CN201212878Y - A device for measuring thermal conductivity - Google Patents

Abstract

The utility model discloses a thermal conductivity measuring instrument. The technical solution includes a casing, a refrigerant inlet (1) and a refrigerant outlet (2) arranged on the casing, the casing is a hollow cylindrical cooling sleeve (3) with both ends sealed, and the outer wall of the cylinder is connected to the refrigerant inlet (1 ) communicates with the refrigerant outlet (2), and the refrigerant circulates and cools between the interlayers of the cooling jacket (3); a copper sleeve (5) and a heating rod (6) are coaxially arranged in the cooling jacket (3), The heating rod (6) is connected with a precision heating source (17); the wall temperature thermocouple (10) is provided on the cooling jacket (3) and the copper sleeve (5), and the wall temperature thermocouple (10 ) is connected with the thermocouple data collector (16). The device can measure the thermal conductivity of solid-liquid phase change medium, granular material and viscous medium; the thermal conductivity of solid-liquid phase change medium in solid phase and liquid phase can be continuously measured; each component is detachable, safe and easy to operate. maintain.

Description

A device for measuring thermal conductivity

technical field

The utility model relates to a thermal conductivity measuring device, which is used for measuring the thermal conductivity of solid-liquid phase-change media, granular materials and viscous media; the thermal conductivity of solid-liquid phase-change media in solid phase and liquid phase can be continuously measured.

Background technique

Phase Change Material (Phase Change Material) is widely used in energy storage systems. Thermal conductivity is the most important thermophysical property of PCM. When researching and utilizing PCM, its thermophysical property data must be obtained first. The thermal conductivity is generally measured by an experimental setup.

Usually, the steady-state plate method based on one-dimensional steady-state heat conduction theory to measure the thermal conductivity of PCM has the following disadvantages and cannot be used: ① PCM is in the change of solid-liquid two-phase, the heating process is carried out, the liquid phase is easy to leak, and it is not easy to prepare test instruments The required molding conditions, etc., the error of the experimental results is very large, especially not conducive to the measurement of liquid, the comprehensive comparison test of solid-liquid two phases cannot be carried out in the same instrument; ② To obtain a reliable average temperature of the sample surface, it is necessary to use a considerable amount of The thermocouple; ③ The steady state method takes a long time to prepare the temperature difference stabilization conditions before the test record, and the experimental test process also takes a long time.

In the prior art, there are the following defects in measuring the thermal conductivity of PCM based on the unsteady infinite plate method: ① PCM can be quickly tested in the solid phase, but the liquid phase cannot be measured, and the solid-liquid two-phase test cannot be carried out in the same instrument ; ② The theoretical model of heat conduction in the unsteady state method is complex; ③ It is difficult to meet the requirements of the test piece.

However, with the requirements of technological progress, there must be suitable and convenient testing instruments to meet production needs.

Contents of the invention

The purpose of the utility model is to provide a thermal conductivity measuring device, which can conveniently test the thermal conductivity of solid phase and liquid phase of phase change materials, and can also measure the thermal conductivity of viscous liquid and granular materials.

The technical solution adopted in order to achieve the purpose of the utility model includes a casing, a refrigerant inlet 1 and a refrigerant outlet 2 arranged on the casing, and it is characterized in that the casing is a cooling jacket 3, and the cooling jacket 3 has two ends Sealed hollow cylinder, the outer wall of the cylinder communicates with the refrigerant inlet 1 and the refrigerant outlet 2, and the refrigerant circulates and cools between the interlayers of the cooling jacket 3; a copper sleeve 5 is coaxially arranged in the cooling jacket 3, A heating rod 6 is coaxially arranged in the copper casing 5, and the heating rod 6 is connected to a precision heating source 17 through a heating rod connection 9; Couple 10, wall temperature thermocouple 10 is connected with thermocouple data collector 16.

In the above-mentioned thermal conductivity measuring device, the two ends of the cooling jacket 3 are respectively sealed by the casing end cap 7 and the casing end cap 8 with external threads, and one end of the inner wall of the cooling jacket 3 is processed with an internal thread and an external thread. The threaded casing end cap 7 is matched, and the other end of the cooling jacket 3 is glued to the casing end cap 8 .

