简介：

简介：AhomogeneoustheoreticalmodelisdevelopedtopredicttheperformanceofR22andR290inadiabaticcapillarytubes.Themodelisbasedonconservationequationsofmass,momentumandenergy.Metastablebothliquidandtwo-phaseflowregionsareconsideredinthemodel.Inmetastabletwo-phaseregion,superheatedliquidisintroducedintothemetastablemixtureviscosityandtwomethodsarepresentedtoevaluateit.Themodelisvalidatedbycomparingthepredictedpressureandtemperatureprofileandmassflowratewithseveralinvestigators′experimentaldataofR22andoneofitsalternativesR290reportedinliterature.Allofthepredictedmassflowratesarewithin±8%ofmeasuredvalues.Comparisonsarealsomadebetweenthepresentmodelandotherinvestigators′modelsorsizingcorrelation.Themodelcanbeusedfordesignorsimulationcalculationofadiabaticcapillarytubes.

简介：

简介：CharacteristicsofR22anditsnewalternativerefrigerantR290flowingthroughadiabaticcapillarytubesareinvestigatedbasedonthehomogeneousmodel.Extensiveflowvariablesalongtubelengthsuchaspressure,temperature,viscosity,velocity,Reynoldsnumber,frictionfactorandvaporqualityetcarecomparedbetweenthetwofluidsunderthesameoperatingcondition.Twocasesareconsidered,namely,eitherthesametubelengthorthesamemassflowrateasinletcondition.TheresultsshowthatthemassflowrateinthecapillarytubeofR290is40%lowerthanthatofR22duetothedifferencesofphysicalpropertiesbetweenthetwofluids.Further,aparametricanalysisisperformedanditappearsthateffectsofgeometricandthermodynamicparametersonmassflowrateofR290areweakerthanthatofR22.Whenthecondensingtemperatureisincreasedfrom40℃to50℃,themassflowrateforR22isincreasedby16%,whiletheincreasingrateforR290is13%.

简介：摘要：四生课堂理论以生命性、生长性、生活性和生成性为基本特征。基于四生课堂理论的小学英语阅读教学模式能够彰显阅读教学主体的生命性，重视阅读教学目的的生长性，体现阅读教学内容的生活性，显示阅读教学过程的生成性。基于四生课堂理论的小学英语阅读教学设计实践探索是提高小学英语阅读课堂教学水平的积极实践。

简介：摘要：本文探讨了单元主题探究的定义、步骤及实际操作，详细介绍了在英语阅读教学中的应用方法。以思维导图为工具，分析了其基本构建与设计原则，并以具体案例展示了在《A child of Two Cuisines》单元中的实际应用。重点关注学生参与思维导图设计的操作与反馈，通过深入案例分析，全面呈现了这一教学模式在提升学生阅读理解能力方面的实际效果。通过研究，期望为高中英语阅读教学提供新的思路与实践经验。