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1、套管换热器实验报告我们组做的是实验I:1,0=吗14t求K得先求Q卜4QtI,其中,C;所以得先求吗,q,,Vm=VpsiSl要得求VSjVsl=UA,vsl=CA0gR(o-)为空流系数,(=0.85520为空口面积,A的计算方法如下:A丹d2,d=20.32mm,故004。UA=工)2=3.24329310,m2D41000R为压计差读数AJ%d?,d为内管内径:20mm,用内插法求解空气密度p值这样求得msl,2C1的求法为先查表的相近温度下空气的C值,然后用内插法求得对应平均温度对应的的Cl值O3t3求不1tt+1,-4-22t为进口温度t2为出口温度进口温度t的求解方法由热电偶中的电
2、位vt,按照公式求Et=vtl0394645Et再由t=1557410-3+1.60810-4E-490,852求得t值8.0410-51出口温度t2的求解方法由热电偶中的电位Vt,按照公式Et=VfO+1.0394645。+0.000040M求得Et再由t一45574x1g+1681_490.852求得t值8.04x10-52由以上步骤求出Q2,由Q=KAt求出K值.Q由第一步已经求出,A为内管内径对应的面积,Ari,r=17.8mm=0.0178m,A=23.140.01781.224=0.13682362m23,求Re,Nu流体无相变强制湍流经圆形直管与管壁稳定对流传热时,对流传热准数关
3、联式的函数关系为:Nu=f(Re,Pr,l)d对于空气,在实验范围内,Pr准数基本上为一常数;当管长与管径的比值大于50时,其值对Nu的影响很小;则Nu仅为Re的函数,故上述函数关系一般可以处理成:Nu=aRem式中,a和ID为待定常数。Re=CUP。d=20.0178m=0.0356m,u=Vs(110.01782)P和P用内插法,先查表的相近温度的p,P,再用线性关系计算求得。测量空气一侧管壁的中区壁温Tw,由热电偶按前面公式求得;由下式可以计算空气与管壁的对流传热系数QCt-AE)W式中,t一空气进出口温度的平均值。OtdNU=入d=0.0356m,A还得用内插法求解,先找到相近温度的,
4、假定人的线性变化,求得人。然后用以下公式:IogNu=mlogRe+IOgaIogNu-Iogn-IogReNu可求得m,再由Nu=aRema=求得对应Re,NU下的a值。Rem然后做Nu/Re图用计算机软件计算的数据汇总如下:序号单管压力计读数空气进口空气出口R,1-211mu1120IfOmmlIgROmmHg进口温度计H(X?)热电偶mv)出口温度计CC)热电偶(mv)零位75.2012.0016.1026.005.9492.5024.13最高107.1055.5068.2034.506.0596.1020.901101.2050.1063.1034.506.3096.0020.8021
5、00.0045.1057.0033.906.2095.8020.80396.5040.3019.5031.005.6895.8020.75491.8035.2042.5030.106.6795.8022.05588.5030.1037.5029.806.4794.2021.86684.8025.3031.8028.006.2094.6024.10781.2020.2026.5027.506.0994.0023.94877.1015.0019.0026.706.0592.8023.96序号液位高度差(mmHg)由热电偶计算而得的进口电位差计校正读数由热电偶计算而得的出口电位差计校正读数4.1进口
6、温度t(4C)Etl(mv)出口温度tI温度(C)Et2(mv)零位12.729.231.1880109.96264.826最高1329.751.210096.43714.18111.930.941.260096.01344.16o9.230.471.240096.01344.1637.327.981.136095,80154.1547.432.711.3340IOL28814.4156.531.751.2910100.48944.37266.330.471.2400109.83844.827-129.941.2180109.17544.788829.751.2100109.25834.792
7、序号管壁蒸汽k-l.I进口温度计(C)热电偶(inV)热电偶(mv)压力/cm2零位111.0025.1525.500.60最高110.0024.0023.900.581110.0023.8023.700.592109.8023.7023.800.553109.9023.8023.780.574110.0023.9024.920.595109.5025.0324.800.556110.2024.9024.830.607110.0024.9124.770.558110.0024.8724.770.53序号由热电偶计算而得的进口电位差计校正读数由热电偶计算而得的管壁电位差计校正读数进口温度T.CC
8、)Et(mv)管壁温度TWCC)EtW(InV)零位114.175.03115.615.1,二;109.424.8109.014.781108.591.76108.184.742108.184.71108.594.763108.594.76108.514.7564109.014.78113.224.9845113.685.006112.734.966113.14i.112.854.9667113.184.982112.614.9548113.024.974112.614.954序号平均温度内插法平均温度对应的密度P(Kg11b)内插法求比热Co(KgZkg)内插法求黏度P(10sPa*s)零位
9、69.594090311.030258321.0172.057970452最而63.094294861.0504076861.0172.025471474I曲47QO2QRRLQ1921S71017Q63.240555791.0499542771.0172.02620277961.890969351.0541379951.0172.019454847466.996847161.0383097741.0172.04498423666.12192701L041022026L0172.040609635670.15303531.0285255911.0172.060765176r69.5589848
10、7I.0S0367I471.0172.057794924869.504892451.0305348331.0172.057524462序号VsmSQTm(C)零付0.01074842R0.01107365773.762359126.86R18878最拓0.0187317980.0196791761262.751&1636.762101010.0189655540.0198989431284.63943735.75208783O0.0181390430.0190451661224.90215535.3470686530.0159173690.0167791031056.12902536.8441
11、14880.0142864410.0148337511010.70941929.93925968C0.014365210.0149545011005.6303137.6326396160.0135448820.013931258993.934445924.6506423770.0133229490.013727529971.10582226.119738780.0106151160.010939247773.256813825.66768145序号Ku(ms)Re零位213.198887810.7539367219165.69048124.4890676出岛251.047850518.7443
12、993534606.15001201.00163141262.614538618.9752734234959.41296210.0423407Q253.271847718.H83397333479.11658197.38897633209.501807115.9255262929594.23455165.5679979246.731261I14.2937628525836.49211159.7947214C195.3(M66H14.372572726102.64383157.69352366294.692052913.5518236324078.77196170.12191937271.729414713.3297770823760.89503164.87562618220.179072610.6205564318937.16389131.1197993序号(102*m*C)Numa零位0.029671586149.3621123