Fluid mechanics/machinery

Manometers, pressure measurement
ESE2013-6a15


Hydrostatics
ESE2014-4c10




Buoyancy and floating


Flow kinematics


Flow dynamics


Orifices
ESE2014-1e10


Notches and weirs
ESE2015-6b5

Viscous flow(correction factors)


Turbulent flow
ESE2013-1f5 Turbulent flow described by equation: u=5+0.5 sin t, then u'? and (u'^2)^1/2?




Pipe flow
ESE2015-7b10


Dimensional analysis, similitude
ESE2013-5a15 Find expression for thrust F on propeller of ship if it is function of mass density(rho), dynamic viscosity(mu) of fluid and dia d, speed of advance v, rotational speed n of propeller
ESE2014-7c10
ESE2015-2a10

Boundary layer flow
ESE2013-1e5 Discuss various factors affecting boundary layer thickness
ESE2013-5b10 Smooth flat rectangular plate placed edgewise in a stream of fluid. At what fraction of length from leading edge would drag force on front portion be equal to half of total drag force?
Assume boundary layer to be laminar.
ESE2014-5c10
ESE2015-1c10
ESE2015-6b5



Drag and Lift



Open channel flows
ESE2013-6b15

Jet impact
ESE2014-1c5


Turbines
ESE2013-1g5 Expression for hydraulic efficiency of water turbine? How does it vary with part load?
ESE2013-5c15 Derive expression for work done per second by water on runner of Pelton turbine.
Prove that for a given jet speed, volume flow rate, turning angle and wheel radius the max efficiency occurs when turbine bucket moves at half the jet speed.
ESE2014-1d10
ESE2015-3a10



C-pumps
ESE2013-1h5 Explain slip and slip factor, as applied to c-pump, write expressions
ESE2015-1e10

Reciprocating pumps
ESE2014-1f10
ESE2014-2c10
ESE2015-5e10

RAC 1

Refrigeration and Air conditioning


1kcal=4.186kJ=3.968Btu, 1Btu=1.055kJ
Ton refgn 1TR is equivalent to production of cold at rate at which heat is to be removed from 1 US tonne of water at 32degF to freeze it to ice at 32degF in 1 day(24 hours)
1TR=200Btu/min=3.5167kW

Ways of producing low temperatures
*throttling expansion of liquid with flashing
*reversible adiabatic expansion of a gas[T2/T1 = (p2/p1)^(γ-1 / γ)]
*irreversible adiabatic expansion(throttling) of real gas[Joule Kelvin effect]
*thermoelectric cooling[Peltier effect]
*adiabatic demagnetization of a paramagnetic salt

Reverse Carnot cycle

VC cycle
CSE2003B7a30

CSE2004B7a40

CSE2006B6a30

CSE2006B5b20

CSE2008B5d20

CSE2010B6b20

CSE2012B7c20

CSE2013A1e10

CSE2015B7a20

LVHE
CSE2007A3a30

CSE2008B7b15

Refrigerants properties, coding




Multistage and cascading systems
CSE2005B5b20

Compressors
CSE2010B5d20

Condensers
CSE2009B7c25

CSE2015B6c10

Expansion valves
CSE2011B5a15

CSE2011B6c20

CSE2015B5a10

Gas cycles(Joule or reversed Brayton)
CSE2013B8b25

VA system
CSE2010B7b20

Moist air properties
CSE2008B7a15
CSE2011B5b15
CSE2014B6c10



Psychrometry of AC processes
CSE2007A3b30
CSE2008B7c30
CSE2009B8b20
CSE2010B8c20
CSE2012A3c20
CSE2013B5d10
CSE2013B8a25
CSE2015B6a20


Comfort AC and ET
CSE2003B7b30
CSE2005B7a40
CSE2006A1c20
CSE2006B6b30
CSE2009B5d20
CSE2009B8a40
CSE2011B7b30
CSE2014B7b20/2004B5b20
CSE2014B5d10

