LIQUID METAL HIGH-TEMPERATURE OSCILLATING HEAT PIPE AND TESTING METHOD

Abstract

A liquid metal high-temperature oscillating heat pipe and a testing system are provided. The testing system contains the high-temperature oscillating heat pipe, a high-temperature heating furnace, a cooling liquid block, a high-pressure pump, a constant temperature liquid bath, a mass flowmeter, a filter, a cooling liquid valve, and a measurement and control connected to the aforementioned devices. The constant temperature liquid bath, the high-pressure pump, the filter, the cooling liquid valve, a liquid filling port tee-junction, the cooling liquid block, a liquid outlet tee-junction, and the mass flowmeter are connected in sequence and the mass flowmeter is connected to the constant temperature liquid bath. The front side of the cooling liquid block is provided with a channel connected to a condenser of the high-temperature oscillating heat pipe. The adiabatic section of the high-temperature oscillating heat pipe being connected to the high-temperature heating furnace.

Claims

1. A liquid metal high-temperature oscillating heat pipe, wherein the high-temperature oscillating heat pipe (21) comprises a tee junction liquid filling port (30) and a stainless steel tube array (31) integrated by a evaporator (34), an adiabatic section (33) and a condenser (32); two ports in a horizontal direction of the tee junction liquid filling port are connected to two ports of the stainless steel tube array (31);working fluid in the stainless steel tube array (31) is liquid metal which is at least one of sodium-potassium alloy, metal sodium, metal potassium, metal cesium and metal rubidium, wherein a mass fraction of potassium in the sodium-potassium alloy ranges from 25% to 75%.

2. The liquid metal high-temperature oscillating heat pipe according to claim 1, wherein a filling ratio of the high-temperature oscillating heat pipe (21) ranges from 10% to 90%.

3. The liquid metal high-temperature oscillating heat pipe according to claim 1, wherein a material of the high-temperature oscillating heat pipe (21) is at least one of stainless steel, nickel base alloy or Inconel nickel base alloy; and a wall thickness of the high-temperature oscillating heat pipe (21)is 0.5 to 3 mm, an inner diameter conforms to the following equation: $D_e<D={\left\{\frac{4p_{g}q}{u\pi h_c\left[\frac{\Phi }{\phi }{\rho }_{L,0}-{\rho }_{L,\mathrm{av}}\right]}\right\}}^{\frac{1}{2}};$ and wherein: De represents the inner diameter of the high-temperature oscillating heat pipe with a unit of m; D represents a startup critical tube diameter of the oscillating heat pipe with a unit of m; Φ represents a filling ratio with a unit of %; φ represents a percentage of the liquid to a total pipe volume after applying input power with a unit of %; ρ.sub.L,0 represents a liquid density at an operating temperature before applying input power with a unit of kg/m.sup.3; ρ.sub.L,av represents an average density of the liquid working fluid after applying input power with a unit of kg/m.sup.3; u represents a rising speed of a bubble relative to the liquid with a unit of m/s; h.sub.c represents latent heat of vaporization of the working fluid at a cold end temperature with a unit of J/kg; q represents input power with a unit of J/s; and p.sub.g represents latent heat ratio with a unit of %.

4. A testing method for the liquid metal high-temperature oscillating heat pipe according to claim 1, for measuring heat transfer performance of the high-temperature oscillating heat pipe, wherein the testing method is to measure by means of a testing system comprising a high-temperature heating furnace (20) connected to the high-temperature oscillating heat pipe (21), a cooling liquid block (22), a high-pressure pump (27), a constant temperature liquid bath (26), a mass flowmeter (25), a filter (28), a cooling liquid valve (29), and a measurement and control system in signal connection with the aforementioned devices; the constant temperature liquid bath (26) is connected with one side of the high-pressure pump (27), the other side of the high-pressure pump (27) is connected with one side of the filter (28), the other side of the filter (28) is connected with one side of the cooling liquid valve (29), the other side of the cooling liquid valve (29) is connected with one side of the cooling liquid block (22) through a set liquid filling port tee junction (23), the other side of the cooling liquid block (22) is connected with one side of the mass flowmeter (25) through a set liquid outlet tee-junction (24), the other side of the mass flowmeter (25) is connected with the constant temperature liquid bath (26), and all the aforementioned devices form a circular connection loop; the cooling liquid discharged from the constant temperature liquid bath (26) flows counterclockwise and finally back into the constant temperature liquid bath (26), and the cooling liquid achieves circular flow through the high-pressure pump (27); an outer front side of the cooling liquid block (22) is provided with channels matched with an outer diameter of the high-temperature oscillating heat pipe (21), and the channels are connected with the condenser (32) of the high-temperature oscillating heat pipe (21); the adiabatic section (33) of the high-temperature oscillating heat pipe (21) is connected with the high-temperature heating furnace (20), and the evaporator (34) of the high-temperature oscillating heat pipe (21) is arranged in the high-temperature heating furnace (20); and the testing method is as follows: starting the high-pressure pump (27) to cycle the cooling liquid, adjusting cooling liquid flow by adjusting the opening of the cooling liquid valve (29) and reading mass flowmeter (25) data, filtering the cooling liquid by the filter (28) to remove impurities; starting the constant temperature liquid bath (26) to adjust the cooling liquid temperature to provide stable cooling environments for the high-temperature oscillating heat pipe (21); adjusting the high-temperature heating furnace (20) to a low-power heating state for warming-up, during the warming-up process, debugging thermocouples, RTD temperature sensor, and the measurement and control system to ensure the data accuracy; controlling and adjusting heating temperature, heating speed, input power and inclination angle of the high-temperature oscillating heat pipe (21) by adjusting parameters setting of the high-temperature heating furnace (20);setting multi-stage heating process parameters by adjusting a heating program of the high-temperature heating furnace (20), adjusting the heating speed and target temperature of the furnace and keeping warm, and ensuring constant heating input of the high-temperature oscillating heat pipe (21) after stable operation and recording testing data; closing the high-temperature heating furnace (20), turning down the temperature of the constant temperature liquid bath (26) into a cooling process, and the test being ended once the cooling process ended.

5. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 4, wherein a temperature of the cooling liquid discharged from the constant temperature liquid bath (26) is 5° C. to 300° C.

6. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 4, wherein a periphery of the high-temperature oscillating heat pipe (21) and the cooling liquid block (22) is overall wrapped with an thermal insulation layer whose material is a high-temperature resistance thermal insulation material, and at least four thermocouples are arranged inside and outside the thermal insulation layer respectively to measure the temperature of the inner and outer walls of the thermal insulation layer to obtain heat leakage.

7. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 4, wherein the liquid filling port tee-junction (23) and the liquid outlet tee-junction (24) are both connected with RTD temperature sensors inserting into a central position of cooling liquid pipeline.

8. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 4, wherein the high-temperature furnace (20) is a structure of seal box, the top of which is provided with an upper cover of furnace chamber having a stepped hole (35), and a through hole in the middle of the stepped hole (35) is connected with the high-temperature oscillating heat pipe (21); a side gap formed between the stepped hole (35) and the high-temperature oscillating heat pipe (21) perpendicular to the upper cover of furnace chamber is sealed by filling high-temperature resistance thermal insulation material; a flange plate is welded at central positions of both sides of body of the high-temperature heating furnace (20), and an angle adjusting device composed of gear transmission mechanisms is installed on the flange plate to adjust the overall inclination angle of the high-temperature heating furnace (20), wherein a inclination angle ranges from 0 to 180°.

9. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 4, wherein the evaporator (34), adiabatic section (33) and condenser (32) of the high-temperature oscillating heat pipe (21) are respectively provided with at least one thermocouple, and a transverse tube at the upper part of the condenser (32) of the high-temperature oscillating heat pipe (21) is provided with at least one thermocouple, for obtaining the temperature change of the high-temperature oscillating heat pipe, analyzing the heat transfer characteristics and calculating the thermal resistance of that.

10. The testing method for the liquid metal high-temperature oscillating heat pipe according to claim 9, wherein the thermal resistance of the high-temperature oscillating heat pipe conforms to the following equation: $R=\frac{{\stackrel{\_}{T}}_e-{\stackrel{\_}{T}}_c}{Q_e};$ wherein R represents the thermal resistance of the high-temperature oscillating heat pipe with a unit of K/W; T.sub.e represents an average temperature of the evaporator during stable operation of the high-temperature oscillating heat pipe with a unit of ° C.; T.sub.c represents an average temperature of the condenser during stable operation of the high-temperature oscillating heat pipe with a unit of ° C.; Q.sub.e represents the input power of the high-temperature oscillating heat pipe with a unit of W; the input power of the high-temperature oscillating heat pipe conforms to the following equation:
Q.sub.e=C.sub.pq.sub.mΔT+q;
T=T.sub.1−T.sub.2; wherein Q.sub.e represents the input power of the high-temperature oscillating heat pipe with a unit of W; q represents the heat leakage with a unit of W; q.sub.m represents a mass flow of cooling water measured by the mass flowmeter with a unit of kg/s; T.sub.1 represents the temperature measured by the RTD temperature sensor at the liquid outlet tee-junction with a unit of ° C.; T.sub.2 represents the temperature measured by the RTD temperature sensor at the liquid filling port tee junction with a unit of ° C.; T represents a temperature difference at the liquid filling port and outlet with a unit of ° C.; C.sub.p represents a specific heat capacity of the water at the operating temperature with a unit of J/(kg.Math.K); and (T.sub.1+T.sub.2)/2 is the operating temperature with a unit of ° C.; the heat leakage conforms to the following equation: $q=\frac{kA\Delta T_l}{L};$ and wherein q represents the heat leakage with a unit of W; k is represents a thermal conductivity of the thermal insulation layer material with a unit of W/(m.Math.k); A represents an area of the thermal insulation layer with a unit of m.sup.2; T.sub.l represents a temperature difference between inside and outside the thermal insulation layer with a unit of ° C.; and L represents a thickness of the thermal insulation layer with a unit of m.

