Modellierung des Wärmeübergangs - Analysis of the heat transfer for convective boiling flow over metallic surfaces

The rapid increase of the specific power output of modern internal combustion engines is accompanied by increasing thermal loads on the structure of the combustiion chambers. Highly efficient cooling systems are needed to keep the wall temperatures below acceptable limits. Concerning the heat flux from the cylinder wall to the liquid coolant jacket the desired high heat transfer rates can be achieved by providing for a controlled transition from single-phase to subcooled boiling heat transfer. The present project is focussed on a detailled investigation of several effects on the subcooled boiling heat transfer. In particular the influence of the roughness and the orientation of the heater surface, of eventual depositions on the surface due to fowling, of varying pressure gradients, and vibrations of the heater surface are to be examined. Based on the boiling flow experiments which will be specially designed and conducted for this study the modeling of the subcooled boiling heat transfer shall be improved.