離心葉輪變工況氣動性能計算及CFD驗證.pdf

1、天津大學碩士學位論文離心葉輪變工況氣動性能計算及CFD驗證姓名：郝維申請學位級別：碩士專業(yè)：流體力學指導教師：劉正先201112ABSTRACTWhenanaircraftfliesatahypersonicspeed，thetemperatureofgasinnerboundarylayernearthewallisSOhighbecauseoftheexistenceofshockwaveandtheeffectofviscosit

2、ythatpartkineticenergyoftheairtransformintotheenergyofmolecularrandommotionThefreedomdegreeofmolecularvibrationisexcitationandthenthedissociationorionizationofthemolecularandexcitationofelectronicTheairisnolongeraperfect

3、gasanymorebutarealgasconstitutedbythemolecules，atoms，ionsandelectronsTheequationofgasstateandthethermodynamicpropertiessuchascompressibilityfactorenergyenthalpythespecificheatandSOonaredeviatefromvaluesofperfectgasThethe

4、rmodynamicpropertiesofairwithdissociationshouldbestudiedinordertostudythestabilityofhypersonicboundarylayerandpredictthetransitionlocationwellInthispaper，thethermodynamicpropertiesarestudiedwiththemethodsofthedegreeofdis

5、sociationandtheequilibriumconstantThefollowingconclusionscanbedrawn：1、ThedegreeofdissociationofoxygenandthecompressibilityfactoroftheairarefunctionsofpressureandtemperatureThedegreeofdissociationandthecompressibilityfact

6、oroftheairincreaseasthetemperatureincreasesatthesamepressureAndthedegreeofdissociationandthecompressibilityfactoroftheairdecreaseasthepressureincreasesatthesametemperature2、Theinternalenergyandtheenthalpyoftheairincrease

7、asthetemperatureincreases，andgetamaximumvalueintheendofdissociationreactionThespecificheatpermolatconstantdensityandthespecificheatpermolatpressureofmixedgasaredecreaseafterthefirstincreaseastheraiseoftemperatureAndthesp

8、ecificheatgatthemaximumvalueatthetemperaturewherethereactionrateofdissociationislargestThegasconsideringthedissociationabsorbsmoreheatthanthatofperfectgaswiththetemperatureraisesthesameamount，namelythegasconsideringthedi

9、ssociationraiseslessdegreesoftemperaturethanthatofperfectgaswiththegasabsorbsthesameamountofheat3、TheratioofspecificheatandisentropicexponentofmixedgaschangeasthedissociationofoxygenTheydecreaseafterthefirstincreaseasthe