Experimental study on evaporation of pentane from a heated capillary slot

• An experimental investigation of evaporation of a pentane meniscus from a heated capillary slot is presented.
• A novel aspect is that both the wicking height and steady state evaporation mass flow rate are measured simultaneously.
• From this data an apparent contact angle is estimated and compared to that obtained from evaporating thin-film theory.
• Both show similar trends but the estimated contact angle is slightly larger.
• Depression of meniscus with heat input is primarily due to change in apparent contact angle.

An experimental investigation of evaporation of a pentane meniscus from a heated capillary slot is presented. A novel aspect of this study is that both the wicking height and steady state evaporation mass flow rate are measured simultaneously. Based on a macroscopic force balance, the apparent contact angle of the evaporating meniscus is experimentally estimated from the wicking height and mass flow rate. This is compared with the results obtained using evaporating thin-film theory. The experimentally estimated contact angle is slightly larger than that obtained from the thin-film model but both show similar trends. Further, it is found that the reduction in the meniscus height is primarily due to an increase in the apparent contact angle. The liquid and vapor pressure drops in the capillary are insignificant relative to the capillary pressure.