Description

DETAILED DESCRIPTION OF DRAWINGS

[0032] To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show some embodiments of the present disclosure, and a person of ordinary skill in the art may still derive other accompanying drawings from these accompanying drawings without creative efforts.

[0033] FIG. 1 is a schematic diagram of the high-temperature oscillating heat pipe of the present disclosure.

[0034] FIG. 2 is a schematic diagram of the testing system of the present disclosure.

[0035] FIG. 3 is a schematic diagram of the high-temperature oscillating heat pipe and the cooling liquid block of the present disclosure.

[0036] FIG. 4 is a schematic diagram of the upper cover of furnace chamber of the high-temperature heating furnace of the present disclosure.

[0037] FIG. 5 is a distribution diagram of the installation positions of the thermocouples on the high-temperature oscillating heat pipe of the present disclosure.

[0038] FIG. 6 is temperature curves when the high-temperature oscillating heat pipe is started and the furnace temperature of the high-heating furnace is 850° C. of the present disclosure.

[0039] FIG. 7 is temperature curves when the furnace temperature of the high-temperature heating furnace is 900° C., 950° C. and 1000° C. respectively of the present disclosure.

[0040] FIG. 8 is temperature curves when the furnace temperature of the high-temperature heating furnace is 1050° C. and 1100° C. respectively of the present disclosure.

[0041] FIG. 9 is temperature curves when the furnace temperature of the high-temperature heating furnace is 1150° C. and 1200° C. respectively of the present disclosure.

[0042] FIG. 10 is a curve of the temperature difference between the cold and hot ends of the high-temperature oscillating heat pipe changing with the power.

[0043] FIG. 11 is a curve of the heat resistance of the high-temperature oscillating heat pipe changing with the input power.

[0044] 1. thermocouple No. 1; 2. thermocouple No. 2; 3. thermocouple No. 3; 4. thermocouple No. 4; 5. thermocouple No. 5; 6. thermocouple No. 6; 7. thermocouple No. 7; 8. thermocouple No. 8; 9. thermocouple No. 9; 10. thermocouple No. 10; 11. thermocouple No. 11; 12. thermocouple No. 12; 13. thermocouple No. 13; 14. thermocouple No. 14; 15. thermocouple No. 15; 16. thermocouple No. 16; 17. thermocouple No. 17; 18. thermocouple No. 18; 19. thermocouple No. 19; 20. high-temperature heating furnace; 21. high-temperature oscillating heat pipe; 22. cooling liquid block; 23. liquid inlet tee-junction; 24. liquid outlet tee-junction; 25. mass flowmeter; 26. constant temperature liquid bath; 27. high-pressure pump; 28. filter; 29. cooling liquid valve; 30. tee-junction liquid filling port; 31. stainless steel array; 32. condenser; 33. adiabatic section; 34. evaporator; 35. stepped hole.

DETAILED DESCRIPTION OF PREFERRED EMODIMENTS

[0045] It should be noted that, in the case of no conflicts, the embodiments and the features in the embodiments of the present disclosure can be combined mutually. The present disclosure will be described in detail below with reference to the accompanying drawings and the embodiments.

[0046] To make the objectives, technical solutions, and advantages of the present disclosure clearer, the following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely some rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation on the present disclosure and its application or use. Based on the embodiments of the present disclosure, all the other embodiments obtained by those of ordinary skill in the art without inventive effort are within the protection scope of the present disclosure.

Embodiment 1

[0047] As shown in FIG. 1, the present disclosure discloses a liquid metal high-temperature oscillating heat pipe, including a tee-junction liquid filling port 30 and a stainless steel tube array 31 integrated by a evaporator 34, an adiabatic section 33 and a condenser 32. The two ports in a horizontal direction of the tee-junction liquid filling port are weld connected to the two ports of the stainless steel tube array 31. The stainless steel tube array 31 is filled with liquid metal, which has a high latent heat of vaporization at high temperature environments, as working fluid. The liquid metal is sodium-potassium alloy, and the mass fraction of potassium in the sodium-potassium alloy ranges from 25% to 75%. The sodium-potassium alloy has the characteristic of being liquid at room temperature, which can remove the melting process in the heating process, make the start-up of the high-temperature oscillating heat pipe 21 more simple and improve the start-up performance of the high-temperature oscillating heat pipe 21 and reduce the difficulty of filling process.

