Max. Marks: 100 Class: Third Year Semester: VI Name of the Course: Manufacturing Planning and

Instructions: • Attempt any FIVE questions out of Seven questions.

• Figures to the right indicate full marks

• Assume suitable data wherever required.

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. End Exam May 2016

Q. P. Code: Duration: 3 hr. Program: Mechanical Engineering

Control Course Code : ME355

\--Acks,;-ex le

April May June 700 500 850

ihNto eiz-hc-

A company manufactures air-conditioners. The company currently has [10] confirm orders for 6 months into future. The company can schedule its production over the next 6 months to meet the order on either a regular or on overtime basis. Consider orders and the associated production costs for

the next 6 months as follows.

Months Orders 590

Cost in Rs for regular 50 52

production Cost in Rs. Overtime 62

Production With 75 air-conditioners in stock at the beginning of January the company wishes to have at least 10 air-conditioners in stock at the end of the June. The inventory carrying cost for air-conditioners is Rs. 10 per unit per month Maximum regular production and overtime production are limited

to 500 and 300 units respectively. Formulate LPP. A Project schedule has the following details.

Time weeks I Activity

1-2 4 5-6

1 6-8

1

Q1A

z 0 2 0

CO2 M6

Jan Feb March 610 650

58 69

51 55 47 50 1 1

78 155 66 i .

2-4

Q1B 3_4 1 7-8 12

3-5 6 8-10 5

4-9 5 9-10 I 7 Construct the network, Compute E and L for each event. Find EST,LST,EFT,LFT and float for each activity. Find the critical path

Activity

1-3 5-7

Times [ weeks 4 8

[101 CO2 M5

A book store has following business data for inventory. Demand is probabilistic and replenishment of stock takes 2 days[ i.e. if an order is placed on March 1 , it will be received at the end of 3rd March. The probabilities of the demand are given below.

[10] ,

CO2, CO3

M7

Demand 1 0 I [daily] 1

1 2 3 I 4 1

Probability 0.05 0.1 0.3 1 0.45 1 0.1 Q2A Each time an order is placed, the store incures an ordering cost of Rs 10 per

order. The carrying cost is 0.5per book per day. If 5 books are ordered when the inventory at the beginning of the day plus orders outstanding is less than or equal to 8 books, compute the carrying cost, ordering cost and Total cost.

Currently the store has an inventory of 8 books plus 6 books are ordered 2 days ago and expected to arrive next day. Refer the two digit random numbers 89,34,78,63,61,81,39,16,13,73. Use Monte Carlo simulation for 10 cycles.

1

The project activities has following time estimates. [10] CO2 M5 I Job [i-j] t duration

Optimistic Most likely duration

Pessimistic duration 1

1-2 3 6 15 , , 2-3 6 12 30

3-5 5 11 17 7-8 4 19 28 5-8 1 4 7

Q2B 6-7 f

27 4-5 3 6 15 1-6 2 5 14 2-4 2 5 8

• Draw • Compute • Find Critical • Find duration

1 • Find probability

Project Network E,and L for each event

path of project

of completing the project in 31 weeks ._

, A firm assembles and sells two different types of motors, A and B , using four resources. The production process can be described as follows:

[10] C01, CO2

M6

Resources Capacity per month

Motor unit shop resource 400 Type A units or 250 Type B units Or any linear combination of the two.

Type A gear and drive shop resources 175 Type A units Q 3A Type B gear and drive shop resources 225 Type B units

Final assembly resources 200 Type A units or 350 Type B Units Or any linear combination of the two

Type A units bring in a profit of Rs.90 each and type B units, Rs.60 each. What should be the optimum product mix? Solve Graphically.

Two jobs are expected to be processed on 5 machines. The sequence of each job on the respective machine A,B,C,D,E is given as follows.

[10] C01, CO2

M4

Jobl Sequence IA B C D IE

Time in hours 1 7 9 5 13 5

Job2 Sequence IB C A I D 1 Q3B Time in hours 1 11 9 1 7 i 5 I 13

Use graphical method to find the optimal time required to process the two

jobs on the machines. Find the Idle time for each job Find which job will be processed first on each machine Five jobs 1,2,3,4 and 5 are to be done assigned to 5 machines A, B, C, D,

and E. The cost of assigning these jobs to machines in rupees is given in the following matrix. Determine the optimal assignment algorithm, so as to minimize the total cost. Calculate the total cost of the assignment.

[10] CO2 M7

Jobs Machines

Q4A i A B C D E

1. 6 7 5 9 4

2. 7 5 10 9 6

3. 5 4 3 6 5

4. 8 3 5. 4 7 5 6 6

-

Q4B

Compute the Safety Stock , Reserve Stock and Buffer stock for the data

given below. Normal Usage=100 per week Lead Time=4 to 6 week Minimum Usage=50per week Maximum Usage= 150 per week Reorder Point =600 units Calculate the reorder level, minimum and maximum levels of inventory and

also average level of inventory.

[10] CO3 M3

Q5A

An auto industry purchase spark plugs at the rate of Rs25 per piece. The annual consumption of spark plugs is 18000 units. If ordering cost is Rs 250/- per order and carrying cost is 25% pa what would be the EOQ? If the supplier of spark plus offers a discount of 5 % for order of 3000 units per order do you accept the discount offer.

[10] CO3 M3

Q5B

Five jobs are expected to be processed on three machines A,B,C in the

order of ABC. The processing time is given in table. Find Optimal sequence, Total elapsed time, Idle time for each machine

[10] CO2 M4

, 1 Jobs

Processing Time

1 2 3 4 5

Machine A 8 10 6 7 11

, Machine B 5 6 2 3 4

rMachine C 4 9 8 6 5

Q6A

The forecasted demand for a product for 6 months cycle is shown. Each unit requires 10 man-hours and labour cost is Rs.6 per hour regular time and Rs.9 per overtime. The total cost per unit is Rs.200 and can be subcontracted at the cost of Rs.208 per unit. Currently there are 20 workers employed. Hiring and training costs for additional workers are Rs.300 per person and layoff costs are Rs.400 per person. Company policy is to retain a safety stock of 20% of monthly inventory forecast and each month safety stock becomes beginning inventory of the next month. There are currently 50 units in stock carried at a cost of Rs.2 per month. Stock out costs is Rs.20 per unit er month.

