Transport Processes and Separation Process Principles (Includes Unit Operations) Fourth Edition

2.3. GENERAL MOLECULAR TRANSPORT EQUATION FOR MOMENTUM, HEAT, AND MASS TRANSFER

2.3A. General Molecular Transport Equation and General Property Balance

1. Introduction to transport processes

In molecular transport processes in general we are concerned with the transfer or movement of a given property or entity by molecular movement through a system or medium which can be a fluid (gas or liquid) or a solid. This property that is being transferred can be mass, thermal energy (heat), or momentum. Each molecule of a system has a given quantity of the property mass, thermal energy, or momentum associated with it. When a difference in concentration of the property exists for any of these properties from one region to an adjacent region, a net transport ...