Sharif Digital Repository

Two-phase flows are widely used in petrochemical industry, chemical processes, boilers, nuclear reactors, cooling systems and air conditioning equipment. Since the problem of earth’s ozone layer and global warming, the analysis of flow characteristics in evaporators are necessary to improve performance of refrigerating systems and saving the environment. Most of the researchers have been studied the evaporation of two phase flow refrigerant through experimental studies and numerical analysis has less attention in the literature. In this Thesis, a mathematical model based on the two-phase separated flow model is developed to simulate the evaporation of pure refrigerant under constant heat... 

Developing of electric instruments with high performance needs high capacity heat transfer equipments. Pulsating heat pipes have better performance compared with normal heat pipes and can be used for cooling electronic instruments in near future. Also, one specific kind of heat pipes, which is called rotating pulsating heat pipe, can be used in cooling the turbine blades. Rotating pulsating heat pipe is a mechanism in which the pipes can rotate around the axis perpendicular to the plane of pipes. In this research one rotating heat pipe was built and the effects of heat input, filling ratio and rotational acceleration were examined experimentally. The Innovation in the research was to obtain... 

The mechanical spray evaporator (MSE) is a method of enhanced evaporation technology, normally designed to reduce the particle size of a wastewater droplet to volatilize water content of it as quickly as possible. A model of MSE has been built at the Institute of Water and Energy at Sharif University of technology. The aim of this research is to study the efficiency of enhanced evaporation technology for waste disposal. To achieve the accurate results, the required pumping rates and power consumption, sustained evaporation rates while operating the fans, and the performance during various temperature, wind speed and relative humidity, are required. Mechanical Spray Evaporator technique...