Mathematical relationship between N1 and N2
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Mathematical relationship between N1 and N2
Assuming a "standard" LP/HP jet engine (say that of a B737 NG), what is the relationship between N1 and N2? As there is no direct linkage between the two shafts the ratio between N1/N2 won't be constant. Is there a way to calculate N1 from N2 (if the parameters such as air density, temperature etc... are known)?
Thanks!
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Assuming a "standard" LP/HP jet engine (say that of a B737 NG), what is the relationship between N1 and N2? As there is no direct linkage between the two shafts the ratio between N1/N2 won't be constant.
Is there a way to calculate N1 from N2 (if the parameters such as air density, temperature etc... are known)?
That would be valid for a stable engine condition. Under acceleration the relationship would be subtly different, but could be modelled if one knew the time history of the other parameters, rather than a single set of conditions.
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Engine Decks
And given the data from the deck, it is possible to non-dimensionalise (is that a word?) and cross-plot the parameters to give you a steady state engine model that will work across the flight envelope. Indeed I spent a happy couple of weeks doing just that, much number crunching through Excel, of all things!
Tuning the accels and decels is a whole different ball game though.
Tuning the accels and decels is a whole different ball game though.
Last edited by aidey_f; 9th Feb 2008 at 10:54. Reason: corrected spelling