buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

More documents

Recommendations

Info

142 Anca Elena Eliza Sterpu and Anca Iuliana Dumitriu 1. Introduction Diesel engines are the axis of world industry, dominating sectors like road transport, agricultural, military, construction, maritime propulsion and stationary electricity production. In recent years, the concern over the depleting world reserves of fossil fuels and more stringent emission regulations for harmful pollutants have led to the resolute efforts in searching for renewable alternative fuels and ultra-low emission combustion strategies. Biodiesel fuel, which is identified as a clean alternative fuel, has become commercially available in a number of countries (Zheng et al.., 2008),. In addition, this biofuel is completely miscible with petroleum diesel, allowing the blending of these two fuels in any proportion. Biodiesel can be used neat or blended in existing diesel engines without major modification in the engine hardware. However, differences in the chemical nature of biodiesel (mixture of monoalkyl ester of saturated and unsaturated long chain fatty acids) and conventional diesel fuel (mixture of paraffinic, naphthenic and aromatic hydrocarbons) result in differences in their basic properties, affecting engine performance and pollutant emissions. Biodiesel, produced from any vegetable oil or animal fat, generally has higher density, viscosity, and cetane number, and lower volatility and heating value compared to commercial grades of diesel fuel (Benjumea et al., 2008). Biodiesel most commonly are made from soybean oil in the United States and from rapeseed (Canola) oil in Europe using methanol. 1.1. Biodiesel as Engine Fuel Since most modern diesel engines have direct injection fuel systems, and these engines are more sensitive to fuel spray quality than indirect injection engines, a fuel with properties that are closer to diesel fuel is needed (Canakci, 2007). The best way to use vegetable oil as fuel is to convert it in biodiesel. Biodiesel is made from natural, renewable sources such as new or used vegetable oils and animal fats. The resulting biodiesel is almost similar to conventional diesel in its main characteristics. Biodiesel is an oxygenated fuel and leads to more complete combustion; hence CO emissions reduce in the exhaust. Biodiesel contains no petroleum products, but it is compatible with conventional diesel and can be blended in any proportion with mineral diesel to create a stable biodiesel blend. The level of blending with petroleum diesel is referred as Bxx, where xx indicates the amount of biodiesel in the blend (i.e. B20 blend is 20% biodiesel and 80% diesel). It can be used in compression ignition (CI) engine with no significant modifications to the engine (Agarwal, 2007). 1.2. Combustion Characteristics of Biodiesel It is important to know the combustion properties of biodiesel–diesel blends. Some of these properties are required as input data for predictive and
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 143 diagnostic engine combustion models. Additionally, it is necessary to know if the fuel resulting from the blending process meets the standard specifications for diesel fuels. Given the difficulty of obtaining the combustion properties of the blend by measurement, the ability to calculate these properties using blending or mixing rules is very useful. Some authors (Clements, 1996) proposed blending rules for estimating the density, heating value, viscosity, cetane number and cloud point of biodiesel as a function of its methyl esters profile. By comparing predicted values with experimental data, they found that the typical average errors were less than 2%, with the exception of viscosity, where the average error was 10%. Similar blending rules for calculating properties of methyl ester blends have also been used by other researchers for estimating properties of biodiesel–diesel blends. Tat and Van Gerpen (Tat & Van Gerpen, 1999, Tat & Van Gerpen, 2000) carried out a study on the density and kinematic viscosity of a commercial soybean oil biodiesel and its blends with two samples of diesel fuels at 75%, 50% and 20% biodiesel (by weight). Results showed that both density and viscosity increased with the increase in the percentage of biodiesel. Blend kinematic viscosities were estimated by means of a blending rule. The maximum differences between predicted and measured viscosities were less than 3.74% of the measured values for the biodiesel blends with both diesel fuels. Experimental investigations have been carried out by Yuan, Hansen and Zhang (Yuan et al., 2004) to examine the density using three types of biodiesel (two produced from soybean oil and another biodiesel prepared from yellow grease). These were blended with diesel fuel at 75%, 50% and 25% biodiesel (by weight), and tested from close to the biodiesel crystallization onset temperature up to 100 o C. The measurements indicated that all biodiesel fuels and their blends with diesel fuel had a linear specific gravity–temperature relationship similar to pure diesel fuel. The densities of the blends estimated by a mixing rule showed an average absolute deviation (AAD) of less than 0.43% for all tested fuels in the temperature range studied. The present paper presents experimental density and viscosity data, together with the flash point and distillation curves for rapeseed oil biodiesel and its blends with diesel fuel. Additionally, the calculated cetane index and heating value of the tested neat fuels and their blends is obtained by ASTM D976 and ASTM D4737 for cetane index and ASTM D4868 for heating value recommended for hydrocarbon fuels. The aim of this work is to evaluate mixing rules for predicting the combustion properties of rapeseed oil biodiesel–diesel fuel blends as a function of biodiesel content (volume fraction). This approach is more likely to be applicable to other biodiesel fuels and blends than empirical correlations, which would be valid only for the specific blends tested.
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: BULETINUL INSTITUTULUI POLITEHNIC D
Page 115 and 116: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 127: Bul. Inst. Polit. Iaşi, t. LVIII (
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: BULETINUL INSTITUTULUI POLITEHNIC D
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 220 and 221:
Page 222 and 223:
Page 224 and 225:
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 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239:
Page 242 and 243:
230 Victor Cotoros and Emil Budescu
Page 244 and 245:
Page 246 and 247:
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?