Magnetic resonance velocimetry and applications ininternal channels of turbine blades
Magnetic resonance velocimetry(MRV)is based on the electromagnetic characteristics of the nucleus.It can obtain the velocity distribution by analyzing the phase difference of the Larmor precession under the gradient magnetic field.Compared with optical measurement techniques,MRV can rapidly obtain the 3D flow field in a space with complicated geometry.By MRV,the spatial distribution of the 3D velocity in the multi-pass channel was measured.Combined with the heat transfer distribution characteristics of multi-pass channels,the characteristics of the flow field and the flow structures affecting heat transfer enhancement in the ribbed channel were analyzed.The coupling mechanism of flow heat transfer was explored.Results indicate that MRV has the capability to accurately resolve the complex 3D flow in a multi-pass channel.The flow field near the bend has complex three-dimensional characteristics.The secondary flow is obvious on the cross-sections near the bends of the multi-pass channel.The main reason for local heat transfer enhancement is the impingement toward the endwall which is driven by the secondary flow induced by the rib turbulator.
magnetic resonance velocimetry3D flow field measurementmulti-pass ribbed channelsecondary flowflow and heat transfer
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