Geography previous year questions

Geography is one topic where output/input ratio is quite high. All one has to do is study the 4 NCERTs of 11-12th, GC Leong + any Atlas(all those pages that one usually skips) + bit of Yearbook(states chapter, water resources etc) and wiki surfing

Indian physical
2014
10degree channel separates : Andaman.... and ....Nicobar
Correctly paired? Dampa TR:Mizoram, Gumti WLS:Sikkim(Tripura), Saramati peak:Nagaland
Which are coral reefs: Andaman and Nicobar Is, Gulf of Kucch, Gulf of Mannar, Sundarbans
Indian soil erosion problem is associated with: terrace cultivation, deforestation,tropical climate
River flowing thru Arunachal Pradesh: Barak, Lohit, Subansiri
Correctly paired? Cardamom hills:Coromandel coast, Kaimur hills:Konkan coast, Mahadeo hills: Central India, Mikir hills: NE India
Trees found in Himalayas? Oak, Rhododendron, Sandalwood
2013
Correctly paired? CorbettNP:Ganga, Kaziranga NP:Manas, Silent Valley NP:Kaveri
Narmada flows west while large peninsular rivers flow east, Why? It occupies rift valley, It flows between Vindhyas and Satpuras, Land slopes to west from Central India
Correctly paired? Nokrek BR:Garo hills, Loktak lake:Barail range, NamdaphaNP:Dafla hills
Characteristics of Indian coal: High ash content, low sulfur content, low ash fusion temperature
About laterite soils of India:Generally red color, rich in nitrogen and potash, well developed in RJ and UP, Tapioca and cashew nuts grow well in these
True/False: Natural gas occurs in Gondwana beds, Mica occurs in abundance in Koderma, Dharwars are famous for petroleum
2012
Which state: is located on same latitude as North RJ, has over 80% area under forest cover, over 12% forest cover as protected area--Arunachal Pradesh
While travelling Himalayas, we see: Deep gorges, U turn river courses, Parallel mtn ranges, Steep gradients causing land sliding(all above)
True/False: Duration of monsoon decreases from south to north(T), Amount of annual rainfall in northern plains decreases from east to west(T)
2011
Brahmaputra, Irrawady, Mekong rivers originate in Tibet and flow thru narrow and parallel mtn ranges in their upper reaches. Of these, Brahmaputra takes u-turn due to: Uplift of folded Himalayan series, Syntaxial bending of geologically young Himalayas, Geotectonic disturbance in tertiary folded mountain chains
2010
T/F: Biodiversity hotspots are located only in tropical regions(F), India has 4 biodiversity hotspots--E Himalayas, W Himalayas, W Ghats, Andaman and Nicobar Is (F)
Which are appropriate methods of soil conservation in India: Crop rotation, Sand fences, Terracing, Wind breaks(all above)
Correctly paired? Mineral vs state with 90% of reserves: Copper-Jharkhand(~40%), Nickel--Odisha, Tungsten--Kerala(RJ)
India is party to Ramsar convention. Best description of how to maintain sites as per convention: Conserve all sites thru ecosystem approach and allow simultaneous sustainable use



Indian human
2014
Match regions and what it is well known for
Kinnaur--Arecanut(areca nut in moist tropical), Mewat--Mango, Coromandel--Soyabean
Match NH and connected cities
NH4--Chennai to Hyd, NH6--Mumbai to Kolkata, NH15Ahmedabad to Jodhpur
Communities/tribes that have a month long ecologically imp festival in which they plant fruit bearing trees-->Gond and Korku, Bhutia and Lepcha, Irula and Toda, Sahariya and Agariya
True about Changpa: live mainly in Uttarakhand(Zanskar JK), rear Pashmina goats yielding fine wool, kept in ST
2013
Of following industries, max consumer of water in India: Engg, PaperPulp, Textiles, Thermal power
Correctly paired? Limbu tribe:Sikkim, Karbi:HP, Dongaria Kondh:Odisha, Bonda:TN
Kharif? Cotton, Groundnut, Rice, Wheat
2012
Used as pulse, fodder, green manure: Cowpea, Green gram, Pigeon pea
Predominantly rainfed crop: Groundnut, sesamum, pearl millet
2011
Which state has most suitable climatic conditions for cultivation of variety of orchids with minimum cost of production, and can develop export oriented industry in orchids--Arunachal Pradesh
Lower Gangetic plain is characterized by humid climate with high temp thru out the year. Which pair of crops is most suitable for this region--Paddy and jute, wheat+jute, wheat+cotton, paddy+cotton
Which state has, its north part arid and semiarid, central part producing cotton, cultivation of cash crops is predominant over food crops -- GJ, AP,KA,TN
2010
Hot and humid climate, annual rainfall 200cm, hill slopes upto altitude 1100m, annual range of temp 15C to 30C, suitable for crop -- mustard, cotton, pepper, tobacco



