One-dimensional heat problem is solved for the two-dimensional model of a wheel (disc) with consideration of the angular symmetry of the 'arbitrary' frictional heat flow into the wheel approximated by a power series in case of small Fourier numbers and heat dissipation into the environment. The effect of heat dissipation into the environment on the wheel surface temperature is estimated depending on the braking time. Simple analytical dependences of the wheel surface temperature are obtained for the one-dimensional non-stationary heat problem with consideration of heat dissipation into the environment for small Fourier numbers corresponding to emergency and long (up to 30 min) brakings. The two-dimensional wheel model and the radial frictional heat flow whose time dependence was approximated by the power series have been considered. It was shown that decrease in the wheel surface temperature owing to the consideration of heat dissipation into environment does not exceed 7-8% at emergency braking (tk<=1 min) and 30-35% at long braking (tk<=30 min). In case of the simple model for which the time dependences of the frictional heat flow and velocity coincide for uniformly retarded motion of the wheel has been found that calculated temperatures agree with the statement on wheel overheating in emergency braking at velocities over 140 km/h.
Effect of heat dissipation into environment on surface temperature of wheel at braking
Einfluss der Wärmeabführung an die Umgebung auf die Oberflächentemperatur des Eisenbahnrades beim Bremsen
Journal of Friction and Wear ; 28 , 1 ; 51-64
2007
14 Seiten, 4 Bilder, 23 Quellen
Aufsatz (Zeitschrift)
Englisch