Level, Class, and Prospected Safety Performance of a Lightning Protection System for a Complex of Structures (LPCS)
The Standard IEC 62305 provides advanced information for the design of lightning protection of structures (LPS). In determining the position of the air-termination system, two methods are generally suggested: the protective angle method and the rolling sphere method. Adopting a 3-D graphical simulation, the “rolling sphere” method allows one: to analyze the protected volume at the building roof inside of the rolling ply surface; to verify the behavior of the designed air-termination system; to evaluate the contribution of the surrounding structures in limiting the lightning current flowing in the down-conductors. This current affects the probability of dangerous sparking and the separation distance for the protection of internal installations. This paper presents this approach by a case study of a building in a complex of structures: it highlights particularly the worst cases of the lightning impact related to the designed air-termination system.
Study of a daylight “filter” zone in tunnels
In tunnels high energy consumption is required for guarantying the visual adaptation to the light contrast between daylight and tunnel luminance. The opportunity to graduate daylight in the threshold zone could create an area of adaptation of the human eye to the tunnel' s interior luminance, reducing consumption. In this paper a daylight “filter” structure, called pre-tunnel, is placed before the tunnel's portal, to investigate how a gradual reduction of luminance maintaining uniformity could be achieved; the structure presents very small circular holes on the ceiling giving access to natural light. A scale model has been constructed to test the effect of different diameters of holes on luminance and to evaluate the reduction of the lighting percentage. Results show the ability of this solution to have a potential control daylight management at the entrance of the tunnel.
Research on velocity distribution in semi-dry flue gas desulfurization tower
As an accurate high-quality instantaneous measurement technology, particle image velocimetry (PIV in acronym) has applied widely in single-phase flow and multiphase flow. The velocity distribution in semi-dry FGD tower directly influences gas-solid mix and contact situation. In base of the tower, gas-solid two-phase flow field is more complex, and has the quite tremendous influence to the overall system desulphurization efficiency. This paper utilized PIV to study velocity distribution in Semi-dry flue gas desulfurization tower and obtained velocity distribution.