The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform

Nasser Darabiha - One of the best experts on this subject based on the ideXlab platform.

  • Sectional soot model coupled to tabulated chemistry for Diesel RANS simulations
    Combustion and Flame, 2015
    Co-Authors: Damien Aubagnac-karkar, Pauline E. Vervisch-kljakic, O. Colin, Jean-baptiste Michel, Nasser Darabiha
    Abstract:

    In future Euro norms, the soot volume fraction and the soot number density will be regulated. Car manufacturers need therefore accurate soot models for piston Engine emissions prediction in order to develop future Engine concepts. This paper addresses this question by coupling a sectional soot model with a tabulated combustion model for RANS simulations of Diesel Engines. The sectional soot model, based on the work of Netzell et al. (2007), is implemented in the IFP-C3D RANS CFD code. At each time and location, transport equations are solved for several soot sections, including source terms for collisional and chemical processes. The soot model is coupled to a tabulated combustion model derived from the Engine Approximated Diffusion Flame one (EADF) (Michel and Colin, 2013). It allows to represent the minor species required by the soot model with a much lower computational cost than a kinetic solver. In order to evaluate the soot model coupled to the resulting combustion model called Variable Pressure Homogeneous Tabulated Chemistry (VPTHC), it is compared to the same soot model directly coupled to a complex chemistry solver. As this comparison can hardly be performed on a real Diesel Engine Case due to the very high CPU time involved by the chemical solver, it is performed on a variable volume and fuel/air ratio Case which retains the essential features of a Diesel Engine. Results show that the proposed coupling recovers with reasonable accuracy the evolution of the soot volume fraction and distribution. Finally, an experimental database of Diesel operating points is simulated. The database includes points with a commercial Diesel fuel and the computed surrogate (30% 1-Methylnaphthalene and 70% Decane in liquid volume) to validate the models against the experiments. Soot yields predictions from the model show an improvement against the current standards and reach industrial target of accuracy for most of the database while the model also provides a good estimation of the soot particles distributions in size.

P. Tappert - One of the best experts on this subject based on the ideXlab platform.

  • Monitoring blade passage in turbomachinery through the Engine Case (no holes)
    Proceedings IEEE Aerospace Conference, 2002
    Co-Authors: C. Roeseler, A. Von Flotow, P. Tappert
    Abstract:

    It is possible to detect passage of turbomachinery blades without penetrating the Engine Case. This "look through the wall" eddy current sensor eases the addition of a PHM system to an Engine. This paper introduces this sensing concept, summarizes the physics, and presents results of preliminary tests. Blade material and geometry, Case material, thickness and temperature, blade tip clearance, sensor detail and design and blade tip velocity all affect the strength and quality of the signal detected.

  • Autonomous PHM with blade-tip-sensors: algorithms and seeded fault experience
    2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542), 2001
    Co-Authors: P. Tappert, A. Von Flotow, Mathieu Mercadal
    Abstract:

    Blade tip sensors embedded into the Engine Case have been used for decades to measure blade tip clearance and blade vibration. Many sensing technologies have been used; capacitive, inductive, optical, microwave, infra-red, eddy-current, pressure and acoustic. These sensors generate data streams far greater than have been historically used in Engine diagnostic units. Data streams of about 10,000 samples per second per sensor are about the minimum achievable, with some sensor front-ends delivering data streams of greater than 1Megasamples per second per sensor. In a PHM application, this data cannot be stored for later human analysis, but must be analyzed and discarded. This paper outlines autonomous algorithms for the real-time analysis of this data stream for PHM purposes. The application of these algorithms to several seeded fault tests is described. The need for a series of additional seeded fault tests is highlighted, for the purpose of maturing these algorithms prior to introduction into service.

  • Health monitoring and prognostics of blades and disks with blade tip sensors
    2000 IEEE Aerospace Conference. Proceedings (Cat. No.00TH8484), 2000
    Co-Authors: A. Von Flotow, Mathieu Mercadal, P. Tappert
    Abstract:

    Blade tip sensors embedded in the Engine Case have been used for decades to measure blade tip clearance and blade vibration. Many sensing technologies have been used: capacitive, inductive, optical, microwave, infrared, eddy-current, pressure and acoustic. This paper outlines the technology of blade and disk health monitoring with such sensors. The basic measurement techniques are reviewed, along with damage signatures which might be recognized with such sensors. The compromise between system complexity (in terms of sensor count) and data quality is discussed.