In the above-mentioned thermal conductivity measuring device, a hole is drilled in the center of the sleeve end cap 7 and the sleeve end cap 8 with external threads, the outer diameter of the copper sleeve 5 matches the inner diameter of the hole, and the copper sleeve 5 passes through the outer diameter of the belt. The threaded casing end cap 7 and the center hole of the casing end cap 8 are installed symmetrically.

In the above-mentioned thermal conductivity measuring device, the outer diameter of the heating rod 6 is installed axially symmetrically with the inner diameter of the copper sleeve 5, and the gap between them is filled with heat-conducting silicone grease; the two ends of the copper sleeve 5 and the heating rod The spaces surrounded by the two ends of 6 are respectively filled with heat-insulating cotton.

In the above-mentioned thermal conductivity measuring device, there are grooves on the inside of the cooling jacket 3, and at least 3 pairs of wall temperature thermocouples are embedded; grooves are made on the outer wall of the copper sleeve 5, and at least 3 pairs of wall temperature thermocouples are embedded. .

In the above thermal conductivity measuring device, the refrigerant inlet 1 is connected to the outlet of a constant temperature tank 15 , and the refrigerant outlet 2 is connected to the inlet of the constant temperature tank 15 .

In the above-mentioned thermal conductivity measuring device, a handle is welded on the casing end cap 7 with external threads, which is convenient for disassembly.

In the above-mentioned thermal conductivity measuring device, the precision heating power supply 17 is a DC precision stabilizing power supply.

In the above-mentioned thermal conductivity measuring device, the constant temperature tank 15 is provided with a temperature regulating device.

The beneficial effect of the utility model is that in a test installation process of the PCM medium, the thermal conductivity of the solid phase can be measured, and the thermal conductivity of the PCM liquid phase can be measured after the viscous medium and the temperature rise; the test process medium is sealed , will not leak. The temperature of the refrigerant for different PCM media can be adjusted; the load of the heating rod can be adjusted; the circuit and refrigerant circulation are simple, the system debugging is simple, and the components are detachable and easy to maintain.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a cross-sectional view of a heating tube and a thermocouple layout of an embodiment of the present invention;

Fig. 3 is a sectional view of the arrangement of the cooling jacket 3 and the thermocouples according to an embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

In Fig. 1, Fig. 2 and Fig. 3: 1. Refrigerant inlet; 2. Refrigerant outlet; 3. Cooling sleeve, in this embodiment, its material is copper, which is convenient for good heat transfer; 4. The material to be tested; 5. Copper Sleeve; 6. The heating rod is a DC resistance wire in this embodiment, and cannot be connected to an AC power supply; 7. The casing end cap with external threads, which is made of red copper in this embodiment, is threaded with the cooling jacket 3 Connection, easy to disassemble, the center is perforated, and two handles are welded on the outside of the end cover, which is easy to disassemble; 8. The casing end cover, in this embodiment, is made of copper, welded with the cooling jacket 3, and the center is perforated; 9. The wiring of the heating rod connected to the precision heating source; 10. The wall temperature thermocouple connected to the thermocouple data collector; 11. Insulation cotton; 12. The insulation section at the end of the casing, PVC material is used in this embodiment, Fill in insulation cotton; 13. The heat insulation section at the end of the casing, which is made of PVC material in this embodiment, is filled with heat insulation cotton; 14. Heat insulation cotton; 15. Constant temperature bath; 16. Thermocouple data collector; 17. Precision heating power supply , in this embodiment, it is a DC precision stabilized voltage power supply; 18. Refrigerant, water is used as a medium in this embodiment, and the temperature can be adjusted; high temperature resistant oil can be used when measuring high temperature phase transition temperature, and antifreeze can be used when measuring low temperature phase transition temperature liquid etc.

The refrigerant inlet 1 on the cooling jacket 3 is tightly connected to the outlet of the constant temperature tank 15 through a hose, and the refrigerant outlet 2 on the cooling jacket 3 is tightly connected to the inlet of the constant temperature tank 15 through a temperature-resistant tube.

One end of the cooling jacket 3 has an internal thread and is threadedly connected with the casing end cap 7 with an external thread; the other end of the cooling jacket 3 is glued to the casing end cap 8 .

