Basic Principles and Energy Transfer in Centrifugal Compressor Part - I

About this Video

• Video Title: Basic Principles and Energy Transfer in Centrifugal Compressor Part - I
• Channel: Fluid Machines
• Speakers: (Speaker name not explicitly mentioned in transcript)
• Duration: 00:25:01

Introduction

This video lecture introduces centrifugal compressors, explaining their basic principles and energy transfer mechanisms. The instructor contrasts them with previously discussed fluid machines (turbines and pumps using water) and highlights the unique characteristics of compressible flow machines using air or gases. The video focuses on the three main components of a centrifugal compressor (casing, impeller, and diffuser) and details the energy transfer processes within each.

Key Takeaways

• Introduction to Centrifugal Compressors: The video differentiates centrifugal compressors from pumps, emphasizing their use of compressible fluids (air, gases) and their role in increasing fluid static pressure.
• Compressor Components: Centrifugal compressors comprise three key parts: a stationary casing, a rotating impeller (rotor), and a stationary diffuser (stator).
• Energy Transfer and Pressure Rise: The impeller imparts energy to the fluid, increasing both its static pressure and velocity. The diffuser then decelerates the fluid, converting kinetic energy into additional static pressure. This pressure rise is explained using concepts of centripetal acceleration and centrifugal force. The radial outward flow is key to the pressure increase.
• Velocity Triangles: The lecture uses velocity triangles at the impeller inlet and outlet to illustrate the relationship between absolute, relative, and tangential velocities. These diagrams aid in understanding the flow direction and energy transfer within the compressor.
• Energy Transfer Equation: The energy transferred to the fluid per unit mass is derived using the theorem of angular momentum, resulting in an equation that considers tangential velocity components at the inlet and outlet of the impeller. In the specific case of the radial blade design presented, this simplifies to U₂².