简介:Theoreticalandexperimentalinvestigationsofheattransferinflatcurvilinearchannelhavebeencarriedout.Linearandnon-lineareffectsofDeanvortexesonintensityofheattransferweretakenintoaccount.Thelineareffect,whichdescribeharmonic(sinuous)variationoftheheattransfercoefficientneartheconcavesurfaceofthechannelandthenon-lineareffectcausesthegeneralincreaseoftheheattransfercoefficientduetoaugmentationofheattransferengenderedbytheDeanvortexes.Forbotheffects,mathematicalrelationswereobtainedintheformofquadratures.Thesenumericalresultsweremodifiedtotheformconvenientinengineeringcalculations.TheinvestigationshaveshownthatbothlinearandnonlinearcomponentsgrowupwiththeDeannumber.NonlinearcomponentQ0Tincreasesmoreabruptly,whilethelinearoneQ1Tismoreconservative.Thisisaconfirmationofstabilityofvortexstructures.
简介:Amathematicalmodelbasedonthetheoryofheatandmasstransferinporousmediawasdevelopedtosimulatetheevolutionofgraintemperatureandmoisturecontentinawheatstoragebinduringventilationwithcoolingairattheconstanttemperatureandhumidity.Unlikethepreviousworksonthisaspect,thepresentworkwasnotfocusedoncoolingthestoredgrainbyventilationwithambientair,butwiththerefrigeratedair.Validationwasperformedbycomparingbetweenpredictedandmeasuredgraintemperatureandgrainmoisturecontentfortwocases.Predicteddatawereinreasonablegoodagreementwithmeasuredones.Themodelandtheparametervaluesusedinthemodelareapplicableforpredictingtemperatureandmoistureofstoredgrainsunderventilationconditions.