Fangzhou Zhao

Acoustofluidic technology enables the precise motion control of microfluids and their suspended matter through microscale flow channels or acoustic streaming mechanisms, featuring multi-functionality, high throughput, dynamic controllability, fast response, high precision, and low energy consumption. In recent years, numerous literatures have reviewed the development of acoustofluidic technology, discussing the acoustic manipulation modes of particles in microfluids and their applications. However, research on the surface acoustic wave-based acoustic manipulation of particles and fluids in different microfluids remains scarce. This paper aims to provide a comprehensive review of this topic, delving into the fundamental principles of surface acoustic wave-based acoustofluidic technology and discussing the latest advancements in this field. First, the basic theory of acoustofluidic technology is introduced along with the forces involved in manipulating particles and fluids, then the advantages and disadvantages of different types of surface acoustic wave devices are reviewed. Microfluids are categorized into two main types: Fluids within microchannels and droplets on open surfaces. The surface acoustic wave-based acoustic manipulation methods for their internal fluids and suspended particles are discussed separately. Subsequently, the advantages and limitations of surface acoustic wave-based platforms in the acoustic manipulation of fluids and particles are analyzed. The work concludes with a summary of the challenges faced by acoustic streaming in the field of fluid and particle manipulation, followed by prospects for the future development of acoustofluidic technology. Document Type: Invited review Cited as: Peng, L., Zhou, Y., Guan, W., Zhao, F. Surface acoustic wave manipulation of fluids and suspended particles in microchannels and sessile droplet: A review. Capillarity, 2025, 17(1): 1-15. https://doi.org/10.46690/capi.2025.10.01

The imbibition process plays a crucial role in the development of shale reservoirs, particularly during the volume fracturing and water injection development phases. This process significantly influences the production capacity of shale and also serves as a essential parameter for assessing reservoir performance. Clay minerals contribute to the formation of numerous micro-pores and micro-fractures, exhibit strong plasticity and are prone to swelling. The unique structures and properties of clay minerals have a profound impact on shale imbibition. This review analyzes the effects of clay minerals on imbibition from different perspectives, finding that the effect is closely related to the total amount of clay minerals, as well as to specific mineral types and content. Clay minerals exhibit a dual impact on imbibition, which can either facilitate imbibition by promoting micro-fractures formation or hinder it by reducing pore throats and migrating to block flow paths due to swelling. While capillary action is usually considered the main mechanism for fluid displacement during the imbibition, the osmotic pressure formed by clay minerals can also serve as a driving force for imbibition, positively contributing to shale oil and gas recovery. This review aims to provide a comprehensive understanding of the role of clay minerals on the imbibition, providing a theoretical foundation and practical guidance for future research and efficient development of shale reservoirs. Document Type: Invited review Cited as: Wang, L., Wang, H., Xia, X., Zhao, F., Masoodi, R., Xia, Y. The effects of clay minerals on imbibition in shale reservoirs: A review. Capillarity, 2025, 14(1): 13-22. https://doi.org/10.46690/capi.2025.01.02