Volume 3 Issue 1
Authors: Qiaoli Chou; Congzhuo Jin; Wei Wei
Abstract: As an innovation seawater desalination technology in the world, flash vapor compression is a flash process with the best product freshwater quality, driven by a vapor compression manner with the highest heat-power conversion efficiency, to avoid condensation latent heat loss of multi-stage flash and multi-effect distillation, scaling and corrosion of distillation, seawater adaptability of reverse osmosis. It has technological advantages of independent flash operation and modular production, as the optimum technology integration of desalination processes, it is achieved by producing the highest index freshwater with the lowest power consumption index. This paper first introduces the flash vapor compression process flow, then shows energy-saving features of recycling latent heat and sensible heat with a pressure-enthalpy diagram, and finally draws process device energy flow distribution. A principle model machine is produced. Thus, the test research of flash vapor compression technology is carried through.
Keywords: flash; vapor compression; desalination; device
Authors: Parviz Ghadimi; Afshin Loni; Hashem Nowruzi; Abbas Dashtimanesh; Sasan Tavakoli
Abstract: Trim tab is a useful apparatus for improving the performance of planing hulls and is considered an important element in the design of planning vessels. In this paper, usage of trim tab is mathematically investigated and empirical equations are utilized. A flowchart is proposed for determination of the running trim tab and resistance of the vessel. To validate the proposed algorithm and the developed computer program, the obtained results are compared against available data for a planing boat with trim tab. To accomplish the main goal of this paper, two different planing hulls are considered; a small and light planing hull and a heavy planning hull with different parameters. Effects of span length on the resistance and dynamic trim angle of the small boat are examined. Also, Effects of deflection angle of the trim tab on the performance is undertaken as a subject of study. Based on the performed hydrodynamic analyses and the obtained results, it can be concluded that deflection angle affects the trim angle and the required horse power of both hulls, and it is necessary to optimize deflection angle of the trim tab. A simple method is proposed for determination of the optimized deflection angle in order to reduce the running trim angle for two different planing crafts. Finally, by using the optimized deflection angle, effective horse power (EHP) and trim angle for both planing hulls are computed and compared against the values of EHP and trim angle of the vessels without using the trim tab. It is demonstrated that as a result of using a trim tab, trim angle decreases, while EHP increases in both cases.
Keywords: Planing Hulls; Mathematical Investigation; Savitsky’s Method; Trim Angle; Trim Tab; Parametric Study