换热器设计(最终版)

过热蒸汽排放压力pi已知0.5Mpa过热蒸汽排放温度ti已知250℃过热蒸汽排放量qmi已知5t/h过热蒸汽焓值hi查表2960kJ/kg过热蒸汽比体积vi查表0.47432m3/kg饱和蒸汽排放压力po查表0.5Mpa饱和蒸汽温度to查表151.867℃饱和蒸汽排放量qmo查表5t/h饱和蒸汽焓值ho查表2748.6kJ/kg饱和蒸汽比体积vo查表0.37486m3/kg过热蒸汽比热容Cpi查表2.33kJ/(kg•K)过热蒸汽热导率λi查表0.029905W/(m•K)过热蒸汽密度ρi查表2.681kg/m3过热蒸汽粘度μi查表0.00001396Pa•s进口温度tc,i已知20℃出口温度tc,o已知85℃定性温度tctc=(tc,i+tc,o)/252.5℃密度ρc查表986.85kg/m3定压比热容Cpc查表4.175kJ/(kg•K)热导率λc查表0.651W/(m•K)粘度μc查表0.0005295Pa•s热流量QQ=（hi-ho）*1000qmo/3600293.6111111kJ/s冷却水消耗量WcWc=Q/(Cpc(tc,o-tc,i))1.081938687kg/s平均温差△tlm△t=(△t2-△t1)/ln(△t2/△t1)147.8151163℃温度修正系数FT查表0.951有效平均温差△tm△tm=FT·△tlm140.4243605℃传热系数k假设600W/(m2•K)估算换热面积AA=Q/(k*△tm)3.484807409m2实际传热面积A0A0=1.15A4.00752852m2换热管外径×壁厚d×δ119×2mm管内流速u1m/s单程传热管数NsNs=(Wc/ρc)/(πdi2*u/4)6.207251324根7传热管长度（按单程管计算）LL=A/（π*d0*Ns)9.596112544m9.230769管程数(用多管程结构)NpNp=L/l3.198704181程40.021998传热管长l3m传热管总根数NtNt=Ns*Np28根壳程数单壳程管心距tt=1.25d023.75mm25管板利用率η0.75壳体内径DD=1.05t(Nt/η)1/2160.3901493mm325圆缺高度hh=0.25*D81.25mm80折流板间距BB=D/3108.3333333mm150折流板数NBNB=l/B-119块19拉杆直径φ1212mm拉杆数量4表面传热系数αiαi=0.023λcRe0.8Pr0.4/di5333.549519W/m2·K管程流体流通截面积SiSi=πdi2Nt/4Np0.001236375m2管程流体流速uiui=(Wc/ρc)/Si0.886750189m/s雷诺数ReiRei=diuiρc/μc24790.06867普朗特数PriPri=Cpcμc/λc3.395794931壳层对流换热系数α0α0=0.36λ1Re0.55Pr1/3(μ/μw)0.14/de6764.937284W/m2·K当量直径dede=4(t2-π/4d02)/πd00.022904123m壳程流通截面积S0S0=BD(1-d0/t)0.0117m2壳程流体流速uu=1000qmo/ρiS044.277677m/s雷诺数ReRe=diuρi/μi127552.0616普朗特数PrPr=Cpiμi/λi1.087670958管外侧污垢热阻R00.000086m2·K/W管内侧污垢热阻Ri0.00086m2·K/W热导率(碳钢在该条件下)50m·K管壁热阻Rw0.00005m2·K/W传热系数传热系数keke=1/((d0/αidi)+(Rid0/di)+(Rwd0/dw)+R0+1/α0)618.6101094W/m2·K计算传热面积AcAc=Q/ke△tm3.379971348m2实际传热面积ApAp=πdolNt3.9564m2面积裕度Hh=(Ap-Ac）/Ac0.165411911处于15%～20%之间壳程数Ns1管程数Np4结构校正因素Ft对d×δ1为19×2的管子取1.51.5摩擦系数λλ=0.01227+0.7543/Re0.380.028403128直管摩擦阻力的压降△pL△pL=λl(ρcui2/2)/di2204.042125Pa弯管摩擦阻力的压降△pr△pr=3(ρcui2/2)3491.935705Pa管箱进出口的压降△pn△pr=1.5(ρcui2/2)1745.967853Pa管程总压力降△pi△pi=(△pL+△pr)FtNpNs+△pnNs35921.83483Pa壳程数Ns1壳程结垢校正因素Fs对气体取值为1.01流经管束的阻力△po△po=Ffonc(Nb+1）ρcui2/29184.850523Pa管子排列方法对压降的修正系数F对三角形排列取值为0.50.5壳程流体摩擦因子fofo=5.0Re-0.2280.34266777横过管束中心线的管子数ncnc=1.1Nt0.55.820652884壳程流通截面积Ao0.032161139m2壳程流速uouo=Vo/Ao18.5344694m/s流过折流板缺口的阻力△pp△pp=Nb(3.5-2B/D)ρcui2/222546.65863Pa总阻力△Ps△Ps=△Po+△Pp31731.50915Pa过热蒸汽生产生活热水换热器热力计算平均传热温差估算换热面积饱和蒸汽壳程压力降压降核算管内表面换热系数污垢热阻和管壁热阻壳程冷凝表面换热系数热流量核算传热面积裕度管程压力降管径和管内流速管程数和传热管数工艺结构尺寸设计壳体内径其他附件折流挡板)(ocodNDBA管程389520/850.4定性温度/℃52.5密度/(kg/m3)986.9定压比热容/(kJ/kg∙K)4.175粘度/Pa∙s5.295×10−4热导率/Wm∙K0.651普朗特数3.396形式浮头式壳程数1壳体内径/mm325台数1管径/mm∅19×2管心距/mm25管长/mm3管子排列正三角形排列管数目/根28折流板数/个19传热面积/m24折流板间距/mm150管程数4材质碳钢参数壳程流率/(kg/h)5000进/出口温度/℃250/151.867设备结构参数压力/MPa0.5物性参数140.42.682.330.1396×10−40.31.088主要计算结果管程壳程流速/（m/s)0.8944.3表面换热系数/(W/m2∙K)5333.56764.9污垢热阻/(m2∙K/W)0.000860.000086压降/MPa0.035920.03173热流量/kW传热温差/K传热系数/(W/m2∙K)裕度/%293.69.12618.617%