Động lực học bay của khinh khí cầu dạng đĩa elípsoid

Tuyen tap Cdng trinh Hdi nghi Khoa hge Ca hge Thiiy Todn qudc, Phan Thiit, 2008 439 Dong luc hoc bay cua khinh cau dang dTa Eh'psoid Nguyen Minh Xuan*", Ngo Minh Tuin'^', Hoang Anh Tii*^' (I) Hoe viin Ky thudt Qudn sir (2) Hoe vien Phdng khdng - Khdng qudn Tdm tia.iBdi viet dua nghien ciru vi chi tgo khinh cdu (KKC) cd diiu khien nhirng vdn de quan trgng vd phire tgp cua khoa hoc vd ky thudt Mgt nhirng bdi todn dgc tnrng cdn giai quyet dd Id ddng lire hoc bay KKC Abstract:Thls paper gtved the research about making control ellpsoid balloon - the Impotant and complicate problems of science and technics One of specific problems that need to solve is dynamic of flights of balloon Dat bai toan / / Dgt vdn de Gan day tai nhieu qudc gia ngudi ta lai quan tam nghien ciiu cac phuang tien bay nhe ban khdng Khac vdi nhung giai doan trude day, cac nha thiet ke dinh hudng cac quan tam tdi viec che tao cac khinh cau van tai cd kha nang mang cac tai Idn tdi cac viing xa hoac cac vi tri khd tiep can cua hanh tinh Sy phat trien cua cong nghe may tinh tao kha nang cho cac nha thiet ke nghien ciiu cac dac trung dgng lyc bgc, thiet ke va thir nghiem cac md hinh vdi chinh xac cao Tinh loan cac tham sd dgng lyc bgc bay, dac biet la tinh toan cac bai toan ve quy dao la giai doan quan trgng qua trinh thiet ke Trong dieu kien nhat djnh bai loan xac djnh cdng suat, cac dac tinh can thiet cho chuyen bay cua khinh cau dang dTa elipoid tren co so cac nghien cuu thi nghiem ddi vdi cac dac tinh dgng ciia md hinh KKC dng thdi dgng 1.2 Xay dung bdi todn a Tinh todn cdc tdc thuc cua md hinh KKC che bay bdng dn lap, tai mot chi lam viic cua ddng ca Md hinh KKC dang dTa elipsoid tao hinh da dugc thiet ke (binh I) va dugc dat dng thdi Chuyen bay thyc te cua KKC dang dTa quyen kha pbirc tap Khi cat canh KKC phai chuyen dgng dudi tac dgng cua lyc nang tTnh - theo phuong thang dirng Heli tao nen nap vao KKC hoac ket hgp vdi cac dgng co Ngoai tao gdc nghieng cua dgng ca KKC cd the thuyen dgng vdi quy dao nghieng, cong va quy dao phire khac Cac gia thiet tinh loan: - Cac dgng co khdng chuyen dgng va chiing tao lyc day & song song vdi vecta toe bay - Cac lyc tTnh khdng ddi - Cac gdc tan khai thac cua KKC thay ddi khoang tir 0-25° 440 Ddng lue hoc bay cua khinh cdu dang dia Elipsoid Tinh toan thyc hien cho KKC dudng kinh 16m, chieu cao 4m, khdi lugng 700kg (khi bay vdi 02 phi cong) Bai toan khao sat d che bay: cat canh, bay bang va dg cao Doi vdi KKC thiet ke, bay bang la che khai thac ca ban ciia KKC Trong che dd cd lyc nang dgng tac ddng len KKC Ya = Cj^ pV\S Vdi Cya- he sd lyc nang; p - mat khong d cao cho trude; V tdc KKC; S- dien tich viing that nhd nhat KKC; Xglyc can chinh dien KKC; G=mg-lyc trgng trudng tac dung len KKC Mirc tang lyc nang tTnh la: AK^^„ = mg - T^,^, , dd Yasi-liJ'C nang Asimet hay lyc nang tTnh Gia tri thir nghiem thdi md hinh KKC dng thdi dgng De tao lyc nang tTnh ngudi ta nap vao KKC 600m Heli Lyc nang dgng dugc tao bdi dgng ca pitton cd lyc day mgt dgngca la 58 kW c ,3 L ^''^- "A /> < :) N ~ Hinh 1: Hinh chiiu mat ciia md hinh Khinh cdu thiit ke Kit qua thir nghiem thdi mo hinh KKC dang dTa 6ng dgng thi hien hinh 2, Nguyen Minh Xudn, N^d Minh Tudn Hodns Anh Tu Hinh 2: Quan he hisd lire ndng vd gdc ('^'^ 441 Hinh 3: Quan hi hi sd lire ndng vd he sd luc cdn b Xdc dinh dgc tinh Idy cao dn lap Khi bay theo quy dao nghieng tang din, KKC bi tac dgng bdi cac lye sau: luc nang dgng Y^, lyc nang khia tTnh Y^,„ lyc can X^ va lyc diy dpng co Pj, Liy cao dac trung bang tdc ddng V, gdc nghieng quy dao He phuang trinh chuyin dgng cua KKC lay cao dn lap, [1]: r /;;gcos6'-r,-y„„cos6' = 0; X^, + mg cos e = P,f, (1) Vy = r s i n ' ; dt ' V - ^ '~dtvdi dH - muc gia tang cao, dL - muc gia tang tam xa bay Giai quyet cua bai toan a Xdc dinh cdc tdc thdng qua tinh todn dgc trung cdng sudt Tir muc tieu khao sat, phuang trinh can bang KKC cd the vilt: I Ci ~ ^a - Oi Trong dd P^ - lyc day can thiet Tir phuang trinh can bang cd the xac djnh tdc bay bing KKC, [2]: V,, = J ' : r" C ^pS • yu Cdng suat can thilt xac djnh la: =J-::-^ CyapS • ya (2) Ddng lue hoc bay cua khinh cdu dang dia Elipsoid 442 A^ = {'ng-Y^,„)V,, AK,„K,,, K K (3) (f> day K - he s6 chit lugng dgng KKC Cdng suit hicn cd cua dgng co KKC bang tdng cong suat tren true cua cac canh quat yV( = n Nad, n = ^Vr/t " ^° ^^"^ ^°^' ^'^'^' ''°"§ ^^^^ ^^^ '^^^^ ^^' Cdng suit tuang duong cua dgng ca pitton bang cong suat hieu qua cua dgng eg: A'td = A'e,H- Khi ddcdng suat hieu qua cua dgng co xac dinh theo cao, [3]: A'e.ll= A'cO ^ (3') P^-0.11 Cdng suat mdt ddng co xac dinh thdng qua cdng suat tuong duang: N^f = ^,,^ A^tdTrong tinh toan cdthe chgn ?7^