EXPERIMENTAL STUDY ON FACTORS AFFECTING THE END EFFECT FOR NITROGEN FLOW IN MICRO TUBE

In this work, we studied factors affecting the end effect in microtubes by conducting nitrogen microscale flow experiments in 31~100 μm tubes under the conditions of 5~20 MPa and 25~60℃. We proposed the double tube-length differential pressure calculation method for end-effects induced additional differential pressure Δ p _end. Using this method, it is found that there is a negative correlation between Δ p _endand tube diameter d, and Δ p _endincreases monotonically with the flow velocity v. The effect of pressure on Δ p _endis not significant under low flow rate conditions, however Δ p _endincreases with increasing pressure under high flow rate conditions. Under the experimental conditions in this paper, temperature has little effect on Δ p _end. Finally, we established an empirical model to describe the relationship between Δ p _endand v, d.