Heat conduction in fluids

WL 422


  • The measurement of heat conduction in fluids is very demanding due to the relatively poor conductivity and associated low heat fluxes.

  • Two cylinders form the main component of the experimental unit: an electrically heated inner cylinder situated in a water-cooled outer cylinder.

  • There is a concentric annular gap between the two cylinders. This annular gap is filled with the fluid being studied. The heat conduction occurs from the inner cylinder, through the fluid to the outer cylinder.

  • The narrow annular gap prevents the formation of a convective heat flux and allows a relatively large pass-through area while at the same time providing a homogeneous temperature distribution.

  • This method allows the thermal conductivity of liquid and gaseous fluids to be investigated.

Accurate measurement

  • special shaping of the inner cylinder and the water flow in the outer cylinder result in a homogeneous temperature distribution

  • the special structure of the experimental setup leads to low parasitic heat fluxes and low disturbance variables

Quickly reach the steady state

  • low masses of inner and outer cylinder allow rapid heating

  • patented pressure balancing piston allows constant pressure in the fluid when heating


  • investigation of the thermal conductivity of common fluids, e.g. water, oil, air or carbon dioxide

  • concentric annular gap between 2 cylinders containing the fluid being studied

  • inner cylinder, continuously electrically heated

  • water-cooled outer cylinder

  • display of temperatures and heating power in the software

  • due to integrated microprocessor-based instrumentation no additional devices with error-prone wiring are required

  • functions of the GUNT software: system operation, data acquisition, educational software

  • network capability: LAN/WLAN connection of any number of external workstations with GUNT software for observation and evaluation of the experiments

  • E-Learning: multi-media didactic materials accessible online

Learning objectives/ experiments

steady heat conduction in gases and liquids:

  • determine the thermal resistance of fluids

  • determination of thermal conductivities k for different fluids at different temperatures

transient heat conduction in fluids:

  • interpret transient states during heating and cooling

  • introduction to transient heat conduction with the block capacity model


  • multi-media online course, which enables learning independent of time and place

  • access via Internet browser

  • educational software including different learning modules

  • course in the fundamentals

  • detailed thematic courses

  • check through targeted review of the learning objectives

  • authoring system with editor that enables you to integrate your own, local content into the educational software


  • effect of different fluids on heat conduction

  • network capability: network access to ongoing experiments by any number of external workstations

  • GUNT software: operation and control of the experimental unit, data acquisition and educational software

  • E-Learning: multi-media didactic materials accessible online

Technical data


  • heating power: 350W

  • temperature limitation: 95°C

  • Heat transfer area: 74,39cm2

Annular gap

  • height: 0,4mm

  • average diameter: 29,6mm

  • Inner cylinder

  • mass: 0,11kg

  • specific heat capacity: 890J/kg*K

Measuring ranges

  • temperature: 2x 0…325°C

  • heating power: 0…450W

  • 230V, 50Hz, 1 phase

  • 230V, 60Hz, 1 phase; 120V, 60Hz, 1 phase

  • UL/CSA optional

Dimensions and weight

  • LxWxH: 670x350x480mm

  • Weight: approx. 18kg

Required for operation

  • cold water connection max. 30°C, min. 1L/h

  • drain

  • PC with Windows