buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

More documents

Recommendations

Info

184 Vasile Gabriel Nenerica et al. pressure depression due to the acceleration of the fluid. If the static pressure falls below vapour pressure then the phenomenon of cavitation will take place (Bergwerk, 1959). This is one of the most dangerous and thus one of the most difficult problems of the injectors. This problem was solved by changing the geometry of the spray holes. In the case of the cylindrical nozzle, the minimum pressure suddenly falls to a minimum value of 0 MPa in an area that can be located at the upper corner of the orifice inlet. Considering that the vapour pressure is 0.08 MPa, the critical pressure conditions of the onset of cavitation are achieved for the cylindrical nozzle. Nevertheless, for the convergent nozzle the minimum pressure is 6 MPa at the orifice exit, thus avoiding any cavitation phenomenon. Therefore, considering this definition, a critical cavitation number of Kcrit=1.25 is found for the cylindrical nozzle which is the same as the value found experimentally for the pressure of 30 MPa in Fig. 6. Nevertheless, in the case of the convergent nozzle, even with an injection pressure of 130 MPa, critical cavitating conditions were not reached, as experiments have shown (Payri et al., 2004). Fig. 6 – Results of the pressure field for the cylindrical (left) and conical (right) nozzle. Pi=30 MPa, Pb=6 MPa. 3. Conclusions 1. Common rail injection system can operate at very high pressures and thus combustion is much better, so pollution is much lower 2. With the advent of new processing technology and games could shrink the componentsand diameter spray holes leading to increased pressure injection. 3. The cylindrical nozzle, cavitation was detected due to a collapse of mass flow. 4. This resultmeans that the discharge coefficient will decrease when the cavitation coefficient decreases.
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 185 5. Conical nozzle cavitation effects have not even under severe pressure, which was explained by means of numerical simulations. REFERENCES Bergwerk., Flow Pattern in Diesel Nozzle Spray Holes. Proc. Inst. Mech. Eng., 173(25) (1959). Chaves H., Knapp M., Kubitzek A., Experimental Study of Cavitation in the Nozzle Hole of Diesel Injectors Using Transparent Nozzles. SAE Paper 950290 (1995). Kampmann S., Dittus B., Mattes P., Kirner M., The Influence of Hydro at VCO Nozzles on the mixture preparation in a DI diesel engine. SAE Paper 960867 (1996). Payri F., Bermudez V., Payri R., Salvador F.J., The Influence of Cavitation on the Internal Flow and the Spray Characteristics in Diesel Injection Nozzles. Fuel, 83, 419-31 (2004). Payri R., Garcia J.M., Salvador F.J., Gimeno J., Using Spray Momentum Flux Measurements to Understand the Influence of Diesel Nozzle Geometry on Spray Characteristics. Science Direct Paper Fuel, 84, 551-561 (2005). Pierpont D.A., Reitz R.D., Effects on Injection Pressure and Nozzle Geometry on DI Diesel Emissions and Performance. SAE Paper 950604 (1995). Rajaratnam N., Turbulent Jets. Elsevier, Amsterdam, 1974. Sazhin S.S., Feng G., Heikal M.R., A Model for Fuel Spray Penetration. Fuel, 80,2171- 2180 (2001). Siebers D., Scaling Liquid-phase Penetration in Diesel Sprays Based on Mixing-limited Vaporization. SAE Paper 1999-01-0528 (1999). Soteriou C., Smith M., Andrews R., Direct Injection Diesel Sprays and the Effects of Cavitation and Hydraulic Flip on Atomization. SAE Paper 950080 (1995). INTRODUCERE ÎN SITEMUL DE INJECŢIE COMMON RAIL (Rezumat) Se prezintă sistemul de injecţie Common Rail, adică rampa comună, componenta cât şi modul de funcţionare. De asemenea, am prezentat şi una din cele mai dificile probleme ale injectorului acestui sistem de injecţie şi anume cavitaţia. Acest fenomen este prezent în interiorul injectorului dar cel mai frecvent apare la orificiile de pulverizare. Fenomenul de cavitaţie poate fi evitat prin modificarea formelor geometrice ale orificiilor, şi anume din orificii cilindrice în orificii conice. Experimentele au arătat că astfel fenomenul de cavitaţie nu mai apare şi mai mult de atât, forma jetului este mult mai bună.
