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时间:2019-06-18
《化工实验报告水-蒸汽给热系数的测定》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、嘉应学院化学实验教学中心实验报告学生姓名罗燕群专业应用化学班级094学号35课程名称化工原理实验实验指导老师李勇实验时间2011-11-28实验题目:水-蒸汽给热系数测定 数据记录与处理!.实验原始数据记录实验次数冷流体流量m3/h冷流体进口温度t1/°C冷流体出口温度t2/°C蒸汽温度°C冷流体进口壁温tw1°C冷流体出口壁温tw2°C10.1324.268.4103.271.787.420.122469103.472.28830.1123.870.5103.473.889.540.1023.671.3103.275.190.450
2、.0923.373.0103.478.791.860.0823.174.4103.279.892.270.072375.4103.379.194.480.0622.978.1103.481.896.490.0522.979.7103.490.897.2100.0422.980.7103.492.497.82.根据记录所得数据,分别计算冷流体的平均温度t,并查数据表得各个温度下得Cp,计算的(t2-t1)、(tw1-t1),(tw2-t2)、(tw-t)m=并代入公式α2=,即可求得α2,如下表:实验次数平均温度t°C冷流体温差(t2-
3、t1)/°C冷流体进口壁温差(tw1-t1)/°C冷流体出口壁温差(tw2-t2)/°C壁面与冷流体的对数平均温差(tw-t)m°C各温度下Cp/(KJ`Kg-1`K-1)传热面积A2/m2对流传热系数α2/(W`m-2`°C-1)146.344.247.51931.104.1740.02518525.45246.54548.21931.377944.86347.1546.7501932.047399.45447.4547.751.519.132.676739.09548.1549.780.118.833.876095.30648.7
4、551.35617.8353325682.63749.252.458.81935.234804.78850.555.26518.336.854148.39951.356.867.917.537.173525.801051.857.869.517.137.372855.23.由说的数据根据经验公式=计算出经验值平均温度t/°C对流传热系数经验值//Cp/λd/m-3RePr46.38525.4577277.80989.82417464.28588.30.0089674.720.0382046.57944.8672484.49989.82
5、417464.28588.30.0088930.510.0382047.157399.4568111.81988.89417464.41578.20.0088321.480.0374747.456739.0963111.46988.89417464.41578.20.0087564.980.0374748.156095.3058486.07988.96417464.54568.30.0086927.580.0367548.755682.6353226.80988.96417464.54568.30.0086157.850.036754
6、9.24804.7848215.83988.96417464.67558.80.0085479.720.0360650.54148.3942932.86988.07417464.8549.40.0084772.960.0353951.33525.8037404.28988.54417464.91540.40.0084045.640.0347551.82855.2031301.02989.01417464.91540.40.0083238.050.034763.数据分析实验测得对流传给热系数经验值/相对误差d8525.4577277.8
7、00.897944.8672484.490.897399.4568111.810.896739.0963111.460.896095.3058486.070.895682.6353226.800.894804.7848215.830.904148.3942932.860.903525.8037404.280.912855.2031301.020.91结果分析:在对实验值与理论值进行比较得,在温度的较小时误差较大,随着温度的升高,误差减小。产生误差的原因可能有:随着温度的升高,气体的粘度增大。4.思考题1).实验中冷流体和蒸汽的流向,对
8、传热效果有何影响?答:无影响。因为。不论冷流体蒸汽是顺流还是逆流流动,由于蒸汽的温度不变,故不变,而和不受冷流体和蒸汽的影响,所以传热效果不变。2).在计算冷流体质量时所用到的密度值与求雷诺数时的密度值是否一致?他们分别
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