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Matthew Montgomery - One of the best experts on this subject based on the ideXlab platform.

  • Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance
    Journal of Turbomachinery-transactions of The Asme, 2013
    Co-Authors: S. Sakulkaew, Choon S. Tan, Eric Donahoo, Christian Cornelius, Matthew Montgomery
    Abstract:

    Compressor Efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 × 106 to 7 × 106. The results reveal three distinct behaviors of Efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in Efficiency with tip gap is nonmonotonic with an optimum tip gap for maximum Efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the Efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the Efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize Compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall Compressor performance enhancement in terms of Efficiency, pressure rise capability, robustness to end gap variation, and potentially useful operable range broadening.

  • Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance
    Volume 8: Turbomachinery Parts A B and C, 2012
    Co-Authors: S. Sakulkaew, Choon S. Tan, Eric Donahoo, Christian Cornelius, Matthew Montgomery
    Abstract:

    Compressor Efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 to 7×106. The results reveal three distinct behaviors of Efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in Efficiency with tip gap is non-monotonic with an optimum tip gap for maximum Efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the Efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the Efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize Compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall Compressor performance enhancement in terms of Efficiency, pressure rise capability, robustness to end gap variation and potentially useful operable range broadening.© 2012 ASME

Giuseppe Bianco - One of the best experts on this subject based on the ideXlab platform.

S. Sakulkaew - One of the best experts on this subject based on the ideXlab platform.

  • Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance
    Journal of Turbomachinery-transactions of The Asme, 2013
    Co-Authors: S. Sakulkaew, Choon S. Tan, Eric Donahoo, Christian Cornelius, Matthew Montgomery
    Abstract:

    Compressor Efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 × 106 to 7 × 106. The results reveal three distinct behaviors of Efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in Efficiency with tip gap is nonmonotonic with an optimum tip gap for maximum Efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the Efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the Efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize Compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall Compressor performance enhancement in terms of Efficiency, pressure rise capability, robustness to end gap variation, and potentially useful operable range broadening.

  • Compressor Efficiency Variation With Rotor Tip Gap From Vanishing to Large Clearance
    Volume 8: Turbomachinery Parts A B and C, 2012
    Co-Authors: S. Sakulkaew, Choon S. Tan, Eric Donahoo, Christian Cornelius, Matthew Montgomery
    Abstract:

    Compressor Efficiency variation with rotor tip gap is assessed using numerical simulations on an embedded stage representative of that in a large industrial gas turbine with Reynolds number ∼ 2 to 7×106. The results reveal three distinct behaviors of Efficiency variation with tip gap. For relatively small tip gap (less than 0.8% span), the change in Efficiency with tip gap is non-monotonic with an optimum tip gap for maximum Efficiency. The optimum tip gap is set by two competing flow processes: decreasing tip leakage mixing loss and increasing viscous shear loss at the casing with decreasing tip gap. An optimum tip gap scaling is established and shown to satisfactorily quantify the optimal gap value. For medium tip gap (0.8%–3.4% span), the Efficiency decreases approximately on a linear basis with increasing tip clearance. However, for tip gap beyond a threshold value (3.4% span for this rotor), the Efficiency becomes less sensitive to tip gap as the blade tip becomes more aft-loaded thus reducing tip flow mixing loss in the rotor passage. The threshold value is set by the competing effects between increasing tip leakage flow and decreasing tip flow induced mixing loss with increasing tip gap. Thus, to desensitize Compressor performance variation with blade gap, rotor should be tip aft-loaded and hub fore-loaded while stator should be tip fore-loaded and hub aft-loaded as much as feasible. This reduces the opportunity for clearance flow mixing loss and maximizes the benefits of reversible work from unsteady effects in attenuating the clearance flow through the downstream blade-row. The net effect can be an overall Compressor performance enhancement in terms of Efficiency, pressure rise capability, robustness to end gap variation and potentially useful operable range broadening.© 2012 ASME

Mika Luoranen - One of the best experts on this subject based on the ideXlab platform.

  • Centrifugal Compressor Efficiency improvement and its environmental impact in waste water treatment
    Energy Conversion and Management, 2015
    Co-Authors: Juha Viholainen, Aki-pekka Grönman, Pirkko Ukkonen, Kaisa Gronman, Ahti Jaatinen-värri, Mika Luoranen
    Abstract:

    Energy costs typically dominate the life-cycle costs of centrifugal Compressors used in various industrial and municipal processes, making the Compressor an attractive target for energy Efficiency improvements. This study considers the achievable energy savings of using three different diffuser types in a centrifugal Compressor supporting a typical end-use process in a waste water treatment plant. The effect of the energy Efficiency improvements on the annual energy use and the environmental impacts are demonstrated with energy calculations and life-cycle assessment considering the selected Compressor task in the waste water aeration. Besides the achievable energy saving benefits in the wastewater aeration process, the presented study shows the influence of the additional material needed in the diffuser manufacturing on the total greenhouse gas emissions of the Compressor life-cycle. According to the calculations and assessment results, the studied diffuser types have a significant effect on the Compressor energy use and environmental impacts when the Compressor is operated in the aeration task. The achievable annual energy savings in this case were 2.5-4.9% in comparison with the baseline scenario. Also, the influence of the additional material and energy use for manufacturing the diffuser are insignificant compared with the avoided greenhouse gas reduction potential.

Giancarlo Scalabrin - One of the best experts on this subject based on the ideXlab platform.