This paper presents a computational fluid dynamics (CFD) analysis of the air and temperature distribution in a representative railway vehicle, with the objective of evaluating passengers' thermal comfort. The CFD model developed is featuring the wagon geometry in detail including air diffusers geometry, passengers, and luminaires. A set of different scenarios are studied, covering occupancy levels, state of the doors and windows (open/closed), inlet temperature, and air diffuser design. The results show a clear influence of the air supply system and design geometry on comfort, as local velocities well above 1 m/s were obtained for the original design. A new diffuser design proposed clearly improved the velocity field distribution enhancing passengers' thermal comfort. Exhaust vents are also presenting high velocities, which are significantly reduced down to 2 m/s when windows are open. It is observed that thermal comfort is not appropriate when air inlet temperature is conditioned to 19 °C, especially for the original diffuser design.

A cooling system design for the processing of radioactive waste drums is investigated in this work, with the objective of providing insights for the determination of the air flow rate required to ensure an acceptable slag temperature (323 K or below) after 5 days. A methodology based on both 3D and 2D axisymmetric Computational Fluid Dynamics (CFD) modelling is developed. Transient temperature distributions within the drums in time and space determined by the heat transfer characteristics are studied in detail. A sensitivity analysis is also carried out assuming different physical properties of the radioactive slag. It was found out that for all variations analyzed, the maximum temperature of slag at the end of five days cooling is below 323 K, where the maximum outlet air temperature for a minimum air inlet velocity of 1 m/s is between 320 K and 323 K depending on the radioactive slag properties. When glass-like radioactive slag properties are assumed, the internal heat conduction within the slag is limiting the overall heat transfer, therefore requiring significantly longer cooling times.

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