Steady-state pressure drop and heat transfer in He II forced flow at high Reynolds number Original Research Article

An experiment to study forced flow superfluid helium (He II) at high Reynolds number has been recently developed at the national high magnetic field laboratory (NHMFL). The liquid is pushed from a bellows pump through a 1 m long, 9.8 mm inside diameter smooth tube test section to attain a maximum velocity of 18 m/s and a Reynolds number up to 2×107. The test section is instrumented with eight bare chip thermometers, a heater and a differential pressure transducer. Measurements of pressure drop have been performed to determine the friction factor for Reynolds number exceeding 107. These are compared to results from previous forced flow experiments at lower velocities and to some existing correlations. The temperature rise in He II forced flow, due to the isenthalpic expansion in the test section, has also been measured for velocities between 0.5 and 16 m/s. These temperature profiles are related to the Joule–Thomson coefficient. The heater, positioned in the middle of the test section, allows heat transfer measurements and can be used as a thermal flow meter.