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A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.?
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A holler marine propeller shaft turning at 110 rpm is required to prop...
Solution:
Given data:
Propeller shaft speed (N) = 110 rpm
Vessel speed (V) = 25 knots
Shaft power (P) = 8450 hp
Efficiency of the propeller (η) = 68%
Diameter ratio of the shaft (d/D) = 2/3
Maximum direct stress due to thrust (σd) = 700 N/cm2
(a) Shaft diameter:
Let D be the diameter of the propeller shaft, then the diameter of the shaft at the coupling end will be (2/3)D.
The thrust (T) developed by the propeller is given by,
T = P/ V
where V is the volume of water displaced by the propeller.
The volume of water displaced by the propeller is given by,
V= πD2/4 × V/60
where V/60 converts the vessel speed from knots to m/s.
Substituting the given values, we get
V= πD2/4 × (25 × 1852)/3600 = 0.4349 D2
Therefore, the thrust developed by the propeller is given by,
T = P/ V = 8450 / 0.4349 D2 = 19413.5 / D2 N
The bending moment (M) on the propeller shaft is given by,
M = T × L / 2
where L is the length of the propeller shaft.
The maximum direct stress due to thrust is given by,
σd = 32 T / π D3
The maximum shear stress due to torque is given by,
τmax = 16 T / π D3
The torque (Tq) on the propeller shaft is given by,
Tq = P / (2πN/60)
Substituting the given values, we get
Tq = 8450 / (2π × 110/60) = 2286.5 N-m
Therefore, the maximum shear stress due to torque is given by,
τmax = 16 Tq / π D3 = 16 × 2286.5 / π D3 = 1155.6 / D3 N/cm2
The diameter of the propeller shaft can be calculated using the maximum direct stress due to thrust as follows,
D3 = 32 T / π σd
D3 = 32 × 19413.5 / π × 700 = 310.64
D = 7.15 cm
The diameter of the shaft at the coupling end will be (2/3)D = 4.77 cm
(b) Maximum shearing stress due to torque:
τmax = 1155.6 / D3 = 1155.6 / (7.15)3 = 24.05 N/cm2
Therefore, the maximum shearing stress due to torque is 24.05 N/cm2.
Conclusion:
The diameter of the propeller shaft is 7.15 cm and the maximum shearing stress due to torque is 24.05 N/cm2.
Given data:
Propeller shaft speed (N) = 110 rpm
Vessel speed (V) = 25 knots
Shaft power (P) = 8450 hp
Efficiency of the propeller (η) = 68%
Diameter ratio of the shaft (d/D) = 2/3
Maximum direct stress due to thrust (σd) = 700 N/cm2
(a) Shaft diameter:
Let D be the diameter of the propeller shaft, then the diameter of the shaft at the coupling end will be (2/3)D.
The thrust (T) developed by the propeller is given by,
T = P/ V
where V is the volume of water displaced by the propeller.
The volume of water displaced by the propeller is given by,
V= πD2/4 × V/60
where V/60 converts the vessel speed from knots to m/s.
Substituting the given values, we get
V= πD2/4 × (25 × 1852)/3600 = 0.4349 D2
Therefore, the thrust developed by the propeller is given by,
T = P/ V = 8450 / 0.4349 D2 = 19413.5 / D2 N
The bending moment (M) on the propeller shaft is given by,
M = T × L / 2
where L is the length of the propeller shaft.
The maximum direct stress due to thrust is given by,
σd = 32 T / π D3
The maximum shear stress due to torque is given by,
τmax = 16 T / π D3
The torque (Tq) on the propeller shaft is given by,
Tq = P / (2πN/60)
Substituting the given values, we get
Tq = 8450 / (2π × 110/60) = 2286.5 N-m
Therefore, the maximum shear stress due to torque is given by,
τmax = 16 Tq / π D3 = 16 × 2286.5 / π D3 = 1155.6 / D3 N/cm2
The diameter of the propeller shaft can be calculated using the maximum direct stress due to thrust as follows,
D3 = 32 T / π σd
D3 = 32 × 19413.5 / π × 700 = 310.64
D = 7.15 cm
The diameter of the shaft at the coupling end will be (2/3)D = 4.77 cm
(b) Maximum shearing stress due to torque:
τmax = 1155.6 / D3 = 1155.6 / (7.15)3 = 24.05 N/cm2
Therefore, the maximum shearing stress due to torque is 24.05 N/cm2.
Conclusion:
The diameter of the propeller shaft is 7.15 cm and the maximum shearing stress due to torque is 24.05 N/cm2.
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A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.?
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A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.?.
A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.?.
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A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.?, a detailed solution for A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? has been provided alongside types of A holler marine propeller shaft turning at 110 rpm is required to propel a vessel at 25 knot for expenditure of 8450 shaft horse power with the efficiency of propellor being 68% if the diameter rtio of the shaft is 2/3 and the direct stress due to thrust does not exceed 700 N/cm2 . determine (a) shaft diameter (b) the maximum shearing stress due to the torque.? theory, EduRev gives you an
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