Abstract: The spray for industrial use are largely developed and optimized in order to have a perfect atomization. The process of atomization is well explained in literature. It is strongly governed by Weber number. This parameter is defined like the ratio between the kinetic energy related to the axial velocity to the surface tension, giving a threshold of the start up of the atomization phenomenon.
The nozzle design and the fluid characteristics, that are involved in the atomization process. The Weber number depends on the square axial velocity of the jet. In many cases, the quadratic dependence on the exit velocity is a limitation for droplets breakup. Today, the fuel injectors have a high capability of atomization by means of high pressure and high exit velocity. The high axial velocity inside a diesel engine , e.g. can impact on the surface of the cylinder before of the combustion phenomenon. In this paper we study how the spray technology can be use in to a gear box lubrication or in general in a kinematic pair. The lubricant film has to be put between the two surfaces of the kinematic pair to ensure proper lubrication. The growth of a thin lubrication film in this case is a function of the coalescence and the speed of drop impact. Not always too high-speed are able to ensure an uniform lubricant film. In the tribology field the high-speed can cause phenomena of instability of the lubricant film. In many industrial applications it is interesting to have atomization with low output speed, In this work an atomiser pressure-swirl for the atomization of fuel oil, is studied to oil lubricants applications. The aim of the paper is to compare the design t parameters of the industrial nozzle le (pressure, density, temperature, etc.) that are sufficient for proper atomization, with parameters that governs the phenomenon of atomization. The first results of this research show how the pressure-swirl atomizer has an output rate lower than that obtained by imposing the critical Weber. The atomization diagnostic of a pressure swirl has to be studied by other parameters than minimum Weber number above which there is atomization.

Brief Biography of the Speaker:
Vincenzo Niola is professor of Applied Mechanics at Naples University Federico II since 31 march 1987. After he got an Univerisity Degree in Mechanical Engineering, he started in january 1978 didactics activity as helper at course of Applied Mechanics and Machines et as member of their committee of examination. Since september 1979 he carried on that collaboration as owner of a scholarship from C.N.R. (National Research Council). Since december 1981 to march 1987 he was a researcher carrying on the practice course for Applied Mechanics, taking a part at examination meeting and working as proposer in many degree thesis. Since 1981 to 1984 he carried on his didactics activity as university teacher for Bioengineering course of locomotive apparatus at Orthopaedy and Traumathology specialization school of 2th Department of Medicine and Surgery of Naples University. Since 31 March 1987 is professor of Applied Mechanics at Naples University Federico II, and since A.A. 86/87 to A.A. 92/93 he carried on the Applied Mechanics and Machines course for electronic engineers, and since A.A. 93/94 to today carry on the Applied Mechanics course for computer science engineers. Since A.A. 88/89 to 89/90 he carried on as supply teacher the Applied Mechanics course for building engineers at Salerno Engineering University. By A.A. 94/95 to A.A. 97/98 he carried on as supply professor Tribology course at Naples University Federico II. By A.A. 2001/2002 he holds the chair of Applied Mechanics for University Degree of "Orthopaedic Technician" at 2th Department of Medicine and Surgery of Naples University. Since A.A. 2005/2006 is professor of Tribology and of Complements of Mechanics. During this years Prof. Vincenzo Niola has been the chairman of his courses examination meetings, and was proposer of many degree thesis.. During his activity Prof. Vincenzo Niola was owner of financings from MURST and (in past and present) cooperate scientifically with research corporation and national industries (MERISINTER, MONTEFLUOS, INDESIT, ALENIA, C.I.R.A.). He's scientific member of Naples research unit for PRIN 2003. He's fellow of Italian Association of Theoretical and Applied Mechanics (AIMETA). He's member of IFToMM Linkages on cams committee. He belongs to the International Scientific Committee of the "World Scientific and Engineering Academy and Society (WSEAS). He is President of the WSEAS Italy Chapter on the "Analysis of the Mechanical Systems". He was been Chairman and "invited author" in some session of Internatinal Conferences. He's author of more than 130 national and international papers.