An?lise da lubricidade do biodiesel brasileiro de ?steres et?licos de soja e girassol

• Main Author: Farias, Aline Cristina Mendes de
• Other Authors: CPF:10973370491
• Format: Others
• Language: Portuguese
• Published: Universidade Federal do Rio Grande do Norte 2014
• Subjects: HFRR; lubricidade; diesel; biodiesel; desgaste; wear; lubricity; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA
• Online Access: http://repositorio.ufrn.br:8080/jspui/handle/123456789/15677

Made available in DSpace on 2014-12-17T14:58:14Z (GMT). No. of bitstreams: 1 AlineCMF_DISSERT.pdf: 4814778 bytes, checksum: 4e9b94164b8595730e3395e99750b38f (MD5) Previous issue date: 2011-02-09 === Fuel is a material used to produce heat or power by burning, and lubricity is the capacity for reducing friction. The aim of this work is evaluate the lubricity of eight fossil and renewable fuels used in Diesel engines, by means of a HFRR tester, following the ASTM D 6079-04 Standard. In this conception, a sphere of AISI 52100 steel (diameter of 6,00&#61617;0,05 mm, Ra 0,05&#61617;0,005 &#956;m, E = 210 GPa, HRC 62&#61617;4, HV0,2 631&#61617;47) is submitted to a reciprocating motion under a normal load of 2 N and 50 Hz frequency to promote a wear track length of 1.1&#61617;0.1mm in a plan disc of AISI 52100 steel (HV0,05 184&#61617;10, Ra 0,02&#61617;0,005 &#956;m). The testing extent time was 75 minutes, 225,000 cycles. Each one test was repeated six times to furnish the results, by means of intrinsic signatures from the signals of the lubricant film percentage, friction coefficient, contact heating, Sound Pressure Level, SPL [dB]. These signal signatures were obtained by two thermocouples and a portable decibelmeter coupled to a data acquisition system and to the HFRR system. The wettability of droplet of the diesel fuel in thermal equilibrium on a horizontal surface of a virgin plan disc of 52100 steel, Ra 0,02 &#61617; 0,005 &#956;m, were measured by its contact angle of 7,0 &#61617; 3,5o, while the results obtained for the biodiesel B5, B20 and B100 blends originated by the ethylic transesterification of soybean oil were, respectively, 7,5 &#61617; 3,5o, 13,5 &#61617; 3,5o e 19,0 &#61617; 1,0o; for the distilled water, 78,0 &#61617; 6,0o; the biodiesel B5, B20 and B100 blends originated by the ethylic transesterification of sunflower oil were, respectively, 7,0 &#61617; 4,0o, 8,5 &#61617; 4,5o e 19,5 &#61617; 2,5o. Different thickness of lubricant film were formed and measured by their percentage by means of the contact resistance technique, suggesting several regimes, since the boundary until the hydrodynamic lubrication. All oils analyzed in this study promoted the ball wear scars with diameters smaller than 400 &#956;m. The lowest values were observed in the scar balls lubricated by mixtures B100, B20 and B5 of sunflower and B20 and B5 of soybean oils (WSD < 215 &#956;m) === Combust?vel ? um material usado para produzir calor ou energia mec?nica atrav?s de um processo de queima e lubricidade ? a capacidade de reduzir atrito. Este trabalho se constitui na avalia??o da lubricidade de oito combust?veis, renov?veis e f?sseis, utilizados em motores que operam ciclo Diesel, por meio de ensaios acelerados em uma bancada HFRR, de acordo com a norma ASTM D 6079-04. Em cada ensaio de 75 minutos, lubrificado por um combust?vel de cada vez, com seis repeti??es, uma esfera (di?metro 6,00&#61617;0,05 mm, Ra 0,05&#61617;0,005 &#956;m, a?o AISI 52100, E = 210 GPa, HRC 62&#61617;4, HV0,2 631&#61617;47) deslizava sobre um disco plano (a?o AISI 52100, HV0,05 184&#61617;10, Ra 0,02&#61617;0,005 &#956;m), em um movimento alternado de 1 mm de curso sob carga normal de 2 N, ? frequ?ncia de 50 Hz. As assinaturas dos sinais do coeficiente de atrito, percentual do filme lubrificante formado, aquecimento do contato e N?vel de Press?o Sonora (NPS [dB]) foram registradas por sensores acoplados ? placa de aquisi??o de dados e ao sistema HFRR. Os combust?veis diesel apresentaram molhabilidade com ?ngulo de contato de 7,0 &#61617; 3,5o; os combust?veis biodiesel B5, B20 e B100, obtidos por transesterifica??o et?lica de ?leo de soja, apresentaram, respectivamente, ?ngulos de contato de 7,5&#61617;3,5o, 13,5&#61617;3,5o e 19,0&#61617;1,0o, enquanto a ?gua destilada, 78,0&#61617;6,0o e os combust?veis biodiesel B5, B20 e B100, obtidos por transesterifica??o et?lica de ?leo de girassol apresentaram, respectivamente, ?ngulos de 7,0&#61617;4,0o, 8,5&#61617;4,5o e 19,5&#61617;2,5o, todos obtidos quando em contato com discos planos de a?o AISI 52100. Constatou-se a forma??o de filmes lubrificantes com diferentes espessuras, medidos por seu percentual atrav?s da t?cnica da resist?ncia de contato, sugerindo desde os regimes de lubrifica??o lim?trofe ? lubrifica??o hidrodin?mica. Todos os combust?veis analisados neste trabalho promoveram na esfera escaras de desgaste com di?metros de (WSD) inferiores a 400 &#956;m. Os menores valores de escara foram constatados nas esferas lubrificadas pelas misturas B100, B20 e B5 de girassol e B20 e B5 de soja (de < 215 &#956;m)