Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance

Nekkanti Sitaram; Vanamala Ushasri

doi:doi:10.11648/j.ijfmts.20200603.12

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Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance

Nekkanti Sitaram, Vanamala Ushasri

Published in International Journal of Fluid Mechanics & Thermal Sciences (Volume 6, Issue 3)

Received: 18 May 2020 Accepted: 13 July 2020 Published: 13 August 2020

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Abstract

The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.

Published in	International Journal of Fluid Mechanics & Thermal Sciences (Volume 6, Issue 3) This article belongs to the Special Issue Fluid Mechanics & Thermal Sciences in Turbomachines
DOI	10.11648/j.ijfmts.20200603.12
Page(s)	79-88
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2020. Published by Science Publishing Group

Keywords

Centrifugal Impeller, Chamfered Blade Tip, Computational Fluid Dynamics, Performance Improvement

References

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[2]	Senoo Y. Pressure losses and flow field distortion induced by tip clearance of centrifugal and axial compressors, JSME Int. Jl. 1980 30 (261) 375-385 https://doi.org/10.1299/jsme1987.30.375.
[3]	Sitaram N. and Sridhara T. N. Recent investigations on tip clearance flows in centrifugal compressors, Int. Jl. of Turbo and Jet Engines, 2000, 17 (1) 65-78 10.1515/TJJ.2000.17.1.65.
[4]	Hayami H. Research and development of a transonic turbo compressor, in: Turbomachinery Fluid Dynamics and Heat Transfer, Ch. Hah (Ed.), 1997 Marcel Dekker Inc., New York, 63-82.
[5]	Pampreen R. C. Small turbomachinery compressor and fan aerodynamics, ASME Jl. of Engg. for Power, 1973, 95 (3) pp. 205-212 https://doi.org/10.1115/1.3445730.
[6]	Sitaram N. and Pandey B. Tip clearance effects in a centrifugal compressor rotor, Jl. of the Aero. Society of India, 1990, 42 (2), 309-315.
[7]	Farge T. Z., Johnson M. W. and Maksoud T. M. A. 1989 Tip leakage loss in a centrifugal impeller, ASME Jl. of Turbomach., 1989, 111 (2) 244-249.
[8]	Senoo Y and Ishida M. Pressure loss due to the tip clearance of impeller blades in centrifugal and axial blowers, ASME Jl. of Engg. for Gas Turbines and Power, 1986, 108 (1), 32-37.
[9]	Ubaldi M., Zunino P. and Cattanei A. Relative flow and turbulence measurements downstream of a backward centrifugal impeller, ASME Jl. of Turbomach., 1993, 115, pp. 543-551 https://doi.org/10.1115/1.2929288.
[10]	Hathaway M. D. and Wood J. R. Application of a multi-block CFD code to investigate the impact of geometry modeling on centrifugal compressor flow field predictions, ASME Jl. of Turbomach., 1997, 119 (4) 820-830 https://doi.org/10.1115/1.2841193.
[11]	Ishida M., Ueki H. and Senoo Y. Effect of blade tip configuration on tip clearance loss of a centrifugal impeller, ASME Jl. of Turbomach., 1990, 112 (1) 14-18, https://doi.org/10.1115/1.2927412.
[12]	Sitaram N. and Swamy S. M. Performance improvement of a centrifugal compressor by passive means, International Journal of Rotating Machinery, Volume 2012, Article ID 727259, 9 pages, doi: 10.1155/2012/727259.
[13]	Senthil S. and Sitaram N. Performance improvement of a centrifugal compressor by means of squealer tips, Proc. of the 4^th ICPF, 2002, Beijing, China, 26-29.
[14]	Da Soghe Riccardo, Bianchini Cosimo, Tommaso Rubino Dante and Toni Lorenzo. Effects of impeller squealer tip on centrifugal compressor performance, ASME Jl. of Engg. for Gas Turbines and Power, V. 139, pp. 032603-1 to 032603-7 https://doi.org/10.1115/1.4034541.
[15]	Jung Y., Choi M., Park J. and Baek J. Effects of recessed blade tips on the performance and flow field in a centrifugal compressor, Proc. Inst. Mech. Eng., 2012, Part A Journal of Power and Energy, 227 (2) 157–166 doi: 10.1177/0957650912465278.
[16]	Mahajan Ashvin, Baert Lieven, Leborgne Michaël, Lonfils Timothée, Parwatha I. Gede and Timoshadchenko Denis. Numerical investigation of impeller tip tailoring and its impact on aerodynamic design of a centrifugal compressor’s impeller, ASME Paper No. GT2014-25641, V02DT42A014, ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 2D: Turbomachinery, Düsseldorf, Germany, 2014 12 pages, doi: 10.1115/GT2014-25641.
[17]	Tallman J. A. A computational study of tip desensitization in axial flow turbines, Part 2: Turbine Rotor Simulations with Modified Tip Shapes, ASME Paper GT-2004-53919, ASME Turbo Expo 2004: Power for Land, Sea, and Air, Vienna, Austria, 2004 12 pages, doi: 10.1115/GT2004-53919.

