Mechanical Engineering Answers

Steam at 3.5 MPa and with a 75.38C superheat rejects 1973.36 kJ per kg of steam heat at a

constant pressure, determine

a. Properties of steam at state 1

b. Properties of steam at state 2

c. Final Temperature

d. Change in specific entropy

A piston-cylinder device initially contains 10L of liquid water at 25C and at atmospheric

pressure of 101.325 kPa. Heat is added at constant pressure until the entire liquid is

vaporized. (a) what is the mass of water (b) final temperature (c) amount of heat absorbed

by the water.

A refrigerator is maintained at 4˚C by removing heat from it at a rate of 8 kW. If the required power input to the refrigerator is 2.5 KW, determine (a) the COPR and (b) the rate of heat rejection to the room that houses the refrigerator

a) Define Maintainability and availability and compare it with reliability.

b) What is inspection and repair availability model? Explain a case for it.  

Perform a qualitative analysis on the following fault tree by expressing the top event in terms of non-reductant basic events using Boolean algebra. If the probability of each basic event is 0.005 and events are independent, what is the probability of the top event?

Find out the reliability using markov analysis for load sharing units?

(b) A manufacturing company operates two production lines when both lines are operating, the production rate on each line is 500 units per hour. At this production rate the failure rate of line 1 is 3 failures per 8-hr day (CFR) and the failure rate of line 2 is 2 failures per 8-hr day. When one line fails, the production rate of the second line must be increased in order to make production quotas. At the increased rate of 800 units per hour, the failure rate of line 1 is 6 per 8 hr day and the failure rate of line is 3 per 8-hr day. Find the reliability and the MTTF and the reliability of the production system over a 1 hr and over an 8 hr production run.

Perform a qualitative analysis on the following fault tree by expressing the top event in terms of non-reductant basic events using Boolean algebra. If the probability of each basic event is 0.005 and events are independent, what is the probability of the top event?

(b) Given a budget of Rs. 700 and the following data on three components that must operate in series .Determine, using marginal analysis, the optimum number of redundant units. Compute the achieved reliability.

Superheated water vapor in a piston-cylinder is cooled at 200 kPa, 300°C is cooled at constant pressure until 70% of it condenses. Determined the work done during this process.

a shaft fitted with a fly wheel rotates at 250 rpm and dried a machine the torque of machine varies in a cyclic manner over a period of 3 revolution. The torque rises from 750 Nm to 300Nm uniformly during half revolution and remains constant for the following revolution . If then fall uniformly to 750 Nm during the next half revolution and remains constant for one revolution the cycle being repeated thereafter. Determine the power required to drive the machine and percentage fluctuation in speed if the driving torque applied to the shaft is constant band and mass of the fly wheel is 500 kg with the radius of gyration at 600mm.

A single cylinder single acting four stroke cycle gas engine develops 22 kw at 300 rpm the fly wheel mass is 100kg hoop stress developed is 5 Mpa density of material of rim of fly wheel is 800Kg/m 3.The speed variation on the either side is 1% of mean speed. Determine the ratio of work done during expansion and compression strokes work done in suction and exhaust stroke is negligible.