Due to a complex channel structure, the coolant flow supplied to the internal cooling passage of a gas turbine blade shows an asymmetrical pattern rather than a fully developed or uniform distribution. In this study, the effect of the non-uniform inlet velocity profile of the coolant on the flow and heat transfer in a ribbed channel was investigated using the numerical analysis method. Four inlet velocity profiles were applied to a stationary ribbed channel and three Reynolds numbers of 10,000, 20,000 and 30,000 were considered. The hydraulic diameter of the channel was 24 mm and the rib installation angle was 60°. The rib height-to-hydraulic-diameter ratio (e/Dh) and the rib-pitch-to-height-ratio (P/e) were 0.125 and 10, respectively. Numerical analysis results showed that in the entrance region, the location and shape of the reattachment and the recirculation region were altered by the local velocity distribution caused by the different inlet velocity profiles. Therefore, the distribution and the strength of the vorticity in the channel were changed, and the local heat transfer coefficient and pressure drop in the channel were affected by the inlet velocity profile. The overall heat transfer coefficients for all cases showed similar values, however, the fully developed flow profile resulted in the highest thermal performance factor due to the lowest value of friction factor.
|Number of pages||12|
|Journal||International Journal of Heat and Mass Transfer|
|Publication status||Published - 2016 Jan 1|
Bibliographical noteFunding Information:
This work was supported by the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20144010200770 ) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2012R1A1A2008083 ).
© 2015 Elsevier Ltd. All rights reserved.
- Friction factor
- Inlet velocity profile
- Nusselt number ratio
- Ribbed channel
- Thermal performance factor
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes