Effect of Dimples/Protrusion Concavity on Heat Transfer Performance of Rotating Channel
Main Article Content
Abstract
The continuing increase in gas turbine inlet temperature requires additional heat transfer at the trailing edge. Therefore, a large amount of research has been carried out to find a highly efficient cooling process for gas turbine blades. Pin-fins have been widely used in the trailing edge of gas turbines to enhance heat transfer performance. Pin-fins also strengthen the structure between the inlet and outlet faces of the gas turbine. According to previous research, the flow structure and heat transfer characteristics are influenced by many parameters of the pin-fin array, especially the pin-fin shape, height, diameter as well as layout. In this study, instead of changing the structure of the pin-fin array, the work focused on the design of protrusion/dimple points on the leading and trailing edges. Numerical simulations using the SST (Shear Stress Transport) turbulence model were performed to investigate the effect of dimple/protrusion concavity on flow structure and heat transfer characteristics in a rotating channel with pin-fin array. The pin-fins are arranged staggered to each other. The results show that when changing the dimple/protrusion concavity on the leading and trailing edges combined with the rotation speed, the heat transfer efficiency changes positively.
Keywords
Pin-fin array, Dimple, Protrusion, RANS, Nusselt number
Article Details
References
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rectangular channels with elliptic pin fins,
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245–250. (1998).
https://doi.org/10.1016/s0142-727x(98)00003-4
[2] Hwang, J. J., Lu, C. C., Lateral-flow effect on endwall
heat transfer and pressure drop in a pin-fin trapezoidal
duct of various pin shapes, Journal of Turbomachinery,
123(1), 133, (2001).
https://doi.org/10.1115/1.1333093.
[3] Xu, J., Yao, J., Su, P., Lei, J., Wu, J., and Gao, T., Heat
transfer and pressure loss characteristics of pin-fins
with different shapes in a wide channel, In Proceedings
of the ASME Turbo Expo (Vol. 5A-2017). American
Society of Mechanical Engineers (ASME) (2017).
https://doi.org/10.1115/GT2017-63761.
[4] Sparrow, E. M., Ramsey, J. W., Altemani, C. A. C.,
Experiments on in-line pin fin arrays and performance
comparisons with staggered arrays, Journal of Heat
Transfer, 102(1), 44, (1980)
https://doi.org/10.1115/1.3244247.
[5] Chyu, M. K., Heat transfer and pressure drop for short
pin-fin arrays with pin-endwall fillet. Journal of Heat
Transfer, 112(4), 926–932. (1990).
https://doi.org/10.1115/1.2910502.
[6] Ostanek, J. K., and Thole, K. A. Effects of varying
streamwise and spanwise spacing in pin-fin arrays, In
Proceedings of the ASME Turbo Expo (Vol. 4, pp. 45–
57), (2012).
https://doi.org/10.1115/GT2012-68127.
[7] Chyu, M. K., Siw, S. C., and Moon, H. K., Effects of
height-to-diameter ratio of pin element on heat transfer
from staggered pin-fin arrays, In Proceedings of the
ASME Turbo Expo (Vol. 3, pp. 705–713), (2009).
https://doi.org/10.1115/GT2009-59814.
[8] Rao, Y., Wan, C., and Zang, S., Comparisons of flow
friction and heat transfer performance in rectangular
channels with pin fin-dimple, pin fin and dimple
arrays, In Proceedings of the ASME Turbo Expo
(Vol. 4, pp. 185–195), (2010).
https://doi.org/10.1115/GT2010-22442.
[9] Rao, Y., Wan, C., Xu, Y., An experimental study of
pressure loss and heat transfer in the pin fin-dimple
channels with various dimple depths, International
Journal of Heat and Mass Transfer, 55(23-24), 6723–
6733. (2012)
https://doi.org/10.1016/j.ijheatmasstransfer.2012.06.081.
[10] Rao, Y., Xu, Y., Wan, C., An experimental and
numerical study of flow and heat transfer in channels
with pin fin-dimple and pin fin arrays, Experimental
Thermal and Fluid Science, 38, 237–247, 2012.
https://doi.org/10.1016/j.expthermflusci.2011.12.012.
[11] Luo, L., Wang, C., Wang, L., Sunden, B. A., Wang, S.,
Heat transfer and friction factor in a dimple-pin fin
wedge duct with various dimple depth and converging
angle. International Journal of Numerical Methods for
Heat and Fluid Flow, 26(6), 1954–1974. (2016)
https://doi.org/10.1108/hff-02-2015-0043.
[12] ANSYS CFX-19.1, 2018, ANSYS Inc.
[13] Dittus, F. W., Boelter, L. M., Heat transfer in
automobile radiators of the turbulator type, University
of California, Berkeley Publication, 02, 443–461,
1930.