Optimization of a Sanding System for a Tramway Car by Numerical Simulation of the Sand-Air Two-Phase Flow

In tramways, sanding systems are used to avoid gliding while accelerating or slowing down the vehicle under bad rail conditions. The total amount of sand required should be a minimum to reduce costs and unnecessary formation of particulate matter in road traffic. The main aim of the present paper is to minimize this total amount of sand by means of modern computational methods. For this purpose, the software ANSYS FLUENT is used to develop a numerical simulation model, which allows the flow of a sand-air mixture to be simulated under the conditions of a sanding system. Of particular importance in the approximation to reality is the correct modelling of the rebound behavior of the sand particles on the surface of the rails. For an accurate prediction of the related physics, a stochastic sub-model was implemented whose parameters were tuned using results from in-house experiments carried out for this purpose. A series of simulation computations led to suggestions of improved design variants of the end piece at the exit of the sanding device and a better focused sand jet. Finally, the improved end pieces were tested in simulations with approximated realistic geometry and boundary conditions.