[10] CO3 M2

Jan Feb March April May ' June Forecast demand

300 500 400 100 200 300 , I

Work days 22 19 21 21 22 20 Worker hr at 8/day

176 I 152 168 168 176 160 1 1

The following plans are proposed. Which will you select? Justify your decision show all calculations. Plan A : Vary workforce size to accommodate the demand Plan B: Maintain the constant work force of 20 and use overtime and idle time to meet demand.

Q6B

Compute the forecast for the next three years using LSM. [10] CO2 M1 Year Y1 Y2 Y3 I Y4 Y5 I Y6 1 Y7 1 Y8 Y9 Y10 I Sales [000]

i 30 33 37 39

I

42 1 46 1 48 1 50I 55 1 1 1 i 1 1 I

, 58 , . I I

Q7A State the factors favor Under-capacity Planning and Over-capacity Planning [10] C01,

CO3 M2

Q7B Explain the terms 5S and Seven wastes as per JIT [10] CO1 Ml,

M4

0

* **

Standard Normal Probabilities

Table entry for z is the area under the standard normal curve to the left of z.

.00 .01 .02 .03 .04 .05 .06 .07 .08 .09

0.0 .5000 .5040 .5080 .5120 .5160 .5199 .5239 .5279 .5319 .5714

.5359

.5753 0.1 .5398 .5438 .5478 .5517 ,5557 .5596 .5636 .5675

.6103 .6141 0.2 .5793 .5832 ,5871 .5910 .5948 .5987 .6026 .6064

.6480 .6517 0.3 .6179 .6217 .6255 .6293 .6331 .6368 .6406 .6443

.6844 .6879 0,4 .6554 .6591 .6628 .6664 .6700 .6736 .6772 .6808

.7190 .7224 0.5 .6915 .6950 .6985 .7019 .7054 .7088 .7123 .7157

.7517 .7549 0.6 .7257 .7291 .7324 .7357 .7389 .7422 .7454 .7486

.7823 .7852 0.7 .7580 .7611 .7642 .7673 .7704 .7734 .7764 .7794

.8106 .8133 0,8 .7881 .7910 .7939 .7967 .7995 .8023 .8051 .8078

.8365 .8389 0.9 .8159 .8186 .8212 .8238 .8264 .8289 ,8315 .8340

.8599 .8621 1.0 .8413 .8438 .8461 .8485 .8508 .8531 .8554 .8577

.8810 .8830 1.1 .8643 .8665 .8686 .8708 .8729 .8749 .8770 .8790

.8997 .9015 1.2 .8849 .8869 .8888 .8907 .8925 .8944 .8962 .8980

.9162 .9177 1.3 .9032 .9049 .9066 .9082 .9099 .9115 .9131 .9147

.9306 .9319 1.4 .9192 .9207 .9222 .9236 .9251 .9265 .9279 .9292

.9429 .9441 1.5 .9332 .9345 .9357 .9370 .9382 .9394 ,9406 .9418

.9535 .9545 1.6 .9452 .9463 .9474 .9484 .9495 .9505 .9515 .9525

.9625 .9633 1.7 .9554 .9564 .9573 ,9582 .9591 .9599 .9608 .9616

.9699 .9706 1.8 .9641 .9649 .9656 .9664 .9671 .9678 .9686 .9693

.9761 .9767 1.9 .9713 .9719 .9726 .9732 .9738 .9744 .9750 .9756

.9812 .9817 2.0 .9772 .9778 ,9783 .9788 .9793 .9798 .9803 .9808

.9854 .9857 2.1 ,9821 .9826 .9830 .9834 .9838 .9842 .9846 .9850

.9887 .9890 2.2 .9861 .9864 .9868 .9871 .9875 .9878 .9881 .9884

.9913 .9916 2,3 .9893 ,9896 .9898 .9901 .9904 .9906 .9909 .9911

.9934 .9936 2.4 .9918 .9920 .9922 .9925 .9927 .9929 .9931 .9932

.9951 .9952 2.5 .9938 .9940 .9941 .9943 .9945 .9946 .9948 .9949

.9963 .9964 2.6 .9953 .9955 .9956 .9957 .9959 .9960 .9961 .9962

.9973 .9974 2,7 .9965 .9966 .9967 .9968 .9969 .9970 .9971 .9972

.9980 .9981 2.8 .9974 .9975 .9976 .9977 .9977 .9978 .9979 .9979

.9986 .9986 2.9 .9981 .9982 .9982 .9983 .9984 .9984 .9985 .9985

.9990 .9990 3.0 .9987 .9987 .9987 .9988 .9988 .9989 .9989 .9989

.9993 .9993 3.1 .9990 .9991 .9991 .9991 .9992 .9992 .9992 .9992

.9995 .9995 3.2 .9993 .9993 .9994 .9994 .9994 .9994 .9994 .9995

.9996 .9997 3.3 .9995 .9995 .9995 .9996 .9996 .9996 .9996 .9996

.9997 .9998 3.4 .9997 .9997 .9997 .9997 .9997 .9997 .9997 .9997

Standard Normal Probabilities

Table entry for z is the area under the standard normal curve to the left of z.