World physical
2014
Which phenomena might have influenced evolution of organisms: Continental drift, Glacial cycles
Seasonal reversal of winds is typical characteristic of ---Monsoon climate equatorial, Mediterranean
Turkey is located between--Black sea and Mediterranean
Sequence from South to North: Jakarta, Singapore, Bangkok, Hanoi
Benefits of Integrated Watershed Development Program: prevention of soil runoff,Linking perennial rivers with seasonal riversRainwater harvesting and recharge of groundwater table, Regeneration of natural vegetation
2013
Correctly paired? Abyssinian plateau:Arabia, Atlas mtns:NW Africa, Guiana highlands:SWAfrica, Okavango basin:Patagonia
Variations in length of daytime and nighttime from season to season are due to: earth's rotation on its axis, earth's revolution round sun in ellipse, latitudinal position of place, revolution on tilted axis
On earth, most of freshwater is in ice caps and glaciers, of remaining, largest share is in: Atmosphere as moisture and clouds, In freshwater lakes/rivers, Groundwater,soil moisture
Responsible for bringing dynamic changes on surface of earth: Electromagnetic radiation, Geothermal energy, Gravitational force, Plate movements, Rotation of earth, Revolution of earth
Climate is extreme, rainfall scanty, people used to be nomadic herders:African Savannah,Central Asian Steppe, North American Prairie, Siberian Tundra
During thunderstorm, thunder in skies is produced by: Meeting of cumulonimbus clouds in sky, Lightning that separates nimbus clouds, Violent upward movement of air and water particles, NOTA
2012
Factors influencing ocean currents: Rotation of earth, Air pressure and wind, Density of ocean water, Revolution of the earth
Normally temperature decreases with increase in height from earth's surface coz; Atmosphere can be heated upwards only from earth surface, There is more moisture in upper atmosphere, Air is less dense in upper atmosphere
Acidification of oceans is increasing, this is concern coz: Growth and survival of calcerous phytoplankton will be adversely affected, Growth and survival of coral reefs will be adversely affected, Survival of some animals that have phytoplanktonic larvae will be adversely affected, Cloud seeding and formation of clouds will be adversely affected
Characteristic climate of Tropical savannah region: Definite dry and wet season
Difference between antelopes Oryx and Chiru: Oryx is adapted to live in hot and arid areas whereas Chiru is adapted to live in steppes and semi desert areas of cold high mountains
La Nina is different from El Nino coz: La Nina is characterized by unusually cold ocean temp in equatorial Indian ocean whereas El Nino means unusually warm ocean temp in equatorial Pacific ocean(F), El Nino has adverse effect on SW monsoon of India, but La Nina has no effect on monsoon climate(F)
T/F about micro irrigation: Fertilizer/nutrient loss can be reduced(T), It is the only means of irrigation in dry land farming(F), In some areas of farming, receding of ground water table can be checked(T)
Salinization occurs when irrigation water accumulated in soil evaporates, leaving behind salts and minerals. Effect of salinization: makes soil impermeable
Westerlies in south hemisphere are stronger and persistent than in north hemisphere, coz: South hemisphere has less landmass compared to north hemisphere, coriolis force is higher in S than N
Main reason(s) for formation of African and Eurasian desert belt: located in subtropical high pressure cells, influence of warm ocean currents
Jet aircrafts fly very easily and smoothly in lower stratosphere, coz: no vertical winds in lower stratosphere, no clouds or water vapor in lower stratosphere
2010