[0048] In the embodiment, the filling ratio of the high-temperature oscillating heat pipe 21 ranges from 10% to 90%.

[0049] In the embodiment, the shell tube of the high-temperature oscillating heat pipe 21 is stainless steel 310s, having the characteristics of high-temperature resistance and corrosion resistance and having good compatibility with the working fluid at high temperature environments. The stainless steel 310s has stable performance in the working temperature zone of the high-temperature oscillating heat pipe 21, which can ensure the long time stable operation of the high-temperature oscillating heat pipe 21 in the high-temperature environments. In the embodiment, the wall thickness of the high-temperature oscillating heat pipe 21 ranges from 0.5 to 3 mm, and an inner diameter conforms to the following equation:

[00004]$D_e<D={\left\{\frac{4p_{g}q}{u\pi h_c\left[\frac{\Phi }{\phi }{\rho }_{L,0}-{\rho }_{L,\mathrm{av}}\right]}\right\}}^{\frac{1}{2}};$

[0050] wherein, De represents the inner diameter of the high-temperature oscillating heat pipe, with the unit of m; D represents the start-up critical tube diameter of the oscillating heat pipe, with the unit of m; Φ represents the filling ratio, with the unit of %; φ represents the percentage of the liquid to the total pipe volume after applying input power, with the unit of %; ρ.sub.L,0 represents the liquid density at an operating temperature before applying input power, with the unit of kg/m.sup.3; ρ.sub.L,av represents the average density of the liquid working fluid after adding heat, with the unit of kg/m.sup.3; u represents the rising speed of a bubble relative to the liquid, with the unit of m/s; h.sub.c represents latent heat of vaporization of the working fluid at a cold end temperature, with the unit of J/kg; q represents input power, with the unit of J/s; and p.sub.g represents the latent heat ratio, with the unit of %.

Embodiment 2

[0051] Based on embodiment 1, as shown in FIGS. 2 to 4, the present disclosure also provides a testing method for the liquid metal high-temperature oscillating heat pipe, for measuring heat transfer performance of the liquid metal high-temperature oscillating heat pipe. The testing method is to measure by means of a testing system. The said testing system includes a high-temperature heating furnace 20 connected to the high-temperature oscillating heat pipe 21, a cooling liquid block 22, a high-pressure pump 27, a constant temperature liquid bath 26, a mass flowmeter 25, a filler 28, a cooling liquid valve 29 and a measurement and control system in signal connection with the aforementioned devices.

[0052] The right side of the constant temperature liquid bath 26 is connected with the left side of the high-pressure pump 27 through a pipeline. The water outlet of the high-pressure pump 27 is connected with the left side of the filter 28 through a pipeline. The right side of the filter 28 is connected with the left side of the cooling liquid valve 29 through a pipeline. The right side of the cooling liquid valve 29 is connected with the left side of the cooling liquid block 22 through a pipeline and the liquid inlet tee junction 23. The right side of the cooling liquid block 22 is connected with the left side of the mass flowmeter 25 through the liquid outlet tee-junction 24 and a pipeline. The right side of the mass flowmeter 25 is connected with the constant temperature liquid bath 26. All the aforementioned devices form a circular connection loop. The cooling liquid discharged from the constant temperature liquid bath 26 flows counterclockwise and finally back to the constant temperature liquid bath 26, and the cooling liquid achieves circular flow through the high-pressure pump 27. The outer front side of the cooling liquid block 22 is provided with channels matched with the outer diameter size of the high-temperature oscillating heat pipe 21, and the condenser 32 of the high-temperature oscillating heat pipe 21 is embedded in the channels. The adiabatic section 33 at the middle of the high-temperature oscillating heat pipe 21 is connected with the high-temperature heating furnace 20, and the evaporator 34 of the high-temperature oscillating heat pipe 21 inserts into the high-temperature heating furnace 20. By adjusting the height of the cooling liquid block 22 and the length of the high-temperature oscillating heat pipe 21 inserting into the high-temperature heating furnace 20, the installation lengths of the evaporator 34, adiabatic section 33 and condenser 32 are adjusted. Multi-layer channels are arranged inside the cooling liquid block 22, and the forced convection flow of the cooling liquid in the channels transfers the heat of the condenser 32 of the high-temperature oscillating heat pipe 21 to the cooling liquid, thereby cools the high-temperature oscillating heat pipe 21. The filter 28 is used to filter the impurities in the cooling liquid and protect the mass flowmeter 25. The mass flowmeter 25 is used for measuring the cooling liquid flow, and the mass flowmeter is a high-precision mass flowmeter. The cooling liquid valve 29 adjusts the cooling liquid flow within the measuring range of the mass flowmeter. The constant temperature liquid bath 26 is used to maintain the constant temperature of the discharged cooling liquid. The temperature and flow of the cooling liquid can be controlled by setting the parameters of the constant liquid bath 26, the high-pressure pump 27 and the cooling liquid valve 29.

