《化工原理》作业

  • 2020-10-16 18:31
  • 2020-10-16 18:32

除非另有说明,\(g = \pu{9.81 m/s2}\),\(\rho_{\text{汞}} = \pu{13.6 g/cm3}\)。

第1次作业

第1章习题2

所有螺钉所承受的压力与储油罐孔盖处的压力相等,将所需的螺钉数目记作n,则有:

\[n \pi \left(\cfrac {14}{2}\right)^2 \times 32.23\times10^{6} = 960 \times (9.6 - 0.8) \times 9.81 \pi \left(\cfrac {760}{2}\right)^2\]

求得:

\[n = \cfrac {960 \times 8.8 \times 9.81 \times 760^2}{14^2 \times 3.223 \times 10^7} = 7.58\]

上取整,即至少需要8个螺钉。

3
\[p_{A} = \rho_{\text{水}}gR_3 + \rho_{\text{汞}}gR_2 = \pu{(1000 \times 9.81 \times 0.05 + 13600 \times 9.81 \times 0.05) Pa} = \pu{7.16E3 Pa}\text{(表压)}\] \[p_{B} = p_{A} + \rho_{\text{汞}}gR_1 = \pu{(7.16E3 + 13600 \times 9.81 \times 0.4) Pa} = \pu{6.05E4 Pa}\text{(表压)}\]
4
\[\rho_{\text{煤油}}gh + \rho_{\text{水}}g(H - h) = \rho_{\text{汞}}gR\]

故:

\[h = \cfrac {\rho_{\text{水}}gH - \rho_{汞}gR} {\rho_{\text{水}} - \rho_{\text{煤油}}} = \pu{\cfrac {1000 \times 9.81 \times 1 - 13600 \times 9.81 \times 0.068}{10000 - 820} m} = \pu{0.418 m}\]
6

由于扩大室内径和U型管内径已知,故右侧液面比左侧页面高出:

\[h = \cfrac {R \times d^2}{D^2} = \pu{3 mm}\]

故:

\[p = (\rho_{\text{水}} - \rho_{\text{油}})gR + \rho_{\text{油}}gh = \pu{((998 - 920) \times 9.81 \times 0.3 + 920 \times 9.81 \times 0.003) Pa} = \pu{2.57E2 Pa}\]