Session: 15-04 Turbulated Cooling

Paper Number: 122753

122753 - Heat Transfer Enhancement for Gas Turbine Blade Internal Cooling With Lattice Structured Rib 

In gas turbines, achieving higher efficiency requires an increase in the turbine inlet temperature. However, this elevated temperature can lead to thermal deformation of the turbine blades due to the high-temperature mainstream flow. To address this issue, various methods have been proposed by researchers to enhance gas turbine blade cooling systems. These cooling systems can be broadly categorized into surface film cooling and blade internal cooling.

This study specifically focuses on blade internal cooling to improve gas turbine cooling efficiency. Many researchers have explored methods to enhance cooling efficiency within internal cooling channels, utilizing traditional structures such as normal rib turbulent generators, pin fins, dimples, and others. Nevertheless, recent research suggests that open-cell porous media, including metal foam and lattice structures, offer several advantages compared to other previous passive heat transfer enhancement methods such as fins and normal rib structures.

Among these open-cell porous media, non-stochastic cell structures, such as lattice structures, exhibit substantial advantages over stochastic cell structures like metal foam in terms of increasing gas turbine blade cooling efficiency. Lattice structures eliminate contact thermal resistance between the 3D lattice structure and the cooling channel wall where the structure is located. Additionally, the configuration, porosity, shape, and topology of the struts in lattice structures can be customized for specific cases. This means that the thermo-hydraulic performance in the cooling channel can be more accurately predicted compared to stochastic cell structures.

This study numerically investigates the use of lattice-structured ribs within the gas turbine blade's internal cooling channels to enhance heat transfer performance. Conjugate heat transfer is employed to evaluate the heat transfer performance of these lattice-structured ribs. The numerical model used in this study is validated with experimental results from channel flow, including a fully-filled rib model. A constant temperature boundary condition is applied to the bottom wall of the middle section of the channel. The k-ω and SST models are used as turbulence models, providing accurate predictions of flow separation near the wall region.

Comparing the heat transfer performance of ribs with a lattice structure to that of the fully-filled rib model, the simulation results reveal that the flow passing through the lattice structure is mixed with the bypass flow at downstream. Consequently, the heat transfer performance of ribs with a lattice structure is enhanced due to the flow mixing effect and the increased surface area compared to the heat transfer performance of the fully-filled rib model.

Presenting Author: Sangmin Kim Pusan National University

Presenting Author Biography: Sangmin Kim received his undergraduate degree from Pusan National University, South Korea in 2018. Currently, he is pursuing integrated Ph.D. at Pusan National University, Korea. His research interests are focused on Heat Exchanger, finite volume method, gas turbine blade, ANN and computational fluid dynamics.

Authors:

Sangmin Kim Pusan National University
Yong Gap Park Changwon National University
Sang Youl Yoon Rolls-Royce University Technology Center in Pusan National University
Man Yeong Ha Pusan National University
June Kee Min Pusan National University