z .00 .01 .02 .03 .04 .05 .06 .07 .08 .09

-3.4 .0003 .0003 .0003 .0003 .0003 .0003 .0003 .0003 .0003 .0004

.0002

.0003 -3.3 .0005 .0005 .0005 .0004 .0004 .0004 .0004 .0004

.0005 .0005 -3.2 .0007 .0007 .0006 .0006 .0006 .0006 .0006 .0005

.0007 -3.1 .0010 .0009 .0009 .0009 .0008 ,0008 .0008 .0008 .0007

.0010 -3.0 .0013 .0013 .0013 .0012 .0012 .0011 .0011 .0011 .0010

,0014 ,-2.9 .9019 .0018 .0018 .001-7 .0016 .0016 .0015 .0015 .0014

.0019 -2.8 .0026 .0025 .0024 .0023 .0023 .0022 .0021 .0021 .0020

.0026 -2.7 .0035 .0034 .0033 .0032 .0031 .0030 .0029 .0028. .0027

.0036 -2.6 .0047 .0045 .0044 .0043 .0041 .0040 .0039 .0038 .0037

.0048 .0062, .0060 .0059 .0057 .0055 .0054 .0052 .0051 .0049

.0064 -2,4 .0082 .0080 .0078 .0075 .0073 .0071 .0069 .0068 .0066

.0084 -2.3 .0107 .0104 .0102 .0099 .0096 .0094 .0091 .0089 .0087

.0113 .0110 -2.2 .0139 .0136 .0132 .0129 .0125 .0122 .0119 .0116

.0143 -2.1 .0179 .0174 .0170 ,0166 .0162 .0158 .0154 .0150 .0146

.0183 -2.0 .0228 .0222 .0217 .0212 .0207 .0202 .0197 .0192 .0188

.0233 -1.9 -1.8 .0287

.0359 .0281 .0351

.0274

.0344 .0268 .0336

.0262

.0329 .0256 .0322

.0250

.0314 ,0244 .0307

.0239

.0301 .0294 .0367

-1.7 .0446 .0436 .0427 .0418 .0409 .0401 .0392 .0384 .0375 .0455

-1.6 .0548 .0537 .0526 .0516 .0505 .0495 .0485 .0475 .0465 .0559

-1,5 .0668 .0655 .0643 .0630 .0618 41- .0606 .0594 .0582 .0571 .0681

-1.4 .0808 .0793 .0778 .0764 .0749 .0735 .0721 .0708 .0694 .0823

-1,3 .0968 .0951 .0934 .0918 .0901 .0885 .0869 .0853 .0838 .0985

-1.2 .1151 .1131 .1112 .1093 .1075 .1056 .1038 .1020 .1003 .1170

-1,1 .1357 .1335 .1314 .1292 .1271 .1251 .1230 .1210 .1190 .1379

-1.0 .1587 .1562 .1539 .1515 .1492 .1469 .1446 .1423 .1401 .1611

.1841 1788 .1762 .1736 .1711 .1685 .1660 .1635 .1867

-0.8 .2119 .2090 .2061 .2033 .2005 .1977 .1949 .1922 .1894 .2177 .2148

.14/1 .2420 .2389 .2358 .2327 42296 .2266 .2236 .2206 .2483 .2451

-0.6 .2743 .2709 .2676 .2643 .2611 .2578 .2546 .2514 .2810 .2776

-0.5 .3085 .3050 .3015 .2981 .2946 .2912 .2877 .2843 .3156 .3121

-0.4 .3446 .3409 .3372 .3336 .3300 .3264 .3228 .3192 .3520 .3483

-0.3 -0.2 -0.1 -0.0

.3821

.4207

.4602

.5000

.3783

.4168

.4562

.4960

.3745

.4129

.4522

.4920

.3707

.4090

.4483

.4880

.3669

.4052

.4443

.4840

.3632

.4013

.4404

.4801

.3594

.3974

.4364

.4761

.3557

.3936 ,4325 .4721

.3897

.4286

.4681

.3859

.4247 .4641

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. End Semester Exam

May 2016

lift sizit

Max. Marks: 100 Class: T. Y. Tech. Semester: VI Name of the Course: Internal combustion Engine Instructions:

• Question No. 1 is compulsory. • Attempt any Four questions out of remaining six questions. • Answers to all sub questions should be grouped together. • All questions carry equal marks. • Make suitable assumptions with proper explanations.

Duration: 3 hrs Program: Mech Engg Course Code: ME 354

Mck0--cA, Si e •

Q. No.

Mar ks

CO No.

M N(

Q. 1

Answer the following questions (any five) 20 1 - 3

1-

a) By suitable sketches, show the various possible cylinder arrangements of I C Engines.

b) Explain why a rich mixture is required for idling, maximum power and sudden accelerations.

c) List the requirements of fuel injection system in C I Engines. d) Discuss the effects of supercharging on the performance of I C Engines, e) Discuss the important qualities of C I Engine fuels. Discuss the future of CNG as I

C Engine fuels. 0 What is the reason that mechanical efficiency increases with engine load? What is

the cause of pumping losses? how this can be reduced? Q. 2 (A)

A simple jet carburetor is required to supply 6 kg of air per minute and 0.45 kg of fuel per minute of density 740 kg/m3. The air is initially at 1.013 bar and 27°C

a) Calculate the throat diameter of the choke for flow velocity of 92 m/s. Velocity coefficient = 0.8.

b) If the pressure drop across the fuel metering orifice is 0.75 of that at the choke, calculate the orifice diameter assuming Cd = 0.60.

10 3

(B) How are fuel injection systems in C I Engines classified? Describe them briefly. Why the air injection system is not used now-a-days? What are the most common types of nozzles used?

10 2 & 3

3

Q. 3 (A)

A diesel engine operating on 4-stroke cycle is to be designed to operate with following characteristics at sea level, where the mean conditions are 1.0132 bar and 10°C. BP = 260 kW, volumetric efficiency = 78% (at sea level free conditions), BSFC = 0.247 kg/kWh, A/F ratio = 17, speed = 1500 rpm. Calculate the required engine capacity and the BMEP. The engine is fitted with a supercharger so that it may be operated at an altitude of 2700 m where the atmospheric pressure is 0.72 bar. The power taken by a supercharger is 8 % of the total power produced by the engine and the temperature of the air leaving the supercharger is 32°C. The A/F ratio and thermal efficiency

10 3

remain the same for the supercharged engine as when running unsupercharged at sea level, as does the volumetric efficiency. Calculate the increase of air pressure required at the supercharger to maintain the same net output of 260 kW. Take R = 0.287 kJ/kgK

.

(B) What are the main sources of pollutants from petrol engine? Discuss the adverse effects of emissions on human health.

05 2 5

(C) Explain the effect of fuel viscosity in diesel engine performance. Discuss the advantages of alternative fuels.

05 2 5

Q. 4 (A)

Enumerate the methods by which engine friction can be determined. What are the objectives of lubrication?

05 2 6

(B) Why overheating and overcooling of I C Engines is harmful? What are the two main types of cooling systems? Where these systems are used?

05 2 6

Q. 5 (A)

What are the advantages and disadvantages of Wankel engine? Compare the rotary Wankel engine with reciprocating I C engine.

