Thermal conductivity tester for measuring the thermal conductivity of ethylene glycol

Ethylene glycol, as an important diol compound, is widely used in automotive antifreeze, industrial refrigerants, organic synthesis intermediates, and phase change energy storage materials due to its low freezing point, high boiling point, and good thermal stability. Its thermal conductivity directly affects the heat transfer efficiency of the cooling system and the charging and discharging rate of the energy storage medium. Therefore, accurately measuring the thermal conductivity of ethylene glycol has practical engineering significance.

The traditional steady-state method (such as the flat plate method) requires a long time for thermal equilibrium and is difficult to control the flow of high viscosity liquids; The transient method has become the preferred technique for determining liquid thermal properties due to its fast testing and low requirements for sample state. Among them, the transient planar heat source method (TPS) achieves heating and temperature measurement simultaneously through a double helix heat source, which can avoid sample disturbance and is particularly suitable for high viscosity liquids.

1、 Operation steps of the experiment

1. Measuring equipment:DZDR-AS Thermal Conductivity Tester(Nanjing DaZhan Testing Instrument Production)

2. Measurement operation steps:

Sample pretreatment: Ethylene glycol is pre degassed (ultrasonic degassing for 15 minutes), injected into the sample pool to full (avoiding bubbles), sealed, and placed in a constant temperature water bath for 40 minutes (high viscosity liquids have large thermal inertia, extending the constant temperature time).

Test procedure: Set the heating power to P=0.8W (balancing signal strength and sample stability), heating time to t=15 s, and sampling frequency to f=20 Hz; Start the test, record the temperature rise curve, and the software will automatically calculate k. Repeat the test three times and take the average. Change the water bath temperature (20, 30, 40, 50, 60 ℃) and repeat the above steps.

3. Test results

Table 1 shows the test results of thermal conductivity of ethylene glycol at different temperatures (3 parallel experiments), with a relative standard deviation (RSD) of<2%, indicating good experimental reproducibility (high viscosity liquids have weaker convection and more stable data).