Ice Accretion Prediction Code

Transcription

1 Ice Accretin Predictin Cde Vladimír Hrák University f Defence Institute f Hydrdynamics, Academy f Sciences Czech Republic 1

2 Dedicated t the memry f Dr. Bhumír Hření 2

3 Mtivatin The in-flight icing may affect all types f aircraft. Presence f ice n an aircraft surface can lead t a number f perfrmance degradatins: changes in pressure distributin decreased maximum lift and increased drag stall ccurring at lwer angles f attack and increased stall speed reduced cntrllability It is imprtant t t understand d hw the different ice shapes affect aircraft aerdynamics. It can be studied by flight tests, wind tunnel measurements, and cmputatinal simulatins. 3

4 Cmputatinal simulatin f ice accretin is an essential tl in design, develpment and certificatin f aircraft fr flight int icing cnditins. Currently, there exist several apprved ice accretin cdes: LEWICE (LEWis ICE accretin prgram) is sftware develped by the Icing Branch at NASA Glenn Research Center CANICE cde develped at the Ecle Plytechniue de Mntreal ONERA (Office Natinal d'etudes et de Recherches Aérspatiales) cde in France TRAJICE cde which was develped by DERA (Defence Evaluatin and Research Agency) in United Kingdm CIRA cde frm Italian Aerspace Research Center. 4

5 Ice Accretin Predictin Cde Cde was develped as a tl fr simulating flight int icing cnditins Presented sftware was subseuently develped and imprved. There are three main cde versins: R-Ice 1.1 Rime ice accretin predictin Ice 3.1 Glaze ice accretin predictin Ice 4.1 Multi-element airfils icing 5

6 Trajectry f water drplets The ptential flw field is calculated using 2-D panel methd. The relatin fr any pint inside the cntrl area is in frm Ptential flw field is then used t determine the trajectries f water drplets and the impingement pints n the bdy. Drplets passing thrugh the atmsphere are cnsidered as spherical elements n that the surrunding fluid frces and gravitatin act. Small water drplets have trajectries similar t streamlines, vice versa large water drplets trajectries are affected by the airfil inherency nly slightly. 6

7 Versin 1.1 Airfil rime ice accretin predictin Impinging super-cled water drplets freeze immediately upn impact. Cde applies a time-stepping prcedure t calculate the shape f an ice accretin. 0,050 0,050 y/c [1] y/c [1] 0,025 0,025 0,000 Chrd= m; Vext=92.54 m.s -1 ; FluidP= Pa; FluidT=257.6 K; Alpha=0 ; PartD= m; PartCntent= kg.m -3 ; RimeIceRh=900 kg.m -3 ; Steps=5; TimeStep=64.8 s; Time=324 s. 0,000 Chrd= m; Vext=92.54 m.s -1 ; FluidP= Pa; FluidT=257.6 K; Alpha=0 ; PartD= m; PartCntent= kg.m -3, RimeIceRh=900kg.m -3 ; Steps=5; TimeStep=244.8 s; Time=1224 s. -0,025-0,025-0,050-0,025 0,000 0,025 0,050 x/c [1] -0,050-0,050-0,025 0,000 0,025 0,050 x/c [1] 7

8 Quantitative cmparisn f using the current cmputatinal iceaccretin simulatin methds. 0,050 y/c [1] 0,025 0,000-0,025 Clean Airfil Experimental ONERA1990 Simn CANICE Paraschiviu TRAJICE ADSE ONERA2000 Duprat NASA R-ICE Generally, current ice accretin cdes give satisfied results f fthe rime ice simulatin. -0,050-0,025 0,000 0,025 0,050 x/c [1] 0,075 0,050 y/c [1] 0,025 0,000-0,025 Clean Airfil Experimental ONERA1990 Simn CANICE Paraschiviu TRAJICE ADSE ONERA2000 Duprat NASA R-ICE -0,050-0,050-0,025 0,000 0,025 x/c [1] 0,050 8

9 Versin 3.1 Airfil glaze ice accretin predictin Glaze ice creates at cmbinatins f temperature clse t freezing. Evapratin In that case, nt all f the impinging ev p water freezes n impact. Liuid water Thin layer f water is flwing very fr slwly alng the surface and freeze at ther lcatins. Ice accretin Bundary layer There are used theretical appraches are generally called as a shallw water thery. The cnservative euatins using fr the slutin f water flw in pen channels are frmally arranged. The flux terms are evaluated using a discntinuus Galerkin methd based n finite-vlume frmulatin. 9

