往年生資格考試2014博資考

博士生資格考試鄭姝影2012310021主要工作進(jìn)展研究背景閃蒸發(fā)生器研究文獻(xiàn)綜述實驗研究模型討論降膜發(fā)生器研究文獻(xiàn)綜述實驗研究模型討論下一步計劃研究背景130℃20℃45℃60℃45℃60℃95℃46℃吸收式換熱器：改變流程可適應(yīng)各種熱源和熱匯溫度品位需求內(nèi)部二元溶液傳熱傳質(zhì)具體過程閃蒸研究背景發(fā)生－冷凝器：高溫?zé)嵩聪虻蜏責(zé)釁R傳熱的過程溶液與水分離場所兩種方式：閃蒸：加熱與蒸發(fā)分離，絕熱發(fā)生過程。降膜：溶液同時被加熱和被濃縮vaporstrongsolutionHotwaterWeaksolutionCoolingwatervapor閃蒸研究背景文獻(xiàn)總結(jié)：閃蒸發(fā)生器：吸收式熱泵中應(yīng)用較少；海水淡化等領(lǐng)域。“Whenasaturatedliquidundergoesasuddenreductioninpressure,theflashevaporationoccurs.”靜態(tài)閃蒸突然降低空間壓力，使流體過熱。蒸發(fā)速率隨時間衰減。從Miyatake(1977,1973)開始.噴淋閃蒸（實驗為主）Adeletal.(2007),純水（40℃70℃）,不同流量和不同真空度YasuyukiIkegamietal(2006,2009,and2010),純水,不同噴淋角度Erasmusetal.(1994),水，流態(tài)研究:nonshatteringliquidjet,partiallyshatteringliquidjet,completelyshatteringliquidjetbutinstage-wisesequenceandflareshatteringliquidjet研究以水或低濃度鹽水（海水淡化）實驗研究為主。閃蒸實驗Figure2.schematicoftheexperimentalsection供液孔后液柱末端液面冷凝壓力kPa溫度℃濃度飽和水蒸汽分壓力kPa溫度℃濃度飽和水蒸汽分壓力kPa溫度℃濃度飽和水蒸汽分壓力kPa溫度℃濃度飽和水蒸汽分壓力kPa93.760.41%10.481.860.92%5.777.261.12%4.570.261.41%3.12.8192.258.99%11.179.059.56%5.872.159.85%4.065.660.13%2.82.8590.558.76%10.679.959.22%6.274.659.44%4.766.659.78%3.12.9061.457.70%2.959.757.77%2.756.157.92%2.253.458.03%1.81.7565.057.56%3.662.057.69%3.057.557.88%2.354.158.02%1.91.7868.358.19%4.065.058.33%3.359.758.55%2.456.258.70%2.01.8272.557.55%5.265.857.83%3.661.958.00%2.956.158.25%2.12.0484.659.30%7.778.659.56%5.772.059.84%4.064.160.17%2.62.3891.357.60%12.280.258.08%7.174.858.31%5.466.858.64%3.53.7279.354.56%9.671.454.91%6.467.055.09%5.159.155.43%3.33.2296.555.52%18.480.256.24%8.575.256.45%6.670.956.64%5.35.5259.552.89%4.455.053.08%3.449.853.30%2.545.053.49%1.92.0475.753.61%8.968.853.91%6.263.354.15%4.756.054.46%3.12.8576.955.31%8.069.355.64%5.464.255.86%4.157.056.17%2.82.5482.656.74%9.174.057.11%5.968.657.35%4.461.757.64%3.02.69101.458.99%16.482.559.81%6.676.660.06%4.972.660.23%3.93.9185.456.25%10.780.756.45%8.575.456.68%6.572.156.83%5.55.52ProcessA:經(jīng)過孔板ProcessB:液柱噴淋ProcessC:撞擊液面過熱壓差：對于某一點：對于某一過程AB:閃蒸實驗閃蒸實驗絕熱過程：能量守恒質(zhì)量守恒傳質(zhì)系數(shù)模型討論（對流條件）邊界條件：對稱軸(r=0)表面(r=R):絕熱，飽和w:massfractionu:velocityofzdirectionv:velocityofrdirection入流(z=0):rz

C(r=R)=Cs

流態(tài)類型Droplet/

liquid

column/

liquid

sheet其中Kapitza

number,粘滯力與表面張力的比值convectiveconditionsboilingconditionsheatfluxdoesnoteffecthmuchn/Aincrease,hincreaseflowratehdecreasedduetothefilmthickness(laminarflow),increase(turbulentflow)independentofflowratetemperaturedecreaseofviscosityleadstodecrwaseinthefilmthicknesssteepertemperatureinhibitbubblegrowth,butn/Aincreasestubediameterchangesthethermalboundarylayerdevelopmentlengthandthebubblegrowth.vaporflowheattransferenhancement降膜研究背景實驗結(jié)果噴淋密度h↑不完全潤濕h↓層流，厚度增加熱阻增加h↑增強對流h→管外側(cè)對流換熱熱阻不是主要矛盾降膜實驗介紹vaporstrongsolutionHotwaterWeaksolutionCoolingwatervaporTestunitrefrigeratorSolutiontankCoolingwatercyclehotwatercycleSolutioncycleFromrefrigeratorElectricalheaterHeatexSolutionpumpHotwaterpumpCoolingwaterpumpTestunit降膜實驗介紹溶液供溶液回溫度℃濃度溫度℃濃度52.750.550356.940.560752.940.566258.330.573555.710.578361.740.58766.270.521164.740.527266.730.508465.450.514655%57.5%45%52.5%50%降膜過程閃蒸過程能量平衡strongsolution,outletCoolingwaterSamplevalveSamplevalvepphotwaterweaksolution,outletCondensedwaterQ1Q2+20%-20%工況舉例Solution,inletAfterflashingSolution,outletHotwater,inletHotwater,outletQ=18.22kWQ=17.3kWN-Sequationsinlet(x=0,0≤y≤

): T=T0,w=w0，u0=0solid-liquidsurface(0＜x≤πr,y=0

): u=0 q=h(T(w)-T(y=0))liquid-vaporsurface(0＜x≤πr,y=

) w(y=δ)=ws