挡板宽度:B=0.1D=0.19 m 搅拌叶间距:S=2 D i =1.27 m 搅拌叶与罐底距离:C= D i = 0.63 m
C +2S =0.63+2×1.27=3.17 m > HL
C + S =0.63+1×1.27=1.9 m < HL ∴取2层搅拌器 令流体为牛顿型流体,符合全挡板条件:
ρ=1050㎏/ m n=140r/min μ=0.1 N S/㎡ 则:Rem= Di2ρn/μ
=0.632×140×1050/(60×0.1) =9.72×103>4000 属过渡流
采用2层六箭叶搅拌浆叶,查《发酵设备》,Np=3.7
轴功率:P0 = Np Di5ρn3
=3.7×0.635×(140/60)3×1050 =49 kW
f校正=1/3[(D/ D i)(HL /D i)]1/2=1.22 ∴实际轴功率P*= f校正×P0
=1.22×4.9 =5.98 kW
两层搅拌功率 P=P×[1+0.6×(2-1)]=9.56 kW
电机功率 N电=1.02 Pg/(η1η2η3 )=10.58kW
η1 =0.95(皮带) η2 =0.98(轴皮带) η3 =0.99(轴)
电机选型: 选用Y180-6型电机 功率:15 kW
转数:970 r/min,效率:89.5%
检验:15×89.5%=13.425 kW>N电
* 3
∴选型合适
7.1.5 中罐配料罐 7.1.5.1 几何尺寸
η0=0.6 ρ=107 ㎏s2/ m4 n=140 r/min μ=0.0102 ㎏ S/㎡ V配料=2.870 m3
V V= V 7.1.5.2 C +S =0.56+1.12=1.32m RV罐= V配料/η0=2.870/0.6=4.78 m3
选1个配料罐
取V1=3.5 m3 令H0/D=2
1=π/4 D2H0=3.5
∴ D=1.31m H0=2D=2.62m 又∵Ha=1/4D=0.42 m H b=0.025 m
封头容积 V2 =π/4 D2(H b +1/6D)
=π/4×1.312×(0.025+1/6×1.31) =0.33 m3
1+ 2V2 = 3.5+2×0.33=4.16 m3
∴假设合理。
罐体总高:H= H0+2(Ha+ H b )=2.62+2×(0.332+0.025)=3.33 m 液柱高:HL = H0η+ Ha+ H b=2.62×0.6+0.33+0.025=1.93 m 搅拌器功率
搅拌器直径:D i =1/3D =0.44 m 挡板宽度:B=0.1D=0.13 m 搅拌叶间距:S=2 D i =0.88 m 搅拌叶与罐底距离:C= D i = 0.44 m
< HL ∴取2层搅拌器 e = D2 iρn/μ
=0.562×140×1050/60×0.01
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