For a marine diesel engine application, a fluid-film journal bearing has a shaft diameter of 32...

For a marine diesel engine application, a fluid-film journal bearing has a shaft diameter of 32 mm and the length of the bearing is 24 mm. The bearing uses SAE grade 20 oil as lubricant and operates under a radial load. The inlet and outlet temperatures of oil are 50oC and 110oC respectively. It is assumed that because of the shearing action there is a uniformly distributed energy release in the lubricant that heats the lubricant film. During run-in operation, the film temperature can be approximated as the average of the inlet and outlet temperatures. Assuming reasonable design data, perform an overall design assessment for the following four cases:

Case 1: Applied load: 2.5 kN, Radial clearance: 0.04 mm, Shaft speed: 1800 rpm

Case 2: Applied load: 5.0 kN, Radial clearance: 0.04 mm, Shaft speed: 1800 rpm

Case 3: Applied load: 2.5 kN, Radial clearance: 0.04 mm, Shaft speed: 3600 rpm

Case 4: Applied load: 2.5 kN, Radial clearance: 0.02 mm, Shaft speed: 1800 rpm

a) Analyze and estimate the bearing design parameters such as, minimum film thickness, power loss, side flow, total flow and maximum film pressure for the above four cases.

b) Which parameter is most influential for economical running of the bearing ? Justify with reasons.

c) Which parameter is most influential for safe running of the bearing ? Justify with reasons.

d) Compare and discuss the results for the above four cases.

Expert Solution

samet mamat answered 2 years ago

all journal bearing has a shaft diameter=1.25in and suppports a load of 1200lbf. the bushing is...

all journal bearing has a shaft diameter=1.25in and suppports a load of 1200lbf. the bushing is 1.25-in long and has a bore diameter=1.25in. shfat speed=1500 rev/min. average film temperature=115.4oF and SAE grade 30 lubricant is used. average clearance =0.001125 in. Find a) magnitud and location of min oil-film thickness b) total lubricant volumetric flow rate c) max oil-folm pressure and its angular location d) power loss

A journal and bearing are to be designed for a shaft that turns at 250 rpm....

A journal and bearing are to be designed for a shaft that turns at 250 rpm. Suppose ISO VG100 (SAE Engine 30) is to be used as lubricant and the bearing length is to be equal to 1.2 times the diameter. If the no-load power loss is not to exceed 2.5 x 10-4 horsepower and the diametral clearance is 0.0045 times the diameter, estimate the maximum diameter that can be used for the journal, and the allowable temperature limit.

A horizontal shaft of 75mm diameter projects from a bearing and, in addition to the torque...

A horizontal shaft of 75mm diameter projects from a bearing and, in addition to the torque transmitted, the shaft carries a vertical load of 8 kN at 300 mm from the bearing. If the safe stress for the material, as determined in a simple tension test, is 135 MN/m2 find the safe torque to which the shaft may be subjected using as a criterion (a) The maximum shearing, stress, (b) The maximum strain energy per unit volume. Poisson’s ratio ?...

1) A four-stroke diesel engine has a piston diameter of 16.5 cm and a stroke of...

1) A four-stroke diesel engine has a piston diameter of 16.5 cm and a stroke of 27 cm. The compression ratio is 14.3, the cut-off 4.23% of the stroke and the mean effective pressure 4.12 bar. The engine speed is 264 rev/min and the fuel consumption is 1.076 kg of oil per hour, having a calorific value of 39150 kJ/kg. Calculate the relative efficiency of the engine 2). A diesel engine has a brake thermal efficiency of 30%. If the...

A shaft inside the sleeve of a journal bearing is being rotated at 1500 rpm. The...

A shaft inside the sleeve of a journal bearing is being rotated at 1500 rpm. The shaft is 6.00 cm in diameter and is rotating in a bearing sleeve that is 6.02 cm in diameter and 40 cm long. The clearance is filled with oil having properties of ?=0.003 m2 /s and SG=0.88. a. Find the torque required to rotate the shaft. b. Find the power required to rotate the shaft. (Answer: 44.1 kW) c. Discussion: How do the torque...

An ideal diesel engine uses air as the working fluid and operates with a thermal efficiency...

An ideal diesel engine uses air as the working fluid and operates with a thermal efficiency ?th =0.5 with a rate of heat addition Qin=120 kW. The temperature at the beginning and the end of the addition heat (combustion) are respectively: T2=900 K and T3=2100 K. Assume constant specific heats (Cp and Cv). The air properties at a room temperature T1=293.0 K are: Cp=1.005 kJ/kg.K, Cv=0.718KJ/kg.K, the gas constant of air is R=0.287 kJ/kg.K and the ratio of specific heats...

A .05 wide journal bearing supporting the loads on a 1 inch shaft just meets the...

A .05 wide journal bearing supporting the loads on a 1 inch shaft just meets the Trumpler’s design criteria for a FACTOR OF SAFTY OF 2.05. The bearing satisfies all the other Trumpler’s design criteria by much larger margin. Your colleague suggests that increasing the bushing width to 0.75 inches would be an adequate design and you would not need to conduct another journal bearing analysis because the greater width would result in a bearing which satisfy all of Trumpler’s...

A bearing used in an automotive application is required to have a nominal inside diameter of...

A bearing used in an automotive application is required to have a nominal inside diameter of 1.5 inches. A random sample of 25 bearings is selected and the average inside diameter of these bearings is 1.4975 inches. Bearing diameter is known to be normally distributed with standard deviation 1inch. (a) Test the hypotheses 1.5 versus 1.5 using 0.01 The true mean hole diameter Entry field with correct answer significantly different from 1.5 in. at alpha equals 0.01. (b) What is...

The existing record shows machine bearing has a mean diameter of 0.6 inches. Bearing diameter is...

The existing record shows machine bearing has a mean diameter of 0.6 inches. Bearing diameter is known to be normally distributed with standard deviation σ = 0.1 inches. (Additional note: If the mean diameter of bearings is larger or smaller than 0.6 inches, then the process is out of control and must be adjusted.) A random sample of 60 bearings are selected, and the average diameter of the bearing from this sample is 0.55 inches. Use α=0.02 to test the...

The J-shaped member shown in the figure is supported by a cable DE and a single journal bearing with a square shaft at...

The J-shaped member shown in the figure is supported by a cable DE and a single journal bearing with a square shaft at A. Determine the reaction forces A_y and A_z at support A required to keep the system in equilibrium. The cylinder has a weight W_B = 5.30 lb, and F = 1.20 lb is a vertical force applied to the member at C. The dimensions of the member are w = 1.50 ft, l = 6.00 ft, and...

Question