Sharif Digital Repository

Oil displacement and recovery efficiency during gas injection depends on the competition between driving forces and capillary resistance that is governed by gas-oil interfacial behavior. Detailed study of the interfacial forces during gas injection is the main objective of this research work. The effects of injecting gas composition and the possibility of asphaltene precipitation in a wide pressure range were determined through comprehensive experimental study. This was performed by measurement of interfacial tension of a highly asphaltenic Iranian crude oil in three surrounding gas mediums. The results showed that as pressure increases, the rate to reach miscibility reduces in the vicinity... 

Pulsating heat pipes (PHPs) are simple, cheap, and efficient heat transfer devices. They have applications in electronic cooling. In the present research, an experimental investigation is conducted on startup and steady thermal performances of open loop pulsating heat pipes (OLPHPs). Effects of working fluid, heat input, non-condensable gases (NCGs), ferrofluid concentration, magnets location, and inclination angle on the thermal performance of OLPHPs have been considered. Obtained results show that using ferrofluid can improve the thermal performance in steady state condition. Furthermore, applying a magnetic field enhances the heat transfer characteristics of ferrofluidic OLPHPs in both... 

A number of numerical simulations is carried out to study the turbulent cavitating flow through an orifice. We use two different two-fluid (consisting of two interpenetrating liquid and vapor phases) and three-fluid (consisting of three liquid, vapor, and non-condensable gas phases) cavitation models to extend our study. We use the finite-volume method to solve the multiphase flow governing equations, the SIMPLEC algorithm to link the pressure and velocity equations, and the standard k- model to treat the turbulence closure problem. We fix the outlet pressure and change the inlet pressure suitably in our simulations. The discharge coefficient values obtained by the two chosen models are...