THERMAL SCIENCE TS

Thermodynamics Thermodynamics is the area of science that includes the relationship between heat and other kinds of energy. TS

System A quantity of the matter or part of the space which is under thermodynamic study is called as system Surrounding Everything external to the matter or space, which is under thermodynamic study is called surroundings or environment. Boundary The boundary that separates the system and surrounding is called as system boundary. The system boundary may be fixed or moving. TS

Thermodynamics Systems  Closed system  Open system  Isolated system  Adiabatic system  Homogeneous system  Macroscopic system Equilibrium Types  Thermal equilibrium  Mechanical equilibrium  Chemical equilibrium TS

Laws of Thermodynamics Zeroth law of thermodynamicsZeroth law of thermodynamics: If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other. First law of thermodynamicsFirst law of thermodynamics: The increase in internal energy of a closed system is equal to sum the heat supplied to the system and the work done on it: ΔU = Q + W Second law of thermodynamicsSecond law of thermodynamics: Heat cannot spontaneously flow from a colder location to a hotter location Third law of thermodynamicsThird law of thermodynamics: As a system approaches absolute zero the entropy of the system approaches a minimum value. TS

 Properties of System  Atmospheric, Gauge, Vaccum and Absolute Pressure  Temperature  Change in Enthalpy & Entropy  Thermodynamic Processes  Thermodynamic Cycle  Steady Flow Energy Equation  Point and Path Function  Specific Heat at constant Pressure & cont. Volume  Equivalence of Kelvin Plank & Clausius statement  Mean Effective Pressure (MEP)  BRAYTON CYCLE  Air Refrigerator working on BELL-COLEMAN Cycle TS

Laws of Perfect/Ideal Gases In perfect or ideal gas the change in density is directly related to the change of temperature and pressure as expressed by the Ideal Gas Law. p V = m R T 1.Boyle’s Lawp * V = constant 2.Charle’s Law 3.Avogadro’s LawV/n=k 4.Regnault’s Law 5.Gay-Lussac Lawp/t=constant 6.Joule’s LawQ=I.I.r.T P= pressure V= Volume T= Temperature R= Gas constant Q= Heat I= current TS

Applications of Steady Flow Energy Equation  Turbine  Pump  Boiler  Compressor  Nozzles TS

Carnot Cycle Carnot cycle is a four stage reversible sequence consisting of 1. adiabatic compression 2. isothermal expansion at high temperature Th 3. adiabatic expansion 4. isothermal compression at low temperature Tc TS

Petrol Engine Petrol engine is an engine that uses petrol as a fuel. Inside the engine, the combustion (burning) of fuel mixed with air produces hot gases that expand against parts of the engine and cause them to move. For this reason, petrol engines are called internal- combustion engines. The motion inside the engine is transferred outside it to turn wheels and propellers or to operate machines. In this way, a petrol engine turns heat energy into mechanical work. The rate at which a petrol engine produces work is usually measured in horsepower or watts. TS

Diesel Engine A diesel engine (also known as a compression-ignition engine ) is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber. This is in contrast to spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to gasoline), which uses a spark plug to ignite an air-fuel mixture. TS