Experimental Investigation of the Ice-Formation in a Planar Nozzle With Forced Convection Flow

The present paper deals with the ice-formation in a planar nozzle with a convergence angle of 2.5 deg. First experiments have been carried out for different wall cooling parameters B in the range between 4 to 18 and for different flow rate Reynolds numbers in the range of 5000 < Re_4h < 46000. For all these experiments only smooth ice-layers could be observed. However, in a cooled parallel plate channel or a diffuser, normally wavy ice-layers are observed for the parameter range reported above. This interesting result can be seen as a first justification for the hypothesis (which has been stated in literature) that the formation of wavy ice-layers is caused by flow laminarisation (due to the rapid growth in ice-layer thickness with increasing axial position from the inlet) and retransition to the fully turbulent state (after the ice-layer thickness reaches a nearly constant value). Thus, wavy ice-layers might be suppressed by superimposing flow acceleration.