HT (B-TECH Automobile Engineering 5th)

Introduction: Concept of heat transfer, Difference between the subject of "Heat Transfer"

and its parent subject "Thermodynamics", Different modes of heat transfer - conduction,

convection, radiation and Combine mode, Basic laws of conduction, convection & radiation,

Effect of temperature and pressure on thermal conductivity of solids, liquids and gases and its

measurement, Thermal diffusivity and its significance, Newtonian heating and cooling of

solids.

Conduction: Fouier's law of heat conduction, Three-dimensional general conduction

equation in rectangular, cylindrical and spherical coordinates involving internal heat

generation and unsteady state conditions. Derivation of equations for simple one dimensional

steady state heat conduction from three dimensional equations for heat conduction though

walls, cylinders and spherical shells (simple and composite), critical thickness of insulation

layers on pipes carrying hot fluids. Internal generation cases along with some practical cases

of heat conduction. Influence of variable thermal conductivity on conduction through simple

cases of walls / cylinders and spheres.

Theory of Fins: Fins, Types of Fins, Straight rod type of fins of uniform cross-section e.g.

circular, rectangular or any other cross-section. Heat dissipation from an infinitely long fin,

heat dissipation from a fin insulated at tip and loosing at tip. Optimum design of straight find

of rectangular and triangular profile cross-sections; fin effectiveness and fin efficiency for

straight rod fins of rectangular and circular cross-section.

Heat Exchanger: Function of heat Exchanger, Classification, types and applications of heat

Exchangers, elements of heat exchanger and Overall coefficient of heat transfer, Different

design criterion for heat exchangers, Log mean temperature difference for evaporator and

condenser tubes, Parallel and counter flow heat exchangers, NTU, Calculation of number and

length of tubes in a heat exchanger.

Radiation: Process of heat flow in radiation, Definition of Emissivity, Absorptivity,

reflectivity and transmissivity, Concept of black and grey bodies, Kirchoff’s law and Stefan

Boltzmann’s law.

Convection Process and Properties: Free and forced convection, laminar and turbulent

flow, Newton Rikhman Law, Nusselt Number, significance of dimensionless numbers.

Heat Transfer in IC Engines: Heat transfer and Engine energy balance, Temperature

distribution and thermal stresses in piston, cylinder linear, cylinder head, and valves