(b)

3. (a)

(b)

4. (a)

(b)

(c)

5% variation in speed. The mass of the sleeve is 5 kg and the friction may be assumed to be equivalent of an additional load of 30 Nat the sleeve. The effort of governor is sufficient to overcome the friction of the sleeve caused by I% change of speed at mid-position. Calculate-(i) the mass offlyballs; (ii) the spring rate; (iii) the initial compression of the spring; (iv) the governor effort for I %change of speed; (v) the power of governor The disc of a torsional pendulum has a moment of inertia of 600 kg-cm2 and is mer. d in a viscous fluid. The brass shaft attached to it is of I 0 em eli ameter and 40~n Wli the pendulum is vibrating, the observed amplitudes on the same side of re o tion for

unit velocity and (iii) the periodic time of vibration. successive cycles are 9, 6 and 4. Find (i) logarithmic decremeno, pt torque at

Assume for brass shaft C = 44 x I 010 N/mm. What would be the J.l cy, if the disc is removed from viscous fluid? f'>. +

30 A hollow column, 400 mm external diameter and 300E~iameter, is hinged at both ends. If the length of column is 5m, E = 075 x I N/~ , factor of safety 5, Rankin's constant 1/1600 and crushing stress 587 N/m ~safe load the column can carry without buckling. Use Euler's and Rankine 5tzt~l'#'\:

30

20

10 -plain the mechanism of fatigue and creep failures.

10

SECnONB 5. Answer any three of the following:

(a) In an orthogonal cutting operation, the following data have been observed: Uncut chip thickness= 0.127 mm Widthofcut=635 mm Cutting speed= 2 mls Rake angle = 10 o

6.

7.

Cutting force= 567 N Thrust force = 2 27 N Chip thickness= 0.228 mm

Determine the shear angle, the friction angle, shear stress along the shear pi ane, and the power for the cutting operation. Also find the chip velocity, shear strain in chip, and the strain rate.

20 (b) With the help of a neat sketch, explain the electro hydraulic forming process for aking

tubular parts and list the variables governing the process. What are the main appr no

(c)

(d)

(a)

(b)

this process?

Ml MZ M3

Jobs-A B C s 7 6 2 1 4 3 7 5

r tng of ECM machine How the machuung rate IS

e the uses of the following preparatory functions: I, G02 and G03

30 control systems used in NC

15

15 Samples of n = 8 items each are taken from a manufacturing process at regular intervals. A quality characteristic is measured, and x and R values are cal cui ated for each sample. After 50 samples, we have j) j) L:~ = 200L;~ = 250 i..J. i..J.

Assume that the quality characteristic is normally distributed. (i) Compute control limits for the x and R control charts.

(b)

(c)

8. (a)

(b)

(c)

(ii) All points on both control charts fall between the control limits computed in part (i). What are the natural tolerance limits of the process?

(iii) If the specification limits are 41 50, what are your conclusions regarding the ability of the process to produce items within these specifications

(iv) Assuming that if an item exceeds the upper specification limit it can be reworked, and if it is bel ow the lower specification limit it must he scrapped, what percent scrap and rework is the process producing?

(v) Make suggestions as to how the process performance can be improved.

A small electronics company produces pocket calculators and records the de n The following demand data are for a representative calculator November 45; em 57; January 60. Using 50 as the first-order exponential smoothing forecast foG orecast February sales with a smoothing constant of 02. Is 02 a good choice as a oothl , constant? Comment.

