Sharif Digital Repository

In this work, a double-high swirl gas turbine model combustor (GTMC) has been experimentally investigated to identify the effects of air partitioning and swirlers geometry on combustion characteristics in terms of flame stability, exhaust gas temperature, NOx generation, and combustion efficiency. This high swirl model combustor is originally developed in the German Aerospace Center (DLR) and known as GTMC and recently reconstructed at Sharif University's Combustion Laboratory (named as SGTMC). Here, SGTMC run for liquefied petroleum gas (LPG) fuel and air oxidizer at room temperature and atmospheric pressure. Eleven different burner geometries, M1-M11, are considered for the aims of this... 

The heat transfer phenomenon in a vortex engine was investigated. A mixture of butane and propane was used as the fuel in which the mole fraction of butane and propane was 0.2 and 0.8, respectively. A series of tests were conducted in different conditions of oxidizer and fuel mass flow rates for a vortex engine. The tests were categorized into two groups to find the effects of the oxidizer mass flow rate on the flux of radiation heat transfer and convective cooling at a fixed equivalence ratio. The effects of the equivalence ratio on the heat transfer phenomena at a fixed oxidizer mass flow rate are also determined. The results revealed that the rate of radiation heat transfer to the chamber... 

In the present experimental study, the effect of operating parameters such as inlet and outlet pressure as well as inlet temperature on the mass separation capability of vortex tubes (VTs) for a gas mixture is investigated. Specifically, concentrating heavier components of a gas mixture in the hot outlet stream is considered. Proposing a semi-empirical index from the experimental study, the simulation of different arrangements of VTs, and the effect of recycling a portion of the hot outlet stream on its mass separation performance are investigated. Moreover, the proposed separation method by VTs is economically compared with commonly used methods by distillation columns and two-phase... 

In this paper, to set R&D priorities at sector level, a developed method is proposed which is combined of scenario planning and critical technologies method and then applied for prioritizing R&D issues of membrane technology in National Iranian Gas Company (NIGC). In the first phase (through 3 steps), scope of NIGC is mapped using national documents and viewpoints of experts and managers. This map includes main process of gas processing and gas conversions. Then strategic goals of gas industry including gas exports, conversions, injection and internal use, are developed. Also Strategic Technology Units (STUs) are identified and twenty distinct membrane technologies including technologies of... 

TCVD growth of multiwalled carbon nanotubes (MWCNTs) was reported by catalytic decomposition of liquefied petroleum gas (LPG) at a temperature range of 580800 °C. Laser ablation was employed as a simple and rapid technique to produce Pd nanoparticles which possess effective catalytic activities for CNT synthesis. UVvisible spectroscopy and TEM images confirmed that the Pd nanoparticles are stable for a long time and have rather spherical shape with average size of 7 nm. SEM and TEM observations and Raman spectroscopy demonstrated that the CNTs have a wavy structure, dense morphology and acceptable crystallinity. Since Pd nanoparticles are inactivated or agglomerated at extremes of the...