World human
2014
True/False: Maize can be used for prodn of starch(T), Oil extracted from maize can be feedstock for biodiesel(T), Alcoholic beverages can be produced using maize(T)
Significances of "Sustainable Sugarcane initiative"--Seed cst is very low in this compared to conventional method of cultivation, Drip irrigation can be practiced effectively in this, There is no application of ehemical/inorganic fertilizers at all in this, Scope for intercropping is more in this compared to conventional method
Arab spring originated from---Tunisia
Members of Arctic Council -- Denmark, Japan, Russian federation, UK, USA
Correctly paired? Chechnya--Russian Fedn, Darfur--Mali(Sudan),Swat valley--Iraq(Pak)
2013
On usefulness of byproducts of sugarcane industry(T/F): Bagasse can be used as biomass fuel for generation of energy(T), Molasses can be used as one of feedstocks for production of synthetic chem fertilizers(F), Molasses can be used for production of ethanol(T)
Contour bunding is method of soil conservation used in Desert margins liable to wind action, Low flat plains liable to flooding, Scrublands liable to weed growth, NOTA
Most imp fishing grounds are found where: warm and cold oceanic currents meet
Characteristics of equatorial forests: Presence of tall closely set trees with crowns, forming continuous canopy, Coexistence of large number of species, Presence of variety of epiphytes
Reason(s) for annual range of temp in interior of continents being higher than in coastal areas: Thermal difference b/w land and water,Variation of altitude b/w continents and oceans, Presence of strong winds in interior, Heavy rains in interior as compared to coasts
2012
Chief characteristic of 'mixed farming': Cultivation of both cash and food crops, Cultivation of 2 or more crops in same field,Rearing of animals and cultivation of crops together,NOTA
2011
Navigation time and distance between India and East Asia can be greatly reduced by: Deepening Malacca straits b/w Indonesia and Malaysia(T), Opening new canal across Kra isthmus b/w gulf of Siam and Andaman sea(T)

Interview diaries 3

My interview was on 1 April 2016, forenoon. I have never felt so much of pressure before in my life. I had appeared for many job interviews in college. Many presentations during my job. I have been grilled many times in life, but somehow I could not stay cool in days before my interview.

I wont be writing my complete transcript, as most of the questions were very much drawn from my DAF and followed from the leads that came up in my answer or from that day's newspaper headlines.

So, largely my subject preparation and random stats ratta was a total waste of time. It came back to sponti maarna.., at which I thought/think am pretty good. But that day I gave many answers below my potential. I must say that the "mock" interviews add to duress and harden concepts, which makes it difficult to think on your feet in the room at upsc. Besides, one is always trying to come up with the "best" answer instead of the natural answer. I feel bad because many of my answers were bit doctored, so after coming out I felt dissatisfied, as the board could not see my natural honest self. 

They might have perceived a scheming guy trying to be smart.

From the mains result to interview date, I could realize my IQ dipping, as I became a dispenser of random facts about India, Maharashtra and Jalgaon, Budget, Govt schemes etc. I consider my prep stage before mains as a peak from which I had been constantly slipping down to pedestrian level of analysis/thinking. Perhaps this was adding to the pressure that mounted in the end.

Further, looking at the transcripts, I thought I would get a chance to highlight my knowledge in various aspects like sci-tech, polity, IR, society, my optional/degree subject. Instead most of my interview wasnt deep. There were no follow up questions, unlike Ive seen in so many transcripts. So, I felt as if these guys were just gauging if I had basic awareness. No chance to highlight analysis etc, I felt like a goof when I came out.

The dies have been cast, arrow has left the bow, etc etc, so no point worrying now. If there is any takeaway from my experience, it would be that one must not forget the purpose of preparation(to serve the poor, which surprisingly no one seems to believe) and stay true to it and keep working, instead of trying to be smart with the process.

Lets get back to the pits and prepare for next round.

