2-1 d??f?2.94 ?w2222222222???CO?CO??SO?SO??O?O??N?N??HO?HO2-2
?0.135?1.976?2.927?0.003?1.429?0.052?1.251?0.76?0.804?0.05 ?1.341kg/m32-3???0p273100858?1432273?1.341???0.8109kg/m3
101325273?t101325273?170273?ST32?CO2??CO20()?1.57?10?5Pas
T?S273273?ST32?SO2??SO20()?1.854?10?5Pas
T?S273273?ST32?O2??O20()?2.781?10?5Pas
T?S273273?ST32?N2??N20()?2.365?10?5Pas
T?S273273?ST32?H2O??H2O0()?1.62?10?5Pas
T?S2731212121212?CO2MCO2?CO2??SO2MSO2?SO2??O2MO2?O2??N2MN2?N2??H2OMH2O?H2O??1212121212 ?CO2MCO2??SO2MSO2??O2MO2??N2MN2??H2OMH2O?2.23?10?5Pas????2.75?10?5m2/s ?dpdp50000???2.5?108Pa dVVd??0.00022-4 ???2-5(1)???dpdpdp?????P?3.923?105Pa
RTdVVd(RT/p)V?2dppV(2)等熵过程有pv??C
???dpdpdp5?????p?5.492?10Pa 1?1?11?dVVd(C/p)Vp?dp/V?2-6 ?V??m?
????p??V???153m3 ?V/V?p/?V
2-13 轴承和轴之间间隙很小,可近似认为速度在此处呈直线分布,由牛顿内摩擦定律,有
du?r????dldy(D?d)2??2?n?????P?50.7kW
60?P?Fv?F?r???F??A
2-14 本题中飞轮受到惯性力和轴承中摩擦力的作用,对飞轮列出定轴转动微分方程,有 d?J??M? (J为飞轮矩,M?为摩擦力矩,G为飞轮重力,r为轴半径) dtGDd?du???Ar4gdtdy????dl2n?60r
r?代入相应数值后得??0.2328Pas
h?3?h??kl?h??0.15m h20(2)这是重力作用下的不可压流动了,此时满足Fr数相等。有 5-2 (1)kl?kvk12l?1?kv?kl12
?qvqvkq?kvkl2?kl52?vq?qv?5v2?339.9m3/skl
(3)此时欧拉数相等,且模型和原型中用的是同种流体,有k??1
则
kpkv2?1?kp?k2v?kl??pe pepe?
?pe??39200Pa kl
5-5 不计粘性影响,此时满足Fr数相等。有
kvkl12?1?kv?kl12?v?vv?v?12?3.415m/skl
模型和原型中用的是同种流体,有k??1 所以 kF?kv2kl2?kl3?F?F? FF??70400N 3klP?Fv?70400?3.415?240.4kW
5-7这是粘性流动,此时有Re数相等
kvklk?v??1?kv?k?kl?
v因为k?=1,所以kl?1kv?vH? ?v?Hv108?103H??Hkl?H?1.5??1m
v?3600?45kF?k?k2kl2?1?vF?F
F?F??1500N
5-10 (1)这是粘性流动,此时有Re数相等
kvklk??1?kv?k?kl?v? v 查表插值得10C,1个标准大气压下,??14.2?10?6m/s2 25C,1个标准大气压下,???15.5?10?6m/s2
v??vk?kl?180?1000?15.5?164m/s
3600?14.2?13风速很大,使风洞的初投资和运行成本大大提高
(2)此时同样有Re数相等
kvklk??1?kv?k?kl?v? v