Numerical Investigation on the Flow and Heat Transfer Characteristics of the Flow-Around Rib Channel

To further improve the heat transfer performance and reduce the pressure loss in the internal cooling of gas turbine blade, the flow and heat transfer characteristics of six rib structures in the rectangular channel were numerically studied by CFX software under the Reynolds number of 20 000-80 000. The aspect ratio of the rectangular channel was 4:1, and the rib spacing to rib height ratio (p/e) was 10. The results show that the recirculation zone has a great influence on the heat transfer performance downstream of the rib, and weakening the recirculation zone will reduce the heat transfer performance. The flow-around rib can eliminate the heat transfer deterioration area near the bottom of the leading/trailing edge of the solid rib channel, and the square flow-around rib channel has better thermal performance than the circular flow-around rib channel. For the flow-around rib channels, with the decrease of the rib cross-sectional area reduction ratio ψ, the thermal performance of the channel improves, but the friction factor is increased. The square flow-around ribs with large side-lengths obtain the best thermal performance and heat transfer performance among the ribs studied in this paper. Compared with the solid ribs, the area average Nusselt number of the square flow-around ribs with large side-lengths increases by 0.92%-2.73%, and the friction factor in the heating section decreases by 10.89%-11.01%, which makes the thermal performance factor increase by 4.92%-6.75%. © 2021, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.