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.
关键词
核磁共振成像测速/三维流场测量/多流程肋化通道/二次流动/流动传热
Key words
magnetic resonance velocimetry/3D flow field measurement/multi-pass ribbed channel/secondary flow/flow and heat transfer
维普
万方数据