hosedup
Junior Member
Joined: October 2019
Posts: 68
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Post by hosedup on Nov 24, 2019 14:45:29 GMT -5
You might find that the comp will be able to flow over in the choke side of the map with an excessively large turbine wheel , it'll depend on the scroll , as long as the scroll isn't "fat" you'll be OK , simply comparing the comp and turb scroll size/shape will give a reasonable indication , the turb scroll needs to be a bit "larger" than the comp but still have similar "shape" . Can you explain that a little more please? I am not sure that I follow. |
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Post by racket on Nov 24, 2019 16:24:38 GMT -5
Because we don't have a "volume regulating" engine between comp and turb stages of the turbo to regulate the compressor flow rate , our engines rely on the turb stage configuration and downstream backpressures to limit compressor flows.
If the flow areas of the turb stage are large ( fat scroll) , then the comp attempts to fill that area , but in the process might flow at a greater rate ( choke flow) than is ideal from an efficiency point, then because the comp is inefficient in compressing the air it needs more horsepower per pound of air per second , this then means the turbine stage will require a greater pressure drop to supply that horsepower which inevitably means less pressure downstream for making thrust or shaft horsepower
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hosedup
Junior Member
Joined: October 2019
Posts: 68
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Post by hosedup on Nov 28, 2019 12:10:30 GMT -5
Because we don't have a "volume regulating" engine between comp and turb stages of the turbo to regulate the compressor flow rate , our engines rely on the turb stage configuration and downstream backpressures to limit compressor flows. If the flow areas of the turb stage are large ( fat scroll) , then the comp attempts to fill that area , but in the process might flow at a greater rate ( choke flow) than is ideal from an efficiency point, then because the comp is inefficient in compressing the air it needs more horsepower per pound of air per second , this then means the turbine stage will require a greater pressure drop to supply that horsepower which inevitably means less pressure downstream for making thrust or shaft horsepower Here are pics of the scrolls. Here are better pics of the scroll profiles. What do you think? (pic shows a broken blade but its just the lighting) Holset 3522950 Inducer diameter: 55mm (opening is 95mm and funnels down to 55mm) Exducer diameter: 75mm   upload png |
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Post by racket on Nov 28, 2019 15:24:40 GMT -5
bit hard to judge from the pics , but I think it'll be OK
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