  • Health monitoring and prognostics of blades and disks with blade\ntip sensors
    2000 IEEE Aerospace Conference. Proceedings (Cat. No.00TH8484), 2000
    Co-Authors: A. Von Flotow, Mathieu Mercadal, P. Tappert
    Abstract:

    Blade tip sensors embedded in the Engine Case have been used for\ndecades to measure blade tip clearance and blade vibration. Many sensing\ntechnologies have been used: capacitive, inductive, optical, microwave,\ninfrared, eddy-current, pressure and acoustic. This paper outlines the\ntechnology of blade and disk health monitoring with such sensors. The\nbasic measurement techniques are reviewed, along with damage signatures\nwhich might be recognized with such sensors. The compromise between\nsystem complexity (in terms of sensor count) and data quality is\ndiscussed

Damien Aubagnac-karkar - One of the best experts on this subject based on the ideXlab platform.

  • Sectional soot model coupled to tabulated chemistry for Diesel RANS simulations
    Combustion and Flame, 2015
    Co-Authors: Damien Aubagnac-karkar, Pauline E. Vervisch-kljakic, O. Colin, Jean-baptiste Michel, Nasser Darabiha
    Abstract:

    In future Euro norms, the soot volume fraction and the soot number density will be regulated. Car manufacturers need therefore accurate soot models for piston Engine emissions prediction in order to develop future Engine concepts. This paper addresses this question by coupling a sectional soot model with a tabulated combustion model for RANS simulations of Diesel Engines. The sectional soot model, based on the work of Netzell et al. (2007), is implemented in the IFP-C3D RANS CFD code. At each time and location, transport equations are solved for several soot sections, including source terms for collisional and chemical processes. The soot model is coupled to a tabulated combustion model derived from the Engine Approximated Diffusion Flame one (EADF) (Michel and Colin, 2013). It allows to represent the minor species required by the soot model with a much lower computational cost than a kinetic solver. In order to evaluate the soot model coupled to the resulting combustion model called Variable Pressure Homogeneous Tabulated Chemistry (VPTHC), it is compared to the same soot model directly coupled to a complex chemistry solver. As this comparison can hardly be performed on a real Diesel Engine Case due to the very high CPU time involved by the chemical solver, it is performed on a variable volume and fuel/air ratio Case which retains the essential features of a Diesel Engine. Results show that the proposed coupling recovers with reasonable accuracy the evolution of the soot volume fraction and distribution. Finally, an experimental database of Diesel operating points is simulated. The database includes points with a commercial Diesel fuel and the computed surrogate (30% 1-Methylnaphthalene and 70% Decane in liquid volume) to validate the models against the experiments. Soot yields predictions from the model show an improvement against the current standards and reach industrial target of accuracy for most of the database while the model also provides a good estimation of the soot particles distributions in size.

Kaoutar Laazaar - One of the best experts on this subject based on the ideXlab platform.

  • Valorization of Moroccan Olive Cake in Small Scale Bumer Through Stirling Engine: Case Study
    2018 6th International Renewable and Sustainable Energy Conference (IRSEC), 2018
    Co-Authors: Nadia Rassai, Noureddine Boutammachte, Kaoutar Laazaar
    Abstract:

    The purpose of the current study is to valorize Moroccan olive waste in a small-scale burner in order to produce electricity through Stirling Engine. To fulfill this purpose, a comprehensive computational fluid dynamics (CFD) modeling of the combustion of the olive cake was presented, in which the pulverized olive particles are injected into the burner through two concentric injection tubes. The numerical method is based on Reynolds averaged Navier-Stokes (RANS) approach opting the realizable $\mathrm{k}-\varepsilon$ turbulence model for turbulence, the non-premixed combustion model for gas combustion, the Lagrangian method (DPM) for the discrete second and the PI for radiation. The contours of velocity, turbulence kinetic energy, DPM burnout and mass of NO was presented and discussed.

