International Scientific Journal

Thermal Science - Online First

online first only

Influence of twisted tape insert on the coolant flow characteristics in swirled film cooling

The Present paper discusses film cooling behavior through numerical simulation in the presence of a twisted tape insert inside the film hole. The twisted tape insert imparts a swirl to the coolant flow. Coolant swirl intensity is controlled by varying the pitch of the twisted tape resulting in swirl numbers (S) of 0.0289, 0.116 and 0.168. The film cooling performance is evaluated using area-averaged effectiveness and heat transfer coefficient for blowing ratios of 0.5, 1.0, 1.5 and 2.0. Results revealed a significant amount of improvement in averaged effectiveness with the addition of swirl. Coolant swirl predominantly modifies the jet trajectory resulting in a reduced jet penetration and increased lateral expansion. Further investigation on the effect of twisted tape thickness on the coolant distribution has been found to be negligible. Pressure losses occurring due to the insertion of twisted tape inside the film hole is evaluated through the coefficient of discharge which indicated the necessity of higher pumping power than the film cooling case with no-swirl.
PAPER REVISED: 2021-07-22
PAPER ACCEPTED: 2021-07-26
  1. Han, J.-C., et al., Gas Turbine Heat Transfer And Cooling Technology, Second Edition, 2012
  2. Bunker, R.S., A Review Of Shaped Hole Turbine Film-Cooling Technology, J. Heat Transfer, 127 (2005), 4, pp. 441
  3. Tian, K., et al., Effect Of Combined Hole Configuration On Film Cooling With And Without Mist Injection, Therm. Sci., 22 (2018), 5, pp. 1923-1931
  4. Wang, J., et al., Effect Of Spherical Blockage Configurations On Film Cooling, Therm. Sci., 22 (2018), 5, pp. 1933-1942
  5. Ravi, D., Parammasivam, K.M., Enhancing Film Cooling Effectiveness In A Gas Turbine End-Wall With A Passive Semi Cylindrical Trench, Therm. Sci., 23 (2019), 3, pp. 2013-2023
  6. Uk, J., et al., Optimization Of The Coanda Bump To Improve The Film Cooling Effectiveness Of An Inclined Slot, Int. J. Therm. Sci., 139 (2019), February, pp. 376-386
  7. Zheng, D., et al., Numerical Investigation On The Effect Of Vortex Generator Shapes On Film Cooling Performance, Thermophys. Aeromechanics, 26 (2019), 3, pp. 455-460
  8. Barahate, S.D., Vedula, R.P., Film Cooling Performance Measurement Over A Flat Plate For A Single Row Of Holes Embedded In An Inclined Trench, Int. J. Therm. Sci., 150 (2020), December 2019, pp. 106215
  9. Taheria, Y., et al., Multi-Objective Optimization Of Three Rows Of Film Cooling Holes By Genetic Algorithm, Therm. Sci., (2020), 0, pp. 230-230
  10. Kavsaoglu, M.S., Schetz, J.A., Effects Of Swirl And High Turbulence On A Jet In A Crossflow, J. Aircr., 26 (1989), 6, pp. 539-546
  11. Niederhaus, C.E., et al., Scalar Transport In A Swirling Transverse Jet, AIAA J., 35 (1997), 11, pp. 1697-1704
  12. Denev, J.A., et al., Structure and mixing of a swirling transverse jet into a crossflow, Proceedings, 4th International Symposium on Turbulence and Shear Flow Phenomena, 2005, pp. 1255-1260
  13. Takeishi, K., et al., Film Cooling With Swirling Coolant Flow, WIT Trans. Eng. Sci., 68 (2010), pp. 189-200
  14. Oda, Y., et al., Large Eddy Simulation Of Film Cooling With Swirling Coolant Flow, ASME/JSME Therm. Eng. Jt. Conf., 38921 (2011), pp. T10102
  15. Yang, X., et al., Numerical Analysis On Effects Of Coolant Swirling Motion On Film Cooling Performance, Int. J. Heat Mass Transf., 90 (2015), pp. 1082-1089
  16. Jiang, Y., et al., Investigation On Film Cooling With Swirling Coolant Flow By Optimizing The Inflow Chamber, Int. Commun. Heat Mass Transf., 88 (2017), September, pp. 99-107
  17. Ashwani K. Gupta, D. G. Lilley, N.S., Swirl Flows, Abacus Press, 1984
  18. Kumar, S.S., et al., Local Heat Transfer Distribution On A Flat Plate Impinged By A Swirling Jet Generated By A Twisted Tape, Int. J. Therm. Sci., 111 (2017), pp. 351-368
  19. ANSYS Inc., ANSYS FLUENT Theory Guide, ANSYS FLUENT 16.0.0, Cononsburg, PA, USA, 2014
  20. Mahesh, K., The Interaction Of Jets With Crossflow, Annu. Rev. Fluid Mech., 45 (2013), pp. 379-407