Flow and Thermal Comfort Simulations for Double Decker Train Cabins with Passengers

Abstract

Results of numerical simulations of the air flow including the heat transport, the thermal radiation and the thermal comfort in a complete double decker train cabin with 96 passengers are presented in this paper. The computations have been performed by coupling flow simulations conducted with the computational fluid dynamics (CFD) code OpenFOAM with finite-element simulations of the heat transport within the passengers using the code THESEUS-FE. With the latter the bodies of passengers were modelled based on various layers with different heat transport characteristics to account for effects such as blood flow, heat transfer through the skin and the clothing as well as activity levels and ambient humidity. Based on these computations the thermal comfort of passengers in the cabin of German Aerospace Centres concept train called the Next Generation Train (NGT) has been simulated and analysed for adiabatic and isothermal temperature wall conditions. The first case represents a cooling case and the second a heating case. As a consequence the comfort analysis is based on the evaluation of equivalent temperatures for summer and winter conditions and local comfort indexes on passenger's bodies. The calculations reveal that temperature distribution in the cabin is inhomogeneous and different between upper and lower deck. This shows that in studies focusing on the performance of different ventilation techniques the complete cabin must be considered.