Abstract:
In this work, we studied factors affecting the end effect in microtubes by conducting nitrogen microscale flow experiments in 31 μm~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
pend. Using this method, it can be found that there is a negative correlation between Δ
pend and tube diameter d and Δ
pend increased monotonically with flow velocity
v. The effect of pressure on Δ
pend is not significant under low flow rate conditions, while Δ
pend increases with increasing pressure under high flow rate conditions. Under the experimental conditions in this paper, temperature had little effect on Δ
pend. Finally, we established an empirical model to describe the relationship between Δ
pend and
v,
d.