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RISS 인기검색어
- 검색키워드
- 저자 : Ammar Asghar (검색결과 3 건)
- 무료
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AMMAR BIN YOUSAF,Muhammad Imran,MAJID KHAN,Muhammad Usman,MUHAMMAD ASGHAR JAMAL 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8
The infuence of particle size on density, ultrasonic velocity and viscosity of magnetite nanofuids have been determined at (298.15 K, 303.15 K, 308.15 K and 313.15 K). Two diferent sized nanoparticles (commercially procured D=20–30 nm and synthesized D=9± 3 nm in the laboratory by co-precipitation method) were dispersed in a citric acid base fuid. The desired parameters have been experimentally determined by loading diferent concentrations of nanoparticles. It has been found that the infuence of particle size and temperature on measured physical parameters (density, ultrasonic velocity and viscosity) is not negligible and can also be taken into account in any practical application. The analyzed physical parameters can describe qualitatively and quantitatively the particle size distribution of nanofuids at a specifc temperature. Results are interpreted in terms of particle–particle and particle–fuid interactions.
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Numerical and experimental investigation on a new modified valve in a valve tray column
Asghar Alizadehdakhel,Ammar Abdulaziz Alsairafi,Masoud Rahimi 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2
This paper reports experimental and computational fluid dynamics (CFD) modeling studies on the performance of three modified valves operating in a valve tray column. The original and modified valves including vnotched, warped and double-valve are tested experimentally. The experimental rig was a Perspex column having a single valve equipped with a fluctuating plate to measure the quality of gas distribution by using laser sensors. Two-stage nested designs were employed to show the repeatability and consistency of the measurements. In the CFD modeling, the volume of fluid (VOF) method was used to model the gas-liquid two-phase flow inside the column. A good agreement was observed between experimental data and the CFD predictions. The results showed that the double-valve layout provides a better gas distribution, smaller bubbles with greater interface area and lower pressure drop in comparison with the original and the two other modified valves.
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Performance evaluation of novel solarpowered domestic air cooler with Peltier modules
Zafar Abbas,A. N. Shah,M. Tahir Hassan,M. Sarfraz Ali,Qamar ud Din,Bilal Naseem,Ammar Asghar,Ali Haider 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11
Shifting of air conditioning and ventilation plants from conventional to renewable energy systems is one of the effective ways to save energy and attain sustainability. In this experimental study, an effort has been made to design, fabricate, and evaluate the cooling performance of a solar-powered domestic air cooler with Peltier plates to meet the comfort criteria as per ASHRAE standards. It also investigates the effect of Peltier modules on the performance of conventional room air cooler. The experiments were conducted in a 12x12 room with one, two, three, and four Peltier modules operating at various ambient temperatures. The experiments were repeated three times at specified conditions. Peltier effect was used to decrease water temperature, and subsequently cooled water was used to decrease the temperature of the air after coming in contact with this water. The cooled air was then used to create a comfort zone. The results indicated a decrease in temperature of the experimental zone by 5 %, 13 %, 19 %, and 23 % using one, two, three, and four Peltier modules respectively. The increase in relative humidity was recorded as 5 % at 27 °C temperature of the experimental zone. The results of energy analysis showed a substantial amount of energy savings in this study and suggest that more than 200 MW energy can be saved by replacing conventional electric air coolers all over the country with proposed Peltier based domestic solar powered air cooler.
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