Ricerc@Sapienza

The work presented in this paper is part of an international project about the Basilica of Nativity in Bethlehem, famous and ancient Church dating back to the late 6th century
and added in 2012 to the UNESCO world heritage list. Here we present a preliminary Computational Fluid Dynamics (CFD) study of indoor ow and temperature elds in
this still well-preserved building. In particular, the aim of the numerical simulation is to examine the impact of windows opening on indoor thermal equilibrium of the church,

The present article deals with the design of a micro turbogas turbine suitable for on board applications, e.g., as a power generator on hybrid transit bus, characterized by a simple constructive approach. Deriving the machine layout from an existing KJ-66 aircraft model engine, the authors propose a theoretical design of a compact, lightweight turbogas turbine, by investigating the technical possibility and limits of the proposed design.

A predictive numerical approach, based on Reynolds-averaged Navier–Stokes simulations including the effects of turbulence, chemistry, fluid/surface interaction, and radiation, has been developed for paraffin-wax/oxygen hybrid rocket engines. A recently fired single-port paraffin-based hybrid rocket engine, with chamber pressures up to 19.1 bar, is taken as reference for the discussion of the results of the numerical simulations, which outline important features of the internal ballistics otherwise not observed in the experiments.

LES computations have limited applications in turbomachinery predictions because of the formidable amount of resources they require. Due to the exponential increase of requirements with Reynolds number, LES is usually limited to elements with moderate flow velocities and to investigate flows characterized by multiple length and time scales that overlaps. It is the case of combustion, aeroacoustics, unstable range of operations such as stalled conditions.

The profound qualitative changes of indoor air and the progressive increase in the absolute number of pollutants, combined with the scientific awareness of the health impacts deriving from spending more than 90% of one’s time inside confined spaces, have increased the attention onto the needs of well-being, hygiene, and the health of users. This scientific attention has produced studies and analyses useful for evidence-based insights into building performance.

This article focuses on evaluating the performance of a relatively new system of a ducted wind turbine with an omnidirectional capture system, the INVELOX system. In the present study, the improvement of such patented system has been developed by performing a detailed numerical analysis varying several geometrical parameters and analysing the effect of changing wind velocity and wind direction.

The effect of humidity on the climatic conditions and the turbulence around an isolated building has not been yet investigated in literature. This paper analyses the simultaneous effect of architectural and environmental parameters on the vortex creation around a building, focusing on the impact of relative humidity. Sixty-four 3D computational fluid dynamics simulations have been performed, coupling 4 values of inlet velocity, air temperature, solar radiation and building height with 4 values of relative humidity.

In the framework of Heavy Liquid Metal (HLM) GEN IV Nuclear reactor development, the focus is in the combination of security and performance. Numerical simulations with Computational Fluid Dynamics (CFD) or system codes are useful tools to predict the main steady-state phenomena and how transitional accidents could unfold in GEN IV reactors. In this paper, to support the validation of CFD as a valid tool for the design, the capability of ANSYS CFX v15.0 to simulate and reproduce mixed natural convection and thermal stratification phenomena inside a pool is investigated.

Buoyancy-driven convention from a pair of horizontal heated cylinders, set side by side
inside a square cooled cavity filled with water, is studied numerically. The system of the
conservation equations of mass, momentum and energy expressed in dimensionless form is
solved through a control-volume formulation of the finite-difference method. The pressurevelocity
coupling is handled using the SIMPLE-C algorithm. Numerical simulations are executed
for different values of the Rayleigh number based on the cylinder diameter, as well as

The flow and heat transfer behavior of laminar incompressible slot jets impingement cooling of an array of heated surfaces in a channel have been investigated numerically. The computations are done for a variety of values of slot jets Reynolds number, channel height and distance between two heated blocks. The influences of these geometrical and physical parameters are predicted. The results, streamline contour, velocity profile, isothermal contour, local Nusselt number, and average Nusselt number are compared and documented.