Turbomachines

Module - I
Introduction: Definition of turbo machine, parts of turbo machines, Comparison with positive
displacement machines, Classification, Dimensionless parameters and their significance, Effect of
Reynolds number, Unit and specific quantities, model studies. (Note: Since dimensional analysis is
covered in Fluid Mechanics subject, questions on dimensional analysis may not be given. However,
dimensional parameters and model studies may be given more weightage.)
Thermodynamics of fluid flow: Application of first and second law of thermodynamics to turbo
machines, Efficiencies of turbo machines, Static and Stagnation states, Incompressible fluids and
perfect gases, overall isentropic efficiency, stage efficiency (their comparison) and polytropic
efficiency for both compression and expansion processes. Reheat factor for expansion process.


Module –II
Energy exchange in Turbo machines: Euler’s turbine equation, Alternate form of Euler’s turbine
equation, Velocity triangles for different values of degree of reaction, Components of energy transfer,
Degree of Reaction, utilization factor, Relation between degree of reaction and Utilization factor,
Problems.
General Analysis of Turbo machines: Radial flow compressors and pumps – general analysis,
Expression for degree of reaction, velocity triangles, Effect of blade discharge angle on energy transfer
and degree of reaction, Effect of blade discharge angle on performance, Theoretical head – capacity
relationship, General analysis of axial flow pumps and
compressors, degree of reaction, velocity triangles, Problems.


Module –III
Steam Turbines: Classification, Single stage impulse turbine, condition for maximum blade
efficiency, stage efficiency, Need and methods of compounding, Multi-stage impulse turbine,
expression for maximum utilization factor.
Reaction turbine – Parsons’s turbine, condition for maximum utilization factor, reaction staging.
Problems.


Module –IV
Hydraulic Turbines: Classification, various efficiencies. Pelton turbine – velocity triangles, design
parameters, Maximum efficiency. Francis turbine - velocity triangles, design parameters, runner
shapes for different blade speeds. Draft tubes- Types and functions. Kaplan and Propeller turbines –
velocity triangles, design parameters. Problems.


Module –V
Centrifugal Pumps: Classification and parts of centrifugal pump, different heads and efficiencies of
centrifugal pump, Minimum speed for starting the flow, Maximum suction lift, Net positive suction
head, Cavitation, Need for priming, Pumps in series and parallel. Problems.
Centrifugal Compressors: Stage velocity triangles, slip factor, power input factor, Stage work,
Pressure developed, stage efficiency and surging and problems. Axial flow Compressors: Expression
for pressure ratio developed in a stage, work done factor, efficiencies and stalling. Problems.


This book explores the working principles of all kinds of turbomachines. The same theoretical framework is used to analyse the different machine types. Fundamentals are first presented and theoretical concepts are then elaborated for particular machine types, starting with the simplest ones.For each machine type, the author strikes a balance between building basic understanding and exploring knowledge of practical aspects. Readers are invited through challenging exercises to consider how the theory applies to particular cases and how it can be generalised.