Numerical Evaluation of Flow Through a Microchannel with Sudden Contractions: Dynamic Aspects

The objective of the work presented is to characterize the dynamic aspect of a microchannel flow with a sudden contraction, for two aspect ratios σ (outlet cross-section/inlet cross-section) of 0.284 and 0.39 and hydraulic diameter of the outlet section is 0.08 mm and Reynolds number values varying from 100 to 1800. The results of this simulation showed the appearance of fluid flow contraction just after the sudden contraction. It can be seen that the dynamic flow parameters, namely, establishment length, reattachment length increase proportionally with Reynolds number and cross-section ratio σ. Our calculations are validated by comparison with experimental measurements and theoretical values, and by numerical correlations. A comparison of the results obtained with conventional theory showed a difference on the singular pressure drop coefficients, while our results are in good agreement with experimental results conducted in mini and microchannels, concerning the singular pressure drop coefficient. These results have been adopted by many researchers working in the field of mini and micro-fluidics. Based on our numerical simulation results, accuracy correlations have been established for Reynolds numbers ranging from 100 to 1800 for aspect ratios σ of 0.284 and 0.39.