بررسي عددي تاثير تغييرات هندسي پره هاي رانريك توربين فرانسيس در عملكرد هيدرو ديناميكي آن

چكيده انگليسي :

AbstractDesigning and producing the runner of Francis turbines which are employed extensively inhydroelectric power stations demands technical considerations and because of their complexities tomake the blades of the runners which have complex three dimensional surfaces is a very subtleactivity One of the important issues in this respect is to pay close attention to the hydrodynamicfunctions of the runner and its dependence upon the size and geometrical features of the blades The present study considers the computer model of a runner made for the water power station ofDez dam which was made by Saya engineering company This model serves for the production of asoftware environment employing fluent to simulate the fluid movement in the runner of Francisturbines In this dissertation the results and primary calculations for simulation and for the sake of producingand arranging the software parameter At the same time the effect of the boundary conditions thenumerical mesh the geometry of the output pipe which are all subject to the users choice have beensystematically investigated and their results have been presented Investigating the results of theconducted researches and performing numerical experiments have led to the production of a basicmodel with boundary conditions and software setup for simulating the flow in the runner of theFrancis turbine Based on empirical observations and investigations made on the dimensions of the bladesconstructed for the runner of Dez dam various geometrical models have been produced insoftware Each of these models has been made through producing a change in the dimensions of theblades of the runner The features of theses models and their runners of production have beenpresented in this dissertation Furthermore the results obtained from numerical simulations of fluidflows in different geometrical models have been presented and analyzed To investigate thehydrodynamic functions of the runner a few important parameters such as fluid flow the torqueexerted on the blades and finally the output power of the runner have been defined and the resultsobtained for these parameters have been presented and compared with one another Theinvestigation of the results reveals that the consistent increase in the width of the blades and theincrease in the roughness of the surfaces of the runner would exert greater influence on the functionof the runner and would make a noticeable decrease in the output of the runner However othergeometrical changes such as the size of the welding seam the temporary change in the width of theblade near the inlet and outlet edges and the existence of obliqueness on the surface of the blade inthe domain of the investigated geometrical dimensions would not make any serious and significantchanges in the hydrodynamic functions of the runner To investigate the effects of these changes 31models were made and analyzed At the end of this dissertation a complete model of a runner with 17 blades has been given whichincludes the inlet region for fluid flow and the outlet pipe The results obtained from this 17 blademodel display that the 1 17 model employed in the simulation process of this research is consistentwith those of the complete model Due to probable problems which might arise in the process of making the blades of the turbine thepossibility of a few co occurring changes exist which have been considered in this dissertation

مهران فر ، بهروز

بررسي عددي تاثير تغييرات هندسي پره هاي رانريك توربين فرانسيس در عملكرد هيدرو ديناميكي آن

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