The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform

Thomas E Strangmen - One of the best experts on this subject based on the ideXlab platform.

  • resistance of silicon nitride turbine components to erosion and hot corrosion oxidation attack
    1994
    Co-Authors: Thomas E Strangmen
    Abstract:

    Silicon nitride turbine components are under intensive development by AlliedSignal to enable a new generation of higher Power density Auxiliary Power Systems. In order to be viable in the intended applications, silicon nitride turbine airfoils must be designed for survival in aggressive oxidizing combustion gas environments. Erosive and corrosive damage to ceramic airfoils from ingested sand and sea salt must be avoided. Recent engine test experience demonstrated that NT154 silicon nitride turbine vanes have exceptional resistance to sand erosion, relative to superalloys used in production engines. Similarly, NT154 silicon nitride has excellent resistance to oxidation in the temperature range of interest - up to 1400 C. Hot corrosion attack of superalloy gas turbine components is well documented. While hot corrosion from ingested sea salt will attack silicon nitride substantially less than the superalloys being replaced in initial engine applications, this degradation has the potential to limit component lives in advanced engine applications. Hot corrosion adversely affects the strength of silicon nitride in the 850 to 1300 C range. Since unacceptable reductions in strength must be rapidly identified and avoided, AlliedSignal and the NASA Lewis Research Center have pioneered the development of an environmental life prediction model for silicon nitride turbine components. Strength retention in flexure specimens following 1 to 3300 hour exposures to high temperature oxidation and hot corrosion has been measured and used to calibrate the life prediction model. Predicted component life is dependent upon engine design (stress, temperature, pressure, fuel/air ratio, gas velocity, and inlet air filtration), mission usage (fuel sulfur content, location (salt in air), and times at duty cycle Power points), and material parameters. Preliminary analyses indicate that the hot corrosion resistance of NT154 silicon nitride is adequate for AlliedSignal's initial engine applications. Protective coatings and/or inlet air filtration may be required to achieve required ceramic component lives in more aggressive environments.

  • Resistance of Silicon Nitride Turbine Components to Erosion and Hot Corrosion/oxidation Attack
    1994
    Co-Authors: Thomas E Strangmen
    Abstract:

    Silicon nitride turbine components are under intensive development by AlliedSignal to enable a new generation of higher Power density Auxiliary Power Systems. In order to be viable in the intended applications, silicon nitride turbine airfoils must be designed for survival in aggressive oxidizing combustion gas environments. Erosive and corrosive damage to ceramic airfoils from ingested sand and sea salt must be avoided. Recent engine test experience demonstrated that NT154 silicon nitride turbine vanes have exceptional resistance to sand erosion, relative to superalloys used in production engines. Similarly, NT154 silicon nitride has excellent resistance to oxidation in the temperature range of interest - up to 1400 C. Hot corrosion attack of superalloy gas turbine components is well documented. While hot corrosion from ingested sea salt will attack silicon nitride substantially less than the superalloys being replaced in initial engine applications, this degradation has the potential to limit component lives in advanced engine applications. Hot corrosion adversely affects the strength of silicon nitride in the 850 to 1300 C range. Since unacceptable reductions in strength must be rapidly identified and avoided, AlliedSignal and the NASA Lewis Research Center have pioneered the development of an environmental life prediction model for silicon nitride turbine components. Strength retention in flexure specimens following 1 to 3300 hour exposures to high temperature oxidation and hot corrosion has been measured and used to calibrate the life prediction model. Predicted component life is dependent upon engine design (stress, temperature, pressure, fuel/air ratio, gas velocity, and inlet air filtration), mission usage (fuel sulfur content, location (salt in air), and times at duty cycle Power points), and material parameters. Preliminary analyses indicate that the hot corrosion resistance of NT154 silicon nitride is adequate for AlliedSignal's initial engine applications. Protective coatings and/or inlet air filtration may be required to achieve required ceramic component lives in more aggressive environments.

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

Wael W. El-dakhakhni - One of the best experts on this subject based on the ideXlab platform.

