S4  Ciências e Engenharia do Petróleo    Titulo: STUDY OF ABRUPT CONTACT FORCES VARIATION ON THE DYNAMICS OF PIGS MOVING THROUGH MULTISIZE PIPELINES   Resumo : SIMULATION OF THE DYNAMICS OF PIG THROUGH GAS PIPELINES WITH VARIABLE CONTACT FORCE IS PRESENTED. THE DIFFERENTIAL MASS AND LINEAR MOMENTUM EQUATIONS WERE NUMERICALLY SOLVED BY A FINITE DIFFERENCE NUMERICAL SCHEME, FOR COMPRESSIBLE FLOW THROUGH PIPELINES. THE FLUID FLOW EQUATIONS WERE COMBINED WITH AN EQUATION REPRESENTING A FORCE BALANCE ON THE PIG. PRESSURE FORCES DEVELOPED DUE TO FLOW THROUGH BY-PASS HOLES IN THE PIG, PIG ACCELERATION AND PIG/PIPE CONTACT FORCES WERE CONSIDERED. A STICK/SLIP MODEL WAS DEVELOPED TO ACCOUNT FOR THE DISTINCT FRICTION REGIMES THAT PREVAIL DEPENDING ON WHETHER THE PIG IS STOPPED OR IN MOTION. AN ADAPTIVE GRID TECHNIQUE WAS EMPLOYED TO ACCOUNT FOR THE MOVING PIG. VERY OFTEN, PIPELINES ARE BUILT WITH DIFFERENT PIPE SETS (PIPES WITH DIFFERENT DIAMETERS, ROUGHNESS, ETC). AS A RESULT, SEVERE CONTACT FORCE CHANGES CAN BE ENCOUNTERED BY PIG ALONG ITS MOVEMENT INSIDE THE PIPELINE, IN WHICH A CLEANING OPERATION MUST BE CARRY ON. FURTHER, FLANGES ALSO INDUCE GREAT CONTACT FORCE VARIATION. AT THE PRESENT WORK, TWO CASES ARE EXAMINED. THE FIRST CASE PRESENTS AN ANALYSIS OF THE EFFECT OF PIPELINE FLANGES IN THE PIG MOTION. THE SECOND CASE EXAMINES THE PIG MOVEMENT ALONG A PIPELINE, WITH DIFFERENT PIPE SETS. THE NUMERICAL SOLUTION EXAMINED HELPS TO UNDERSTAND THE PIG DYNAMICS, TO PREVENT SITUATIONS IN WHICH THE PIG GETS STUCK INSIDE THE PIPELINE.    Autores : Azevedo, Luis Fernando Alzuguir Braga, Arthur M Nieckele, Angela Ourivio     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local