Casing end cap 7 with external threads is drilled in the center of casing end cap 8, and copper casing 5 is set on the center hole; one side of copper casing 5 has internal threads, and is sealed by plugging wire; the inside of copper casing 5 The heating rod 6 is placed in the axial center of the copper casing 5; filled with heat-conducting silicone grease to make the heating rod 6 and the copper casing 5 conduct heat well; One side protrudes; both sides of the copper casing 5 are filled with thermal insulation cotton 11 and 14 respectively.

The inner wall of the cooling jacket 3 in contact with the tested material 4 is grooved, and the wall temperature thermocouples 10 (3 pairs) are buried in the groove; the outer wall of the copper sleeve 5 is grooved parallel to the cooling jacket 3, and the thermocouples 10 (the other 3 pairs) buried in this groove. Additional thermocouples may also be embedded.

The space enclosed by the two ends of the copper sleeve 5 and the two ends of the heating rod 6 constitutes the heat insulating sections 12 and 13 at the ends of the sleeve. The heat insulation sections 12 and 13 at the ends of the casing are filled with heat insulation cotton. The insulation section 12 at the casing end is bonded to the casing end cover 8; the end of the insulation section 12 at the casing end is perforated, and the wall temperature thermocouple 10 protrudes from the end of the insulation section 12 at the casing end to collect data from the thermocouple When testing, the device is erected, and the insulation section 13 at the end of the casing and the casing end cap 7 with external threads are pressed tightly by gravity.

The heating rod 6 is connected with a precision heating power supply 17 through a heating rod connection 9 .

The constant temperature bath 15 is provided with a temperature regulating device, which can regulate the temperature of the refrigerant 18 .

The device is further described through the testing process as follows:

In the embodiment shown in Figure 1, the installation process for the first test is as follows: three pairs of wall thermocouples 10 are embedded in the inner groove of the cooling jacket 3, and the lugs are stretched out → the other three pairs of walls are warmed. Embed the galvanic couple 10 in the groove of the copper sleeve 5 → tighten the sleeve end cap 7 with external threads and one side of the cooling sleeve 3 → insert the copper sleeve 5 into the sleeve end cap 7 with external threads In the center hole→fill the material to be tested 4→set the casing end cap 8 on the copper casing 5, and glue the interface; the casing end cap 8 matches the other side of the cooling jacket 3, and glue the interface Connect → put the heating rod 6 into the center of the copper sleeve 5 → insert the heat insulating cotton 14 into the port of the copper sleeve 5 → seal one side of the copper sleeve 5 with wire plugging → insert the heat insulating cotton 11 into the copper sleeve 5 On the other side of the heating rod 6 and the copper casing 5, pour heat-conducting silicone grease into the gap between the heating rod 6 and the copper casing 5 → fill the insulation cotton in the insulation section 13 at the end of the casing, press the device vertically on the insulation section 13 at the end of the casing → put Drill a hole in the center of the heat insulation section 12 at the end of the tube, and the heating rod connection 9 and the thermocouples (3 pairs) on the outer wall of the copper tube protrude from the center hole → fill in the insulation cotton in the heat insulation section 12 at the end of the casing → the end of the casing The thermal insulation section 12 of the upper part is glued to the casing end cover 8 → the refrigerant inlet 1 on the cooling jacket 3 and the outlet of the constant temperature tank 15 are tightly connected by a hose → the refrigerant outlet 2 on the cooling jacket 3 is connected to the constant temperature tank 15 The inlet is tightly connected through a hose → connect and debug the wall temperature thermocouple 10 and thermocouple data collector 16 → debug the heating rod wiring 9 and the precision heating power supply 17 → turn on the precision heating power supply 17 to heat the material to be tested, and turn on the constant temperature bath 15 Cool the pump → adjust the voltage of the precision heating power supply 17 to test the temperature field of solid and liquid → adjust the system to judge that the temperature field is in a steady state equilibrium and then obtain the data of the thermocouple data collector 16 to judge the state of the phase of the material to be tested → Calculate the thermal conductivity value according to the one-dimensional steady-state heat conduction model of a constant heat flow cylinder.

