected with the wall of the combustion chamber, the fixing sleeve is tightly pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate, and the spring is compressed between the stop block and the thermocouple fixing plate. The fixing sleeve, the spring, the stop block and the thermocouple fixing plate are combined to form a spring compensation type thermocouple fixing method. Meanwhile, the invention also provides a method for measuring the real-time heat flux density of the wall surface of the combustion chamber.)

1. The utility model provides a real-time heat flux density measuring device of combustion chamber wall, includes combustion chamber wall (1) that can heat conduction, combustion chamber wall (1) is tubular structure, its characterized in that:

comprises a measuring component (3) and a fixed limit component (4);

the wall (1) of the combustion chamber is provided with at least one group of measuring holes, the measuring holes comprise n blind holes (2), n is more than or equal to 2, and the n blind holes (2) are radially arranged and axially arranged along the outer wall surface of the combustion chamber;

the number of the measuring assemblies (3) is consistent with that of the blind holes (2), the measuring assemblies comprise thermocouples (31), and springs (32) and stop blocks (33) which are sequentially sleeved on the thermocouples (31), and the stop blocks (33) are fixedly connected with the thermocouples (31);

the thermocouple (31) is arranged in the blind hole (2), and the working end (34) of the thermocouple (31) is contacted with the bottom of the blind hole (2);

the fixed limiting assembly (4) comprises a fixed sleeve (41) and a thermocouple fixing plate (42);

the fixed sleeve (41) is sleeved on the thermocouple (31) provided with the spring (32) and the stop block (33);

the thermocouple fixing plate (42) is arranged on the outer side of the outer wall surface of the combustion chamber; a limiting hole (45) is formed in the thermocouple fixing plate (42), the limiting hole (45) corresponds to the blind hole (2), and the limiting hole is used for limiting and fixing the thermocouple (31) and leading wires on the thermocouple (31) to penetrate through and be led out outwards; the thermocouple fixing plate (42) is fixedly connected with the wall (1) of the combustion chamber, the fixing sleeve (41) is pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate (42), and the spring (32) is compressed between the stop block (33) and the thermocouple fixing plate (42).

2. The apparatus of claim 1, wherein the apparatus comprises: the thermocouple (31) adopts an exposed-end armored thermocouple, the diameter of the exposed-end armored thermocouple is 1-1.5 mm, and the diameter of the end of the working end (34) of the exposed-end armored thermocouple is not more than 0.5 mm.

3. The apparatus for measuring the heat flux density in real time on the wall surface of a combustion chamber according to any one of claims 1 or 2, wherein: the blind hole (2) is a step blind hole, the spring (32) and the stop block (33) are arranged at the large end of the step blind hole, and the working end (34) of the thermocouple (31) is arranged at the small end of the step blind hole and is in contact with the bottom of the step blind hole.

4. The apparatus of claim 3, wherein the apparatus comprises: the diameter of the large end of the step blind hole is 2-3 mm; the diameter of the small end is not less than 1 mm.

5. The apparatus of claim 4, wherein the apparatus comprises: the number of the blind holes of each group of steps is three, the three blind holes of the steps are on the same straight line, and the depth difference between the adjacent blind holes of the steps is the same;

the number of the thermocouples (31), the limiting holes (45), the springs (32) and the stop blocks (33) is three.

6. The apparatus of claim 5, wherein the apparatus comprises: bolt holes (46) are formed in two ends of the thermocouple fixing plate (42), and bolts (43) penetrate through the bolt holes (46) and are screwed into the combustion chamber wall (1) to fix and lock the thermocouple fixing plate (42).

7. The apparatus of claim 6, wherein the apparatus comprises: and a gasket (44) is arranged between the bolt (43) and the thermocouple fixing plate (42).

8. A method for measuring the heat flux density of the wall surface of a combustion chamber in real time is characterized by comprising the following steps:

step 1) measuring the diameter of the outer wall surface of the combustion chamber and the radius of the inner wall surface of the combustion chamber, and respectively recording the diameter as d and R₀(ii) a The blind holes (2) are processed in a radial arrangement and axial arrangement mode along the outer wall surface of the combustion chamber, and the depth of the blind holes (2) is recorded as h from depth to depth₁，h₂...h_i...h_nI is more than or equal to 1 and less than or equal to n-1, and n is more than or equal to 2; corresponding to the depth of the blind hole (2), the radius of the circumference where the bottom of the blind hole (2) is recorded as R₁，R₂...R_i...R_nI is more than or equal to 1 and less than or equal to n-1, n is more than or equal to 2, then R_i＝d/2-h_i，R_n＝d/2-h_n；

