Summary
To determine the amount of heat needed to prevent snow from accreting on the body of a running Shinkansen railcar, tests of snow accretion under conditions close to operation in Shinkansen were carried out in a cold-room using a wind-tunnel, a snow-feeder apparatus, a water-feeder apparatus and a panel-heater.
The cold-room tests were run at air temperatures of −1°, −5°, and −10°C, wind speeds of 5 and 10 ms−1 (wind direction: normal to the panel-heater), snow-drift intensities of 0.05, 0.2, 0.6 and 1 g cm−2 min−1, heating rates of 0, 0.5, 1.5, 2.5 and 3.5 kWm−2, and liquid water contents (ratio of water mass supplied with the water-feeder apparatus to snow mass supplied with the snowfeeder apparatus) of 0%, 5%, 10% and 20% for each intensity of drifting snow.
At 10 min after the tests had started, states on the surface of the panel-heater were classified into the following six modes: (1) water adhesion, (2) snow-jam accretion, (3) snow accretion, (4) ice accretion, (5) ice-film formation, and (6) no accretion.
Impact forces were measured using equal weights of snow containing no water and snow-jam mass filled with water. The maximum impact force of a snow-jam mass was smaller than that of a snow mass.
Results from these tests indicated that the heat needed to melt accreted snow or to transform it into a snow-jam is about 3.5 kWm−2, and the heat capacity to melt accreted snow at a station within 90s is about 1.5 kWm−2.