After the initial test, the material needs to be poured out, and the retest process flow is as follows: disconnect all wiring → turn the device upside down, remove the insulation section 13 at the end of the casing → reverse the direction with the handle of the casing end cap 7 with external threads Unscrew the casing end cap 7 with external thread → pour out the tested material → load the material to be tested → put the copper casing 5 on the casing end cap 7 with external thread → the device stands upright and presses on the end of the casing for heat insulation On section 13 → the refrigerant inlet 1 on the cooling jacket 3 and the outlet of the constant temperature tank 15 are tightly connected through a hose → the refrigerant outlet 2 on the cooling jacket 3 is connected with the inlet of the constant temperature tank 15 through a hose → connection and debugging Wall temperature thermocouple 10 and thermocouple data collector 16 → debug heating rod wiring 9 and precision heating power supply 17 → turn on precision heating power supply 17 to heat the material under test, turn on the pump of constant temperature tank 15 to cool down → adjust precision heating power supply 17 The voltage can test the temperature field of the solid state and the liquid state → the adjustment system judges that the temperature field is in a steady state equilibrium and then obtains the data of the thermocouple data collector 16, and judges the state of the phase of the measured material → according to the one-dimensional steady-state heat conduction model of the constant heat flow cylinder Calculate the thermal conductivity value.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model without limitation. Although the utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the utility model can be Modifications or equivalent replacements of the technical solutions of the new utility model without departing from the spirit and scope of the technical solutions of the utility model shall be covered by the claims of the utility model.

Claims (9)

1, a kind of thermal conductivity measuring apparatus, comprise shell, be located at refrigerant import (1) and refrigerant exit (2) on this shell, it is characterized in that, this shell is cooling collar (3), this cooling collar (3) is sealed at both ends hollow cylindrical, and this cylindrical outer wall perforate communicates with refrigerant import (1) and refrigerant exit (2), and refrigerant circulates cooling between the interlayer of cooling collar (3); The coaxial red copper sleeve pipe (5) that is provided with in this cooling collar (3), the coaxial heating rod (6) that is provided with in this red copper sleeve pipe (5), this heating rod (6) is connected with accurate heating source (17) by heating rod wiring (9); Be provided with wall temperature thermopair (10) on described cooling collar (3) and red copper sleeve pipe (5), wall temperature thermopair (10) is connected with thermopair data acquisition unit (16).

2, coefficient of heat conductivity determinator according to claim 1, it is characterized in that, the two ends of described cooling collar (3) are to seal by band external thread sleeve pipe end-cap (7) and sleeve pipe end cap (8) respectively, cooling collar (3) inwall one end machining internal thread matches with being with externally threaded sleeve pipe end cap (7), and the other end of cooling collar (3) and sleeve pipe end cap (8) stick with glue and connect.

3, coefficient of heat conductivity determinator according to claim 2, it is characterized in that, be with externally threaded sleeve pipe end cap (7) and sleeve pipe end cap (8) centre drill porose, the external diameter of red copper sleeve pipe (5) cooperates with the internal diameter in this hole, red copper sleeve pipe 5 passes with the center pit of externally threaded sleeve pipe end cap (7) with sleeve pipe end cap (8), and symmetry is installed.

4, coefficient of heat conductivity determinator according to claim 1 and 2 is characterized in that, the internal diameter fitted shaft of the external diameter of described heating rod (6) and red copper sleeve pipe (5) is installed to symmetry, and heat-conducting silicone grease is filled in the gap between them; The space that the both ends of the both ends of red copper sleeve pipe (5) and heating rod (6) surround is filled with adiabatic cotton respectively.

5, coefficient of heat conductivity determinator according to claim 1 and 2 is characterized in that, has groove in cooling collar (3) inboard, imbeds (10) at least 3 pairs of wall temperature thermopairs; At red copper sleeve pipe (5) outer wall fluting, imbed (10) at least 3 pairs of wall temperature thermopairs.

6, coefficient of heat conductivity determinator according to claim 1 and 2 is characterized in that, described refrigerant import (1) is connected with the outlet of a calibration cell (15), and described refrigerant exit (2) is connected with the inlet of this calibration cell (15).

According to claim 2 or 3 described coefficient of heat conductivity determinators, it is characterized in that 7, described being with on the externally threaded sleeve pipe end cap (7) is welded with handle, be convenient to dismounting.

8,, coefficient of heat conductivity determinator according to claim 1 and 2, it is characterized in that described accurate heating power supply (17) is the accurate stabilized voltage supply of direct current.

9,, coefficient of heat conductivity determinator according to claim 1 and 2, it is characterized in that described calibration cell (15) is provided with temperature control equipment.

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