Studies on liquid–liquid interfacial tension with standard dissipative particle dynamics method

Abstract

The interfacial tension of immiscible liquid–liquid interface is studied with a standard dissipative particle dynamics (DPD) method, in which two different interfacial tension measuring approaches, i.e. the Irving–Kirkwood approach and droplet retraction approach, are employed. The droplet retraction approach predicts a lower interfacial tension than that predicted by the Irving–Kirkwood approach. With the origin standard DPD method, the conservative parameter between different species () plays an important role in the prediction of the interfacial tension. The smaller the , the more accurate results are obtained. A low-density gap is found around the interface of the standard DPD simulation with a large . For simulating droplet deformation in elongation flow, the large density gap found on the interface between the droplet and its surrounding fluid is believed to be the reason of the overestimation of the interfacial tension. By reducing the compressibility of origin DPD fluid, a better agreement of the interfacial tensions found between these two approaches to be obtained. It also permits a close agreement with the experimental work for droplet deformation in an elongation flow.