The pressure drop of gas-liquid two-phase flow in microchannel is of fundamental importance in heat and mass transfer processes. In this work

the pressure drop of gas-liquid two-phase flow in horizontal rectangular cross-section microchannels was measured by a pressure differential transducer system. Water

ethanol and

n

-propanol were used as liquid phase to study the effects of capillary number on pressure drop;air was used as the gas phase. Four microchannels with various dimensions of 100 μm×200 μm

100 μm×400 μm

100 μm×800 μm and 100 μm×2000 μm(depth×width) were used for determining the influence of configuration on the pressure drop. Experimental results showed that in micro-scale

the capillary number also affected the pressure drop remarkably

and in spite of only one-fold difference in aspect ratio

the variation of pressure drop reached up to near three times under the same experimental conditions. Taking the effects of aspect ratio and surface tension into account

a modified correlation for Chisholm parameter

C

in the Chisholm model was proposed for predicting the frictional multiplier

Φ

1

2

and the predicted values by the proposed correlation showed a satisfactory agreement with experimental data.