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APA Style

Nekkanti Sitaram, Vanamala Ushasri. (2020). Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. International Journal of Fluid Mechanics & Thermal Sciences, 6(3), 79-88. https://doi.org/10.11648/j.ijfmts.20200603.12

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ACS Style

Nekkanti Sitaram; Vanamala Ushasri. Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. Int. J. Fluid Mech. Therm. Sci. 2020, 6(3), 79-88. doi: 10.11648/j.ijfmts.20200603.12

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AMA Style

Nekkanti Sitaram, Vanamala Ushasri. Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. Int J Fluid Mech Therm Sci. 2020;6(3):79-88. doi: 10.11648/j.ijfmts.20200603.12

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@article{10.11648/j.ijfmts.20200603.12,
  author = {Nekkanti Sitaram and Vanamala Ushasri},
  title = {Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance},
  journal = {International Journal of Fluid Mechanics & Thermal Sciences},
  volume = {6},
  number = {3},
  pages = {79-88},
  doi = {10.11648/j.ijfmts.20200603.12},
  url = {https://doi.org/10.11648/j.ijfmts.20200603.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijfmts.20200603.12},
  abstract = {The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.},
 year = {2020}
}

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TY  - JOUR
T1  - Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance
AU  - Nekkanti Sitaram
AU  - Vanamala Ushasri
Y1  - 2020/08/13
PY  - 2020
N1  - https://doi.org/10.11648/j.ijfmts.20200603.12
DO  - 10.11648/j.ijfmts.20200603.12
T2  - International Journal of Fluid Mechanics & Thermal Sciences
JF  - International Journal of Fluid Mechanics & Thermal Sciences
JO  - International Journal of Fluid Mechanics & Thermal Sciences
SP  - 79
EP  - 88
PB  - Science Publishing Group
SN  - 2469-8113
UR  - https://doi.org/10.11648/j.ijfmts.20200603.12
AB  - The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.
VL  - 6
IS  - 3
ER  -

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Author Information

Nekkanti Sitaram

Department of Mechanical Engineering, IIT Madras, Chennai, India
Vanamala Ushasri

Department of Mechanical Engineering, Osmania University, Hyderabad, India

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APA Style

Nekkanti Sitaram, Vanamala Ushasri. (2020). Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. International Journal of Fluid Mechanics & Thermal Sciences, 6(3), 79-88. https://doi.org/10.11648/j.ijfmts.20200603.12

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ACS Style

Nekkanti Sitaram; Vanamala Ushasri. Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. Int. J. Fluid Mech. Therm. Sci. 2020, 6(3), 79-88. doi: 10.11648/j.ijfmts.20200603.12

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AMA Style

Nekkanti Sitaram, Vanamala Ushasri. Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance. Int J Fluid Mech Therm Sci. 2020;6(3):79-88. doi: 10.11648/j.ijfmts.20200603.12

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@article{10.11648/j.ijfmts.20200603.12,
  author = {Nekkanti Sitaram and Vanamala Ushasri},
  title = {Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance},
  journal = {International Journal of Fluid Mechanics & Thermal Sciences},
  volume = {6},
  number = {3},
  pages = {79-88},
  doi = {10.11648/j.ijfmts.20200603.12},
  url = {https://doi.org/10.11648/j.ijfmts.20200603.12},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijfmts.20200603.12},
  abstract = {The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.},
 year = {2020}
}

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TY  - JOUR
T1  - Computational Investigation of Flow in a Centrifugal Impeller with Chamfered Blade Tips: Effects of Stage Loading and Tip Clearance
AU  - Nekkanti Sitaram
AU  - Vanamala Ushasri
Y1  - 2020/08/13
PY  - 2020
N1  - https://doi.org/10.11648/j.ijfmts.20200603.12
DO  - 10.11648/j.ijfmts.20200603.12
T2  - International Journal of Fluid Mechanics & Thermal Sciences
JF  - International Journal of Fluid Mechanics & Thermal Sciences
JO  - International Journal of Fluid Mechanics & Thermal Sciences
SP  - 79
EP  - 88
PB  - Science Publishing Group
SN  - 2469-8113
UR  - https://doi.org/10.11648/j.ijfmts.20200603.12
AB  - The objective of the present investigation is to examine the possibility of performance improvement, improvement of the exit flow uniformity and desensitization of the tip clearance effects on the performance of a low speed centrifugal impeller. Computational investigations using a commercial CFD software are undertaken. Six configurations of blade tips are investigated. They are square tip (Basic), tip chamfered on pressure surface (P1 and P2), tip chamfered on suction surface (P1 and P2) and tip chamfered on pressure and suction surfaces (PS1). Computations are carried out with optimized multiblock grids for these six configurations at five flow coefficients, namely 0.28 and 0.34 (below design flow coefficient), 0.42 (design flow coefficient) and 0.48 and 0.52 (above design flow coefficient) and at three values of tip clearance, viz., 1% (small value), 2% (nominal value) and 5% (large value) of the blade exit height. From the investigations, it is found that the impeller with the chamfer on suction surface shows small improvement in performance. In addition this configuration has minimum tip clearance sensitivity. A decrease in the chamfer on suction surface further may improve the impeller performance. A maximum percentage of 0.18% improvement in the total pressure coefficient is obtained at 5% tip clearance and a flow coefficient of 0.52 for configuration S2. However chamfer on the pressure surface deteriorates the impeller performance.
VL  - 6
IS  - 3
ER  -

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