OK, just got the newest turbo book from HP by Mark Warner and i have a question i hope somone here can answer about the equation for Compressor efficiencies. It is on page 34 if you have the book.

Eq. 4-1
0.283
(T +460)(PR) - (T +460)
T = in in +T
out ___________________________ in
Efficiency
compressor

What in the world is the 0.283? I remember exponents in algebra but always used whole numbers. I really want to understand this better as it is also used in the temp rise calculation on page 37. any help would be greatly appreciated.
Will
Sorry when i post this the equation gets skewed left, the 0.283 is supposed to be right after the PR and right above it.

 

It looks to just be the exponent. It may have been derived from some kind of fraction, for example 1/c where c is a constant. They prolly just left out the 1/c to make things simpler. If you prove the equation from scratch you would prolly see where it came from. I hope this helps, it's all i could think of without seeing the book. But where did you pick up the book, i may have to take a peak.

 

booksamillion had it. printed in june 06. pretty nice. has a lot of updated stuff. not like hp49 that has SO MUCH outdated pictures and stuff. the calcs are the same though.
it's calle street turbocharging hp1488 by mark warner.
Please enlighten me on the use of the 1/c.

 

maybe i didn't explain it right...When i said 1/c i meant that there is some constant being used. For example:
(T +460)(PR)^ (175/q) <-----(not saying this is what it is just that it is an example of a similiar situation) I don't know what constant was used BUT it was most likely left out so that they would not have to explain how the constant was derived or explain it. There are constants for everything, from specific heat to density, so on and so forth.
What i'm saying is that i wouldn't worry about why it is raised to such a weird exponent. It is common to see that in formulas especially when they deal with dynamics or thermo, or any kind of science like that.