Interview diaries 2

I have appeared for 4 mocks till now and have realized that it is largely a futile exercise. Mock interviews are turning into chess boards. So much analysis, counter analysis going on in minds of interviewer and interviewee. It is just tiresome. I feel it is better that you build a pleasant personality over time instead of putting on an attractive mask that hides the flaws. While many say that content is of very less weightage in personality test (about 8-10%) I see most of the interview leaning towards knowledge test. Further, the whole experience just drains you as you feel that there were many things on your DAF which they could have asked and many relevant current issues otherwise.
I suppose the same happens in the upsc interview too, questions seldom matching expectations. But, from what I have heard from close friends, the panel touches upon many things -- economy, polity, society, IR, general discussion. So, it is a well rounded testing and experience. They see what you know and how you present it. While most of the mocks are about what you know and what you dont.
Well, I cant blame the mock interviewers. They have been doing it for years and I suppose somehow that brings in fixed templates about process and people in their minds.

5 days to go. I have so much left to read, which I feel I ought to know, but again I at times think, yaar waise bhi kucch aur hi poochhenge ye log. But, the game is not about feeling or thinking, it is about working...ceaselessly.

So, lets get back to work.

Interview diaries 1

I write this with a fortnight to go for my personality test at UPSC for CSE. It has been an enjoyable experience, these 2 years, in the god forsaken streets of Old Rajinder Nagar(ORN). I say god forsaken because there can not be so much misery as it is seen here, and people(including me) just leave it and move on. Ive seen 3 generation of dogs now on these streets layered by dog shit. Every morning while people eat poha, there is the old woman with her hand held out. One tries to had her eatables but she asks for money for her meals that day. Then there is the boy pushing his cart full of garbage using every muscle in his body, while some random aunty yells a warning(incoming!) and drops a bag full of trash at him, cursing him for not appearing the day earlier. There is the distraught middle aged guy wearing a jacket in middle of summer, smoking a beedi, with the swagger of any hardcore rap artist. To startle these invisibles and to irritate others, the idiots on their Bullet bikes rush past with noise enough to churn people's stomachs and test one's restraint on tongue itching for an outpour of profanity. You feel anger for these inequality and to get away you dive into the small gully at next turn. There is the old woman, who should be sipping lemonade with her grand kids, ironing outlandishly large shirts and pajamas, while her grand child sits beside her toying with chalk and charcoal. The horrendous colorful picture turns black and white in these dim gullies. You decide to go back into the main lane. There is the large building under construction. You wonder the rent one would pay for these marble floored, rosewood finished pigeon holes. 15k per month probably. But as of now the inhabitants are the families of the construction workers living there. The kids are jumping rope with the wiring cables and hop skip jump on chequered patterns with marble pieces for tokens, Their mother prepares meals on a make shift chulha that is enough to match emission levels of the whole building of the future. The mean are busy tying up bamboo support structures, mixing up concrete batches, touching up on the plastered walls. The idea of sustainable development comes to mind and the high handed ideas of intra and inter generational equity. The cruelty of the joke makes it saddening but if one does not laugh at the joke, one could go mind. So, we smile back at the kids playing on the streets and move on.
Its not so sad, this place. There are things joy too. But aaj mood kharaab hai, to frustana hai. To acchi baatein baad me...There is so much misery right in front of our eyes, and it is painful to stop yourself from diving into solving these problems. There is always the voice that says... abey padh le, ye kaam baad me karenge, bade level pe... You think, sahi baat hai...tomorrow youll have the power to do well for these people. Your heart fills up with hope and face lights up with a sense of purpose. You read up on modern Indian history and you feel, Yes!!! I will be the torch bearer of change, bringing light in lives of those living in darkness with empty bellies. Then the guy holed up next to you walks into your room discussing some scandal of some random actress or of some random girl in his friend circle. You have been nice to him in general and trying to nice to people in general. But this guy is unstoppable. He starts blabbering random stuff about how values of girls have fallen these days and there are many fishes in the sea, advising you to go "harpooning". Then there is the other guy talking about the make up and dressing of aunty living in the next block. According to this guy, an expert on sanskaar, she is too old to wear lipstick or a t-shirt and jeans. Then comes the topic of girls in shorts and the trash talk. I think to myself, if only there was some parallel universe, where these guys are being judged for their pot bellies and there is trash talk about their chest that has drooped down to find support on their bellies. Then my mind goes to imagining another universe where there is no judgment on anyone. The irony in my life, is that I have judged many and I am blamed for being very critical of people. This puts me into an introspection period, where I try to correct myself from being overly judgmental of people and put up with their flaws however injurious they might be to my mind or my conception of the right. But, in these times, I find support from my loved ones, who give me comfort by egging me to stick to my ideals and my methods of frankness, pushing me back into my quixotic mode.
If you have read the above and reached here, you might have rightfully concluded that the process has messed me up a bit(for this moment at least). Personality test is a very weird indeed. As, many know certain "namoone"(characters) that make into the final list even when they have obnoxious personalities and worst set of morals which they manage to mask. Kind of putting doubts on efficacy of the personality test. But, the ground is set and one has to lead the charge of the light brigade.