Step 2), enabling the thermocouple (31) sleeved with the spring (32) and the stop block (33) to penetrate through the fixed sleeve (41), placing the thermocouple (31) in the blind hole (2), enabling the thermocouple working end (34) to be in contact with the bottom of the blind hole (2), and enabling one end of the fixed sleeve (41) to be in contact with the outer wall of the combustion chamber; then, the thermocouple fixing plate (42) is placed at the position corresponding to the blind hole (2) and is in contact with the other end of the fixing sleeve (41), and a lead of the thermocouple (31) is led out through the limiting hole (45); and the thermocouple fixing plate (42) is fixedly connected with the wall (1) of the combustion chamber; the fixed sleeve (41) is pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate (42), and the spring (32) is compressed between the stop block (33) and the thermocouple fixing plate (42);

step 3) connecting the lead of the thermocouple (31) with a temperature control instrument, and measuring when the combustion chamber worksThe real-time temperature corresponding to the bottom of the blind hole (2) is recorded as T₁，T₂......T_n；

Step 4) calculating by the following heat flux density formula:

q₀: density of heat flow on the inner wall surface of the combustion chamber;

n: the number of blind holes is more than or equal to 2;

R₀: the radius of the inner wall surface of the combustion chamber;

R_i: the radius of the circumference where the bottom of the No. i blind hole is located is more than or equal to 1 and less than or equal to n-1;

T_i: the hole bottom of the i-type blind hole corresponds to the actually measured temperature;

λ: the thermal conductivity of the metal material used for the wall surfaces of the combustion chamber.

9. The method for measuring the heat flow density of the wall surface of the combustion chamber in real time according to claim 8, wherein the method comprises the following steps: in the step 1), the depth difference between every two adjacent blind holes (2) is 0.5-10 mm.

Technical Field

The invention relates to a heat flux density measurement technology, in particular to a device and a method for measuring the heat flux density of the wall surface of a combustion chamber in real time.

Background

The temperature of fuel gas in the combustion chamber of the aerospace engine is up to more than 3000K, the working thermal environment in the combustion chamber is extremely severe, and the requirement on thermal protection of the wall surface of the combustion chamber is high. The wall surface heat flux density of the combustion chamber is an extremely important physical quantity for evaluating wall surface materials of the combustion chamber, the real-time heat flux density of the wall surface is accurately obtained, the local heat transfer characteristic of the wall surface of the combustion chamber can be quantitatively evaluated, and then the optimization of a heat protection structure of the wall surface of the combustion chamber is guided; meanwhile, the combustion state in the combustion chamber can be reflected, and the combustion performance of the thermal assembly can be evaluated.

In the development process of an aerospace engine combustion chamber, a heat flow density is measured by using a thermal flowmeter, which is a common heat flow density measuring method, but the heat flow density measuring method is not suitable for the high-temperature environment of the aerospace engine combustion chamber due to the large diameter of a working end, long thermal response time, short service life and inaccurate measuring result. Meanwhile, the existing measuring device is directly connected with the measured wall surface through threads or flanges, when the engine combustion chamber is used for combustion, the engine combustion chamber is easy to vibrate to cause measuring point deviation, and a gap is generated between the measuring meter and the measured wall surface to cause large error of measured heat flow density. In summary, the existing heat flux density measurement method has long response time and low measurement accuracy, and cannot realize real-time measurement of the heat flux density on the wall surface of the combustion chamber.

Disclosure of Invention

The invention aims to solve the technical problems that the method for measuring the heat flow density of the wall surface of the combustion chamber in the prior art has long response time and low measurement precision and cannot realize the real-time measurement of the heat flow density of the wall surface of the combustion chamber, and provides a device and a method for measuring the heat flow density of the wall surface of the combustion chamber in real time. The device for measuring the real-time heat flux density of the wall surface of the combustion chamber provided by the invention can be suitable for measuring the heat flux density of the combustion chamber of an aerospace engine in a high-temperature environment in real time.

