Flowrate measurement in turbulent liquid metal channel flow using Time-of-Flight Lorentz force velocimetry:experimental investigations and numerical modeling

摘要

Lorentz force velocimetry(LFV)is a suitable non-contact technique to measure flow velocity andflowrates in electrically conducting high-temperature melts.LFV is based on the principles of magnetohydrodynamics: when an electrically conducting fluid passes the field lines produced by a magnetsystem,eddy currents are induced within the fluid.The interactions of the eddy currents with the magnetic fieldgenerate Lorentz forces.Using LFV the counterforce acting on the magnet system is measured.Such aflowmeter consists of a permanent magnet system and an attached digital force sensor.The force recorded bythe flowmeter is proportional to the flowrate Q and depends on both the electrical conductivity σ of the fluidand the spatial distribution of the applied magnet field B.However,in metallurgical applications,σ is oftenunknown or fluctuates in time as it strongly depends on both temperature and composition of the melt.In thepresent paper we investigate a technique called Time-of-Flight Lorentz force velocimetry ToF LFV.In thistechnique,the flowrate can be determined by just cross-correlating the two force signals recorded by twoflowmeters which are arranged one behind the other separated by a certain distance D.Sensing the passage of the triggered vortices,this ToF LFV measures the transit time τ of these vortices.Then we recalculate thevelocity V according to the relation V = D/τ.We experimentally and numerically study turbulent liquid metalflow in the test facility EFCO(electromagnetic flow control channel)using the eutectic alloy GaInSn as a testfluid.Our experiments show that this electromagnetic ToF LFV is well suited to determine the flow velocity andflowrate.The experiments are accompanied by numerical simulations using the commercial program packageFLUENT.