COMPARISON OF DIFFERENT HEATING METHODS FOR THE TEMPERATURE-CONTROLLED MEASUREMENT OF CONVECTIVE TRANSITION BOILING

For the experimental investigation of the transition boiling regime, s pecial heating and control methods have to be introduced to ensure sta bility. Typical problems of all these methods are the large axial temp erature gradient after the transition boiling mode first appears on th e heat transfer surface and the failure of stability under some condit ions. Through numerical solution of the heat conduction problem relate d to the temperature-controlled test section, which has a strongly non linear boiling topography as one of its boundary conditions, different types of heating methods can be compared in terms of axial temperatur e gradient, extension of the transition boiling mode, and the second-o rder instability.