Question

. A torsion dynamometer is fitted on a turbine shaft to measure the angle of twist. It is

observed that the shaft twists 1.5° in a length of 5 metres at 500 r.p.m. The shaft is solid

and has a diameter of 200 mm. If the modulus of rigidity for the shaft material is 85 GPa,

find the power transmitted by the turbine.​

Answer 1

Answer:

A hollow shaft of diameter ratio 3/8 (internal dia to outer dia) is to transmit 375 kW power at 100 rpm. The maximum torque being 20% greater than the mean torque. The shear stress is not to exceed 60 N/mm² and twist in a length of 4m not to exceed 2º.

Answer 2

The modulus for the strength of the shaft material is 85 GPA,and the power transferred by the turbine are:

• When power is transferred to the shaft, the driving end rotates at a slight angle relative to the driving end.

• The transmitted torque is directly proportional to the twist angle.

• Therefore, the torsion dynamo meter operates with a twist angle target.

• A large metal wheel should be fitted to the shaft of the same material.

• At 27 ° c, the outer diameter of the shaft is 8.70cm and the diameter of the hole in the middle of the wheel is 8.69cm.

• The shaft is cooled using "dry ice".

• Assume that the combined efficiency of the metal expansion should always be at the required temperature range is 1.20x10-5k.