Liquids thermal conductivity measurement

Would you like to have the thermal conductivity of your liquid samples measured? The Calnesis laboratory performs these measurements using the hot wire technique.

The thermal conductivity of a liquid defines its ability to transfer heat. It is expressed in W/m/K.

Along with heat capacity and density, it is one of the quantities used to characterize the thermal behavior of fluids as a function of temperature. These quantities are particularly used to size the heating of the fluid in question, but also for so-called heat transfer fluids whose function is to transfer heat between two points of a system.

Examples of thermal conductivity values

The order of magnitude of the conductivity of liquids varies between 0.01 and 2 W/m/K. The thermal conductivity of polar liquids (water, ammonia, etc.) is generally higher than that of other liquids, especially organic liquids. The table below gives some examples of thermal conductivities measured on common liquids:

Water0,600 W/m/K
Oil0,150 W/m/K
Ethanol0,180 W/m/K

Measurement Method: Hot Wire

At Calnesis, the method used to measure the thermal conductivity of liquids is that of the hot wire. The measurement consists of placing the liquid in a temperature-regulated container between 0 and 100°C. A probe equipped with a conductive wire is placed in the thermostated liquid.

The thermal conductivity of fluids is measured by the hot wire technique, with an accuracy of 5%
Jean-Claude Neyt, COO and Lab Manager, Calnesis

For approximately one second, a current travels through the hot wire and heats the fluid located around it. The temperature variation measured during this heating makes it possible to determine the thermal conductivity of the fluid at this temperature. This is therefore a so-called transitional measure.

The reduced measurement time makes it possible to overcome undesired heat transfer modes that occur in fluids, in particular the main one: convection.

The accuracy of this type of measurement is about 5%

Conditions necessary for thermal conductivity measurement

The fluid must be thermally stable over the entire desired measurement temperature range. The measurement temperature(s) must not be too close to the boiling temperature to avoid degassing or the formation of gas bubbles in the fluid.

Other measurements
Measurement of the thermal Conductivity of Samples over a wide temperature range.
Are you looking to measure the heat capacity of your samples? The Calnesis laboratory carries out these measurements by...
Measurement of the specific heat of samples by calorimetry over a wide temperature range (-80°C to 600°C).