Compressor design

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Post by racketmotorman » Mon Jun 04, 2007 10:01 pm

Hi Lilrex

The blades are "tilted" forward for structual strength to counteract the loading on them from the air .

Max rpm for your comp will be limited by its structural integrity , the TPE331 example is milled from a titanium billot , and tested before use .

Turbo comps are cast wheels , but their sophistication will be beyond you .

As your rpm will be limited (for safety reasons) I'd be forgetting about fancy swept back designs with complex curvatures and go for a ....LOL "simple" straight radial design .

I have a rotating assembly from the turbo off a 1000hp locomotive engine and its 11 inch comp wheel has a 0.5 inch exducer tip height on its 20 radial blades of 0.125" thickness , 6.75 " inducer with 3" hub .

The inducer section is a seperate casting that is pinned to the main comp disc after it has been machined .

This would be a better design for you to make , as the seperate inducer simplifies construction as the main wheel only has straight vanes which will be easy to cast .

The greater size of your construction will allow reasonable efficiency (from a simple comp design) compared with the more complex designes used in smaller comps .

The relationship between inducer and exducer areas is a complex issue that I haven't completely worked out , there doesn't appear to be any reason why one designer/manufacturer uses one ratio and another a different one . Even different wheels from the same manufacturer will have different inlet/outlet area ratios , thats why the "numbers" I've provided in my email of a few days ago were a "middle of the road" set .

Inlet air velocities shouldn't exceed ~500 ft/sec otherwise the relative velocity to the inducer tips will cause sonic shock problems .

You really need to get some good books on compressor design if you want to understand their workings properly . I'd have to write thousands of words otherwise trying to explain their inner workings :-))


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