翻訳と辞書 Words near each other ・ Variable displacement pump ・ Variable dorid ・ Variable dwarf kingfisher ・ Variable electro-precipitator ・ Variable elimination ・ Variable Energy Cyclotron Centre ・ Variable envelope return path ・ Variable fighter ・ Variable force solenoid ・ Variable frame rate ・ Variable gauge ・ Variable Geo ・ Variable Geo (anime) ・ Variable geometry ・ Variable Geometry Acoustical Dome ・ Variable geometry turbomachine ・ Variable goshawk ・ Variable grass mouse ・ Variable hawk ・ Variable import levy ・ Variable interest entity ・ Variable kernel density estimation ・ Variable lymphocyte receptor ・ Variable Message Format ・ Variable mud turtle ・ Variable nebula ・ Variable neighborhood search ・ Variable number tandem repeat ・ Variable oriole ・ Variable oystercatcher Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Variable geometry turbomachine ： ウィキペディア英語版 Variable geometry turbomachine A variable geometry turbomachine is basically a combination of different fixed geometry turbomachines, which uses movable valves to optimize the efficiency at various service requirements. Generally, due to different kinds of service requirements many different kinds of pump (compressor) or turbine are used. And for a particular type of operating requirements we require specific type of pump or turbine, which will provide optimum conditions of operation. Thus a variable geometry turbomachine adjusts to different service requirements. ==Performance characteristics of turbomachines〔== If all fluid velocities at corresponding points within the turbomachine are in the same direction and proportional to the blade speed, then the operating condition of a turbomachine at two different rotational speeds will be dynamically similar. If two points,each on dissimilar head-flow characteristics curve, represent similar dynamic operation of the turbo machine, then the non-dimensional variables (ignoring Reynolds number effects) will have same values. Head coefficient \right),\,〔Dixon, S. L., Fluid Mechanics and Thermodynamics of Turbo-machinery, 5th ed. Elsevier,2011.〕|}} Efficiency \right),\,〔|}} Power coefficient \right),\,〔|}} Where, $N$ is speed of rotation. $Q$ is flow rate. $D$ is impeller diameter. Thus non-dimensional representation is highly advantageous for converging to single performance curve that would otherwise result in multiple curves if plotted dimensionally. Figure 1 shows head characteristics〔 of centrifugal pump versus flow coefficient. Within the normal operating range of this pump, 0.03 3) < 0.06, the head characteristic curves approximately coincide for different values of speed (2500 rev/min) and little scatter appears may be due the effect of Reynolds number. For smaller flow co-efficient, Q/(ND3) < 0.025, the flow became unsteady but dynamically similar conditions still appear i.e. head characteristic curves still coincides for different values of speed. But at high flow rates deviation from the single-curve are noticed for higher values of speed. This effect is due to cavitation,〔S.M,Yahya, Turbines, Compressors and Fans, 4th ed. McGraw,2011〕 a high speed phenomenon of hydraulic machines caused by the release of vapour bubbles at low pressures. Thus during off-design operating conditions, i.e. Q/(ND3) < 0.03 and Q/(ND3) > 0.06, the flow become unsteady and cavitations occurs . So to avoid cavitation increase efficiency at high flow rates we resort to Variable Geometry Turbomachine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Variable geometry turbomachine」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.