Mechanical Guru's

SOURCES OF ENERGY There are mainly two types of sources of energy. Conventional Sources of Energy (Non-Renewable Sources of Energy) Non-conventional Sources of Energy (Renewable Sources of Energy). 1.  CONVENTIONAL SOURCES OF ENERGY - These resources are finite and exhaustible. Once consumed, these sources cannot be replaced by others. Examples include coal, timber, petroleum, lignite, natural gas, fossil fuels, nuclear fuels etc. The examples are Fossil fuel Nuclear energy Hydro energy - Have you not seen the filling of fuel in automobiles? What are the fuels that are being used in automobiles? What type of sources of energy are they? Are they non-conventional? Fossil fuel is an invaluable source of energy produced due to chemical changes taking place in the absence of oxygen, in plants and animals that have been buried deep in the earth’s crust for many million years. Fossil fuels like coal, petroleum and natural gas are formed in this manner. These are conv

LUBRICANT AND LUBRICATION FUNCTION OF LUBRICATION: LUBRICATION PRODUCES THE FOLLOWING EFFECTS: REDUCING FRICTION EFFECT COOLING EFFECT SEALING EFFECT CLEANING EFFECT REDUCING FRICTIONAL EFFECT: THE PRIMARY PURPOSE OF THE LUBRICATION IS TO REDUCE FRICTION AND WEAR BETWEEN TWO RUBBING SURFACES. TWO RUBBING SURFACES ALWAYS PRODUCE FRICTION. THE CONTINUOUS FRICTION PRODUCE HEAT WHICH CAUSES WEARING OF PARTS AND LOSS OF POWER. TO AVOID FRICTION, THE CONTACT OF TWO SLIDING SURFACES MUST BE REDUCED AS FAR AS POSSIBLE. THIS CAN BE DONE BY PROPER LUBRICATION ONLY. LUBRICATION FORMS AN OIL FILM BETWEEN TWO MOVING SURFACES. LUBRICATION ALSO REDUCES NOISE PRODUCED BY THE MOVEMENT OF TWO METAL SURFACES OVER EACH OTHER. COOLING EFFECT: THE HEAT, GENERATED BY PISTON, CYLINDER, AND BEARINGS IS REMOVED BY LUBRICATION TO A GREAT EXTENT. LUBRICATION CREATES COOLING EFFECT ON THE ENGINE PARTS. SEALING EFFECT: THE LUBRICANT ENTERS THE GAP BETWEEN THE CYLINDER LINER, PISTON, AND PISTO

EFFECT OF ENGINE VARIABLES ON FLAME PROPAGATION RATE OF FLAME PROPAGATION AFFECTS THE COMBUSTION PROCESS IN SI ENGINES. HIGHER COMBUSTION EFFICIENCY AND FUEL ECONOMY CAN BE ACHIEVED BY HIGHER FLAME PROPAGATION VELOCITIES. UNFORTUNATELY, FLAME VELOCITIES FOR MOST OF FUEL RANGE BETWEEN 10 TO 30 M/SECOND.  THE FACTORS WHICH AFFECT THE FLAME PROPAGATION's ARE  AIR FUEL RATIO COMPRESSION RATIO LOAD ON ENGINE TURBULENCE AND ENGINE SPEED 5. OTHER FACTORS A : F RATIO:  THE MIXTURE STRENGTH INFLUENCES THE RATE OF COMBUSTION AND AMOUNT OF HEAT GENERATED. THE MAXIMUM FLAME SPEED FOR ALL HYDROCARBON FUELS OCCURS AT NEARLY 10% RICH MIXTURE. FLAME SPEED IS REDUCED BOTH FOR LEAN AND AS WELL AS FOR VERY RICH MIXTURE. LEAN MIXTURE RELEASES LESS HEAT RESULTING LOWER FLAME TEMPERATURE AND LOWER FLAME SPEED. VERY RICH MIXTURE RESULTS INCOMPLETE COMBUSTION AND RESULTS IN PRODUCTION OF LESS HEAT AND FLAME SPEED REMAINS LOW.   COMPRESSION

FUELS AND FUEL INJECTION IN IC ENGINES, THE CHEMICAL ENERGY CONTAINED IN THE FUEL IS CONVERTED INTO MECHANICAL POWER BY BURNING (OXIDIZING) THE FUEL INSIDE THE COMBUSTION CHAMBER OF THE ENGINE. FUELS SUITABLE FOR FAST CHEMICAL REACTION MUST BE USED IN IC ENGINES, THEY ARE FOLLOWING TYPES. HYDROCARBONS FUELS DERIVED FROM THE CRUDE PETROLEUM BY PROPER REFINING PROCESS SUCH AS THERMAL AND CATALYTIC CRACKING METHOD, POLYMERISATION, ALKYLATION, ISOMERISATION, REFORMING AND BLENDING. ALTERNATIVE FUELS SUCH AS-ALCOHOLS, (METHANOL, ETHANOL), NATURAL GAS (METHANE), LPG (PROPANE, BUTANE), HYDROGEN. CLASSIFICATION OF PETROLEUM FUELS USED FOR IC ENGINE: LIQUID HYDROCARBONS- ENGINE FUELS ARE MAINLY MIXTURES OF HYDROCARBONS, WITH BONDS BETWEEN HYDROGEN AND CARBON ATOMS. DURING COMBUSTION THESE BONDS ARE BROKEN AND NEW BONDS ARE FORMED WITH OXYGEN ATOMS, ACCOMPANIED BY THE RELEASE OF CHEMICAL ENERGY. PRINCIPAL PRODUCTS ARE CARBON DIOXIDE AND WATER VAPOUR. FUELS ALSO CONTAIN SMAL

BASICS OF HEAT ENGINE AND ITS CLASSIFICATION HEAT ENGINE: A HEAT ENGINE IS A DEVICE WHICH TRANSFORMS THE CHEMICAL ENERGY OF A FUEL INTO THERMAL ENERGY AND USES THIS ENERGY TO PRODUCE MECHANICAL WORK. IT IS CLASSIFIED INTO TWO TYPES:  EXTERNAL COMBUSTION ENGINE INTERNAL COMBUSTION ENGINE 1.        EXTERNAL COMBUSTION ENGINE: IN THIS ENGINE, THE PRODUCTS OF COMBUSTION OF AIR AND FUEL TRANSFER HEAT TO A SECOND FLUID WHICH IS THE WORKING FLUID OF THE CYCLE. EXAMPLES: IN THE STEAM ENGINE OR A STEAM TURBINE PLANT, THE HEAT OF COMBUSTION IS EMPLOYED TO GENERATE STEAM WHICH IS USED IN A PISTON ENGINE (RECIPROCATING TYPE ENGINE) OR A TURBINE (ROTARY TYPE ENGINE) FOR USEFUL WORK. IN A CLOSED CYCLE GAS TURBINE, THE HEAT OF COMBUSTION IN AN EXTERNAL FURNACE IS TRANSFERRED TO GAS, USUALLY AIR WHICH THE WORKING FLUID OF THE CYCLE.  2.        INTERNAL COMBUSTION ENGINE: IN THIS ENGINE, THE COMBUSTION OF AIR AND FUELS TAKE PLAC