06 1 7

(B) The following data relate to the testing of a 4-stroke, 4-cylinder diesel engine: Bore = 36 cm stroke =40 cm, speed = 350 RPM, BP =257 kW, IMEP = 7 bar,

14 3 4

fuel consumption consumption = 72 kg/h, C.V. of fuel = 43960 kJ/kg, air consumption = 28.2 kg/min, mass of jacket cooling water = 86 kg/min, rise in temperature of jacket cooling water = 41°C, amount of piston cooling oil = 53 kg/min, temperature rise of cooling oil = 23°C, specific heat of cooling oil = 2.09 kJ/kg,K, room temperature = 20°C, exhaust gas temperature = 325°C, Cp of dry exhaust gas = 1.045 kJ/kgK, specific heat of water = 4.18 kJ/kg K. Draw up the heat balance sheet on kW and percentage basis. Calculate indicated, brake thermal and mechanical efficiencies.

1 Q. 6 (A)

A 6-cylinder, 4-stroke C I engine operates on A/F ratio = 20. The diameter and stroke of the cylinder are 100 mm and 140 mm respectively. The volumetric efficiency is 80%. The condition of air at the beginning of compression are 1 bar and 27°C.

(i) Determine the maximum amount of fuel that can be injected in each cylinder per second.

(ii) If the speed of the engine is 1500 rpm, injection pressure is 150 bar, air pressure during fuel injection is 40 bar and fuel injection is carried out for 20° crank angle, determine the diameter of the fuel orifice assuming only one orifice is used. Take density of fuel as 860 kg/m3 and coefficient of discharge for the injector Cf as 0.67

10 3

(B) Discuss the difference between theoretical and actual valve timing diagram of a 4- Stroke diesel engine. Compare the relative advantages and disadvantages of 4-Stroke and 2-Stroke cycle engines.

10 1

Q. 7

Write short note on following (any five) 1

(A)Properties of good lubricant (B) Application of various types of I C Engines (C)Classifications of I C Engines (D) Battery ignition system (E) Stages of combustion in SI engines (F) Scavenging of two stroke engine (G) Volumetric efficiency and various factors that affects the volumetric

efficiency

20 2 1- 7

1-313H-e)(c

Bhartiya Vidya Bhavan's

SARDAR PATEL COLLEGE OF ENGINEERING

( An Autonomous Institution Affiliated to University of Mumbai)

Total marks: 100 Exam , May 2016

CLASS/SEM : TE (Mech) / SEM- VI SUBJECT: Mechanical Vibration

(;_S 'ITCY cf; le

Marks C Module 0

20

• Question No. 1 Compulsory

• Solve any Four out of Six questions of remaining

• Assume suitable Data whenever necessary

• Figures to the right indicate full marks

Q.1 Solve any FOUR

a) Explain different types of Dampers in detail

b) Explain logarithmic Decrement with suitable example

c) What should be length of simple pendulum used in clock so that it will have time period of

1 sec

d) Explain Magnification Factor v/s Frequency Ratio and Phase angle Plot v/s Frequency Ratio

in detail

e) Explain the causes of vibration in detail

f) Explain different Vibration measuring instruments with suitable example

Q.2 a) i)Determine the expression for natural frequency of the system shown in fig. for

small amplitude of vibration ii) If m,lci,k2,a,b are fixed, specify the value of 'a' for which system will not vibrate

iii) Find out the maximum acceleration of mass

iv) What would be the natural frequency of the system if system were taken to moon

where acceleration due to gravity is 1/6111 of that on the earth?

95 o o'is-11)

Q.2 b) Find the natural frequency of torsional oscillations for the system shown in fig. Neglect the mass of steel shaft. Take G=83 GPa

10 II II

çAr

)))'' Q.3 a) A block of mass m moves on a horiz ictionless surface as shown in fig. i) Derive the equation of motion, ii) Find the time period of oscillation iii)For what value of c is the system critically damped iv)Find the response of the system when it is released with the initial conditions

x(0) =0 ,(0)=5 m/s if m=2kg , k=48 N/m , c=4 N s/m

b) Obtain the expression for viscous damping for free vibration also discuss different conditions in detail

Q.4 a) Obtain the expression for Multi-degree of freedom system for Torsional Vibration using Transfer Matrix system and obtain Mode shape in detail

b) For a simple damped vibration system stiffness is 6000 N/m, Critical damping 0.3 Ns/mm , damping ratio is 0.3 , initial velocity is I m/s , initial displacement is zero at equilibrium position. Obtain the maximum displacement.

10 III ifi

10 III III

10 II V

10 II V

Q.5 a) Find the natural frequencies of 3 d.o.f. system shown in fig. 10 11 V

1/3 b) Determine the natural frequencies an mode shapes of the torsional system shown in

fig. 189 for11=1 , 12=21 and Kti —Kt2=-1( 11)

Q.6 a) A steel shaft of uniform diameter, simply supported at the ends carry two discs of weights 600 N and 1000 N as shown in fig. Determine the fundamental natural frequency using Dunkerly method. Take E= ]96x 109 N/m2 and 1=4x 10"7 m4 . Also

explain Dunkerley method.

10 II VI

10 II V

CoON I Im14

07, 1 ) -- -- -

b) Explain Explain Rayleigh method and Rayleigh Ritz method in detail 10 11 V

1

10 II V Q.7 a) A shaft of negligible weight ,6cm diameter and 5m length, is simply supported at the ends and carries four weights of 50 kg each at equal distance over the length of the shaft.Find the frequency of frequency of vibration by using Dunkerley's method .Take E=2 x106 kg /s2

Wci ri) 1

A iD •

t frn ) 1/1 in 4- yr\ br

b) Using Holzer method ,determine the natural frequencies of the system as shown in fig. Take Ki1= Ka= 1, 11= 12=1

10 II VI

ro,so-o

Max. Marks: 100 Class: T Y BTech Semester: VI

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineer' (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. End Semester Exam

May 2016

Duration: 3Hours Program: Mechanical Engineering Course Code : ME 351

Name of the Course: Refrigeration and Air Conditioning

Instructions:

mets)-er Pile 1) Question number 1 is compulsory. Solve any four questions out of remaining six. 2) Use of refrigerant properties and psychrometric chart is permitted. 3) Use of steam table is permitted. 4) Assume suitable data and justify the same.

Question No

Maximum Marks

Course Outcome Number

Module No.

