The Hydraulic Characteristic Research For Volute Chamber Of Cyclone Shaft

Cyclone shaft,as a new type of inner energy dissipater,has very sensational hydraulic characteristic and high energy dissipation.And,cyclone shaft,as a spillway tunnel,that reflects more and more construction project value,has been praised by people.At present,the choice of configuration for volute chamber of cyclone shaft,relies on the discharging capacity mostly.The discharging capacity of volute chamber of circle form is low,that applies on it,less than 500 m3/s.And the discharging capacity of volute chamber of ellipse form is higher,that applies on it,more than 3000 m3/s.However,The discharging capacity of volute chamber contacts with diameter of shaft,that is effected by both of them.So it’s not accurate that using discharging capacity defines it only.On the other hand,there is no definite calculating method of study the water edge of cyclone shaft.However,water surface line is one of the key point in hydraulics,and it has very important impact on the choice of the altitude on volute chamber of cyclone shaft.The passage used the method of model test to study the hydraulic characteristic of volute chamber of cyclone shaft,that measured and analyzed the hydraulic element,like flow condition,water surface profile,pressure,flow velocity.And it had studyed the standard for the choice of volute chamber of cyclone shaft,using the method of model testand introducing the number of aerial drainage.Then the passage putted forward to resolve the problem of water surface profile for volute chamber of cyclone shaft with the way of Liu Hansheng simple shock wave theory.The main content was comprehended for following several respects.(1)Flood-relief channel of Li Xi Gou tailing pond is flood-discharge device with low flow.And the existing method can not choose the configuration for volute chamber of cyclone shaft.The passage adepted the model test to Compare the applicability of volute chamber of circle form and volute chamber of ellipse form.The result indicated:a.Under all kinds of aerial drainage,the flow condition of volute chamber of circle form was more undesirable than it of volute chamber of ellipse form.And the latter could form ideal spiral flow clinging on the wall of a well under all kinds of aerial drainage.b.The flow condition of volute chamber of ellipse form was nice,after increasing the bottom slope of volute chamber,that could adding the area of overcurrent in volute chamber to reduce the possibility of damming.Also diversion hum could work,which could reduce the angle of inflow and swirling recirculation flow.Volute chamber of ellipse form had excellent flow condition and could not cause the prblem of cavitation and erosion,which was the appropriate configuration and could provide the reference for the choice of low flow cyclone shaft in the future.(2)The flow condition of volute chamber of ellipse form was more stable than it of volute chamber of circle form,and the former had better result of rotation.With volute chamber and transition section below of it limits,all the pressure detecting point was positive pressure,which could not generate negative pressure.So it can not cause an adverse effect.And pressure distribution of volute chamber and transition section below of it has obvious disciplinarian.The flow velocity in volute chamber was low,even though at the maximum flow of 22 m3/s,it was just 8.54 m/s at the utmost,which could guarantee security of volute chamber to not cause destruction of cavitation and erosion.(3)The result of engineering calculation cases of li Xi Gou indicated:the problem of water edge by using Ippen shock wave theory and Liu Hansheng simple shock wave theory,and contrasts the experimental data of Lixigou cyclone shaft.Precision of the latter is higher,and counting process of the latter is easier,which do not need complicated process to trial and can satisfy the requirement of practical engineering.Therefore,using Liu Hansheng simple shock wave theory to calculate the problem of water surface profile for volute chamber of cyclone shaft,which can provide the reference for the practical engineering in the future.(4)The number of discharge ηcould describe the discharge capacity of cyclone shaft.The practical engineering and the model test of Li Xi Gou resulted that volute chamber of ellipse form was appropriate configuration to cyclone shaft for the number of discharge in large.Volute chamber of ellipse form not only can maintain excellent flow condition of swirling flow,but also can hold favourable engineering economy.And volute chamber of ellipse form laso can meet the need of the number of dicharge in small.