Sharif Digital Repository

The aim of this work is to investigate the non-equilibrium effects of phase change in cavitating flows. For this purpose, the concept of phase change thermodynamic probability is used along with homogeneous model to simulate two-phase cavitating flows. For simulation of unsteady behaviors of cavitation, which have practical applications, unsteady PISO algorithm based on the non-conservative approach is utilized. For multi-phase simulation, single-fluid Navier-Stokes equations, along with the volume fraction transport equation, are employed. In this paper, phase change thermodynamics probabilities and cavitation model is briefly summarized. Thus, derivation of the cavitation model, starting... 

A precise thermal-hydraulics model is of great importance for developing more effective designs of High Temperature Gas Cooled Reactors (HTGR). Recently, several advancements have been made in the methods of analysis of porous media which could be of significant value in the development of more precise and robust codes. The objective of this research is to incorporate some of the most recent improvements in the development of a new 2D program for thermal-hydraulics analysis of modular high temperature reactors. The program is mainly based on the solution of a coupled set of mass, energy and momentum conservation equations for the gas flow, along with the energy conservation equation in the... 

This work concerns with experimentally and analytically investigation of free gravity drainage process in porous media under the influence of ultrasonic wave radiation. Glass beads ranges from 70 to 100 mesh sizes were packed and used in the tests. The working fluids consist of distilled water, kerosene and Doroud and Paidar crude oils as wetting and air as non-wetting phase. The measured oil recovery data along with Hagoort (1984) backward methodology were used to determine and to compare the relative permeability of wetting phases in presence and absence of ultrasonic radiation. In addition the relative permeability of non-wetting phases for both cases were calculated from inverse modeling...