10

fortoy I and toy 2 respectively. The assembly cost and pa t one unit of type I are Rs. 4 and Rs. 5 respectively, and corresponding figur~ e are Rs. 5 and Rs. 2. The expenditure on assembly and packing is to be kept s c y and up to Rs. 100 and Rs. 8 0 resp ecti vel y. Using Simplex Method, calculate the number ~each type to be manufactured to get maximum profit. ~., v

20 et s d symbols the types of lay produced by

= 0 Wnte also the

20

Cumulative dit.lribution twntdon for U~e ~ht"d"' n34&:1 04:/01 Q-41~ 041:19 G-4010 q.~ (H013 o.am fi3il36 (}:QT (;3($

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OM) ()8881 l)ll882 OOlm l)t9fl4 OM OGG71 1)9!112 ()g973 017

Fattore for constsuctlng variablee control charts

Clulrt for A'lef'&ll C111rt !Qr 8llilnl!11rd Dolri.Uons Q-t Fa~re for Control Fac:tort for Facto111for Control Llmii:IJ -101'111 Ill Lim ita C4l n lnl 1..11'1!1 Sampt, n A At A, c, lie,

" B, II, s.

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Factors for constructing variables tontrol c;harts

ObHrYllt faaora !'or -IGna In Centre line Sampj&, ll II, lid

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~ s

ll T e 1'1 10

11 12 13 14 IS

16 t1 1t 19 ~

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I.

2.

3.

PAP!!~ mil SECnONA

Answer any three of the following parts (Answer to each part should not exceed 200 words)

(a)

(b)

(c)

(d)

(a)

(a)

/3 =edT +T-cb>

, K 0 K~dp +fvdv r~ + where ~ IS the coefficient of cub1cal expans1 on,jfe:~nt of compresS! b1h ty and Cp, Cv are spec1fic heats at constant pressure and cons~~ o e respectively Just! fy m bneL the followmg statements ~., (1) By advancmg the spark tlmmg ~1hty to knock maS I eng~ne mcreases, (ii) Willans line method for tin ctional power can be used only in case of

unthrottled engines. (iii) Exhaust hydrocarbo!tl.io ncrease with increase in surface to volume ratio of an

engme. ~ (iv) Carbon monoxidJ\missw s are low for fuel lean mixtures.

C=89%,H2 = ~ilJJ. andrestN2 An IC roOM B'IM.1r.wiog rompoOtioo Determin the c ai ly correct air-fuel ratio. If 40% excess air is supplied, find the percentage f dry~roducts of combustion by volume.

.. .. , . ._ eat engine operating between thermal reversible reservoir at 800C and 30C 11!1le-s-;~~JTersible refrigerator which refrigerates a space at -l5C and delivers heat to a

a! re ervoir at 30C. The heat input to the heat engine is 1900 kJ and there is a net work from the combined plant (heat engine and refrigerator) of 290 kJ. Determine the heat

. sfer to the 30C thermal reservoir. 30 6 kg of air at 600 K and 5.0 bar is enclosed in a closed system. (i) Determine the availability of the system if the surrounding pressure and temperature

are I 0 bar and 300 K. (ii) If the air is cooled at constant pressure to the atmospheric condition, determine the

availability and effectiveness. For air take, c;, =I 005 kJ/kg K, Cv = 0 718 kJ!kg K and R = 0287 kJ!kg K.

30 A six-cylinder, 4-stroke petrol engine has a swept volume of 30 liters with a compression ratio of 95. Brake output torque is 205 N-m at 3600 r.p.m. Air enters at 85 N/m2 and 60C.

} .: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.: .. :.:.:;

4.

(b)

(a)

(b)

(c)

(a)

The mechanical efficiency of the engine is 85% and air-fuel ratio is 15: I. The heating value of fuel is 44,000 kJikg and the combustion efficiency is 97"/o. Calculate: (i) Rate of fuel flow (ii) Brake thermal efficiency (iii) Indicated thermal efficiency (iv) Volumetric efficiency (v) Brake speci fie fuel consumption

(i) Explain the various stages of combustion in a diesel engine.

(ii) Discuss the effect of volatility of gasoline on engine starting, acce lock. 0 15 A 4-stroke petrol engine has a swept volume of 20 liters and is ru 4000 r.p.m. The

volumetric efficiency at this speed is 0.75 and the air-fu~ s I~ I. The venturi throat diameter of the carburettor fitted to the engine is 30 te \he air velocity at the throat if the discharge coefficient for air is 0.9. The amfj n ons are pressure= I 0 bar, temperature 20C. Calculate the diameter of the fuel if fuel density is 760 kg/m3. For airC 1005 kJ/kg K and R287llkg K. Assume C~.

