JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Overview

Course objectives:

• 1. To explain the phenomenon of heat transfer by conduction, convection, radiation and to study the working of various types of furnaces.
• 2. To study the principles of temperature measurement by various methods.

Course Outcomes

At the end of the course students will be able to:

• 1. Apply the various methods of heat transfer and solve problems.
• 2. Can apply /select a suitable pyrometer for high temperature measurements under various conditions.
• 3. Will be able to select / have knowledge about a particular furnace details and applications.

UNIT - I

Steady State Heat Transfer: Importance of heat transfer, conduction through plane, cylindrical, spherical and compound walls, shape factor and effect of variable thermal conductivity. Unsteady state conduction: Thermal diffusivity equation for uni-directional heat flow. Sudden change of surface temperature of a thick plane wall, cylinder and sphere. Graphical Solutions.

UNIT - II

Dimensional groups. Free and Forced convection. Heat Transfer by combined effect of conduction and convection between two fluids separated by a plane wall and cylindrical wall. Types of Heat exchangers on mode of travel. Log mean temperature difference for both parallel and counter flow exchangers. Radiation - emissivity-luminous and non-luminous flames. Radiant exchange between parallel surfaces enclosed body and enclosure. Combined effect of conduction, convection and radiation. Thermal efficiency of insulation.

UNIT - III

Furnaces: Characteristic features of vertical shaft furnaces, reverberatory furnaces, Electric Arc and Induction furnaces. Tube and muffle type resistance furnaces, continuous furnaces. Sources of heat losses in furnaces and heat balance.

UNIT - IV

Pyrometry: Thermo electric pyrometer- Peltier and Thomas e.m.f’s. Thermo-electric power of thermocouples. Required properties of thermocouples. Noble and base metal thermocouples. Thermo- pile. Measurement of e.m.f by Milli-voltmeters and potentiometers. Cold junction correction. Resistance thermometers – Calendars correction. Principle, construction of resistance thermometers. Measurement of resistance compensation for connection wires.

UNIT - V

Optical pyrometers-principle involved in optical pyrometers, Black body conditions. Wiens and Plancks laws of monochromatic radiation. Principle and construction of disappearing filament optical pyrometer (morse type). F and F optical pyrometer (Wedge type) and Pyro optical pyrometer. The effect of the distance between pyrometer and source, Emissivity of materials. Absorbing media and reflection of optical pyrometer readings. Total radiation pyrometer: Principles, construction of ferry radiation pyrometer, ferry metal spiral radiation pyrometer, fixed focus radiation pyrometer (foster Pyrometer) and pyrometer.

TEXT BOOKS:

• 1. Elements of heat transfer- Jakob & Hawikns. R18 B.TECH MME III YEAR
• 2. Pyrometry - W.P. wood & J. M. Corck

REFERENCE BOOKS:

• 1. Furnaces-J. D. Gilchrist, First edition, Published by Pergamon press.
• 2. Elements of thermodynamics& heat transfer- Obert & Young.
• 3. Control systems & Instrumentation – S. Bhasker. R18 B.TECH MME III YEAR