气汽对流传热综合实验数据处理
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1234孔板压差ΔP(KPa)0.52 1.53 2.56 3.57空气入口温度t1(℃)25.626.126.526.8ρt1(kg/m3) 1.18 1.18 1.18 1.18空气出口温度t2(℃)72.766.166.167.5壁面温度Tw(℃)99.799.799.799.7管内平均温度t m(℃)49.1546.146.347.15ρm(kg/m3) 1.09 1.1 1.1 1.1
λm(W/m·℃)0.0280.0280.0280.028 Cp m(J/kg·℃)1005100510051005
μm(Pa·s)0.00001970.00001950.00001950.0000195空气进出口温差Δt(℃)47.14039.640.7平均温差Δt m (℃)50.5553.653.452.55 20℃时空气流量V20(m3/h)16.3728.0736.3142.88
计量计处空气流量Vt1
(m3/h)16.5228.3636.7143.38
管内平均流量Vm(m3/h)17.9030.9740.0147.10平均流速um(m/s)15.8327.3835.3741.64
传热量Q(W)381.29705.86908.481052.47αi(W/m2·℃)120.03209.56270.73318.71 Re17514.4030892.1839908.6146981.93
Nu85.74149.69193.38227.65
Pr0.710.700.700.70
Pr0.40.870.870.870.87
Nu/Pr0.498.49172.65223.04262.58
孔板压差ΔP(KPa)0.20.7 1.2 1.7
空气入口温度t1(℃)30.631.332.132.4
ρt1(kg/m3) 1.165 1.161 1.158 1.158空气出口温度t2(℃)81.676.776.576
壁面温度Tw(℃)100100100100
管内平均温度t m(℃)56.15454.354.2
ρm(kg/m3) 1.073 1.08 1.08 1.08
λm(W/m·℃)0.2870.2860.2860.286 Cp m(J/kg·℃)1005100510051005
μm(Pa·s) 1.94*10^-6 1.93*10^-6 1.93*10^-6 1.93*10^-6空气进出口温差Δt(℃)5145.444.443.6
平均温差Δt m (℃)43.94645.745.8 20℃时空气流量V20(m3/h)10.1518.9924.8629.59管内平均流量V(m3/h)1120.4126.6731.7
d i=0.02m L=1.00m 冷流体:空气(管内)流体:蒸汽(管外)
平均流速u(m/s)9.7218.0423.5828.03传热量Q(W)168279.4457416.7
αi(W/m2·℃)60.996.66124.3144.8 Re10752201902639031370 Nu42.4467.5986.92101.26 Pr0.6790.6780.6780.678 Nu/Pr0.449.5578.96101.54118.29 Nu036.9160.0873.9284.51 Nu/Nu0 1.15 1.13 1.18 1.2
1234
孔板压差 ΔP(KPa)0.260.76 1.26 1.76空气入口温度t 1(℃)28.528.929.329.7ρt1(kg/m 3
) 1.165 1.165 1.165 1.165空气出口温度t 2(℃)86.5
7873.972.6壁面温度Tw(℃)99.799.799.799.7管内平均温度t m (℃)57.5
53.4551.651.15ρm (kg/m 3
)
1.06 1.09 1.09 1.09λm (W/m ·℃)0.0290.02830.02830.0283Cp m (J/kg ·℃)1005100510051005μm (Pa ·s)0.0000201 1.96E-050.00001960.0000196空气进出口温差Δ
t(℃)
58
49.144.642.9平均温差Δt m (℃)42.246.2548.148.5520℃时空气流量
V 20(m 3/h)
10.15
24.86
33.66
40.6
d i =0.02m L=1.00m 冷流体:空气(管内) 流体:蒸汽(管外)
计量计处空气流量
10.3025.2334.1941.27
Vt1(m3/h)
管内平均流量Vm
10.7626.6836.3243.84
(m3/h)
平均流速um(m/s)9.5223.5932.1138.75传热量Q(W)134.42375.55531.54647.61αi(W/m2·℃)50.69129.22175.86212.27 Re10037.0526239.6735710.2843104.86
Nu34.9691.32124.28150.01
Pr0.700.700.700.70
Pr0.40.870.870.870.87 Nu/Pr0.440.40105.56143.66173.41 Re0.81611843.794039.355194.396056.71 Nu027.6060.4577.7490.64 Nu/Nu0 1.15 1.13 1.18 1.20