Q1 Solve any Four of the followings.

20 1

(a) Explain effect of suction vapour superheat and liquid subcooling on performance of vapour compression refrigeration cycle.

I

(b) What is the secondary refrigerant and where it is used? III

(c) Derive formula for rectangular equivalent of the circular duct given by: D = 1.265 [(ab)°6/(a +b)o.2]. V

(d) Explain what sick building syndrome is. VI

(e) Derive expression for maximum COP of vapour absorption cycle. VII

Q2(a) Explain regenerative aircraft refrigeration system with schematic and T-s diagram.

08 1 II

(b) An ammonia ice plant operates between a condenser temperature of 35°C and an evaporator temperature of -15°C. It produces 10 tons of ice per day from water at 30°C to ice at -5°C. Assuming simple saturation cycle, using only tables of properties for ammonia, determine:

(0 The capacity of the refrigeration plant (ii) The mass flow rate of refrigerant (iii) The discharge temperature (iv) The compressor cylinder diameter and stroke if its

volumetric efficiency is ri„ = 0.65, rpm N = 1200 and stroke/bore ratio LID = 1.2.

(v) The horsepower of the compressor motor if the adiabatic efficiency of compressor ria = 0.80 and mechanical efficiency rim = 0.9.

(vi) The theoretical and actual COP.

12 2 I

Q3(a) Explain actual vapour compression cycle with the help of T-s and p-h diagram.

08 1 I

(b) The following data refers to a reduced ambient refrigeration system. Pressure of ram air is 1.1 bar at 15°C and pressure at the end of main compressor is 4.4 bar. Find (i) COP, (ii) cooling capacity in TR and (iii) power required to operate system for following data.

Main compressor efficiency = 0.8 Heat exchanger effectiveness = 0.8 Pressure at exit of auxiliary turbine 0.8 bar Temperature of air leaving cabin = 25°C Pressure in the cabin = 1.01325 bar Flow rate of air through cabin = 1.0 kg/s Cooling turbine efficiency = 0.8 Auxiliary turbine efficiency = 0.8

12 2 II

Q4(a) 1 State and explain desirable properties of ideal refrigerants. 10 i III (b) A sample of moist air is at 32°C DBT and 23°C WBT. If

barometric pressure is 750 mm of Hg. Calculate for sample of air without using psychrometric chart (i) Relative humidity (ii) Humidity ratio (iii) Dew point temperature (iv) Density and (v) Enthalpy.

10 2 IV

Q5 In an industrial application for winter air conditioning, an air washer is used with heated water spray followed by a reheater. The room sensible heat factor may be taken as unity. The design conditions are: Outside: 0°C DBT and dry Inside: 22°C DBT and 50% RH Room heat loss: 703 kW

The following quantities are known from the summer design. Ventilation air 1600 calm Supply air 2800 cmm Spry water quantity 500 kg/min

The air washer saturation efficiency is 90 percent. The make up water is available at 20°C. Calculate:

(i) The supply air condition to space (ii) The entering and leaving air condition at the spray

chamber. (iii) The entering and leaving spray water temperature. (iv) The reheat, if necessary.

20 3 IV

Q6(a) Name various types of supply air outlets and explain in detail general distribution pattern of various types of supply air outlets. 10 1 V

(b) Explain various duct design methods. 10 1 V Q7(a) What is effective temperature? Explain what comfort chart is and

also explain human comfort. 10 1 VI

(b) Explain three fluid vapour absorption refrigeration system with neat sketch. 10 1 VII

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. Test I / Test II / End Semester Exam

November 2015 / May 2016

Q. P. Code: Max. Marks: 100 Class: S.Y.BTech Name of the Course:

Semester:(IS_ Theory of Machines-I

Duration: 4hrs Program: Mechanical Engineering Course Code : BTM402

Instructions: • Question No 1 is compulsory

• Attempt any four questions out of remaining six.

• Assume suitable data if required and state it clearly.

• Answers to all sub-questions should be grouped together.

cf'1 e .

Q. No

Max Mo CO mar dule No.

ks

Q1 Answer in brief:

a) What is Instantaneous center of rotation? State and prove Kennedy's 4 Ml

theorem.

b) State ad delive law of gearing. 4 M7 3

c) Define Grashors law. State how it is helpful in classifying the four-link 4 MI 1

mechanism in to different types?

d) What do you meant by correct steering? Derive the fundamental 4 M')

equation of steering gear. Which steering gear fulfils this condition?

e) What is the function of flywheel? Define coefficient of fluctuation of 4 M6

speed and fluctuation of energy. Derive the relation between them.

Q2 a) A crank-rocker linkage has 100-mm frame, a 25-mm crank, a 90-mm 06 Ml I

coupler and a 75-mm rocker. Draw the linkage and find the maximum and minimum values of the transmission angle. Locate both toggle

positions and find corresponding crank angles and transmission angles. b) For the above linkage find the angular velocities for coupler and rocker 08 M3

using relative velocity method, when:

i. mechanism is in toggle positions and

ii. Mechanism is in max/min transmission angle position.

c) Locate all the IC's for above linkage in various positions. 06

Q3 a) Deduce the expression for displacement-S, velocity-V and 06 MS 3

acceleration-A of the follower when it moves with SHM motion. Given

: h= total lift, 0= angle of ascent and 0= instantaneous angle, co= angular velocity of cam.

b) Draw the displacement, velocity and acceleration diagram w.r.t. time for 08 3

outward motion of follower, when the follower through 30 mm during 1800 of cam rotation M5 • is moved outwards

with SHM. • dwells for 20° of the cam rotation

• Returns with uniform velocity during the remaining 160° of the

cam rotation. What will be the maximum velocity and acceleratiton of the follower

during the outstroke, if the cam rotates at 1500 riim counter-

clockwise? c) For a tangent cam with roller follower; deduce the expression for

displacement, velocity and acceleration when roller is in Aontact with 06

straight flank.

