Study of the Slurry Erosion Behavoiur in Hydropower Plants

Abstract

Hydropower plants suffer from silt erosion of underwater parts.Particularly in monsoon season,when 90% of the silt particle size is 0.2mm and contain quartz with hardness 7-8 on Moh's scale value.The various parts of the plant are subjected to an environment that contains silt having particle (Mgo,Cao,Al2o3,Sio2,clays,volcanic ash and the like)carried by water.These sediments are formed by the fragmentation of rocks,land erosion and landslides due to heavy rain in monsoon season.It is not cost effective to construct any arrangement to remove this size of silt particles from the running water.The problem of erosion underwater parts of the hydropower plants and measures to minimize such damages has been constantly engaging the attention of hydropower engineers and manufectures of equipment.Presently Baira siul project(3x66MW)Himachal Pradesh (NHPC)handless nearly 10,000 tonnes of silt per day per machine during critical monsoon days.Material loss in guide vanes alon is 10% by weight.Stainless steels are widely used in hydroelectric power plants due to their good corrosion resistence properties and acceptable resistance to solid particle erosion, since many components are in contect with aqueous solution containing hard particle that impact against the surface causing significant materials loss.