化工原理传热实验数据处理.doc

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1、长春工业大学化工原理传热试验数据处理化学工程学院高分子材料与工程专业090604班自己做的，如有错误，敬请谅解六、原始数据记录直管换热序号空气水蒸气孔板压降入口温度出口温度壁温tw1壁温tw2147.0067.1098.6098.602.00252.1070.2098.7098.701.73359.1072.4099.0098.701.17458.3072.4099.0099.000.93556.9071.8099.1098.900.72654.2070.6099.2099.100.54751.6069.5099.4099.000.38848

2、.5068.4099.3098.900.25947.3068.0099.1098.700.141045.8067.6099.0098.500.06加混合器序号空气水蒸气孔板压降入口温度t1出口温度t2壁温tw1壁温tw2160.3081.7098.8098.701.10263.9083.1098.9098.700.95364.6083.2099.1099.000.80463.3083.4099.2098.900.65563.3083.3099.2099.000.54661.4080.9099.1098.900.42759.3080.2099.

3、2098.900.32857.3079.6099.3098.700.23换热管内径d=0.021m，长度L=1.25m数据处理(1)对于直管换热器以第四组数据为例计算Δt=t2-t1=72.40℃-58.30℃=14.10℃Δtm===33.15℃查表得ρ=1.09㎏/㎡Cp=1.005㎏/㎏·Kλ=27.28mol/m·Kμ=18.85uPa·s根据公式Vs=26.2Δp^0.54=26.2×0.93^0.54m³/h=25.19m³/h换热管截面积S=πd²/4=3.14×0.021²/4m²=0.000346m²那么u=Vs/S=25.

4、19/0.000346/3600m/s=20.23m/sQ=Wcp(t2-t1)/3600=ρVscp(t2-t1)/3600=1.09×25.19×1.005×14.10/3600kW=0.1089kW=108.9W又Q=αAΔtmA=πdL=3.14×0.021×1.25=0.082467得α=Q/（AΔtm）=108.9/(0.082467×33.15)=39.56W/㎝²·℃Re=duρ/μ=0.021×20.23×1.09/18.85×1000000=24560.54Pr=Cpμ/λ=1.005×18.85/1000000/27.2

5、8=0.694Nu=αd/λ=39.56×0.021/27.28=30.45=0.864Nu/=35.233(2)对于直管换热器以第五组数据为例计算Δt=t2-t1=83.30℃-63.30℃=20.00℃Δtm===24.18℃查表得ρ=1.08㎏/㎡Cp=1.009㎏/㎏·Kλ=28.12mol/m·Kμ=19.28uPa·s根据公式Vs=26.2Δp^0.54=26.2×0.54^0.54m³/h=18.78m³/h换热管截面积S=πd²/4=3.14×0.021²/4m²=0.000346m²那么u=Vs/S=18.78/0.0003

6、46/3600m/s=15.08m/sQ=Wcp(t2-t1)/3600=ρVscp(t2-t1)/3600=1.08×18.78×1.009×20.00/3600kW=0.11372kW=113.72W又Q=αAΔtmA=πdL=3.14×0.021×1.25=0.082467得α=Q/（AΔtm）=113.72/(0.082467×24.18)=57.05W/㎝²·℃Re=duρ/μ=0.021×15.08×1.08/19.28×1000000=17739.91Pr=Cpμ/λ=1.005×19.28/1000000/28.12=0.69

7、2Nu=αd/λ=57.05×0.021/28.12=42.61=0.863Nu/=49.375直管换热序号ReNuPr^0.4Nu/Pr^0.4137661.3755.430.6950.86455864.11372234599.3250.680.6950.86455858.61958327915.1834.040.6940.8640639.39542424653.8131.350.6940.8640636.28221521495.828.060.6940.8640632.47461618444.9525.000.6940.8640628.9

8、3318715287.9321.520.6950.86455824.89134812216.3518.190.6950.86455821.0396698937.86