A turbomachine is a device where mechanical energy in the form of shaft work, is transferred either to or from a continuously flowing fluid by the dynamic action of rotating blades.Turbine is a rotary engine actuated by the reaction or impulse or both of a current of fluid (such as water, steam, or air) subject to pressure and usually made with a series of curved vanes on a central rotating spindle.Turbomachinery are the machines that transfer energy between a rotor and a fluid, including both turbines and compressors. While a turbine transfers energy from a fluid to a rotor, a compressor transfers energy from a rotor to a fluid. These two types of machines are governed by the same basic relationships including Newton’s second Law of Motion and Euler’s energy equation for compressible fluids. Turbines and compressors usually work with a gas. This course focuses on defining the systems and subsystems that forms the turbomachinery, their working principle, application and thermodynamic process involved in conversion of fluid energy to mechanical energy and vice versa through power producing and power absorbing machines.