Analysis of Effect of Basic Design Variables on Subsonic Axial-flow-compressor Perforwce

~ blade-element theory for aanid--ow compre8sor8has been deoeloped and applied to the anulysi8 of the. effects of basic deeign variabkwvuch as Mach number, blude loading, and mJocily didn”buiion on compree80r performance. A graphi.cul method tlwt ia u8efulfor approximate design cakulati0n8 i8 pre8ented. Tle relati0n8 among 8e8eralefinci48 useful in compressor design are derived and &cu8sed. The po8sible gains in useful operating range obtainable by the use of adjustable 8tator bk.des are discu8sed and a rapid approaz”mdemethod of calculating blade-angleree&”ng8b shown by an ezurnpk. me relatice Mach nwnber is shown to be a dominunt fizctor in determining ihe pressure rahk. Cimeiderabt?eincrease in pres8ure ratio overthd for conventwnul design8 sun be obtained by producing a velocity distribution that gives relative inlet Mach numbers clo8eto the limiting Mach number on alJ blade element8. With a given imkt Mizch number, the pressure ratw obtainable acro88a bbde row increa+weand the 8peczjic ma88 $OWdecrease8as the ratio of mean whtil velocity to am-alvelocity increases for the high-emncy range of thie vebm”ty ratw (that ie, near 1). For compre880rdesigw un”iha dejinite Mach number limitaiian, the ze.hmitydistribution in the inlet stage ia particularly important because the inlet stage limits both the mass j?ow and the rotor 8peedof the compressor and thereby limits the pre+w-ure ratio of the later etage8a8 well as the inlet stage. By the use of inlet guide vanes dev@ed to produce a radial natitwn of axial velocity at the Met to the$rst rotorl a substtzntial increase in 8tuge pre88ure ratio and a 81ight increa8e in 8pecij% ma88 flow over designs boxed on free v&ex with the same turning and Mach number limitations are 8h0umto bepos&ible. In the succeeding stages, ~hemaximum pressure ratio per 8@7eis obtained by increasing the hub diameter to obiain the muximum axial velocity compatible with the Mach number limitation.