The Experts below are selected from a list of 12921 Experts worldwide ranked by ideXlab platform

Terenziano Raparelli - One of the best experts on this subject based on the ideXlab platform.

  • externally Pressurized Gas bearings a comparison between two supply holes configurations
    Tribology International, 2009
    Co-Authors: Federico Colombo, Terenziano Raparelli, Vladimir Viktorov
    Abstract:

    Radial vibration of a vertical rotor with externally Pressurized Gas bearings is analyzed. The time-dependent Reynolds equation is solved together with the journal equation of motion to obtain the response characteristics of the bearing system. The bearings are supplied with either one or two sets of supply orifices. Stiffness and flow rate are compared for both cases. Stability maps are obtained at different supply pressures and with different supply orifice diameters. The mass range from orbital stability to instability is studied as a function of supply hole downstream pressure level.

  • discharge coefficients of orifice type restrictor for aerostatic bearings
    Tribology International, 2007
    Co-Authors: Guido Belforte, Terenziano Raparelli, Vladimir Viktorov, Andrea Trivella
    Abstract:

    The paper describes an experimental study conducted in order to determine the supply hole discharge coefficients of externally Pressurized Gas bearings. Tests were carried out on annular orifices and simple orifices with feed pocket. Air consumption and pressure distributions were measured as a function of supply pressure and air gap height for several different orifice and pocket sizes. Discharge coefficients were approximated by an experimental formula based on the Reynolds number and feeding systems geometry.

  • modeling and identification of Gas journal bearings externally Pressurized Gas bearing results
    Journal of Tribology-transactions of The Asme, 2005
    Co-Authors: Vladimi Viktorov, Guido Elforte, Terenziano Raparelli
    Abstract:

    Static and dynamic characteristics of externally Pressurized Gas journal bearings with four supply orifices positioned at the central cross section for rotating shaft displacements near the bearing center are investigated. Results for transfer functions and for Gas-film coefficients derived using the developed mathematical model are compared with the results derived from numerical computations of a nonlinear distributed parameter model of the Gas bearings. Averaging and corrective coefficients are elaborated. The results obtained demonstrate that analytical data are in good agreement with the numerical data for the wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of this type of externally Pressurized Gas bearings possible. Derived analytical relations for transfer functions and for Gas-film coefficients of Gas bearings provide an efficient means for designing rotor-bearing systems.

  • modeling and identification of Gas journal bearings self acting Gas bearing results
    Journal of Tribology-transactions of The Asme, 2002
    Co-Authors: Guido Elforte, Terenziano Raparelli, Vladimi Viktorov
    Abstract:

    A mathematical model is elaborated with analytical relations for transfer functions and for Gas-film stiffness and damping coefficients for self-acting and externally Pressurized Gas journal bearings with four supply orifices positioned at the center plane for rotating shaft displacements near the bearing center. Averaging and corrective coefficients are elaborated. In this paper static and dynamic characteristics of self-acting Gas bearings are investigated. Results derived using the developed mathematical model are compared with the results derived from numerical computations of a non-linear distributed parameter model of the Gas bearings. The results obtained demonstrate that analytical data are in good agreement with the numerical data for wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of self-acting Gas bearings possible. Derived analytical relations for transfer functions and for Gas-film coefficients of Gas bearings provide an efficient means for designing rotor-bearing systems.

Vladimir Viktorov - One of the best experts on this subject based on the ideXlab platform.

  • externally Pressurized Gas bearings a comparison between two supply holes configurations
    Tribology International, 2009
    Co-Authors: Federico Colombo, Terenziano Raparelli, Vladimir Viktorov
    Abstract:

    Radial vibration of a vertical rotor with externally Pressurized Gas bearings is analyzed. The time-dependent Reynolds equation is solved together with the journal equation of motion to obtain the response characteristics of the bearing system. The bearings are supplied with either one or two sets of supply orifices. Stiffness and flow rate are compared for both cases. Stability maps are obtained at different supply pressures and with different supply orifice diameters. The mass range from orbital stability to instability is studied as a function of supply hole downstream pressure level.