Q4 a) For an offset slider-crank mechanism, find angular velocity and 5-r5 acceleration of connecting rod, also linear velocity and acceleration of slider. Given: crank = 50-mm, connecting rod = 140-mm, eccentricity

(e) = 20-mm, 0 = 450 (ccw with horizontal), co = 200 rad/sec (crank speed

in ccw). b) Solve the above problem using complex-algebra method. (take 10

eccentricity e=0-mm)

Q5 a) Deduce an expression for the ratio of tight and slack side tensions in case 05

of a V-belt drive.

b) The pulleys of two parallel shafts that 8 m apart are 6‘0 mm and 800 05

mm in diameters and are connected by a crossed belt. needed to

change the direction of rotation of the driven shaft by adopting the open-belt drive, Calculate the change in length of the belt.

c) A chain drive is used for speed reduction from 240 rpm to 110 rpm. The 06 number of teeth on the driving sprocket is 22. The center to center distance between two sprockets is 540 mm and the pitch circle diameter of the driven sprocket is 480 mm. Determine the number of teeth on the driven sprocket, pitch and the length of the chain.

d) What are the different types of pulleys? Explain briefly. 04

a) A gear having a module of '4 mm/tooth and 21 teeth drives another gear 03 at a speed of 240 rev/min. How fast is the 21-tooth gear rotating if the

shaft center distance is 156 mm? b) A 6 mm/tooth module, 24-tooth pinion is to drive a 36-tooth gear. The

gears are cut on the 20° full-depth involute system. Find and tabulate the 10 addendum, deciendum, clearance, circular pitch, base pitch, base circle radii, length of paths of approach and recess, and contact ratio.

3

M1 2

M3 2

M6 3

M6 3

M6 3

M6 3

M7 3

M7 3

c) Derive the expression for minimum number of teeth on wheel gear to 04 M7 3

avoid the interference.

d) A pair of spur gears has 16 and 18 teeth, a module 12.5-mm and M7 3

addendum 12,5-mm and pressure angle is 14.50. Show that gears have 03

interference.

Q7 a) What are the constrained and applied forces for a linkage? For the /+2 M4

linkage in the question number 4 b) if the force applied on slider is 500

N. find torque at crank.

b) What is hook's joint? Where it is used? Determine the maximum 2+2 1\42

permissible angle between the shaft axis of a universal joint, if the

driving shaft rotates at 800 rpm and total fluctuation of speed does not exceed 60 rpm. Also find the max. and min speed of driven shaft.

c) Explain Tchebicheff mechanism. 4 tyr

d) Define Kinematic pair, link and chain. How kinerriatic—fiairs—afe 4 M1 I

classified?

e) Define the degree of freedom of mechanism. State the complete 4 M1 1

expression for DOF of a mechanism. Explain the meaning of each term

in it.

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineering (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. End Semester Exam

May 2016

Max. Marks: 100 Class: TY B.Tech Semester: VI Name of the Course: Machine Design I Instructions:

• Assume suitable data wherever necessary. • Use of PSG Data book is permitted • Use of Charts are permitted.

Q. P. Code: Duration: 03 hr

Program: Mechanical Engineering Course Code : ME 352

meksA-er le

Question i No I

Maximum Marks

Course Outcome Number

Module No.

Q1

a. Asthetic Considerations in design b. Stress Strain relationship c. Types of fits d. Modes of failure in design e. Goodman Criteria

20 3 01

Q2 Design a screw jack for lifting a load of 20 KN through a

1 distance of 200 mm. Consider yield strength of 350 N/rnm2. FS H5.

I 20 1, 2 02

Q3 ( a)

Design a closed coil helical spring for a boiler safety valve which is required to blow off steam at pressure of 1.5 Nimm2. The diameter of the valve is 50 mm. The initial compression of

the spring is 40 mm and the lift is limited to 20 mm.

10 2 05

Q3 (b)

spring.

The spring in a truck has 12 leaves , two of which are full length. The spring supports are 1.50 m apart and the central

I band is 85 mm wide. The central load is 5.4 KN and the permissible stress of the material is 280 Nirrim2. Design the

I 10 2 05

Q4 (a)

A 50 mm diameter shaft is made of carbon steel having yield tensile strength of 400 N/mm2 and ultimate strength of 600 IN/rnm2. It is subjected to a torque which fluctuates between 2000 Nm to 800 Nm. Using the soderberg equation calculate

factor of safety

10 2 04

. Q4 (b)

A line shaft is driven by means of a motor placed vertically below it. The pulley on the line shaft is 1.5 m in diameter and has belt tensions 5.4 KN and 1.8 KN on tight and slack side of the belt respectively. Both these tensions may be assumed to be vertical. If the pulley be overhang from the shaft. The distance of the central line of the

pulley being 400 mm. Find the diameter of the shaft

10 2 04

assuming maximum allowable shear stress of 42 Mpa.

05(a)

Find the the most

distance heavily

b in figure loaded rivet

200 mm

90 kN

IIIIIIIIIIIMmllMIMINIMII

if the maximum shearing is to be 93 MPa.

75 75

0 0GI

stress on 10 2 07

75

20 mm rivers

Determine loaded weld weld-is 7.5-N/mm2

i c =37.51 ,

the as

4 4 I

4 I 4

size of the shown in

14.2b6 ninl

weld required for an eccentrically figure. The allowable stress

P ..= 25 !/0 -

— in the

kN

10

.

2 07

05 (b)

I

1

/ ,,

Irerweilvir , 3714 tun

t-=. 50

A 30 KW, 1000 rpm motor transmits power to a stone crushing 06 (a) machine, which operates at 250 rpm. Select a suitable flat belt. 10 2 06 Derive the expression for the effect of centrifugal force on the (b) belts.

05 2 06

(c) Explain : 1. Quarter turn Belt drive. 2. number of plys in belt 05 2 06

A mass of 50 Kg drops through 25 mm at the centre of the 250 mm long simply supported beam. The beam has a square cross , — - —

Q 7 (a)

--1------ section. It is made of steel 3008 (Syt =400 N/mm2 ) and the

factor of safety is 2. The modulus of elasticity is 207000 N/mm2. Determine the dimension of the cross section of the beam.

10 1 03

A forged steel bar, 50 mm in diameter, is subjected to a

Q 7 (b) reverse bending stress of 250 N/mm2 . The bar is made of steel 1 4008 (Sut = 600 N/mm2). Calculate the life of the bar for a

, reliability of 90 %.

