Estimated GT1752 Compressor Map
Turbo Mini Forums

The square of the scale ratio applies to the flow, because it is related to the outlet area ie, the circumference of the wheel times the tip height. Hence square.

The PR varies directly with the scale ratio because it is directly related to the wheel diameter.

Basically, what I said in February was correct. Yesterday I was talking crap!

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

so good Vino

On 20th of Jul, 2007 at 05:34pm fab said:
so good Vino

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I've removed these estimated maps as I now consider them to be incorrect for two reasons.

The Affinity Laws used to calculate the scale factors may have been incorrectly applied. Further research has revealed that the Affinity laws may be different when applied to compressible fluids. Most text books assert that they are equally valid for compressible and incompressible, but there are some websites that state otherwise. It depends which bit of research that you read and agree with.

The other thing is that although the wheels on spec appear to be geometrically similar, the GT1752 actually has a larger tip height, so this will alter the shape of the map considerably.

It is highly likley that the above two issues may well cancel each other out in general terms, but the map will look very different.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."