The technical scheme of the invention is as follows:

the utility model provides a real-time heat flux density measuring device of combustion chamber wall, includes the combustion chamber wall that can heat conduction, the combustion chamber wall is the tubular structure, and its special character lies in:

comprises a measuring component and a fixed limiting component;

the wall of the combustion chamber is provided with at least one group of measuring holes, each measuring hole comprises n blind holes, n is more than or equal to 2, and the n blind holes are radially arranged and axially arranged along the outer wall surface of the combustion chamber;

the number of the measuring assemblies is consistent with that of the blind holes, the measuring assemblies comprise thermocouples, and springs and stop blocks which are sequentially sleeved on the thermocouples, and the stop blocks are fixedly connected with the thermocouples;

the thermocouple is arranged in the blind hole, and the working end of the thermocouple is contacted with the bottom of the blind hole;

the fixed limiting assembly comprises a fixed sleeve and a thermocouple fixing plate;

the fixed sleeve is sleeved on the thermocouple provided with the spring and the stop block;

the thermocouple fixing plate is arranged on the outer side of the outer wall surface of the combustion chamber; the thermocouple fixing plate is provided with a limiting hole, the limiting hole corresponds to the blind hole and is used for limiting and fixing the thermocouple and leading out a lead on the thermocouple after the lead passes through the thermocouple fixing plate; the thermocouple fixing plate is fixedly connected with the wall of the combustion chamber, the fixing sleeve is tightly pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate, and the spring is compressed between the stop block and the thermocouple fixing plate.

The fixing sleeve, the spring, the stop block and the thermocouple fixing plate are combined to form a spring compensation type thermocouple fixing method. The working principle of the spring compensation type thermocouple fixing method is as follows: the spring is contracted and deformed under the pressure action of the thermocouple fixing plate, elastic potential energy is stored, and when the bolt is loosened due to vibration of the combustion chamber, the spring releases the elastic potential energy, so that the working end of the thermocouple can still be tightly attached to the wall surface of the combustion chamber, and the effectiveness and accuracy of the measured temperature are guaranteed.

Furthermore, the thermocouple adopts an exposed-end armored thermocouple, the diameter of the exposed-end armored thermocouple is 1-1.5 mm, and the diameter of the working end of the exposed-end armored thermocouple is not more than 0.5 mm. The armored thermocouple has the characteristics of small heat capacity and short response time, and an exposed end type armored thermocouple with the end head diameter not more than 0.5mm is further selected, so that the thermal response time of the thermocouple is greatly shortened.

Furthermore, the blind hole is a step blind hole, the spring and the stop block are arranged at the large end of the step blind hole, and the working end of the thermocouple is arranged at the small end of the step blind hole and is in contact with the bottom of the blind hole.

Further, the diameter of the large end of the step blind hole is 2-3 mm; the diameter of the small end is not less than 1 mm. The tight laminating of open end formula armoured thermocouple work end and blind hole bottom and then the accurate temperature data that acquire this position department of being convenient for.

Furthermore, each group of step blind holes are three, the three blind holes are on the same straight line, and the depth difference between the adjacent blind holes is the same; the thermocouple, spacing hole, spring and dog are all three. Three exposed-end armored thermocouples with gradient distances are designed into a group, so that high-precision heat flux density of the wall surface of the combustion chamber can be obtained; even if one of the thermocouples fails, the heat flux density and temperature of the combustion wall surface can be obtained by the remaining two thermocouples.

Furthermore, bolt holes are formed in two ends of the thermocouple fixing plate, and the thermocouple fixing plate is fixedly locked by penetrating bolts through the bolt holes and screwing the bolts into the wall of the combustion chamber.

Furthermore, a gasket is arranged between the bolt and the thermocouple fixing plate, so that the thermocouple fixing plate is more firmly installed.

The method for measuring the heat flux density of the wall surface of the combustion chamber in real time is characterized by comprising the following steps of:

step 1) measuring the diameter of the outer wall surface of the combustion chamber and the radius of the inner wall surface of the combustion chamber, and respectively recording the diameter as d and R₀(ii) a Blind holes are processed along the outer wall surface of the combustion chamber in a radial arrangement and axial arrangement mode, the depth of the blind holes is sequentially from deep to shallow,is marked as h₁，h₂...h_i...h_nI is more than or equal to 1 and less than or equal to n-1, and n is more than or equal to 2; corresponding to the depth of the blind hole, the radius of the circumference (taking the central line of the combustion chamber as the axis) of the bottom of the blind hole is recorded as R₁，R₂...R_i...R_nI is more than or equal to 1 and less than or equal to n-1, n is more than or equal to 2, then R_i＝d/2-h_i，R_n＝d/2-h_n；

