Hi all,

After quite alot of searching all over the internet I am still unsure of the relation between number of blades on a turbine and turbine size. To be more specific, what i would like to know is would an 8 blade 40/44mm turbine flow almost the same as a 12 blade 44/53mm turbine in the same housing and how would you go about calculating this?

Any help would be much appreciated.

Thanks in advance

Gareth

 

Only a gas stand would tell you that deal. Controlled Conditions, back to back testing, everything else out of the equation.

Even when people< in the old days picked out a Turbo and Turbine Housing they typically tried a couple of housings to see what effect the Housing had. In your case you are trying to sort out a wheel design vs the same turbine housing size. Again a Turbo Stand question.

And if someone says Oh yah, this one is better, blah, blah, blah, they are blowing smoke up your.................

The Hot Rod Guys (unless they rent a Gas Stand $$$$$$) are going to shoot from the hip on this deal depending on what they have on the shelf and can sell you.

Tom V.

 

I'll have to reiterate Tom's response. 110% spot on.

But... If I read that right, you are wanting to compare the flow rates (At a standard inlet pressure I'd imagine) with to varying size turbines? Welllll... generally, the bigger ones will have more flow area. But you have to start looking into energy extraction rates (this gets into the number of blades and turbine design, also known as the Turbine Swallowing - Phi Parameter) as well as the resultant rotor group RPM's.


Soooo... In essence, sure the bigger the impeller and/or turbine, the more they CAN flow before choked flow is reached. But that doesn't always mean more power or a "better" match.

 

Great post as usual, VR4drive92.

I read his post as being that he was keeping the same Turbine Housing (size, design, etc) but trying to decide which blade configuration was "better" flow wise vs the other one. Maybe I missed the actual question, if so sorry. Because the Turbine supplies the power to the compressor wheel, Energy Extraction capability to drive the compressor wheel, if the Turbine wheel is doing its job in that respect then it comes down to (as was said) when does that turbine wheel design have other issues like Choke at a different map point.

Tom V.

 

Thanks Tom!

Its usually me that misreads stuff. HAHA


Gareth, to more exactly answer your question, you would need to measure/calculate the throat area of each of the turbine's exducers. From there, you can determine which one has the most area. That would be the one that would "flow" more before choking.

But... Are you trying to figure this out because you are concerned with spool up time? (Time to Torque) or are you more worried about max rpm, top end flow rate?