A device for measuring radiant and convective heat flux densities within a cavity

Abstract

The present application relates to a device for measuring radiation and convection heat flux density in a cavity, which comprises a sapphire glass window, a sealing ring, a heat absorber, a thermocouple wire, an inner sleeve, a cooling water inlet pipe, an outer sleeve and a cooling water outlet pipe. The device can realize separate measurement of total heat flux density and radiation heat flux density by changing the distance between the heat absorber and the sapphire glass window, and then calculate the convection heat flux density. The size of the heat flux density is obtained by interpolation calculation of the potential difference between the upper and lower surfaces of the heat absorber in the heat balance state. The device has the advantages of convenience, simple structure and small size.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of cavity radiation and convection heat flow density measuring device, can measure the wall surface radiation and convection heat flow density of flame cylinder, combustion chamber and other cavity structures under high temperature, high pressure environment. BACKGROUND

[0002] With the rapid development of theory and application, single temperature index is not enough to evaluate the performance of thermodynamic system comprehensively and objectively, and heat flow density, as a key physical quantity to characterize the heat transfer capacity of system, is of great significance to measure and study. At present, heat flow density measurement is widely used in electronic devices, aerospace, nuclear reactors, metrology calibration, metal smelting and other fields. When the system to be measured is in high temperature environment, the proportion of radiation heat transfer will surpass convection heat transfer. Accurate measurement of radiation heat transfer and convection heat transfer not only helps to analyze the heat transfer mechanism in thermodynamic system, but also provides reference for heat protection structure design, fuel ratio, material selection, system optimization and numerical simulation process.

[0003] Compared with convection heat flow meter, the related research of radiation heat flow meter started later. The existing radiation heat flow meter can be roughly divided into traditional type and calorimetric type. The former has been developed and can achieve a measurement accuracy better than 3%, and is widely used. The latter is limited by structure, processing precision and cost, and is currently mainly used for laboratory research. However, the above heat flow meters are limited to measuring radiation or convection heat flow density. When both kinds of heat flow densities need to be measured, the heat flow meter needs to be replaced and measured again, which is complex to operate and needs to consider the size adaptation problem between different types of heat flow meters. At present, it is urgent to develop an integrated measuring device that can measure both radiation heat flow density and convection heat flow density to solve this problem. SUMMARY

[0004] The present application is to solve the technical problems that the existing heat flow meter can only measure radiation or convection heat flow density, and the operation of different types of heat flow density meters is complex. An integrated device for measuring radiation and convection heat flow density in a cavity is provided, which does not need to replace the heat flow meter and consider the adaptation problem between different types of heat flow meters when in use.

[0005] The technical solution adopted by the present application to solve the above technical problems is:

[0006] A device for measuring radiation and convection heat flow density in a cavity, the device comprising a sapphire glass window 1, a sealing ring 2, a heat-absorbing body 3, a thermocouple wire 4, an inner sleeve 5, a cooling water inlet pipe 6, an outer sleeve 7 and a cooling water outlet pipe 8.

[0007] Sapphire glass window 3 is fixed to the inner surface of the outer sleeve 7; two sealing ring grooves are opened in the front end of the heat absorber 3 to place the sealing ring 2, and the interference fit provides compression force to the sealing ring 2; thermocouple wire 4 is fixed to the front and rear end faces of the heat absorber 3; the inner sleeve 5 is fixed to the rear end of the heat absorber 3, and moving the inner sleeve 5 drives the heat absorber 3 to move; two through holes are opened on the inner sleeve 5 to place the water inlet pipe 6 and the water outlet pipe 8.

[0008] Further, the surface of the outer sleeve 7 has external threads, which are fixed in the sleeve extending from the surface of the cavity to be measured.

[0009] Further, the sapphire glass window 3 is fixed to the inner surface of the outer sleeve 7 by gluing.

[0010] Further, the thermocouple wire 4 is fixed to the front and rear end faces of the heat absorber 3 by welding.

[0011] Further, the front end of the inner sleeve 5 is welded to the rear end of the heat absorber 3.

[0012] Further, the water inlet pipe 6 and the water outlet pipe 8 on the inner sleeve 5 are sealed by welding, and the cooling water enters from 6 and flows out from 8.

[0013] Further, the sapphire glass window 1 and the outer sleeve 7 are connected by high-temperature adhesive;

[0014] Further, the opening angle between the two sealing rings 2 is 180°, which has a sealing effect.

[0015] Further, the heat absorber 3 is welded to the inner sleeve 5, and moving the inner sleeve 5 forms an approximately vacuum area between the heat absorber 3 and the sapphire glass window 1.

