Solar energy measuring liquid heat conductivity coefficient experimental instrument and measurement method thereof

Abstract

The invention discloses a solar energy measuring liquid heat conductivity coefficient experimental instrument and a measurement method thereof, and belongs to the field of physical experimental instruments. The instrument comprises a sliding rail, a heating plate rack, a cooling plate rack, a liquid sample containing tank, a heating plate, a cooling plate, a temperature sensor I, a temperature sensor II, a heat dissipation fan, a single chip computer temperature measurement and control instrument, a compression bolt, a compression nut, a solar photovoltaic power supply system and an electronictimer. The instrument is used for measuring the heat conductivity coefficient of liquid through a steady-state method, is simple to operate, visual in phenomenon, accurate in measurement data, smallin measurement error, high in repeatability, convenient in disassembly and assembly of all components, and convenient for experiments to be smoothly performed, and avoids the problem of slow teachingprogress caused by inconvenience in disassembly and assembly of the existing instruments.

Description

technical field [0001] The invention specifically relates to an experimental instrument for measuring liquid thermal conductivity by solar energy and a measuring method thereof, belonging to the field of physical experimental instruments. Background technique [0002] Thermal conductivity is a physical quantity that characterizes the thermal conductivity of a substance; changes in the structure of materials and differences in impurities have a significant impact on the value of thermal conductivity of materials, so the thermal conductivity of materials often needs to be specifically determined by experiments; [0003] The common experimental method for measuring thermal conductivity is the steady-state method; first, the sample is heated by a heat source, and the temperature difference inside the sample makes the heat conduct from high temperature to low temperature, and the temperature of each point inside the sample will change with the influence of heating speed and heat t...

AI Technical Summary

Problems solved by technology

[0005] 1) The existing experimental instruments are mostly used to measure the thermal conductivity of poor conductors (such as rubber, glass, ceramics, plexiglass, plastics), and cannot accurately measure the thermal conductivity of liquids;

[0006] 2) When the FD-TC-B thermal conductivity tester is in use, the sample needs to be placed between the heating plate and the heat dissipation plate. The sample is required to be completely aligned with the heating plate and the heat dissipation plate, and then fixed; Fine-tune the screw so that the sample is in good contact with the heating plate and heat dissipation plate, but be careful not to be too tight or too loose: too tight will compress the thickness of the sample, and too loose will cause poor contact between the sample and the heating plate and heat dissipation plate, and there is an air gap in between; these It will lead to the inability to accurately measure the thermal conductivity of the sample; the control of the bonding degree of the contact surface of the existing equipment is not flexible, and the sample cannot be well adjusted to be in good contact with the heating plate and the cooling plate;

[0007] In the experiment, the heating plate, the disc sample, and the cooling plate have the same circular area, and they are stacked together from top to bottom. The sample is required to be completely aligned with the heating plate and the cooling plate. It is inconvenient to completely align the heating plate, sample, and heat dissipation plate; then adjust the three fine-tuning screws at the bottom to make the sample contact with the heating plate and heat dissipation plate; when adjusting the three fine-tuning screws at the bottom, the heating plate and the disc sample 1. The heat dissipation plate is easy to tilt, causing the heating plate, the disc sample, and the heat dissipation plate to be misaligned with each other, and cannot be completely aligned, which affects the experimental measurement. A little carelessness will lead to inaccurate measurement results, and the entire installation and adjustment process is cumbersome; in addition , When replacing the sample, it is necessary to remove or raise the heating plate and the electric heater on the heating plate to replace the sample. It is easy to be scalded during operation, and the operation is not flexible; when calculating the thermal conductivity, it is necessary to measure the diameter and thickness of the heat sink. The diameter and thickness of the sample; therefore, it is necessary to remove the heat sink and the sample for measurement, and it is inconvenient to install and disassemble the existing equipment; the disassembly and assembly of the equipment in the whole experiment is not easy, which leads to the unsmooth experiment, which wastes the limited teaching and experiment time and delays teaching progress;

[0008] 3) Steady-state method to measure the thermal conductivity of bad conductors and metal materials. In the experiment, the bad conductor needs to be set as a circular plate with a diameter of 10cm and a thickness of 10mm; the metal needs to be set as a cylinder with a length of 20cm and a cross-sectional diameter of 10cm; One end of the sample is in full contact with a stable uniform heating body, and the other end is in contact with a uniform heat sink; the bad conductor is a flat sample, and its side area is much smaller than that of the flat plane, so it can be considered that the heat is only transmitted along the vertical direction of the flat plane , the heat dissipated from the side can be ignored, that is, it can be considered that there is only a temperature gradient in the direction perpendicular to the sample plane in the sample, and in the same plane, the temperature is the same everywhere; while the side area of ​​the metal sample is larger than the cross-sectional area, the side The dissipated heat will greatly affect the measurement results;

[0009] 4) The FD-TC-B thermal conductivity tester does not have an electronic timer, and it is equipped with timers such as stopwatches, electronic watches, mobile phones, etc. The inconsistent timers cause timing errors;

[0010] 5) The FD-TC-B thermal conductivity tester adopts the electric heating method, which consumes electricity and completely depends on the power supply from the external power grid, and cannot be used when the power is off;

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