  • Performance of battery rack Auxiliary Power Systems under FEMA 461 quasi-static seismic loading protocol
    Structures, 2020
    Co-Authors: Ahmed Ghith, Mohamed Ezzeldin, Michael Tait, Wael W. El-dakhakhni
    Abstract:

    Abstract The performance of nonstructural components in nuclear Power plants (NPPs), which is primarily based on experience and historical data, has been attracting increased interest from researchers following the Fukushima Daiichi nuclear disaster in 2011. This disaster demonstrated the importance of using batteries in NPPs as an Auxiliary Power system, where such Systems can provide the necessary Power to mitigate the risk of serious accidents. However, little research has been conducted on such nonstructural components (e.g., Auxiliary battery Power Systems) to evaluate their performance following the post-Fukushima safety requirements, recommended by several nuclear regulators worldwide [e.g., Nuclear Regulatory Commission (NRC), and Nuclear Safety Commission (NSC)]. To address this research gap, the current study investigates the lateral performance of an Auxiliary battery Power system similar to those currently existing/operational in NPPs in Canada. The rack system was experimentally tested under displacement-controlled quasi-static cyclic fully-reversed loading that simulates lateral seismic demands, following the FEMA 461 guidelines “Interim testing protocol for determining the seismic performance characteristics of structural and nonstructural components”. Following a brief summary of the experimental program, the test results are presented in terms of the rack hysteretic response, damage sequence, stiffness degradation, ductility capacity, member strains, and local deformations. Subsequently, a simplified mechanistic model and a concentrated plasticity model in OpenSees have been developed and calibrated using the experimental results. The results show that without detailed modeling of the rack system connections (i.e., L-shaped connection and sliding nuts), incorrect performance prediction of such Systems may result. The findings of the current study can be utilized, within the next generation of performance-based seismic design approaches, to enhance the robustness and improve the reliability of damage state predictions of Auxiliary battery Power Systems in critical facilities.

Adisa Dedić - One of the best experts on this subject based on the ideXlab platform.

  • Electricity efficiency of Auxiliary Power Systems in coal thermal Power plant
    International journal of electrical and computer engineering systems, 2020
    Co-Authors: Azrina Mujanović, Tatjana Konjic, Adisa Dedić
    Abstract:

    Renewable energy sources such as hydro, wind and solar energy are taking an increasing share in the electricity mix. However, electricity production from thermal Power plants is independent of the weather conditions and is still important as a back-up Power source to renewable energy sources. Given the fact that the electricity market is open, it is clear that each MWh is important. Therefore, Auxiliary Power Systems as a part of thermal Power plants should be also energy efficient. The main aim of the presented research was to investigate the efficient operation of different consumers in the Auxiliary Power system in the old-dated thermal Power plant ‘’Tuzla’’ depending on different Power at generator output. The performed analysis identified consumers suitable for electricity efficiency improvement giving results of Power savings obtained on modestly available measurements and old-date technical documentation. Following obtained results, some recommendations for improving electricity efficiency were proposed with a rough calculation of possible savings. Measurements of Auxiliary Power system consumption depending on Power at generator output in new thermal Power plant ‘’Stanari’’ was presented. Future trends and directions in thermal Power plant automation were also discussed.

Narinder Trehan - One of the best experts on this subject based on the ideXlab platform.

  • Auxiliary Power System Neutral Grounding and its Performance in Nuclear Power Plants
    1st International Energy Conversion Engineering Conference (IECEC), 2003
    Co-Authors: Narinder Trehan
    Abstract:

    Selection of system grounding for Auxiliary Power Systems in nuclear Power generating stations is an important aspect of the electric Power system. Most design engineers prefer a grounded system, though very few prefer an ungrounded system. A review of reports from 1986 to 2001 showed that the operation of the grounding system occurred due to a ground of main generator stator neutral, vibration Induced wear, cracked busbar Insulator, ground fault in the main generator due to fire, personnel errors, design deficiency, failure of grounding strap/brush in the main generator stator water cooling pumps, long term insulation degradation in the low-voltage side bus duct of a transformer, inadequate procedures, improper ground installation, and ground in the speed control circuit due to moisture in oil. In nuclear Power generating stations, system grounding is recommended (except for the main generator and emergency diesel generator) to provide a safe path for the dissipation of fault currents, lightning strikes, and EMI/RFI signals.* Index Terms -Grounding, generating stations, nuclear Power, solidly grounded, high resistance ground, ungrounded, personnel errors, moisture.