. 10 1 03

.2c_tke)

'2-'4 ( 2-o 6

Bhartiya Vidya Bhavan's

SARDAR PATEL COLLEGE OF ENGINEERING

( An Autonomous Institution Affiliated to University of Mumbai)

• Question No. 1 Compulsory • Solve any Four out of Six questions of remaining

• Assume suitable Data whenever necessary • Figures to the right indicate full marks

Total marks: 100

CLASS/SEM : TE (Mech) / SEM- VI

Exam , May 2016

SUBJECT: Mechanical Vibration

r \e .

Marks C 0

Module

Q.1 Solve any FOUR 20

a) Explain Rayleigh Method for point loads and distributed mass m I HI

b) Explain different types of dampers I III

c) Explain detail steps involved in Vibration analysis I I

d) Explain Principle of Seismic Instrument I IV

e) Explain Newtons method for equatiorrof fflotion III I

f) Explain Classification of Vibration Iv VII

Q.2 a) i) Determine the N/m , m=10 kg

,

t t:

IIt p, ii r , iiafpn

i

.1 li .4 I

natural frequency of

, / /

v ft hl

,' of motion for a simple

f ,

1

the system

pendulum

shown in fig. Given that K=1x105

using energy method

10 1 ii

Q.2 b) i. A vibratory system is designed with following parameters: m=10 kg , k=40 N/m. Determine the damping coefficient C of the system if

10 II II

amplitude of vibration is observed to decrease to 25% of original value after 5 cycles.

ii. A body of mass 5 kg is supported on a spring of stiffness 1000 N/m and has a dashpot connected to it which produces a resistance of 0.01 N at a velocity of 1 m/s. In what ratio will be amplitude of vibration be reduced after 5 cycles?

1 Q.3 a) Find out the frequency ratio for which amplitude in forced vibration will be 10 III III

maximum.Also determine the peak amplitude and the corresponding phase angle.

b) Discuss the different conditions for Viscous damping and derive the expression 10 In m

Q.4 a) Explain Transfer Matrix for Multi-degree of freedom system for Torsional Vibration 10 I I V

b) Consider a spring —mass-damper system with K=4000 N/m , m=10 kg and C=40 Ns/m 10 II v

Find the steady state and total response of the system under the harmonic force F=200sinlOt N and initial conditions x=0.1 m and x=0 at t=0

Q.5 a) Find the natural frequencies and mode shapes of 3 d.o.f. system shown in fig. using 10 1 H v

matrix method . Given mi = m2 = m3 = m and kl= k2 = k3= k /e/// ///a/

- — — - —

, ilt

1.1 1

. '41 7C2- 41

,1 I

S K

14 A

tO 313) Xs

!,' !

b) Write t quitibbs 6f motion for the system shown in fig and find out the natural ,e' to II VI

frequencies for the given data m1=200 kg , m2=50 kg , K1 =100,000 N/m, K2=

200,00

11 Ic-

illti

1111111111111017.11111

Q.6 ,

a) Determine the fundamental natural frequency for a three —rotor torsional system as shovvn in fig. using Dunkerley's method

10 II v

ri =PO pn , kt1=500 Nmirad wi =10 kg r2=5 ern , kt =1000 Nm/rad w2=40 kg r3 =10 cm , kt3=800 Nm/rad w3 =20 kg

4_1

b) Using Rayleigh method , find out the first natural frequency of transverse vibration of a 10 II V

uniform simply supported beam.

Q.7 a) A beam of negligible weight and length 1.2 m is simply supported at the ends and 10 II V

carries three transverse loads of 200N ,800N and 400N at a distance of 0.3 m ,0.6 m and 0.9m from the left support.Find the frequency of transverse vibration by dunkerley method.

2-"1•1 toot,' c‘rw I 1

---'17- r 1-- 0.3 rn 1—

-4 / 1 01 7r1

2 Vrt I I ),

b) Using Holzer method ,with suitable example 10 H VI

I Il

_

b

Max. Marks: 100 Class: T Y BTech Semester: VI

Bharatiya Vidya Bhavan's

Sardar Patel College of Engineer (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. Re-Exam June 2016

Duration: 3Hours Program: Mechanical Engineering

Course Code: ME 351 Name of the Course: Refrigeration and Air Conditioning

Instructions: 1) Question number ONE is compulsory and solve any FOUR questions out of remaining six. 2) Use of refrigerant properties table, psychrometric chart and steam table is permitted. 3) Answer of sub questions should be grouped together.

M as4-6A- ( I e . 4) Assume suitable data and justify the same. Pi

Question No

Maximum Marks

Course Outcome Number

Module No.

Q.1(a) Differentiate between heat pump and refrigerator.

1

I (b) State advantages of air as a refrigerant in aircraft refrigeration

system. II (c) Define terms for moist air (i) Specific humidity (ii) Relative

humidity (iii) Degree of saturation (iv) Wet bulb temperature and (v) Dew point temperature

20 IV

(d) Explain in detail sick building syndrome and methods to avoid sick building syndrome. VI

Q.2(a) Explain reduced ambient aircraft refrigeration system with schematic diagram and T-s diagram. 08 I ll

(b) An R-134a simple saturation cycle refrigerator operates at 40°C condenser and -16°C evaporator temperatures. Determine COP and HP/TR. If a liquid —vapour regenerative heat exchanger is installed in the system, with the suction vapour at 15°C, calculate the chan!e in COP and HP/TR.

12 2

Q3(a) Explain effect of condenser pressure, evaporator pressure, suction vapour superheat and liquid subcooling on the •erformance of vapour compression refrigeration system.

08 I I

(b) For a boot strap air refrigeration system for an aircraft flying at an altitude of 2000 m. The ram air temperature and pressure are 17°C and 1.08 bar respectively. The ambient conditions are being 80 kPa and 0°C. At the end of isentropic compression the air is at 4 bar and is cooled to 27°C using ram air. At this temperature air is further compressed in secondary compressor driven by cooling turbine. The air is then cooled in an auxiliary heat exchanger to 27°C and finally expanded to a cabin pressure of 1 atmosphere. Obtain the pressure at the exit of secondary

12 2 II

compressor if air leaves the cabin at 25°C. Q4(a) Explain the designation system for all types of refrigerants. 10 Iii (b) The pressure and temperature of mixture of dry air and water

vapour are 0.98256 bar and 21°C. The dew point temperature of the mixture is 15°C. Find the followings:

(i) Partial pressure of water vapour in mixture (ii) Relative humidity (iii) Specific humidity (iv) Enthalpy of mixture per kg of dry air (v) Specific volume of mixture per kg of dry air

10 2 IV

A building has the following calculated cooling loads: Room sensible heat gain = 310 kW Room latent heat gain = 100 kW

The space is maintained at DBT of 25°C and relative humidity of 50 %. The outdoor air is at 38°C and 50% R.H, And 10 % by mass of air supplied to the building is outdoor air. If the air . supplied to the space is not at temperature lower than 18 C. Find (i) Minimum amount of air supplied to space in m3/s. (ii) Volume flow rates of return air and outdoor air (iii) State and volume flow rate of air entering the cooling coil. (iv) Capacity, ADP, BPF and SHF of the cooling coil.