[0053] In the embodiment, a temperature range of the cooling liquid discharged from the constant temperature liquid bath 26 ranges from 5° C. to 300° C.

[0054] In the embodiment, the periphery of the high-temperature oscillating heat pipe 21 and the cooling liquid block 22 is wrapped with an thermal insulation layer to ensure that the heat of the condenser 32 of the high-temperature oscillating heat pipe 21 is transferred to the cooling liquid and the heat transferred by the high-temperature oscillating heat pipe 21 can be accurately measured; the material of the thermal insulation layer is the high-temperature resistance thermal insulation material. Four thermocouples are arranged inside and outside the thermal insulation layer respectively. The thermocouple is K-type thermocouple with high-temperature resistance ceramic Nextel sheath. The average temperature of the inside and outside the thermal insulation layer is measured through the readings of the thermocouples inside and outside the thermal insulation layer to calculate heat leakage.

[0055] In the embodiment, the liquid filling port tee-junction 23 and the liquid outlet tee junction 24 are both connected with RTD temperature sensors, with the model of PT 100, inserting into the central position of cooling liquid pipeline.

[0056] In the embodiment, the high-temperature furnace 20 is used to heat the high-temperature oscillating heat pipe 21 and is a sealed box structure. The top of the high-temperature furnace is provided with an upper cover of furnace chamber having a stepped hole 35. The high-temperature oscillating heat pipe 21 inserts into the high-temperature heating furnace 20 through the middle through hole of the stepped hole 35, and the adiabatic section 33 is wrapped with high-temperature resistance thermal insulation material and is vertically installed in the middle through hole. The upper cover of furnace chamber is arranged on the top of the high-temperature heat furnace 21, and heating rods are installed on the front, rear, left and right sides of the high-temperature heating furnace, to heat the high-temperature oscillating heat pipe 21 evenly. There is a side gap formed between the stepped hole 35 and the vertically installed high-temperature oscillating heat pipe 21, which is sealed by filling high-temperature resistance thermal insulation material through the stepped hole 35, thus the structure can be more stable and avoid falling of the thermal insulation material caused by the vertical hole. A flange plate is welded at the central position of both sides of the body of the high-temperature heating furnace 20. An angle adjusting device composed of gear transmission mechanisms is installed on the flange plate to adjust the overall inclination angle of the high-temperature heating furnace 20, thereby adjust the inclination angle of the high-temperature oscillating heat pipe 21, wherein the inclination angle ranges from 0 to 180°. The heating temperature, the heating speed, the input power and the inclination angle of the high-temperature oscillating heat pipe 21 can be controlled and adjusted by adjusting the parameter of the high-temperature heating furnace 20. By adjusting the heating program of the high-temperature heating furnace 20, the multi-stage heating process parameters can be set, the heating speed and the target furnace temperature can be adjusted and keep the temperature, and the input power is kept constant wherein the high-temperature oscillating heat pipe 21 works stably.

[0057] In the embodiment, the evaporator 34, the adiabatic section 33 and the condenser 32 of the high-temperature oscillating heat pipe 21 are respectively provided with at least one thermocouple, and a transverse tube at the upper part of the condenser 32 of the high-temperature oscillating heat pipe 21 is provided with at least one thermocouple. The thermocouples provided on the high-temperature oscillating heat pipe 21 are K-type thermocouple with high-temperature resistance ceramic Nextel sheath, and are used to detect the temperature changes of the evaporator 34 and the condensing section 32 of the high-temperature oscillating heat pipe 21, to get the temperature curves and the thermal resistance of the high-temperature oscillating heat pipe, thereby study the heat transfer performance of the high-temperature oscillating heat pipe 21. The temperatures of the evaporator 34 and the condenser 32 can be measured by the thermocouple readings of the evaporator 34 and the condenser 32, and the average temperatures of the evaporator 34 and the condenser 32 can be calculated by averaging the readings of a plurality of thermocouples.

