Problem 4.188[Difficulty: 3]Given:Data on rotating spray systemFind:Torque required to hold stationary; steady-state speedSolution:Basic equation: Rotating CVAssumptions: 1) No surface force; 2) Body torques cancel; 3) Sprinkler stationary; 4) Steady flow; 5) Uniform flow; 6) L<<rThe given data isQ15Lmin⋅=R225 mm⋅=d5mm⋅=ρ999kgm3⋅=For each branchV12Qπ4d2⋅⋅=V6.37ms=The basic equation reduces to a single scalar equation (FOR EACH BRANCH)TshaftVrα→r×()×ρ⋅⌠⎮⎮⌡d−A→rVxyz→⎯⎯×ρ⋅Vxyz→⎯⎯⋅⌠⎮⎮⌡d=where αis the angular accelerationButrα→r××r2α⋅=(r and αperpendicular); the volume integral isVrα→r××ρ⋅⌠⎮⎮⌡dVr2α⋅ρ⋅⌠⎮⎮⌡d=R33α⋅
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This note was uploaded on 10/19/2011 for the course EGN 3353C taught by Professor Lear during the Fall '07 term at University of Florida.