The Transient Hot Wire Liquid Thermal Conductivity Meter (THW-L1) is a precision analytical instrument for directly measuring the thermal conductivity, thermal diffusivity and specific heat of liquids and low viscosity pastes, from -150 to 300°C. The THW-L1 is available in three models:
THW-L1: 10 to 200°C
THW-L1S: -50 to 200°C
THW-L1E: -100 / -150°C to 300°C.
The Thermtest Transient Hot Wire (THW-L1) Liquid Thermal Conductivity Meter is an advanced measurement system for direct determination of the thermal conductivity liquids and pastes in accordance with ASTM D7896-19 – Standard Test Method for Thermal Conductivity of Engine Coolants and Related Fluids by Transient Hot Wire Liquid Thermal Conductivity Method.
The THW-L1 Meter was designed with speed and operational simplicity in mind. With a single measurement of 1 second in duration, small volumes of liquids and low viscosity pastes can be accurately and precisely measured for thermal conductivity, thermal diffusivity, and specific heat. The THW-L1 Meter uses a non-stationary measurement approach and rapid test times, limiting convective effects for samples with a wide range of viscosities (0.1 to 10,000,000 mPas).
Thermal Conductivity Results
Water is a Standard Reference material for the calibration of liquid thermal conductivity instruments. Our THW-L1 device is using a single-point calibration at 20 oC and DIUF water ASTM Type II is recommended.
During the present work, the thermal conductivity, thermal diffusivity, and the calculated volumetric specific heat (thermal conductivity (λ) / thermal diffusivity (α)) of Water were measured and the data are given in Tables 1-3. Three measurements were taken at each temperature step and the percentage relative standard deviations given at each temperature. To confirm the accuracy of the measurements taken with the THW-L1 device, the data is compared with the Reference values as they were calculated in the NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP): Version 10.
Table 1. Thermal Conductivity Measurements of Water under back pressure of 3 bars and comparison data as calculated in the REFPROP database.
Lemmon, E.W., Bell, I.H., Huber, M.L., McLinden, M.O. NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 10.0, National Institute of Standards and Technology, Standard Reference Data Program, Gaithersburg, 2018.