Step 2) enabling the thermocouple sleeved with the spring and the stop block to penetrate through the fixed sleeve, placing the thermocouple in the blind hole, enabling the working end of the thermocouple to be in contact with the bottom of the blind hole, and enabling one end of the fixed sleeve to be in contact with the outer wall surface of the combustion chamber; then, the thermocouple fixing plate is placed at the position corresponding to the blind hole and is in contact with the other end of the fixing sleeve, and a lead of the thermocouple is led out through the limiting hole; and fixedly connecting the thermocouple fixing plate with the wall of the combustion chamber; the fixed sleeve is tightly pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate, and the spring is compressed between the stop block and the thermocouple fixing plate;

step 3) connecting the thermocouple lead with a temperature control instrument, and measuring the real-time temperature of the bottom of the corresponding blind hole as T when the combustion chamber works₁，T₂......T_n；

Step 4) calculating by the following heat flux density formula:

q₀: density of heat flow on the inner wall surface of the combustion chamber;

n: the number of blind holes is more than or equal to 2;

R₀: the radius of the inner wall surface of the combustion chamber;

R_i: the radius of the circumference (taking the central line of the combustion chamber as the axis) of the bottom of the No. i blind hole is more than or equal to 1 and less than or equal to n-1;

T_i: the hole bottom of the i-type blind hole corresponds to the actually measured temperature;

λ: the thermal conductivity of the metal material used for the wall surfaces of the combustion chamber.

Further, in the step 1), the depth difference between adjacent blind holes is 0.5-10 mm.

The invention has the beneficial effects that:

(1) the device has the advantages of reasonable design, simple structure and convenient processing, and is combined with an exposed end type armored thermocouple with the end diameter smaller than 0.5mm, so that the thermal response time is shortened, and the measurement precision is high.

(2) The device adopts a spring compensation type thermocouple fixing method, the working end of the thermocouple is always kept in close fit with the bottom of the blind hole when the thermocouple measures the temperature, and effective data of the wall surface temperature and the heat flux density of the combustion chamber can be obtained in real time.

(3) The device is provided with three exposed-end armored thermocouples with gradient distances to measure the heat flow density of the wall surface of the combustion chamber, so that the high-precision heat flow density of the wall surface of the combustion chamber can be obtained; even if one of the thermocouples fails, the temperature and the heat flux density of the wall surface of the combustion chamber can be obtained by the remaining two thermocouples.

(4) The method for measuring the heat flux density by the device is simple and easy to implement, has high measurement precision, can obtain real-time wall surface heat flux density data of the combustion chamber, and has guiding significance for the development of the combustion chamber of the aerospace engine.

Drawings

FIG. 1 is a schematic view of an apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of a portion of an open-ended sheathed thermocouple selected for use in the embodiment of FIG. 1;

fig. 3 is a schematic structural view of a thermocouple fixing plate in the embodiment of fig. 1.

Description of reference numerals:

1-a combustion chamber wall; 2, blind holes; 3-measuring component, 31-thermocouple, 32-spring, 33-stop block, 34-thermocouple working end; 4-fixing a limiting component, 41-fixing a sleeve, 42-a thermocouple fixing plate, 43-a bolt, 44-a gasket, 45-a limiting hole and 46-a bolt hole.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

As shown in fig. 1 to 3, a device for measuring the heat flux density on the wall surface of a combustion chamber in real time comprises a combustion chamber wall 1 capable of conducting heat, a measuring component 3 and a fixed limiting component 4, wherein the combustion chamber wall 1 is of a cylindrical structure;

and drilling a group of measuring holes in a radial arrangement and axial arrangement mode along the direction of the outer wall of the combustion chamber facing the inner wall of the combustion chamber, wherein the group of measuring holes are three blind holes 2. In this embodiment, the blind hole 2 is a step blind hole, three step blind holes are on the same straight line, and the depth difference of the adjacent step blind holes is the same. The step blind holes are flexible and adjustable in position, are determined according to actual engineering requirements, and the number of the step blind holes can be increased according to actual requirements.

The number of the measuring assemblies 3 is consistent with that of the step blind holes, and the measuring assemblies comprise thermocouples 31, and springs 32 and stop blocks 33 which are sequentially sleeved on the thermocouples 31, wherein the stop blocks 33 are fixedly connected with the thermocouples 31; the spring 32 has one end contacting the stopper 33 and the other end contacting the thermocouple fixing plate 42 in the fixing position restricting assembly 4. The thermocouple 31 in this embodiment is an exposed-end armored thermocouple; an exposed end type armored thermocouple is placed in each step blind hole, a spring 32 and a stop block 33 are arranged at the large end of each step blind hole, and a working end 34 of the exposed end type armored thermocouple is arranged at the small end of each step blind hole and is in contact with the bottom of each step blind hole. The diameter of the large end of the step blind hole is 2-3 mm, the diameter of the small end is not smaller than 1mm, and the exposed end type armored thermocouple working end 34 can be tightly attached to the bottom of the step blind hole conveniently, so that accurate data of the position can be obtained. Selecting an exposed-end armored thermocouple with the diameter of 1-1.5 mm, wherein the diameter of the end of a working end 34 of the exposed-end armored thermocouple is not more than 0.5 mm; based on the characteristics of small heat capacity and short response time of the armored thermocouple, the exposed end type armored thermocouple with the end head diameter not more than 0.5mm is further selected, and the thermal response time is greatly shortened.