Let me say this now. I did not have an interview call last year and have seen how those who have it, speak as if they know something more than others or are better than others. To all my friends and others, if I come across in such a manner, please pardon me for my lightheadedness. I assure everyone, that let people judge you. Stoke that fire in your heart. Remember these faces, from streets of ORN and know, who you work for. These are the people who look upto you with faith. Be fair to them and work hard. Yaari dosti sab chalti rahegi...let go of those who dont get you and drag you...
Look at me, again I am instructing people on life. Alright, I suppose bahot jyada bol gaya main aaj...
In coming 14 days, I might some more of these frustu posts and then after interview date, I will go into the jungles, away from the chatter, into the womb of mother nature...Cheers!!!

PS I am not going to proof read this, as I might correct something or just delete the whole thing and close the draft. So, please bear with the poor grammar or the frust level in this rant..

IC Engines 1

IC engines is a scoring area, there are usually straightforward questions from engine testing, carburetion or diesel injection, emissions, knocking etc. So, good returns on specific minimal effort. No need for PhD in engines.Below, I have taken up numericals first because 1.they are the scoring areas and need immediate attention., 2.they can be understood even with general sense of engines. Books usually put them in end. By that time, we know much about engines, but we run out of energy to push thru these tedious procedural questions.

Please feel free to give your inputs/corrections/suggestions on any topic or any solved question below. Do quote the Q no. ex 2015A3b20 or topic name while doing so. Cheers!

General
Difference between External combustion engine and Internal combustion engine

Basic engine parts, nomenclature, materials used, dimension terms

Classification of engines

4 stroke and 2 stroke engines, valve timings, differences






Engine testing numericals
ip, bp, n-ith, n-bth, n-m, n-v, isfc, bsfc, F/A, A/F
Balance sheet on minute basis

2015A3b20 Petrol engine, 4S, 9cyl, D=14.5cm, L=18cm, r=7, bp 350kW @ 2000rpm, when mix is 15% weak with 82.5%C ad 14.8% H2,  CV=47MJ/kg , vol eff=0.76 at 15degC, 1 bar, (eta-m)=0.9, R=0.287kJ/kgK, to find: (eta-ith)
Ans: Now, bp=350kW so, ip =bp/(eta-m)=350/0.9 =388.9kW
(eta-ith)=ip/(mf x CV) and (eta-v)= ma /( rho x pi D^2 L /4 x N/120 x n)
now that catch in the question is to get air mass rate ma and then A/F, then mf and hence eta-ith
so, ma= (eta-v) x RT/p x pi D^2 L /4 x N/2 x n
ma= 0.76 x 287 (273+15) /10^5 x pi x 0.145^2 x 0.18 /4 x 2000/120 x 9 = 0.28 kg/s
in above, i have used rho =RT/p gas eqn, vol of cyl =pi D^2 L/4, cycles per sec=N/(2x60), n=9 cyls
Now, consider 100kg fuel, mixed in stoichiometric ratio then
(82.5/12)C + (14.8/2)H2 +(aO2 + 79.1a/20.9 N2) -->bCO2 +dO2 + eN2 +fH2O
so, b=6.875, d=0 no excess air, a=d+b+f/2 = 0+6.875+7.4/2=10.575 kmoles(air required for stoichio)
So for 15% weak mix, air required =0.85 x 10.575 kmoles=8.98875 kmoles
so, ma=(ax32 + 79.1a/20.9 x28)= (32 + 79.1/20.9x28)x8.98875=1241.57kg/s when mf=100kg/s
or A/F=ma/mf=12.4157, so for ma=0.28 kg/s, mf=0.28/12.4157=0.02255 kg/s
(eta-ith)=388.9kW/(0.02255 kg/s x 47000 kJ/kg) = 0.367


