Design And Flow Analysis Of Two-vane Bulb Turbine

High specific speed moving vane bulb turbine can be applied to hydropower station with3~25m low water head and large discharge, is valued and intensifying develop as the bestturbine to use low head energy water resources. In coastal area industry has developed rapidly,the regional power shortage is very severe, and consider tide-power stations request, so thedevelopment of bulb turbine that can be applied to lower water head is more urgent. Bulbturbine is new model compared with other turbines applied to middle-and high-head waterresources; ultra low head turbine has been used in abroad. However the turbine mostly usesthe empirical design, the theory researches and design reports are hardly seen. Today somemanufacturer technologies of bulb turbine are imported.In this dissertation, two-vane bulb turbine was studied to obtain higher specific speedturbine applied to lower head and larger discharge hydro machine base on the results of CFDcalculation and model experiments of three-vane, four-vane, five-vane bulb turbine done byour lab. The new idea of fair blade-loading design method was used in the paper, in order tomade the load distribution along the camber line rational by means of regulating the Eulerenergy which is relevant to the blade-loading, consequently get optimized design angles alongeach camber line, thereby obtain the vane shape of runner. As designing the runner vane, boththe control of the objectives of each camber line and the associations between the camberlines should be considered, to keep the consistency of the flow, to fundamentally keep theexcellent performance of the vane. The objectives to be controlled include: distribution offlow angle, alteration of Euler energy, load distribution of runner vane.After designed the runner vane, we did the whole flow passage numerical experiments tothe designed turbine, analyzed inner flow field of the two-vane bulb turbine especially of therunner and evaluate the performance of them, compared internal flow of the turbine in the bigopen, small open and the optimal condition, analysis showed that the designed turbine hasgood flow characteristics. The numerical simulations of designed two-vane bulb turbineshowed that the new designed two-vane bulb turbine has optimal performance, proves thefeasibility of the design, the research results can provide technical support to optimal designand unit operating. The designed two-vane runner has moving vane, in the operation can alterthe setting angle of runner vane to fit the change of water head and discharge. In thisdissertation, we used CFD numerically analyze method successfully predict the con-camcombination between guide vane setting angle αGand runner vane setting angle φR, gaining the on-cam performance curve of turbine, the turbine operated on the condition of the on-camcurve can get higher efficiency and better instability. However, in the past the on-cam curve isobtained by physical experiment, it needs test equipment, high fees, and a lot of time.The paper compared the designed two-vane bulb turbine with three-vane, four-vane,five-vane bulb turbine, explored the performance differences of turbine with variety vanenumber, try to accomplish and perfect the design of turbine.