10 Mass, mtin, and energy cnservative euatins culd be written in the general frm x t S S F Q general frm Q A Vectrs f variables Q, flw F and surces S, S are given by relatins: flw crss-sectin mass flux A EQ I g A Q Q E Q A n 1 2, F Q flw crss-sectin flw vlume thermal energy mass flux mmentum flux flux f energy A EQ E A dx dp A g I g t 2 0 S Internal T T T T A dx dp A g I g e e e w w w e e w w t n 2 S surces: f ev w fr w p e v v v S External surces: 10 ev ev w fr fr w p p e ev w fr w px p e L L ct ct ct v v v S surces:

11 Example f glaze ice-accretin simulatin. Airfil NAC 0012, chrd 0.45 m, angle f attack α = 0, velcity v =772ms , MVD = 18 μm, LWC = 0.32 g m -3, air temperature T = K, icing expsitin 300 s ,06 y/b 0,04 0,02 0,00-0,02-0,04-0,06-0,02 0,00 0,02 0,04 0,06 0,08 x/b 0,10 Clean Airfil Experimental Paraschiviu CANICE ADSE TRAJICE Duprat ONERA NASA LEWICE Cmparisn f current ice-accretin cdes shws there is still rm fr imprvement in the uality f predictins. 11

12 Air temperature influence n iced airfil shapes Stream-wise shape (b), (c) Duble-hrn shape (d), (e) Span-wise ridge shape (f) (a) Rime ice (b) T = K (c) T = K (d) T = K (e) T = K (f) T = K Airfil NFL0414, chrd 0.45 m, angle f attack α = 0, velcity v = 77.2 m s -1, MVD = 18 μm, LWC = 0.32 g m -3, icing expsitin 900 s. 12

13 Versin 4.1 Multi-element airfils icing The latest cde versin enables slutin f multi-element airfils up t eight separate parts. Mutual flw verlap f circumfluent bdies ccurs. Drplet trajectries near an airfil with a sltted flap Drplet trajectries near an airfil with a sltted flap in landing psitin 13

14 Example f flapped airfil icing Ice accretin n the flap causes the reductin f the gap size between main element and flap. Cnseuently, it can have a large impact n the perfrmance degradatin f iced multi-element airfils. There is a ptential mechanical prblem in the elevatr mechanism itself. 14

15 Input file Cnfiguratin file: _ice.cfg Icing parameters # cnfiguratin file # PrfDta=NACA0018 # NACA0018 Chrd=1 # 1.0;<0.1,10> Vext=50 # 50.0;<10,200> Alpha=5 # 5.0;<-20,20> FluidP= # 1.e5;<0.1e5,1.2e5> 1e5 1 FluidT=263 # 263;<200,300> PartCntent=0.001 # 1.e-3;<0.05e-3,5.e-3> PartD= # 100e-6;<5.e-6,5000.e-6> PartT= # ;<200,300> BdyT= # ;<200,300> RimeIceRh=900 # 900;<700,1000> GlaseIceRh=917 # 917;<700,1000> # TimeStep=120 # 120;<1,600> Steps=5 # 5;<1,1000> MinBdyPints=50 # 50;<20,500> 15

16 Graphical utput files Airfil gemetry gem004.eps Successive ice accretin by steps mdif004.eps Drplet trajectries near iced airfil part004.eps p 16

17 beta004.eps Water drplets lcal cllectin efficiency β, nrmal v n and tangential v t velcity with regard t the airfil surface at impact lcatin 17

18 blay004.eps Parameters f bundary layer: Lcal frictin cefficient c f, displacement bundary layer thickness δ 1 (mass) and δ 2 (impulse), and Nusselt number Nu 18

19 flw004.eps Distributin f pressure cefficient c p and relative velcity v/v 19

20 flw005.dta Text utput file Chrd [m] Length [m] Alpha [st] Vext [m/s] e+005 FluidP [Pa] FluidT [K] FluidRh [kg/m^3] e-005 FluidNu [m^2/s] e-004 PartD [m] PartT [K] e-003 PartCntent [kg/m^3] PartRh [kg/m^3] BdyT [K] # s[m] x[m] y[m] v[m/s] beta[-] vn[m/s] vt[m/s] cp[-] cf[-] Nu[-] e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e e+003 #end 20

21 Clsing remarks ICE cde enables cmputatinal rime ice and glaze ice accretin predictin n single and multi-element airfils in acceptable time f slutin. Mathematical ti mdel has recently been mdified d fr variable wall temperature alng the airfil surface. The cde was als imprved fr the better apprximatin f transitin bundary layer lcatin. Presented cde culd be cnsidered at least as a fully cmparable with the current ice accretin predictin cdes. 21

22 Thank yu fr yur attentin 22