An optimization process experience for HVAC noise emission and flows distribution inside a passenger s train wagon

Noise emission from train HVAC systems has become an important factor for passenger comfort. Consequently, efforts are made during the design phase to minimize noise generation, and to improve sound quality. Predictive tools for the fluid dynamics and acoustic behavior of components, subsystems and whole systems early on in the design phase are therefore desirable. In this paper a combined Computational Fluid Dynamics (CFD) and Acoustic BEM approach for the prediction of sound generation and propagation has been used to evaluate and optimize the system performances, with reference to a new train platform. As a first step of the activity, preliminary models have been assessed on the basis of design inputs; results of the simulation process have been demonstrated some lack of performances with reference the technical specification documents. A system design modification has so been implemented in the direction of requirement fulfillment in the respect of design constraints. Numerical simulation first and experimental measurements later have been demonstrated the good results of this approach, both in terms of better flows distribution and of noise emission inside the wagon. Within the paper, the numerical modeling methods, the numerical results and the experimental evaluation comparison are presented and discussed.