Week 2 - Lecture 3
Shell Balance Technique
by Tan Ching Mun (16002662)
Lecture 3 focuses on the application of shell balance technique to solve the momentum balance equation.:
The steps shown in this topic are applicable to solve the momentum balance for all systems.
Some of the most common types of questions of momentum flow will be:
- Sketching of momentum flux
- Sketching of velocity profiles
- Determination of maximum and average velocities
- Determination of mass/volume flow rate
- Determination of force exerted on a surface/plane by fluid
- Determination of film thickness
- Derivation of pressure drop
Some of the common examples of momentum transport problems are:
- Flow of fluid between parallel plate
- Falling film/ flow of liquid along an inclined plane
- Flow through a circular tube/pipe
- Flow through the annulus of circular tubes (2 pipes)
The important assumptions that must be made for our shell are:
- laminar flow
- steady-state
- incompressible fluid
The common boundary conditions that will be taken into account in Transport Phenomena are:
- Solid-fluid interface, where the velocity of the fluid equals the velocity of the solid surface at the solid-fluid interface due to the 'no-slip' condition.
- Gas-liquid interface, where the viscous stress is assumed zero owing to the fact that the gas viscosity is low. Therefore the velocity of the fluid will not be affected by the surface in gas state.
The steps shown in this topic are applicable to solve the momentum balance for all systems.
Some of the most common types of questions of momentum flow will be:
- Sketching of momentum flux
- Sketching of velocity profiles
- Determination of maximum and average velocities
- Determination of mass/volume flow rate
- Determination of force exerted on a surface/plane by fluid
- Determination of film thickness
- Derivation of pressure drop
Some of the common examples of momentum transport problems are:
- Flow of fluid between parallel plate
- Falling film/ flow of liquid along an inclined plane
- Flow through a circular tube/pipe
- Flow through the annulus of circular tubes (2 pipes)
The important assumptions that must be made for our shell are:
- laminar flow
- steady-state
- incompressible fluid
The common boundary conditions that will be taken into account in Transport Phenomena are:
- Solid-fluid interface, where the velocity of the fluid equals the velocity of the solid surface at the solid-fluid interface due to the 'no-slip' condition.
- Gas-liquid interface, where the viscous stress is assumed zero owing to the fact that the gas viscosity is low. Therefore the velocity of the fluid will not be affected by the surface in gas state.
Reflection
The steps provided are useful in allowing us to solve the momentum balance step-by-step. Besides that, I also learned about the combined momentum flux which consists of conductive (molecular) and convective transport. I am clear on how to obtain the momentum flux but still a bit confused on how to solve the remaining problems such as average velocity, maximum velocity, mass (volume) flow rate, the force exerted and etc.
