co空气微通道蒸发器两相区熵产分析

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1、CO2空气微通道蒸发器两相区熵产分析第65卷第12期化工学报Vol.65No.122014年12月CIESCJournalDecember2014CO2-空气微通道蒸发器两相区熵产分析吕静，石冬冬，徐峰，朱思倩（上海理工大学环境与建筑学院，上海200093）摘要：微通道已成为换热器研究领域的热点，以CO2微通道蒸发器为研究对象，建立了CO2微通道蒸发器两相区内、外侧均有相变的熵产模型，通过建立的CO2微通道蒸发器二维分布参数模型求解系统熵产数。分析CO2与空气侧质量流率、空气入口温度及CO2蒸发温度对系

2、统熵产数的影响。结果表明：CO2质量流率对系统熵产数影响很小；系统熵产数主要由CO2与空气两侧温差传热引起；系统熵产数随空气入口温度的增大而增大，随CO2的蒸发温度的增大而减小；随着空气质量流率的增大，系统熵产数增大，且蒸发温度越高，空气质量流率对系统熵产数的影响越大。关键词：二氧化碳；微通道；两相流;熵产数;数值模拟DOI：10.3969/j.issn.0438-1157.2014.12.012中图分类号：TK124文献标志码：A文章编号：0438—1157（2014）12—4734—08Entrop

3、yanalysisofCO2-airmicrochannelevaporatorintwo-phaseflowregionLüJing,SHIDongdong,XUFeng,ZHUSiqian(SchoolofEnvironmentandArchitecture,UniversityofShanghaiforScienceandTechnology,Shanghai200093,China)Abstract:Microchannelshavebecomeahotissueinheatexchangerr

4、esearch.Inthispaper,themicrochannelevaporatorwithCO2wastakenasresearchsubject.AnewentropymathematicalmodelwasproposedformicrochannelevaporatorwithCO2flowinginsideandairflowingoutside.Phasetransitionexistedonbothsides.EntropygenerationnumberNsrepresentedt

5、helossesduetotemperaturedifferenceofheattransferandpressuredrop.Asteadystatedistributedparametermodelforthemicrochannelevaporatorwasestablishedtosolveentropygenerationnumber.Comparisonsofanalyticalandexistingexperimentaldataweremadetoverifyandvalidatethe

6、model.TheeffectsofmassflowrateofCO2andair,CO2evaporationtemperatureandinletairtemperatureonsystementropygenerationnumberwereanalyzed.TheresultsfromthemathematicmodelshowedthatmassflowrateofCO2hadlittleeffectonsystementropygenerationnumber.Systementropywa

7、smostlycausedbytemperaturedifferenceofheattransferbetweenCO2andairsides.Withrisinginletairtemperature,entropygenerationnumberbecamelarger.WhilewithrisingCO2evaporationtemperature,systementropygenerationnumberdecreased.Withincreasingairmassflowrate,system

8、entropygenerationnumberincreased.Thehighertheevaporationtemperature,thegreatertheimpactofairmassflowrateonsystementropygenerationnumber.Keywords:carbondioxide;microchannels;two-phaseflow;entropygenerationnumber;numericalsi