[0016] Further, the outer sleeve 7 of the measuring device is made of high-temperature resistant alloy material, and the melting point of the alloy material is not lower than the failure temperature of the high-temperature adhesive.

[0017] Beneficial effects

[0018] (1) The cavity radiation and convective heat flux density measuring device of the present application can measure both radiation heat flux density and convective heat flux density. In use, it does not need to replace the heat flow meter, and it does not need to consider the size adaptation problem between different types of heat flow meters, which has the advantages of convenience and speed.

[0019] (2) The cavity radiation heat flow device of the present application measures the potential difference between the front and rear end faces of the internal heat absorber in the thermal equilibrium state to realize the measurement of heat flux density, which is beneficial to reduce the geometric size of the measuring device, and has the advantages of simple structure and small size. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The working schematic diagram of the present application in measuring the radiation heat flow of the combustion chamber wall surface;

[0021] Figure 2 The overall structural section view of the present application;

[0022] Figure 3 The three-dimensional perspective view of the present application in measuring the total heat flow density;

[0023] Figure 4 The three-dimensional perspective view of the present application in measuring the radiation heat flow density.

[0024] Reference numerals

[0025] Sapphire glass window 1, sealing ring 2, heat-absorbing body 3, thermocouple wire 4, inner sleeve 5, cooling water inlet pipe 6, outer sleeve 7, cooling water outlet pipe 8, heat flow density measuring device 9, combustion chamber wall surface 10.

[0026] Figure 1 Only the outer contour of the heat flow density measuring device 9 is drawn, and the specific structural components are referred to Figure 2 . DETAILED DESCRIPTION

[0027] Combining Figures 1-4 The application of the heat flow density measuring device of the present application in the measurement of the radiation heat flow of the combustion chamber wall surface is described.

[0028] Please refer to Figure 1 , which is the partial structure of the combustion chamber. In order to place the device of the present application, a sleeve with internal threads needs to be machined in advance on the combustion chamber wall surface 10, and the inner diameter of the sleeve is determined according to Figure 2 the size of the outer sleeve 7 in the present application. When measuring, the heat flow density measuring device 9 needs to be screwed into the sleeve in advance. The heat flow density measuring device 9 and the sleeve extending from the combustion chamber wall surface 10 are connected by threads.

[0029] Figure 2 The overall structural section view of the device of the present application, which is composed of a sapphire glass window 1, a sealing ring 2, a heat-absorbing body 3, a thermocouple wire 4, an inner sleeve 5, a cooling water inlet pipe 6, an outer sleeve 7, and a cooling water outlet pipe 8.

[0030] The sapphire glass window 3 is fixed to the inner surface of the outer sleeve 7 by means of cementation; two sealing ring grooves are formed at the front end of the heat absorber 3 to facilitate the placement of the sealing ring 2; the thermocouple wire 4 is fixed to the front and rear end surfaces of the heat absorber 3 by means of welding; the inner sleeve 5 is welded to the rear end of the heat absorber 3 at the front end, and the heat absorber 3 can be moved by moving the inner sleeve 5; in addition, through holes are formed on the inner sleeve 5 to place the water inlet pipe 6 and the water outlet pipe 8, and the sealing is ensured by welding; in order to achieve good cooling effect, the cooling water enters from 6 and flows out from 8. In order to realize the function of the present application, the opening angle of the two sealing rings 2 is 180°, so as to ensure good sealing effect, and the pressing force of the sealing ring is provided by interference fit.

[0031] The outer sleeve 7 of the device is made of high-temperature resistant alloy material, and the melting point of the alloy material is not lower than the failure temperature of the high-temperature adhesive. The specific size of the outer sleeve 7 can be considered according to the measurement environment, processing precision and cost trade-off.

[0032] Figure 3 and Figure 4 are three-dimensional views of the device of the present application when measuring total heat flux density and radiant heat flux density. For this embodiment, since only the wall surface radiant heat flux density needs to be measured, the specific measurement method is as follows:

[0033] First, the inner sleeve 5 is moved outward to make the front end surface of the heat absorber away from the rear end surface of the sapphire glass window 1, and since the measuring device is well sealed, a low pressure area similar to vacuum will be formed between the heat absorber 3 and the glass window 1 at this time. Considering that only radiant energy can propagate in vacuum, the heat flux reaching the front end surface of the heat absorber 3 at this time is only the radiant heat flux part;

[0034] Secondly, the cooling water flows into the water inlet pipe 6 and flows out of the water outlet pipe 8, which can form a good cooling effect on the rear end surface of the heat absorber 3 at this time. When the heat dissipation of the cooling water and the heat transfer of the system reach thermal equilibrium, the temperature of the front and rear end surfaces of the heat absorber 3 remains stable. The potential difference of the thermocouple wire 4 welded on the heat absorber can be measured to obtain the potential difference of the front and rear end surfaces of the heat absorber 3;

[0035] Finally, the heat flux density flowing through the heat absorber 3 at this time is obtained by interpolation with the previously calibrated potential difference-heat flux density curve, which is the wall surface radiant heat flux density of the combustion chamber to be measured.

