Mixed Flow Turbine Phenomena. 1

[faisalh]

can anybody proffessional help me out, about Mixed flow in turbines,
my friend told me the concept, but didnt show me the diagram/picture of the specific turbines,
can anyone of you show me ? or reffer a site abt the phenomena..
me, the new one ..
help me out.

 

[radomir]

Supposedly a term mixed flow means that beside steam there are water droplets (two phase flow). That could happen in low pressure stages when vapour (steam) temperature drops significantly and it is highly undesired. Those droplets are damaging blades and it is a kind of "cavitation" in steam turbines.

That is the reason why those stages are under partial vacuum. To keep water in gaseous-vapour stage even below 100 degrees Celsius.

 

[poetix99]

"Mixed flow" might also refer to the distinction between axial flow turbines and radial flow turbines.

Axial flow is the nominal design of virtually all large steam turbines.

Radial flow turbines have some specialized applications, some of which are related to relative simplicity of construction and/or the high speeds at which they can run. One particular design looks very much like a centrifugal compressor; the flow is radially INWARD instead of outward.

"Mixed flow" turbines utilize - in various details of the flow path - some aspects of the (nominal) axial and the radial flow designs. This is a designation rather than a definition because it is not rigorous; you'll typically know one type from the other when you see them.

Consult an introductory turbomachinery text; many specialized turbine texts will be focused exclusively upon axial flow designs. I'm sorry that I do not have any specific recommendations for you.

 

[faisalh]

however thanks both of you,
but i need some images for blades used in mixed flow turbine flow,
can anybody/?

 

[smckennz]

Mixed flow water turbines are very common in the hydro power industry. They are characterised by a medium specific speed which as poetix says means they are part way between a centrifugal and an axial flow device.

Cheers

Steve