  • Valorization of Moroccan Olive Cake in Small Scale Bumer Through Stirling Engine: Case Study
    2018 6th International Renewable and Sustainable Energy Conference (IRSEC), 2018
    Co-Authors: Nadia Rassai, Noureddine Boutammachte, Kaoutar Laazaar
    Abstract:

    The purpose of the current study is to valorize Moroccan olive waste in a small-scale burner in order to produce electricity through Stirling Engine. To fulfill this purpose, a comprehensive computational fluid dynamics (CFD) modeling of the combustion of the olive cake was presented, in which the pulverized olive particles are injected into the burner through two concentric injection tubes. The numerical method is based on Reynolds averaged Navier-Stokes (RANS) approach opting the realizable k-ε turbulence model for turbulence, the nonpremixed combustion model for gas combustion, the Lagrangian method (DPM) for the discrete second and the P1 for radiation. The contours of velocity, turbulence kinetic energy, DPM burnout and mass of NO was presented and discussed.

A. Von Flotow - One of the best experts on this subject based on the ideXlab platform.

  • Monitoring blade passage in turbomachinery through the Engine Case (no holes)
    Proceedings IEEE Aerospace Conference, 2002
    Co-Authors: C. Roeseler, A. Von Flotow, P. Tappert
    Abstract:

    It is possible to detect passage of turbomachinery blades without penetrating the Engine Case. This "look through the wall" eddy current sensor eases the addition of a PHM system to an Engine. This paper introduces this sensing concept, summarizes the physics, and presents results of preliminary tests. Blade material and geometry, Case material, thickness and temperature, blade tip clearance, sensor detail and design and blade tip velocity all affect the strength and quality of the signal detected.

  • Autonomous PHM with blade-tip-sensors: algorithms and seeded fault experience
    2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542), 2001
    Co-Authors: P. Tappert, A. Von Flotow, Mathieu Mercadal
    Abstract:

    Blade tip sensors embedded into the Engine Case have been used for decades to measure blade tip clearance and blade vibration. Many sensing technologies have been used; capacitive, inductive, optical, microwave, infra-red, eddy-current, pressure and acoustic. These sensors generate data streams far greater than have been historically used in Engine diagnostic units. Data streams of about 10,000 samples per second per sensor are about the minimum achievable, with some sensor front-ends delivering data streams of greater than 1Megasamples per second per sensor. In a PHM application, this data cannot be stored for later human analysis, but must be analyzed and discarded. This paper outlines autonomous algorithms for the real-time analysis of this data stream for PHM purposes. The application of these algorithms to several seeded fault tests is described. The need for a series of additional seeded fault tests is highlighted, for the purpose of maturing these algorithms prior to introduction into service.

  • Health monitoring and prognostics of blades and disks with blade tip sensors
    2000 IEEE Aerospace Conference. Proceedings (Cat. No.00TH8484), 2000
    Co-Authors: A. Von Flotow, Mathieu Mercadal, P. Tappert
    Abstract:

    Blade tip sensors embedded in the Engine Case have been used for decades to measure blade tip clearance and blade vibration. Many sensing technologies have been used: capacitive, inductive, optical, microwave, infrared, eddy-current, pressure and acoustic. This paper outlines the technology of blade and disk health monitoring with such sensors. The basic measurement techniques are reviewed, along with damage signatures which might be recognized with such sensors. The compromise between system complexity (in terms of sensor count) and data quality is discussed.

  • Health monitoring and prognostics of blades and disks with blade\ntip sensors
    2000 IEEE Aerospace Conference. Proceedings (Cat. No.00TH8484), 2000
    Co-Authors: A. Von Flotow, Mathieu Mercadal, P. Tappert
    Abstract:

    Blade tip sensors embedded in the Engine Case have been used for\ndecades to measure blade tip clearance and blade vibration. Many sensing\ntechnologies have been used: capacitive, inductive, optical, microwave,\ninfrared, eddy-current, pressure and acoustic. This paper outlines the\ntechnology of blade and disk health monitoring with such sensors. The\nbasic measurement techniques are reviewed, along with damage signatures\nwhich might be recognized with such sensors. The compromise between\nsystem complexity (in terms of sensor count) and data quality is\ndiscussed