Session: 15-01 Impingement Cooling I

Paper Number: 121343

121343 - Numerical Study on Effects of Different Corrugated Height and Initial Crossflow on Impingement Jet Heat Transfer 

Today, more efficient gas turbines are required to realize a decarbonized society. To improve gas turbine performance, it is important to increase turbine inlet temperature and to decrease the mass flow rate of turbine cooling air. Impingement cooling is well-known as an effective heat transfer method, and it is commonly used to cool high temperature turbine components. One of the key problems found with impingement cooling is that crossflow created by upstream impingement negatively impacts the performance of downstream jets. Literature shows that corrugated style impingement geometries are a reliable and effective way to manage crossflow. Meanwhile, the growing capabilities of additive manufacturing enable corrugated geometries to be manufactured more easily and offer a new level of flexibility in the design space. However, the internal space of airfoil is limited, limiting the maximum corrugated height. Therefore, it is important to clarify the impact of corrugated height in crossflow mitigation, to understand the key flow mechanisms and to consider the effects in high crossflow scenarios found in larger impingement hole arrays.

In this study, the effect of corrugated height and initial crossflow on impingement jet heat transfer are numerically investigated. To quantify performance, pumping power and Nusselt number are compared between flat plate, low corrugated type and high corrugated type impingement geometries. A control volume methodology is implemented to evaluate the contributions of crossflow and impingement to overall loss. Vortical structures are visualised to analyse the key mechanisms by which crossflow interacts with succeeding impingement jets. Impingement jet diameter, jet to jet pitch and distance from impingement plate to target plate are kept the same for each structure. Calculations are performed for Reynolds numbers of 10,000 and an SST k-ω turbulence model is used. The results of the study show that under the low crossflow condition, Nusselt number enhancement is 5-10% and increases up to 20% under the high crossflow condition, even at a small corrugated height. Improved cooling allows designers to decrease the mass flow rate of cooling air, enabling improved gas turbines efficiency.

Presenting Author: Masayoshi Hatta Mitsubishi Heavy Industries, Ltd.

Presenting Author Biography: Masayoshi Hatta received Master of Science degree in mechanical engineering from Osaka Prefecture University in 2012. He joined Mitsubishi Heavy Industries in 2012 and works as a gas turbine design engineer at MHI Takasago Factory in Japan. He also has experience working at Mitsubishi Power Americas as a gas turbine service engineer in 2018 and as a visiting researcher at the University of Oxford in 2023. He is a member of Gas Turbine Society of Japan.

Authors:

Masayoshi Hatta Mitsubishi Heavy Industries, Ltd.
Thomas Merritt-Webster University of Oxford
Budimir Rosic University of Oxford