Thermal conductivity tester for measuring the thermal conductivity of glass fiber cotton

The core of testing the thermal conductivity of glass fiber cotton using a thermal conductivity tester is to simultaneously achieve heating and temperature sensing through a double helix plane probe, and calculate the thermal conductivity using the material's thermal response curve. Due to the porous, low thermal conductivity, compressibility, and moisture absorption characteristics of glass fiber cotton, strict control of sample state and instrument parameters is required for testing.

1、 Operation steps of the experiment

1. Measuring instruments:DZDR-AS Thermal Conductivity Tester

2. Sample preparation requirements:

Drying treatment: The surface of glass fiber cotton is prone to absorbing water vapor, and it needs to be dried in a 105 ℃ oven for 24 hours. After removal, it should be placed in a dryer and cooled to room temperature before testing.

Surface treatment: Fluffy fiber cotton can cause uneven surfaces, which may increase contact thermal resistance. 2-3 layers of samples can be stacked, and an acrylic or resin board can be added to the periphery of the sample to ensure uniform pressure and a smooth surface of the sample.

3. Operation steps: First calibrate the instrument with a standard sample, then lay the sample to be tested flat on both sides of the probe, gently press to ensure that the probe is in close contact with the sample, ensuring no gaps. Start the instrument, set the heating time (usually 160 seconds), and record the real-time temperature change data of the probe over time.

4. Data processing and result analysis

4.2 Analysis of Measurement Results:

Moisture influence: The test results of the undried samples are greater than the theoretical range, indicating that moisture has a significant impact on glass fiber cotton and pre drying treatment is necessary.

Repeatability: The same batch of samples was tested 5 times, and the relative standard deviation (RSD) was less than 3%, indicating good repeatability of the method.

4.3 Factors causing measurement errors:

Humidity control: Before testing, dry the sample in a 105 ℃ oven for 2 hours to remove adsorbed water (moisture can increase thermal conductivity by about 10% to 30%).

Temperature stability: The test should be conducted in a constant temperature environment (such as 25 ± 1 ℃) to avoid temperature fluctuations affecting the results.

Sample uniformity: Ensure that the sample density and fiber distribution are uniform (avoiding local agglomeration), and if necessary, take multiple locations for testing and take the average.

Boundary effect: If the sample thickness is insufficient, edge heat dissipation will interfere with the temperature field, resulting in result deviation. The sample thickness can be increased or a protective ring can be used.