homework for the former two chapters

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1、HOMEWORKFortheformertwochaptersTheThermodynamicsofMaterialsandItsApplicationsGraduateCourse,NanchangUniversity1.1aleadbulletisfiredatafrigidsurface.Atwhatspeedmustittraveltomeltonimpact,ifitsinitialtemperatureis25℃andheatingoftherigidsurfaceoftherigidsurfaceisneglected?Themeltingpointofleadis

2、327℃.Themolarheatoffusionoftheleadis4.8kJ/mol.ThemolarheatcapacityCPofleadmaybetakenas29.3J/(molK)1.2whatistheaveragepowerproductioninwattsofapersonwhoburns2500kcaloffoodinaday?Estimatetheaverageadditionalpowderproductionof75Kgmanwhoisclimbingamountainattherateof20m/min1.3Onecubicdecimeter(1d

3、m3)ofwaterisbrokenintodropletshavingadiameterofonemicrometer(1um)at20℃.(a)Whatisthetotalareaofthedroplets?(b)Calculatetheminimumworkrequiredtoproducethedroplets.Assumethatthedropletsarerest(havezerovelocity)Waterhaveasurfacetensionof72.75dyn/cmat20℃(NOTES:thetermsurfaceenergy(ene/cm2)isalsous

4、edforsurfacetensiondyn/cm)1.7Methaneisdeliveredat298Ktoaglassfactory,whichoperatesameltingfurnaceat1600K.Thefuelismixedwithaquantityofair,alsoat298K,whichis10%inexcessoftheamounttheoreticallyneededforcompletecombustion(airisapproximately21%O2and79%N2)(a)Assumingcompletecombustion,whatisthecom

5、positionofthefluegas(thegasfollowingcombustion)?(b)Whatisthetemperatureofthegas,assumingnoheatloss?(c)Thefurnaceprocesses2000kgofglasshourly,anditsheatlossestothesurroundingsaverage400000kJ/h.calculatethefuelconsumptionatSTP(inm3/h)assumingthatforgasH1600-H298=1200KJ/KG(d)Aheatexchangerisinst

6、alledtotransfersomeofthesensibleheatofthefluegastothecombustionair.Calculatethedecreaseinfuelconsumptionifthecombustionairisheatedto800KDATASTPmeansT=298K,P=1atm1.11aparticularblastfurnacegashasthefollowingcompositionby(volume):N2=60%,H2=4,CO=12%,CO2=24%(a)ifthegasat298Kisburnedwiththestochio

7、metricamountofdryairat298K,whatisthecompositionofthefluegas?Whatistheadiabaticflametemperature?(b)repeatthecalculationfor30%excesscombustionairat298K(C)whatistheadiabaticflametemperaturewhentheblastfurnacegasispreheatedto700K(thedryairisat298