Page 1:
BULETINUL INSTITUTULUI POLITEHNIC D
Page 5 and 6:
Page 7:
VICTOR COTOROS şi EMIL BUDESCU, As
Page 10 and 11:
ALEXANDRU RADU, CONSTANTIN PANĂ an
Page 13 and 14:
Page 15 and 16:
Bul. Inst. Polit. Iaşi, t. LVIII (
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
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:
Page 42 and 43:
30 Daniel Dragomir-Stanciu and Mari
Page 44 and 45:
32 Daniel Dragomir-Stanciu and Mari
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:
Page 64 and 65:
52 Ionel Oprea and low viscosity ar
Page 66 and 67:
54 Ionel Oprea COP PT Puterea speci
Page 68 and 69:
56 Ionel Oprea 8. GWP - global warm
Page 70 and 71:
58 Ionel Oprea suplimentari, cum ar
Page 72 and 73:
60 Răzvan Florin Barzic et al. Cur
Page 74 and 75:
62 Răzvan Florin Barzic et al. 3-
Page 76 and 77:
64 Răzvan Florin Barzic et al. 3.
Page 78 and 79:
66 Ionel Ivancu et al. the second s
Page 80 and 81:
68 Ionel Ivancu et al. a b Fig. 4 -
Page 82 and 83:
70 Ionel Ivancu et al. Gut J.A.W.,
Page 84 and 85:
72 Ion Zabet and Graţiela-Maria Ţ
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
82 Victor Pantilie et al. many rese
Page 96 and 97:
84 Victor Pantilie et al. industria
Page 98 and 99:
86 Victor Pantilie et al. Another i
Page 100 and 101:
88 Victor Pantilie et al. At the en
Page 102 and 103:
90 Victor Pantilie et al. Tang X.,
Page 104 and 105:
92 Alexandru Radu et al. Furthermor
Page 106 and 107:
94 Alexandru Radu et al. Spark timi
Page 108 and 109:
96 Alexandru Radu et al. Fig. 3 - B
Page 110 and 111:
98 Alexandru Radu et al. 4. The bes
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127:
Page 130 and 131:
118 Eugen Rusu et al. in PM emissio
Page 132 and 133:
120 Eugen Rusu et al. also be used
Page 134 and 135:
122 Eugen Rusu et al. Fig. 3 - Maxi
Page 136 and 137:
124 Eugen Rusu et al. Fig. 6 - HC e
Page 138 and 139:
126 Eugen Rusu et al. Pe lângă ce
Page 140 and 141:
128 Adrian Sabău et al. arguments
Page 142 and 143:
130 Adrian Sabău et al. The energy
Page 144 and 145:
132 Adrian Sabău et al. during fue
Page 146 and 147: 134 Adrian Sabău et al. 11 T ⎛ 0
Page 148 and 149: 136 Adrian Sabău et al. No experim
Page 150 and 151: 138 Adrian Sabău et al. calculated
Page 153 and 154: BULETINUL INSTITUTULUI POLITEHNIC D
Page 155 and 156: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 163: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 166 and 167: 154 Marius Receanu et al. where: qr
Page 168 and 169: 156 Marius Receanu et al. In Fig. 2
Page 170 and 171: 158 Marius Receanu et al. the ambie
Page 184 and 185: 172 Mariana Lupchian Propulsion eng
Page 186 and 187: 174 Mariana Lupchian Fig. 1 - The p
Page 200 and 201: 188 Costică Atanasiu et al. comput
Page 202 and 203: 190 Costică Atanasiu et al. γ= ε
Page 204 and 205: 192 Costică Atanasiu et al. The sa
Page 206 and 207: 194 Costică Atanasiu et al. Fig. 1
Page 208 and 209: 196 Costică Atanasiu et al. elasti
Page 210 and 211: 198 Ovidiu Niţă et al. rejection
Page 212 and 213: 200 Ovidiu Niţă et al. aluminium
Page 214 and 215: 202 Ovidiu Niţă et al. a b Fig. 5
Page 216 and 217: 204 Ovidiu Niţă et al. căreia ac
Page 218 and 219: 206 Ovidiu Niţă and Vasile Braha
Page 226 and 227: 214 Marian Teodor Popescu et al. 2.
Page 228 and 229: 216 Marian Teodor Popescu et al. Sp
Page 230 and 231: 218 Marian Teodor Popescu et al. Th
Page 242 and 243: 230 Victor Cotoros and Emil Budescu
Page 244 and 245: 232 Victor Cotoros and Emil Budescu
Page 246 and 247:
234 Victor Cotoros and Emil Budescu
Page 248 and 249:
Page 250 and 251:
Page 252 and 253:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
PC Cell calibration Bul. Inst. Poli
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317:
show all

buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?