deutsch
The thermal conductivity lambda (λ) of a solid, a fluid or a gas may basically be understood as the speed at which a defined amount of heat travels as it goes through a particular substance. A low λ value means low thermal conductivity.
For both liquids and gases the thermal conductivity highly depends on the temperature, whereas its pressure dependence is comparitively low. The measure for lambda is W/(m*K) (Watts per Meter and Kelvin).
Typical lambda values for different fluids
| Fluid | Thermal conductivity λ / [W/(m*K)] |
| gasoline (RT) | 0,140 |
| glycerin (RT) | 0,286 |
| machine oil (RT) | 0,126 |
| ethanol (RT) | 0,185 |
| water @ 50°F (10°C) | 0,580 |
| water @ 140°F (60°C) | 0,644 |
Measuring λ of fluids, pastes and gels (flucon LAMBDA)
flucon's LAMBDA Thermal Conductivity Meter allows you to determine the temperature-dependent thermal conductivity of liquids, pastes or gels with ease. With its transient hot-wire technology, LAMBDA is both highly accurate and very easy to handle. Its measuring range from 0,01 to 2 W/(m*K) and its temperature range -50°C to 300°C make it the perfect tool for your thermal fluid analysis.
Workflow for the determination of the thermal conductivity (flucon Fluid Analysis)
flucon does not only offer the portable LAMBDA instrument but also contract testing. These in-house fluid analysis services are carried out in our unique Fluid and High-Pressure Laboratories.
Customers may send in small samples (40 ml min.) of their liquid to have the following steps performed for them:
- Laboratory measurement of the thermal conductivity as a function of temperature and/or pressure by means of LAMBDA's transient hot-wire method, preventing any influence of convective flow of heat on the measuring result
- Mathematical description of the pressure-/temperature-dependant thermal conductivity
- Numeric and graphical data preparation
