Magnetic Resonance Velocimetry of a Turbine Blade With Engine-Representative Internal and Film Cooling Structures

Abstract

Abstract As a key technology to ensure the survival of turbine blade, gas turbine cooling encompasses a whole range of cooling strategies with ever-increasing geometric complexities. Flow measurement for turbine blade with such intricate internal and external cooling structures is very challenging, and calls for non-intrusive, three-dimensional measuring techniques. As a response, this work measures the three-dimensional velocity field in a gas turbine blade cooling design by Magnetic Resonance Velocimetry (MRV). A scaled GE-E3 turbine blade with engine-representative internal and film cooling structures was employed. The internal cooling structure includes leading edge impingement cooling, U-shaped serpentine passage with/without turbulence ribs at blade mid-chord and trailing edge pin fins. The external cooling structure includes film holes near the leading edge stagnation point, at the blade tip and in the trailing edge. The experiment was performed using water as the working fluid and the Reynolds number local to the leading edge, mid-chord and trailing edge cooling channels is 1.3 × 103, 5.1 × 103 and 2.3 × 103, respectively, which falls within the range typically found in literature. This is the first time that MRV is used to measure the flow field of a gas turbine blade with all the typical internal and external cooling geometries combined. The results show that MRV has great capacity in measuring the complex fluid flow of a gas turbine blade cooling design. Vortical flow features in leading edge impingement cooling, and at the U-bends of three-pass serpentine channel are captured. Interestingly, internal flow around pin fins at the blade trailing edge redistributes the velocity of external flow injected from trailing edge slots and film holes, indicating strong coupling between the internal and film cooling flow of the turbine blade.