Study On Optimization Of Axial Flow Turbine With Ultra-low-ratio Rotational Speed

At present,industrial cooling towers more than recovery turbine typically uses the ultra low specific speed Francis turbine,but because of its larger size,easily affect the dryer ventilation.In addition,because of its very flat weld is very difficult.If axial-flow hydraulic turbine could be used to replace,you can solve these problems.But the conventional generation of axial-flow turbine specific speed is higher,achieving ultra low specific speed not available theory to guide.At very low specific speed Francis turbine flow,speed,flow parameter is equivalent to the target,and has been designed with low specific speed axial-flow hydraulic turbine.Achieved a technological breakthrough solved for ultra low-specific-speed of axial-flow turbine problem;Meanwhile,an open structure of axial flow turbine,solves the problem of manufacturing difficulties.This super low-specific speed axial-flow hydraulic turbine efficiency is low,to take full advantage of complementary energy,improve energy efficiency,in the simulation of initial design model based on the analysis of using single-factor methods,respectively,on volute part,water bodies and the wheel parts are optimized.Through analysis turbine had flow parts of streamlines,and pressure distribution,and import and export speed distribution,for spiral shell internal exists large Eddy problem,proposed has spiral shell within wall Hou moved 20,and 40,and 50 mm three species improved programme,and will initial design and three species improved programme spiral shell internal pressure distribution,and streamlines distribution for has compared,and analysis has this several programme on guide water institutions and runner part of imports speed of effect,select out efficiency highest Shi of spiral shell optimization model for follow-up calculation.On guide water institutions and runner part respectively for has guide leaves number and leaves number of optimization select,guide leaves number in initial design 8 guide leaves of based Shang increased has 10,and 12,and 14 guide leaves three species programme,leaves is in initial model 16 leaves of based Shang increased has 14,and 18,and 203 species programme,and on initial model and optimization programme for has pressure distribution,and flow field distribution analysis compared,and on remaining had flow parts speed vector,and streamlines distribution of effect.When you select the most efficient solution is the best option.