[0036] The working principle of the device of the present application for measuring radiant and convective heat flux density is as follows:

[0037] First, move the inner sleeve 5 inward to make the front end of the heat-absorbing body 3 closely contact with the rear end of the sapphire glass window 1. At this time, the heat flux from the system is transferred through the sapphire glass window 1 and absorbed by the front end of the heat-absorbing body, and a temperature gradient is formed in the heat-absorbing body. Since the cooling water flows into the inlet pipe 6 and flows out of the outlet pipe 8, the rear end of the heat-absorbing body 3 can be well cooled. When the heat dissipation of the cooling water and the heat transfer of the gas in the system reach thermal equilibrium, the temperature of the front end and the rear end of the heat-absorbing body 3 remains stable. The potential difference between the front end and the rear end of the heat-absorbing body 3 can be measured by the thermocouple wire 4 welded on the heat-absorbing body, and the total heat flux through the heat-absorbing body 3 at this time can be obtained by interpolating the previously calibrated potential difference-heat flux density curve.

[0038] Then, move the inner sleeve 5 outward to make the front end of the heat-absorbing body 3 away from the rear end of the sapphire glass window 1. Since the measuring device is well sealed, a low-pressure area similar to a vacuum will be formed between the heat-absorbing body 3 and the glass window 1 at this time. Considering that only radiant energy can propagate in a vacuum, the heat flux reaching the front end of the heat-absorbing body 3 at this time is only the radiant heat flux. By measuring the potential difference between the front end and the rear end of the heat-absorbing body 3 in the state of thermal equilibrium, the radiant heat flux density at this time can be calculated.

[0039] Finally, the convective heat flux density can be calculated by subtracting the radiant heat flux density measured in the second step from the total heat flux density measured in the first step. When only the radiant heat flux density needs to be calculated, only the second step described above needs to be performed.

Claims

1. An apparatus for measuring radiant and convective heat flux densities within a cavity, characterized by, The device comprises a sapphire glass window (1), a sealing ring (2), a heat absorber (3), a thermocouple wire (4), an inner sleeve (5), a cooling water inlet pipe (6), an outer sleeve (7) and a cooling water outlet pipe (8). The sapphire glass window (3) is fixed to the inner surface of the outer sleeve (7); the heat absorber (3) has two sealing ring grooves at the front end to place the sealing ring (2), and the sealing ring (2) is pressed by interference fit; the thermocouple wire (4) is fixed to the front and rear end faces of the heat absorber (3); the inner sleeve (5) is fixed to the rear end of the heat absorber (3), and moving the inner sleeve (5) drives the heat absorber (3) to move; the inner sleeve (5) has two through holes to place the inlet pipe (6) and the outlet pipe (8).

2. The apparatus for measuring radiant and convective heat flux densities within a chamber according to claim 1, wherein, The outer sleeve (7) has external threads on the surface, and is fixed in the sleeve extending from the surface of the cavity to be measured.

3. The apparatus of claim 1, wherein, The sapphire glass window (3) is fixed to the inner surface of the outer sleeve (7) by gluing.

4. The apparatus of claim 1, wherein, The thermocouple wire (4) is fixed to the front and rear end faces of the heat absorber (3) by welding.

5. The apparatus of claim 1, wherein, The front end of the inner sleeve (5) and the rear end of the heat absorber (3) are welded together.

6. The apparatus of claim 1, wherein, The inlet pipe (6) and the outlet pipe (8) on the inner sleeve (5) are sealed by welding, and the cooling water flows into the inlet pipe (6) and flows out of the outlet pipe (8).

7. The apparatus of claim 1, wherein, The sapphire glass window (1) and the outer sleeve (7) are connected by high-temperature adhesive.

8. The apparatus of claim 1, wherein, The opening angle between the two sealing rings (2) is 180°, so that they have a sealing effect.

9. The apparatus of claim 1, wherein, The heat absorber (3) and the inner sleeve (5) are welded, and moving the inner sleeve (5) forms an approximately vacuum area between the heat absorber (3) and the sapphire glass window (1).

10. The apparatus for measuring radiant and convective heat flux densities within a chamber according to claim 7, wherein, The outer sleeve (7) in the measuring device is made of high-temperature resistant alloy material, and the melting point of the alloy material is not lower than the failure temperature of the high-temperature adhesive.

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