Embodiment 3

[0058] In the embodiment, a high-temperature oscillating heat pipe 21 with an inner diameter of 6 mm, a wall thickness of 1 mm and a pipe material of stainless steel 310s is selected for the test. The volume filling ratio of the working fluid in the high-temperature oscillating heat pipe 21 is 45%, and the working fluid is sodium-potassium alloy in which the mass fraction of potassium is 75%. In the embodiment, a distribution diagram of the installation position of the thermocouples on the high-temperature oscillating heat pipe 21 is as shown in FIG. 5, and nineteen thermocouples are arranged on the high-temperature oscillating heat pipe 21. Thermocouple No. 19 is arranged on the transverse pipeline at the tee junction liquid filling port 30 of the stainless steel tube array 31. The evaporator 34, the adiabatic section 33 and the condenser 32 of the two adjacent tubes of the first elbow on the left are respectively provided with thermocouple No. 1 and thermocouple No. 2, thermocouple No. 7 and thermocouple No. 8, and thermocouple No. 13 and thermocouple No. 14. The evaporator 34, the adiabatic section 33 and the condenser 32 of the two adjacent tubes of the first elbow on the right are respectively provided with thermocouple No. 5 and thermocouple No. 6, thermocouple No. 11 and thermocouple No. 12, and thermocouple No. 17 and thermocouple No. 18. For the elbows in the middle, one tube on each of the two selected elbows is provided with thermocouples, and the evaporator 34, the adiabatic section 33 and the condenser 32 of the two tubes are respectively provided with thermocouple No. 3 and thermocouple No. 4, thermocouple No. 9 and thermocouple No. 10, and thermocouple No. 15 and thermocouple No. 16. The above thermocouples are all K-type thermocouples with high-temperature resistant ceramic Nextel sheath.

[0059] The working process is as follows:

[0060] 1. First, the adiabatic section 33 of the high-temperature oscillating heat pipe 21 is fixed in the stepped hole 35 of the upper cover of furnace chamber of the high-temperature heating furnace 20 and the length of the evaporator 34 of the high-temperature oscillating heat pipe 21 in the high-temperature furnace 20 is adjusted, then the side gap formed between the stepped hole 35 and the installed high-temperature oscillating heat pipe 21 is sealed by filling high-temperature resistance thermal insulation material. The high-temperature heating furnace 20 is adjusted to a certain inclination angle after the adiabatic section 33 of the high-temperature oscillating heat pipe 21 is fixed. The inclination angle in the embodiment is 90°. Then, the high-temperature oscillating heat pipe 21 and the cooling liquid block 22 are integrally wrapped in multiple layers with high-temperature resistance thermal insulation material, and all devices in the testing system are connected.

[0061] 2. The high-pressure pump 27 is started to circulate the cooling liquid. The cooling liquid flow is adjusted by adjusting the opening of the cooling liquid valve 29 and reading the date of mass flowmeter 25, to make the cooling liquid flow reach the preset value and stabilize for 10 minutes. The cooling liquid is filtered through the filter 28 to remove impurities.

[0062] 3. The constant temperature liquid bath 26 is started to adjust the cooling liquid temperature to make the cooling liquid temperature reach the preset temperature of 58° C., providing a stable cooling environments for the high-temperature oscillating heat pipe.

[0063] 4. The high-temperature heating furnace 20 is adjusted to the low-power heating state for warming-up. In the low-temperature state, the excessive heating speed of the high-temperature heating furnace 20 is easy to damage the globar. During warming-up, the thermocouples, the RTD temperature sensors and the measurement and control system are debugged to ensure the accuracy of data. When the warming-up of high-temperature heating furnace 20 is completed, proceed to the next step.

[0064] 5. The input power of the high-temperature furnace 20 is increased to adjust the target temperature of the high-temperature heating furnace 20 to 850° C. for heating up. After the temperature in the high-temperature heating furnace 20 reaching 850° C., the temperature is maintained for 20 minutes; during this process, the input power of the high-temperature oscillating heat pipe 21 remains constant. After the data is recorded, proceed to the next step.

[0065] 6. The target temperature of the high-temperature heating furnace 20 is adjusted to 900° C. for heating up. After the temperature in the high-temperature heating furnace 20 reaching 900° C., the temperature is maintained for 20 minutes; during this process, the input power of the high-temperature oscillating heat pipe 21 remains constant. After the data is recorded, proceed to the next step. Repeat the above heating process to heat up the temperature in the high-temperature heating furnace 20 to 950° C., 1000° C., 1050° C. and 1100° C. respectively. The heat transfer performance of the high-temperature oscillating heat pipe 21 under different input power is tested. Record the testing data and proceed to the next step.