30 Explain the necessary modifications that 4 : - ade to convert a bus running on diesel fuel to Compressed Natural Gas \'-''"'-' '"'

20 Discuss the advantages of usi carburettor.

10

20x3=60 :erc1nes, the temperature profile for hot and cold fluids as a function of path for

condenser and gas-heated boiler Show that the COP of a cascade refrigeration system is

COP= COlJ. x COP:! I + COJl + C0/'2

where COP1 and COP2 and COP's of low temperature and high temperature side respectively.

(c) An air compressor has eight stages of equal pressure ratio 1.35. The flow rate through the compressor and its overall efficiency are 50kg/s and 82 percent respectively. If the condition of air at entry are 1.0 bar and 4 0C, determine: (i) the state of air at the compressor exit, (ii) polytropic or small stage efficiency,

6.

7.

8.

(iii) efficiency of each stage, (iv) power required to drive the compressor assuming overall efficiency of the drive as

90%. Take Cp = 1005 kJikg K andy= 1.4.

(d) A central power station has annual factors as follows

(a)

(b)

(a)

Load factor= 0.6, Capacity factor= 0.4 and Use factor= 0.45. The power station has a maximum demand of 15 MW.

Deternune ~ (1) Annual energy production (u) Reserve capacity over and above peak load (m) Hours per year the plant IS not m serv1ce ~""' Two large parallel plates at Tt = 1000 K and =750 K have emtSSIVI~~d 9.2 = 0 8 respectively A radiation shield haVIng an enussiVIty of 83, 1 = 2 o ne stde and an enussiVIty of 83, 2 = 0-08 on the other Side 1s placed between the p alculate the heat transfer rate by radiation per square meter With and Wlthout0 on i ' d Take cr = 5.67 K x 108 W/m2 K'.

30 With usual notations, develop an expression fo~f.l"'ol?~fi:!.!:cill pncy of a fin of uniform cross-section when the heat loss from the tip is consi I e.

30 An air conditioning plant is designed ain a room at a condition of 20 C dry bulb temperature and specific humidity dry air when the outside condition is 30 C dry bulb temperature and 40% on. The corresponding heat gains are 18000W (sensible) and 3600W Qatent). upp r contains one-third outside air by mass and. the supply temperature is to be b temperature. The plant consists o f.'1fil~(~i:h n er for fresh and recalculated air, an air washer with chilled spray water ~~tency of 80%, an after heater battery and a supply fan. Neglecting temp~re c anges in fan and ducting, Calculate (i) th ass e of supply air necessary; (ii) ci~humidity of the supply air;

eating load on the after heater. 40

lain the working principle of Electrostatic Precipitator (ESP). Discuss the factors which affect its efficiency.

A small compressor has the following data Air flow rate= 1.5778 kg/s Pressure = I 6 Rotational speed= 54,000 rpm Efficiency= 85% State ofairatentry, Po,= 1.008 bar; 10, =300 K c;, for air= I 009 kJikg K. (i) Calculate the power required to drive this compressor.

20

'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"'"~

(b)

(ii) A geometrically similar compressor of three times the size is constructed. Determipe, for this compressor L mass flow rate, IL Pressure ratio, IlL speed and IV. the power required. Assume same entry conditions and efficiency for the two compressors and also assume kinematics and dynamic similarities between the two machines.~

Explain clearly what do you understand by Fanno flow. Show its plot on h - a an~ give its characteristics. ~ Air flows in an insulated duct with a Mach number of 0.2. The initi tern . ature and pressure are 290 K and 20 bar respectively. Determine:

(ii) the distance between these two points if the duct di r 1t em and friction factor is 0.004.

(iii) what will be the maximum length of the duct avoi choking?

Use the following table

!M 0-2 0-8

P/P"

0-073

30

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