6-3 空气[γ=1.4，R=287J/(kg·K)]在400K条件下以声速流动，试确定：①气流速度。②对应的滞止声速。③对应的最大可能速度。
解：ccr??RT?400.899m/s
v?400.899m/s
c0?c??1cr2?439.163m/s
v??1max?ccr??1?981.998m/s
6-6 空气管流[γ=1.4，R=287.43J/(kg·K)]在管道进口处T1?300K，
p1?3.45?105Pa，v1?150m/s，A1?500cm2，在管道出口处T2?277K，p2?2.058?105Pa，v2?260m/s，试求进出口处气流的各种状态参数：T0，p0，ρ0，Tcr，pcr，ρcr，λ，vmax。
解：进口处：
c1??RT1?347.4487m/s
?1?p1?4.00097kg/m3 RT1v1 ?0.4317184c1Ma1????12?T10?T1?1?Ma1??311.183K
2????T10p10?p1??T?1?T10?10??1??T?1T1cr?T10???15?Pa ?3.92?10??????1??1?4.3843kg/m3
2?259.319K ??1?p1cr?2???15?p10????1???2.071?10Pa
???1cr??10???2?????1??1??1?2.7788kg/m3
c1cr??RT1cr?323.033m/s
?1?v1?0.4643 c1crv1max?c1cr出口处：
??1?791.266m/s ??1c2??RT2?333.8643m/s
?2?p2?2.58484kg/m3 RT2A2?A1?1v1?446.498cm2 ?2v2Ma2?v2 ?0.7787595c2???12?T20?T2?1?Ma2??310.598K
2????T20???15?Pa p20?p2??3.0723?10?T??2?1?20?T20???2??T???2???1?3.4414kg/m3
T2cr?T202?258.832K ??1?p2cr?2???15?p20????1???1.6230?10Pa
??1?2cr??20???2??????1???1?2.1816kg/m3
c2cr??RT2cr?322.730m/s
?2?v2?0.8056 c2crv2max?c2cr
??1?790.524m/s ??1
6-11 空气气流在收缩喷管截面1上的参数为p1?3?105Pa，T1?340K，
v1?150m/s，d1?46mm，在出口截面2上马赫数为Ma?1，试求出口的压强、温度和直径。
解：c1??RT1?369.6106m/s
Ma1?v1 ?0.4058325c1?2??12?Tcr?T1??Ma???1??11???292.6663K
????Tcr???15?Pa pcr?p1??1.7752?10?T??1?dcr?d1Ma1?2??12???Ma???1??11??????12??-1??d1Ma1?Tcr??T?1??????12??-1??36.694mm
或 ?1?p1?3.074kg/m43 RT1pcr?2.11345kg/m3
RTcr?cr?vcr?ccr??RTcr?342.9188m/s