三层薄膜挤出吹塑过程中才机头流场的模拟分析-机械工程专业毕业论文.docx

r in g se c tio n . A e e o rd in g to th e f irst k in d o f d ia g ra m it e a n s e e th e u n if or m ity o f sP e e d d istr ib u tio n o n se c tio n ，it e a n o b se r v e th e sP e e d e h a n g in g a lo n g th e c ire u m f ere n tia l d ire e tio n d ire e tly f ro m th e s e e o n d k in d o f d ia g ra m . A lla ly Z in g th e c h a n g e s o f e n tra n c e v e lo e ity ，b u f fe r ta n k le n g th ，c a s e 一h a rd e n e d le n g th a n d th e n o n 一n e w to n ia n in d e x b r in g so m e in f lu e n e e to f lo w f ie ld ，su m m a ri Z in g th e f lo w f ie ld e h a n g in g r u le o f th e d if fe re n t P a ra m e te rs e h a n g in g ，a n a ly Z in g th e P a ra m e te rs e h a n g in g b r in g so m e in f lu e n c e to t h e u n if or m ity o f e x it sP e e d ， in le t P re ssu re a n d P r es su r e d r o P . R e s u lts sh o w th a t e h a n g in g e n tra n e e v e lo c ity a n d n o n 一n e w to n ia n in d e x b r in g g r e a te in f lu e n e e to th e u n if or m ity o f e x it v e lo e ity d istr ib u tio n ，in le t P re s su re a n d P re ssu re d ro P ，b u t e h a n g in g b u f fe r ta n k le n g th a n d e a se一h ard en e d len gth h a s n o t an y in flu en e e to th e u n iform ity o f th e e x it v e lo e ity d istr ib u tio n n e a rly .A lld it a ls o h a s v e r y b ig e f fe c t to th e in le t P re s su re a n d P re s s u re d r o P .T h e stu d y P ro v id e s th e b a sis o f o P tim iz a tio n f lo w str u e tu re to P e o P le . K eyw o rd s: P la stie film ，F in ite E lem en t M eth o d (F E M ) ，F lu id m eeh an ies，E x trusio n b lo w m o ld in g ，H e a d f lo w f ie ld . 1 11  目 录 摘 要 ...........................……，.............................……，... .................................................................……I A