4.37 The following readings were taken with a rotational viscometer. N ON 3 4.5 6. 100...

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4.37 The following readings were taken with a rotational viscometer. N ON 3 4.5 6. 100 5.5 9.0 14.5 19.0 32.5 200 300 600 a. Using the power-law model, compute the fric- tional pressure gradient resulting from a 50-gal/min flow rate in a 2.9-in.-ID drillpipe. Assume the flow pattern is laminar. Answer: 0.00586 psi/ft. b. Compute the shear rate at the wall of the drillpipe. What two rotational readings would you expect to give the best n and K factors for the pressure gradient computation. Answer: 86 seconds -1. c. Make a plot of flow velocity vs. pipe radius and a plot of shear stress vs. pipe radius. 4.37 The following readings were taken with a rotational viscometer. N ON 3 4.5 6. 100 5.5 9.0 14.5 19.0 32.5 200 300 600 a. Using the power-law model, compute the fric- tional pressure gradient resulting from a 50-gal/min flow rate in a 2.9-in.-ID drillpipe. Assume the flow pattern is laminar. Answer: 0.00586 psi/ft. b. Compute the shear rate at the wall of the drillpipe. What two rotational readings would you expect to give the best n and K factors for the pressure gradient computation. Answer: 86 seconds -1. c. Make a plot of flow velocity vs. pipe radius and a plot of shear stress vs. pipe radius.