Experimental and Numerical Study of Swirling ... - Solid Mechanics

More documents

Recommendations

Info

Experi imental and Numerical N Stud dy of Swirling g Flow in Scaveenging Processs for 2-Stroke Marin ne Diesel Engin nes Figur re 6.1: Outline of the section-cut t of mesh geometry g for Fully Op pen Intake Port. The numerical simul lations presentted here are cconducted for cylinder length L=4D and piston positions with fullly open intakke port only. 6.1 The me esh used for fully f open poort case is unsstructured hexx mesh and hhas approx. . 2 million cell ls. 6.1.1 Comput tational DDetails Turbulen nce Models Chapter 6 The tur rbulence mod dels used are already availaable in the AAnsys v12.1 and a the value es of model cconstants usedd are the on default. . The computa ations are connducted first bby running a s with standard k model. Thee Reynolds Sttress model u model by b (Speziale et t al., 1991) witth quadratic fo formulation fo of the pressure p strain n term. This RSSM model does not require account t for the wall-r reflection effeect in order to obtain a satisf in the logarithmic l re egion of a turrbulent bounddary layer and accurac cy particularly y for flows wwith streamlinne curvature Figure 6.2 shows a flow chart showing the steps follow differen nt simulations using differennt turbulence models. ® FLUENNT nes available bby steady state caase used is the SSSG or the rapid paart e a correction to factory solutioon d has improveed (Ansys, 20099). wed to perforrm 148 Numerical Modeling
Experi imental and Numerical N Stud dy of Swirling g Flow in Scaveenging Processs for 2-Stroke Marin ne Diesel Engin nes Fig gure 6.2: Flow w Chart Showing steps followed f to perfo form differ rent Simulations s (Full ly Open Port Cas se). The con nverged soluti ion for the stteady state k model is then used ass a starting g point for the e steady state RNG k and Reynoldds stress modeels (RSM). This step is ad dopted to see if the steady sstate solution converges i.e. if the nu umerical simulation doess not converge then it indicates thhe unstead diness of the flow. f In case of steady statee simulations for both RNNG k and a Reynolds stress (RSM) mmodels, the reesiduals droppped to 1e-02 annd then re emained cons stant (periodiic behavior wwith small ammplitude). Thhe steady state s results fo or individual mmodels are thhen used as the starting point for the unsteady RAN NS (URANS) ssimulations. 6.1.2 Boundary y Conditioons Chapter 6 At the inlet i of the computational ddomain ‘veloc is defin ned. For the coordinate c syystem at the i system is defined for r the velocity components. velocity y in terms of radial, tangenntial and axial given case is very rea asonable. The total inlet ve volume e flow rate and d the magnitudde of radial r are calc culated from the t mean velo (Equation 6.1-6.3). The T value of a kept at 26 which is close c to the da the inle et section geom metry allows t directio on, the value of o axial velocity e-04 ins stead of zero value to avoid a v city inlet’ bounndary conditioon inlet, cylindriical coordinattes This facilitattes defining thhe l componentss which for thhis elocity is calcuulated from thhe r and tangential v velocitiies ocity by definning the anglee between them angle for all the simulaations has beeen ata based on LDDA results (Fiigure 4.4). Since the flow only tto be in radiall and tangentiial y component at the inlet is defined v =1.446 z any numericall issue. 149 Numerical Modeling
Page 1:
Experimental and Numerical Study of
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Experi imental and Numerical N Stud
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118: Experi imental and Numerical N Stud
Page 125 and 126: Experimental and Numerical Study of
Page 167: Experimental and Numerical Study of
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Manuscript J Mar Sci Technol manus
Page 247 and 248:
00000000 11111111 piston screen con
Page 249 and 250:
50 % and 75 % partially closed inta
Page 251 and 252:
V θ / V b V θ / V b V θ / V b 1.
Page 253 and 254:
V θ / V b V θ / V b V θ / V b 1.
Page 256:
DTU Mechanical Engineering Section
show all

Experimental and Numerical Study of Swirling ... - Solid Mechanics

Create successful ePaper yourself

Delete template?

Save as template?