INTRODUCTION

A steam engine uses steam as the working medium. It is the earliest prime mover developed to convert thermal energy into mechanical energy. It is called a prime mover because it is used to drive other devices like locomotives, compressors, lathe, shear presses, etc. On account of their low efficiency steam engines have become obsolete. However, they are still being used in locomotives and some industries.

A steam engine is called an external combustion engine as the fuel is burnt in the boiler and the steam raised is used to reciprocate the engine piston for generating power.