20 3 IV

Q6(a) Explain in detail various duct design methods. 10 (b) Discuss about types of filters used in air conditioner. 5 1 V (c) Explain three fluid refrigeration system. 5 1 VII

Q7(a) Explain the mechanism of body heat loss and how it is related to human comfort. Also draw and explain comfort chart. 10 1 VI

(b) Explain with neat sketch practical single effect water lithium bromide absorption chiller. 10 1 VII

SZAvl

C I PAI 2- 2-

Bharatiya Vidya Bhavan's

Sardar Patel College of Enginee (A Government Aided Autonomous Institute)

Munshi Nagar, Andheri (West), Mumbai — 400058. End Semester Exam — RE EXAM

June 2016 Q. P. Code:

Max. Marks: 100 Class: TY B.Tech

Semester: VI Name of the Course: Machine Design I Instructions:

• Assume suitable data wherever necessary. • Use of PSG Data book is permitted • Use of Charts are permitted.

Duration: 03 hr Program: Mechanical Engineering

Course Code : ME 352

Masi-e r 11) e

Ques tion No

Maxi mum Marks

Course Outcom e Number

Modu le No.

a. Ergonomic Considerations in design b. Stress Strain relationship c. Draw the standard location of elements of a welding

symbol. d. Comparison of Failure theories e. Mechanical Properties of Engineering materials

20 3 01

Q2

A knuckle joint is completely made of plain carbon steel 4008 (Syt = 380 Nimm2) and subjected to an axial pull of 80 KN. Design the joint with a factor of safety 4. Assume the compressive strength of the material to be 20 % more than the tensile strength.

20 1, 2 02

Q3 (a)

A helical tension spring is used in the spring balance to measure the weights. One end of the spring is attached to the rigid support while the other end, which is free which carries the weight to be measured. The maximum weight attached to the spring balance is 1500 N and the length of the scale is approximately 100 mm. The spring index can be taken as 6. The spring is made of oil hardened and tempered steel wire with ultimate strength of 1360 Nimm2 and the modulus of rigidity of 81370 Nimm2. The permissible shear stress in the spring wire should be taken as 50% of the ultimate tensile strength. Design the spring and calculate

i. Wire diameter ii. Mean coil diameter

iii. Number of active coils iv. Required spring rate v. Actual spring rate

10 2 05

Q3 (b)

A semi elliptic leaf spring used for automobile suspension consist of three extra full length leaves and 15 graduated length leaves, including the master leaf. The centre to centre distance between two eyes of the spring is 1 m. The maximum force that can act on -

10 2 05

the spring is 75 KN. For each leaf, the ratio of width to thickness is 9:1. The modulus of elasticity of the leaf material is 207000 N/mm2. The leaves are pre stressed in such a way that when the force is maximum, The stress induced in all leaves are same and equal to 450 N/mm2. Determine

i. The width and thickness of the leaves ii. The initial nip iii. The initial preload required to close the gap C between

extra full length leaves and graduated length leaves.

•

A steel shaft made of 4008 is used to drive a machine. The pulley X, Y and bearings A, B are located as shown in figure along with belt tensions. Determine the diameter of the shaft using A.S.M.E code. Yield strength of the shaft material is 330 N/mm2 and ultimate tensile strength is 600 N/mm2. Take Kb = 1.5 and Kt = 1.2.

All dimensions are in mm 4;15N 1 xv

20 2 04

Q4 0.-- 200 ---'*4.-

1021 *I a= MI= -2°G

I

e 11;1:11 114

A bracket is supported by means of 4 rivets of same size as shown in figure. Determine the diameter of the rivet if the maximum shear stress is 140 N/mm2.

10 2 04

so 20 kN All the dimensions are in mm.

Q5 (a)

3 i

i

'SO 2 i

1

A welds permissible

16 mm thick plate

as shown in figure. shear stress

t 4 r

is welded to a vertical support Determine the size of the

for the weld material is 75

250 r11111 -t•

by two fillet weld, if the

MPa. t,IN.

10 2 07

45 (b) —

•

07 10 A flat belt, 8 mm thick and 100 mm wide transmits power between two pulleys, running at 1600 m/min. The mass of the belt is 0.9 kg/m length. The angle of lap in the smaller pulley is 165° and the coefficient of friction between the belt and the pulley is 0.3. If the maximum permissible stress in the belt is 2

MN/m2, find (i) Maximum power transmitted and (ii) initial

10 06

10 06

03 10

tension in the belt. A V belt is to transmit 20 KW from a 250 mm pitch diameter

I sheave to a 900 mm diameter pulley. The centre distance between the two shafts is 1000 mm. The groove angle is 40° and the coefficient of friction for the belt and the sheave is 0.2 and the coefficient of friction between the belt and the flat pulley is 0.2. The cross section of the belt is 40 mm wide at the top, 20 mm wide at the bottom and 25 mm deep. The density of the belt is

1000 kg/ m3 and the allowable tension per belt is 1000N. Find the

number of belts required A mass of 50 Kg drops through 25 mm at the centre of the 250 mm long simply supported beam. The beam has a square cross section. It is made of steel 3008 (Syt =400 N/mm2) and the factor

of safety is 2. The modulus of elasticity is 207000 N/mm2.

Determine the dimension of the cross section of the beam. A forged steel bar, 50 mm in diameter, is subjected to a reverse bending stress of 250 N/mm2. The bar is made of steel 4008 (Sut

= 600 N/mm2). Calculate the life of the bar for a reliability of 90

%.

1