  • discharge coefficients of orifice type restrictor for aerostatic bearings
    Tribology International, 2007
    Co-Authors: Guido Belforte, Terenziano Raparelli, Vladimir Viktorov, Andrea Trivella
    Abstract:

    The paper describes an experimental study conducted in order to determine the supply hole discharge coefficients of externally Pressurized Gas bearings. Tests were carried out on annular orifices and simple orifices with feed pocket. Air consumption and pressure distributions were measured as a function of supply pressure and air gap height for several different orifice and pocket sizes. Discharge coefficients were approximated by an experimental formula based on the Reynolds number and feeding systems geometry.

Guoqing Zhang - One of the best experts on this subject based on the ideXlab platform.

  • improvement on load performance of externally Pressurized Gas journal bearings by opening pressure equalizing grooves
    Tribology International, 2014
    Co-Authors: Guoqing Zhang, Tun Liu
    Abstract:

    To improve the load performance of externally Pressurized Gas journal bearings (EPGJBs), the influences of structural parameters of pressure-equalizing grooves (PEGs) such as the length, depth, number and location on the load capacity and stiffness are studied systematically. It is found that the depths of the circumferential PEGs have great impacts on the load performance. Compared with opening the circumferential PEGs, opening the axial PEGs is more helpful to improve the load capacity, even opening only one or two axial PEGs. The layout of the axial PEGs has great influence on the load performance. A group of experiments were performed to verify the simulation results, it is found that the experimental results were in agreement with the simulation results.

Jose Maria Lagaron - One of the best experts on this subject based on the ideXlab platform.

  • Electrospraying assisted by Pressurized Gas as an innovative high-throughput process for the microencapsulation and stabilization of docosahexaenoic acid-enriched fish oil in zein prolamine
    Innovative Food Science and Emerging Technologies, 2019
    Co-Authors: María A. Busolo, Sergio Torres-giner, Carlos Prieto, Jose Maria Lagaron
    Abstract:

    Zein, a prolamine obtained from maize, was employed to encapsulate a fish oil highly enriched with docosahexaenoic acid (DHA) by an innovative process termed electrospraying assisted by Pressurized Gas (EAPG). This technology combines high electric voltage with pneumatic spray to yield a high-throughput encapsulation process. Semi-spherical zein flowable capsules with mean sizes of 1.4 μm containing the DHA-enriched fish oil were produced by EAPG from inert ethanol solutions at room conditions, presenting a high encapsulation efficiency. The oxidative stability tests carried out in the zein microcapsules obtained by EAPG showed that the DHA-enriched fish oil was efficiently protected over storage time. Sensory tests were also performed on fortified reconstituted milk with the freshly prepared zein/DHA-enriched fish oil microcapsules, suggesting negligible oxidation effects after 45 days. The results described herein indicate that EAPG is a promising innovative high-throughput electrospraying-based methodology for the encapsulation of bioactives and, therefore, the resultant DHA-enriched fish oil containing microcapsules can be industrially applied for the formulation of fortified foods. Industrial relevance: An innovative process, termed electrospraying assisted by Pressurized Gas (EAPG), is herein originally presented as a novel encapsulation methodology. This technology is based on the combination of high voltage and pneumatic spray, allowing the formation of microcapsules at room temperature conditions. Thus, EAPG shows a great deal of potential to encapsulate nutraceuticals and other bioactives that are sensitive to thermal degradation and/or oxidation. The resultant bioactive-containing capsules can be, thereafter, applied to develop novel fortified food products.

Tun Liu - One of the best experts on this subject based on the ideXlab platform.

  • improvement on load performance of externally Pressurized Gas journal bearings by opening pressure equalizing grooves
    Tribology International, 2014
    Co-Authors: Guoqing Zhang, Tun Liu
    Abstract:

    To improve the load performance of externally Pressurized Gas journal bearings (EPGJBs), the influences of structural parameters of pressure-equalizing grooves (PEGs) such as the length, depth, number and location on the load capacity and stiffness are studied systematically. It is found that the depths of the circumferential PEGs have great impacts on the load performance. Compared with opening the circumferential PEGs, opening the axial PEGs is more helpful to improve the load capacity, even opening only one or two axial PEGs. The layout of the axial PEGs has great influence on the load performance. A group of experiments were performed to verify the simulation results, it is found that the experimental results were in agreement with the simulation results.