[0066] 7. The high-temperature heating furnace 20 is closed. The temperature of the constant temperature liquid bath 26 is turned down to enter the cooling process. When the cooling process is over, the test is over.

[0067] 8. The input power of the high-temperature oscillating heat pipe 21 is calculated. The input power of the high-temperature oscillating heat pipe conforms to the following equation:

Q.sub.e=C.sub.pq.sub.mΔT+q;

ΔT=T.sub.1−T.sub.2;

[0068] wherein, Q.sub.e represents the input power of the high-temperature oscillating heat pipe, with the unit of W; q represents the heat leakage, with the unit of W; q.sub.m represents a mass flow of cooling water measured by the mass flowmeter, with the unit of kg/s; T.sub.1 represents the measured temperature of the RTD temperature sensor at the liquid outlet tee-junction, with the unit of ° C.; T.sub.2 represents the measured temperature of the RTD temperature sensor at the liquid filling port tee-junction, with the unit of ° C.; T represents the temperature difference at the liquid filling port and outlet, with the unit of ° C.; C.sub.p represents the specific heat capacity of the water at the operating temperature, with the unit of J/(kg.Math.K); and (T.sub.1+T.sub.2)/2 represents the operating temperature.

[0069] 9. The heat leakage is calculated.

[0070] The heat leakage is obtained by measuring the average temperatures inside and outside the thermal insulation layer by the readings of the thermocouples arranged inside and outside the thermal insulation layer, conforming to the following equation:

[00005]$q=\frac{kA\Delta T_l}{L};$

[0071] wherein, q represents the heat leakage, with the unit of W; k is represents the thermal conductivity of the thermal insulation layer material, with the unit of W/(m.Math.k); A represents the area of the thermal insulation layer, with the unit of m.sup.2; T.sub.l represents the temperature difference between inside and outside the thermal insulation layer, with the unit of ° C.; and L represents the thickness of the thermal insulation layer, with the unit of m.

[0072] 10. The heating resistance of the oscillating heat pipe is calculated, conforming to the following formula:

[00006]$R=\frac{{\stackrel{\_}{T}}_e-{\stackrel{\_}{T}}_c}{Q_e};$

[0073] wherein, R represents the thermal resistance of the high-temperature oscillating heat pipe, with the unit of K/W; T.sub.e represents the average temperature of the evaporator during stable operation of the high-temperature oscillating heat pipe, with the unit of ° C.; T.sub.c represents an average temperature of the condenser during stable operation of the high-temperature oscillating heat pipe, with the unit of ° C.; and Q.sub.e represents the input power of the high-temperature oscillating heat pipe, with the unit of W.

[0074] FIG. 6 is the temperature curves when the high-temperature oscillating heat pipe 21 is started and the furnace temperature of the high-temperature heating furnace 20 is 850° C. As can be seen from FIG. 6, the high-temperature heating furnace 20 finishes warming-up at 2700 seconds and starts the heating stage, and the temperature rising speed is accelerated. When the temperature of the evaporator 34 reaches 790° C., the temperatures of the evaporator 34 and the adiabatic section 33 decrease sharply and the temperature of the condenser 32 rises sharply, and the high-temperature oscillating heat pipe 21 is started. At this time, the temperature of the high-temperature heating furnace 20 has not reached the preset temperature of 850° C., and the input power of the heating furnace is in the rising stage. At this time, the heating input of the high-temperature oscillating heat pipe 21 cannot maintain a stable oscillating movement. At 3300 seconds, some elbows of the high-temperature oscillating heat pipe 21 stop working, and the temperatures of thermocouple No. 1, thermocouple No. 2, thermocouple No. 3 and thermocouple No. 4 rise and temperatures of thermocouple No. 13, thermocouple No. 14, thermocouple No. 15 and thermocouple No. 16 drop, indicating that the pulsation of the tube appears weakened. The temperatures of thermocouple No. 5 and thermocouple No. 6 are stable, indicating that the corresponding cold end temperature has no sharp change and the two tubes work normally. With the continuous temperature rise of the heating furnace, the high-temperature oscillating heat pipe 21 is started again and reaches the preset temperature at 3900 seconds, and the high-temperature oscillating heat pipe 21 begins to work stably.

