Interior air flow simulation in railway rolling stock

Abstract

For the thermal comfort of passengers in modern trains thermodynamic parameters such as pressure, temperature and relative humidity are important, but also technical features such as location, velocity and direction of the air supplied to the compartment must not be neglected. By applying computational fluid dynamics (CFD) to the simulation of the interior air flow, time- and cost effectiveness can be increased significantly: in an early development phase, where influencing the design and the concept is still possible with low additional effort, air conditioning can be optimized in a very cost- and time-effective way. Thus, by exceeding the normative requirements the passenger's needs are met more closely and more easily. After validation of the method and numerical model by full-scale measurements, a powerful and sound tool for parameter variations and the design and construction of air-conditioning facilities is obtained. The interior air flow in the first-class compartment of a regional train was simulated numerically. Thermodynamic and aerodynamic parameters were measured in a full-scale test train for the validation. The results show the ability of CFD to deal with parameter variations and the prediction of thermal comfort. Benefits and drawbacks and the limits of the application of CFD have been worked out.