Study on thermal contact resistance in stationary and moving joints

Aim of project
Thermal contact resistance is associated with a drop of temperature on contact surface of two bodies that is proportional to heat flux across the joint. It is the thermal resistance to heat fl ow resulting from the diff erence in the actual and nominal area of contact. The actual area of contact constitutes a small fraction of the nominal one.

In most cases, thermal contact resistance is a disadvantageous phenomenon which leads to an increase in maximum temperature and heat fl ux especially in highly thermally-loaded parts of machines. High temperature gradients can cause significant thermal stresses that in turn can lead, for example, to destruction of a surface. In case of sliding contact, beside thermal contact resistance, additional heat generation due to friction on contact surface can appear. Temperature increase close to contact of two bodies can cause a change in their material properties, oxidation, corrosion, decrease in lubricating properties of oil and even its decomposition. High temperature and a resulting change in body dimensions can lead to their deformation, wear, increase in friction losses and noise.

Despite significant importance of thermal contact resistance in many technical applications, the phenomenon has not been fully studied. The general relationship has not been worked out yet which would allow to predict thermal contact resistance for the given conditions.

The main objective of the project is qualitative and quantitative investigation of heat transfer in the presence of thermal contact resistance in stationary as well as in sliding joints. This will lead to better comprehension of the phenomenon. This means, in particular:

Theoretical and experimental study of influence of different factors on thermal contact resistance in stationary contact especially in terms of directional properties of surface roughness;

Working out a microscopic model of thermal contact resistance and comparison of its predictions with other models and experimental data;

Carrying out experimental studies and numerical modeling of heat transfer across sliding joints. Expected results

Formulation of an updated microscopic model of thermal contact resistance;

Building an experimental stand, unique in Poland, for investigation of thermal contact resistance in stationary joints (enabling measurements in a vacuum);

Preparation and publication of the second edition of a monograph — Furmański P., Wiśniewski T.S., Banaszek J.: ”Thermal Contact Resistance and Other Thermal Phenomena at Solid- Solid Interface”, completed with the newest results of research carried out in the world and by the authors.