Experimental Study On The Icing And Ice Melting Of Contact Wires In An Icing Wind Tunnel

Frequent accidents of icing have a great impact to the contact wire system gradually with the development of the electrified railway.Firstly, a contrast between icing of the overhead wires and railway contact wires based on the basic concept and mechanism of ice was made,the results indicate that there are some different areas between them like the line structure, reasons of icing and so on, then some assumptions and simplicities for the melting model were made by the author, so the formula for melting calculation was obtained.Secondly, an experimental investigation in an artificial environment room had been conducted to determine the characteristics of icing on a contact wire based on the analysis of the icing conditions. The results indicate that the ice type begin to change when the temperature is -4℃and the LWC maintained a fixed value, when the temperature is above -4℃, glaze and Mixed phase ice which are harmful were formed subsequently, rime ice was formed adversely; higher the air temperature, higher the density and weight of ice, the wind speed which restricted by the experimental device have a impact to the structural strength of ice, higher the wind speed, the strength also increased; when other parameters maintained a fixed value, the weight of icing increased with the grow up of the time; the melting experimental was finished by altering thickness, then the theoretical model based on the experimental results was amended, so a amended formula for melting calculation was obtained.Thirdly, for preventing such accidents caused by melting because of the asymmetry of icing, a math and physics model was established, through this model, the temperature distribution can be obtained by calculation. A new concept named critical current was putted forward according to two extreme conditions.Finally, an expert system had been developed by labview which has great advantages in communication with hardware based on the experimental results and theoretical research.The experimental results and the expert system have a positive meaning for icing prevention and ice melting in the contact wire system.