Emissions related theory and numericals
Apparatus for measuring exhaust emissions

Gasoline engine emission control


Diesel smoke and control



Air standard cycles
Carnot

Stirling 1816

Ericsson
Lenoir

Constant volume or Otto


Diesel cycle

Dual cycle


Atkinson

Joule or Brayton cycle

Fuel air cycles and actual cycles(no numericals from here, don't break your head over them)
Assumptions made in fuel air cycle


Loss due to variation of specific heat on p-v diagram


Effect of disassociation on temperature at different mixture strength, and on power


Effect of variable on p, T in cylinder
1.compression ratio

2.F/A ratio
   -on efficiency
   -on max power
   -on max temp
   -on max pr
   -on exhaust temp
   -on mep

Losses in an actual cycle
-Time losses
-Direct heat losses
-Exhaust blowdown loss
-Pumping losses
-Rubbing friction loss


Combustion in SI engines
Stages

Effect of engine variables on ignition lag
-fuel
-mixture ratio
-initial p,T
-electrode gap
-turbulence

Effect of engine variables on flame propagation
-F/A ratio
-compression ratio
-intake p,T
-engine load
-turbulence
-engine speed
-engine size

p-theta for different rates of combustion

Abnormal combustion

Detonation/knocking

Effects of detonation

Theories of detonation


Factors affecting detonation

Control of detonation

knock evaluation in cfr engine(Philips knock meter)

Abnormal combustion knock(surface ignition)
-wild ping, rumble etc

CC design principles

CC desings
-T head
-I head
-F head

Combustion in CI engines
Stages

A/F ratio in CI engines

Delay period or ignition lag

Variables affecting delay period

Diesel knock

Methods of controlling diesel knock(reduce delay period)

Methods of generating swirl

M-chamber

Cold starting

SI vs CI engines, comparison


Fuels and additives
Fuel desirable properties
Refining process

Volatility and effect on engine performance
-cold and hot starting
-vapour lock
etc

Knock rating
-HUCR
-octane number
-RON, MON
-PN
Effect of fuel structure on knocking

Diesel fuels
-flash point, fire point, viscosity, cloud point, pour point
Cetane number

Diesel index
Aniline point
API gravity


Additives
-antiknock


Fuels for gast turbines and jet engines
ATF


Alternative fuels
Methanol, Ethanol

Volumetric efficiency
factors affecting
-inlet air temp
-inlet and exhaust pr
-inlet mach number
-piston speed and engine size
-induction heat transfer
-valve timing




Carburetion
-A/F for max power, max sfc

Automotive engine operation F/A ranges
-idling and low loadm cruising, max power

Simple carburettor(no need to look at variants)
Theory and formula for simple carb

Exact analysis, considering compressibility

Electronic fuel injection--features, compare with conv carburetion

Altitude compensation


Diesel injection
Heat release diagram


Types of injection systems(no need for details, only overview)

Numericals on quantity of fuel per cycle, nozzle orifice size




Ignition, Lube system, cooling system



Supercharging
objective, p-v diagram compare

Effect on engine performance
-on power output


-on mechanical efficiency

-on fuel consumption


Gas turbine cycle
p-v and efficiency calcs