The fixing limit assembly 4 includes a fixing sleeve 41, a thermocouple fixing plate 42, and a bolt 43. The fixing sleeve 41 is sleeved on the exposed-end armored thermocouple provided with the spring 32 and the stop block 33, and the fixing sleeve 41 is used for overcoming the defect that the spring 32 cannot be effectively compressed and rebounded in the working process due to the fact that the acting force of the spring 32 is prone to offset due to the fact that a lead wire on the exposed-end armored thermocouple is soft. The thermocouple fixing plate 42 is arranged on the outer side of the outer wall surface of the combustion chamber, a limiting hole 45 is formed in the thermocouple fixing plate 42, the limiting hole 45 corresponds to the step blind hole, and a lead wire used for limiting and fixing the exposed-end armored thermocouple and on the exposed-end armored thermocouple penetrates through and is led out outwards; bolt holes 46 are formed in two ends of the thermocouple fixing plate 42, and the thermocouple fixing plate 42 is fixedly locked by penetrating the bolt holes 46 through bolts 43 and screwing the bolts into the combustion chamber wall 1; the fixing sleeve 41 is pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate 42, and the spring 32 is compressed between the stopper 33 and the thermocouple fixing plate 42.

The fixing sleeve 41, the spring 32, the stopper 33 and the thermocouple fixing plate 42 are combined to form a spring compensation type thermocouple fixing method. The working principle of the spring compensation type thermocouple fixing method is as follows: the spring 32 is contracted under the pressure action of the thermocouple fixing plate 42 and stores elastic potential energy, and when the bolt 43 is loosened due to the vibration of the combustion chamber, the spring 32 releases the elastic potential energy, so that the exposed end type armored thermocouple working end 34 can still be tightly attached to the bottom of the step blind hole, and the effectiveness and the accuracy of the measured temperature are ensured.

The heat flux density measurement method of the present embodiment is:

step 1) measuring the diameter of the outer wall surface of the combustion chamber and the radius of the inner wall surface of the combustion chamber, and respectively recording the diameter as d and R₀(ii) a Step blind holes are processed along the outer wall surface of the combustion chamber in a radial arrangement and axial arrangement mode, and the depth of the step blind holes is recorded as h from depth to depth₁，h₂，h₃(ii) a Corresponding to the depth of the step blind hole, the radius of the circumference (taking the central line of the combustion chamber as the axis) where the bottom of the step blind hole is positioned is recorded as R₁，R₂，R₃Then R is₁＝d/2-h₁，R₂＝d/2-h₂，R₃＝d/2-h₃(ii) a The depth difference between the blind holes of the adjacent steps is 0.5-10 mm;

step 2) enabling the exposed-end armored thermocouple sleeved with the spring 32 and the stop block 33 to penetrate through the fixed sleeve 41, placing the exposed-end armored thermocouple in the step blind hole, enabling the working end 34 of the exposed-end armored thermocouple to be in contact with the bottom of the step blind hole, and enabling one end of the fixed sleeve 41 to be in contact with the outer wall surface of the combustion chamber; then, the thermocouple fixing plate is placed at the position corresponding to the step blind hole and is in contact with the other end of the fixing sleeve, and a lead of the exposed-end type armored thermocouple is led out through the limiting hole 45; screwing the bolt 43 through the bolt hole 46 to fixedly connect the thermocouple fixing plate 42 with the combustion chamber wall 1; the fixing sleeve 41 is pressed and fixed between the outer wall surface of the combustion chamber and the thermocouple fixing plate 42, and the spring 32 is compressed between the stopper 33 and the thermocouple fixing plate 42;

step 3) connecting the exposed-end type armored thermocouple lead with a temperature control instrument, and recording the real-time temperature of the bottom of the corresponding step blind hole as T when the combustion chamber works₁，T₂......T_n；

And 4) substituting the specific numerical value into a heat flux density formula to calculate:

q₀: density of heat flow on the inner wall surface of the combustion chamber;

λ: the thermal conductivity of the metal material used for the wall surfaces of the combustion chamber.