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Study on low pressure evaporation of fresh water generation system model
정한식,Supriyanto Wibowo,Berkah Fajar,Yonghan Shin,정효민 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2
A low pressure evaporation fresh water generation system is designed for converting brackish water or seawater into fresh water by distillation in low pressure and temperature. Distillation through evaporation of feed water and subsequent vapor condensation as evaporation produced fresh water were studied; tap water was employed as feed water. The system uses the ejector as a vacuum creator of the evaporator, which is one of the most important parts in the distillation process. Hence liquid can be evaporated at a lower temperature than at normal or atmospheric conditions. Various operating conditions, i.e. temperature of feed water and different orifice diameters,were applied in the experiment to investigate the characteristics of the system. It was found that these parameters have a significant effect on the performance of fresh water generation systems with low pressure evaporation.
Analysis and attenuation of impulsive sound pressure in large caliber weapon during muzzle blast
Hafizur Rehman,Seung Hwa Hwang,Berkah Fajar,정한식,정효민 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.10
Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensity impulsive sound pressure is created,which has negative effects in many respects. Therefore, the high pressure waves generated due to muzzle blast flow of tank gun during firing is a critical issue to examine. The purpose of this paper is to study and analyze this high pressure impulsive sound, generated during the blast flow. The large caliber 120 mm K1A1 tank gun has been selected especially for this purpose. An axisymmetric computational domain has been constructed by employing Spalart Allmaras turbulence model to evaluate pressure and sound level in the tank gun using Computation Fluid Dynamics technique. Approximately 90% of pressure and 20 dB of sound level have been attenuated due to use of the three baffle silencer at the muzzle end of the gun barrel in comparison to the tank gun without silencer. Also, the sound pressure level at different points in the ambient region shows the same attenuation in the results. This study will be helpful to understand the blast wave characteristics and also to get a good idea to design silencer for large caliber weapon system.