[0075] FIG. 7 is the temperature curves when the furnace temperature of the high-temperature heating furnace 20 is 900° C., 950° C. and 1000° C. respectively. As can be seen from FIG. 7, when the furnace temperature of high-temperature heating furnace 20 is 900° C. and 950° C., the high-temperature oscillating heat pipe 21 works stably, and the stratification of the adiabatic section 33 is small. At this time, the temperature of the evaporator 34 increases with the increase of the furnace temperature while the temperature of the condenser 32 increases, the temperature difference between the cold and hot ends decreases, the heating input increases and the thermal resistance decreases. When the stratification of the condenser 32 of the first elbow on the left weakens, the condenser 32 of the first elbow on the right still has stratification. The temperature difference between thermocouple No. 17 and thermocouple No. 18 is large, because there will be a single elbow heat transfer when the high-temperature oscillating heat pipe 21 works stably; and the temperature of thermocouple No. 19 is stable. When the furnace temperature of the high-temperature heating furnace 20 is 1000° C., the temperature of the evaporator 34 fluctuates and the adiabatic section 33 is stratified; the temperatures of thermocouple No. 13 and thermocouple No. 14 of the first elbow on the left fluctuate violently and show the opposite change trend; the temperature of thermocouple No. 19 rises rapidly, at this time, the pulsation is violent and trends to circulate.

[0076] FIG. 8 is the temperature curves when the temperature of the high-temperature heating furnace is 1050° C. and 1100° C. respectively. As can be seen from FIG. 8, when the temperature of high temperature furnace 20 is 1050° C., the temperatures of thermocouple No. 7 and thermocouple No. 11 drop, and the temperatures of thermocouple No. 8 and thermocouple No. 12 rise rapidly, and the temperatures of thermocouple No. 9 and thermocouple No. 10 continue to maintain high temperature, and the temperatures of thermocouple No. 8 and thermocouple No. 12 are greater than those of thermocouple No. 7 and thermocouple No. 11, at the same time, the temperature of thermocouple No. 19 rises fast; the adiabatic section 33 stratified obviously, and the temperature of the corresponding condenser 32 has the same change trend, forming a good stable circulation state, thereby enhancing the heat transfer effect. When the temperature of the high-temperature furnace 20 is 1100° C., the temperature of each thermocouple appears fluctuation and the temperature rises compared with that of the temperature of 1050° C., and the circulation state also fluctuates.

[0077] FIG. 9 is the temperature curves when the temperature of the high-temperature heating furnace is 1150° C. and 1200° C. respectively. As can be seen from FIG. 9, when the temperature of the high-temperature heating furnace 20 is 1150° C., the temperatures of thermocouple No. 7 and thermocouple No. 11 increase rapidly, and the temperature of thermocouple No. 18 decreases rapidly, and the temperatures of thermocouple No. 13 and thermocouple No. 14 increase, and the temperature of thermocouple No. 19 decreases rapidly; the temperature fluctuation of the evaporator 34 disappears, and then the working state tends to be stable. At this time, the one-way cycle disappears and the pulsation state is restored again. When the temperature of the high-temperature heating furnace 20 is 1200° C., the temperatures of thermocouple No. 7 and thermocouple No. 11 fluctuate violently, and the temperature of thermocouple No. 18 rises; the high-temperature oscillating heat pipe 21 works unstable and the performance deteriorates.

[0078] FIG. 10 is a curve of temperature difference between the cold and hot ends of the high-temperature oscillating heat pipe changing with the power. As can be seen from FIG. 10, the temperature difference between the cold and hot ends of the high-temperature oscillating heat pipe 21 first decreases then increases with the increase of the input power. The temperature difference is the minimum when the input power of the high-temperature oscillating heat pipe 21 is 3306.4 W (the temperature is 1050° C.).

[0079] FIG. 11 is a curve of the thermal resistance of the high-temperature oscillating heat pipe 21 changing with the power. As can be seen from FIG. 11, the thermal resistance of the high-temperature oscillating heat pipe 21 first decreases then increases with the increase of the input power. The temperature difference is the minimum when the input power of the high-temperature oscillating heat pipe 21 is 3306.4 W (the temperature is 1050° C.).

[0080] As can be seen from FIGS. 6 to 9, the high-temperature oscillating heat pipe 21 in the embodiment has the ability to work at high temperature environments exceeding 500° C. It can be seen from FIGS. 10 and 11 that the smaller the thermal resistance of the high-temperature oscillating heat pipe 21, the better the performance.

[0081] As can be seen from FIGS. 6 to 11, the testing data of the high-temperature oscillating heat pipe 21 under different working conditions can be accurately measured by using the whole set of the testing system, thereby the testing system in the embodiment meets the testing requirements for the high-temperature oscillating heat pipe 21 under the high-temperature environments.

[0082] At last, it should be stated that the above various embodiments are only used to illustrate the technical solutions of the present invention without limitation; and despite reference to the aforementioned embodiments to make a detailed description of the present invention, those of ordinary skilled in the art should understand: the described technical solutions in above various embodiments may be modified or the part of or all technical features may be equivalently substituted; while these modifications or substitutions do not make the essence of their corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present disclosure.