Entrance Loss & Exit Loss
What is Entrance Loss?
Entrance loss is the energy loss that occurs at the entrance to a piping system. This is primarily related to the turbulence that occurs as the fluid enters the piping system, meaning that energy is lost due to the velocity changes and directional changes that occur as the fluid enters the piping.
Types of entrance loss
Entrance loss can be categorized into four types based on the shape of the entrance.
- Straight pipe: As the name suggests, this is when the entrance of the pipe is straight. In this case, the fluid does not directly hit the pipe wall, but travels straight inside the pipe, resulting in the least amount of flow rate loss.
- Round edge: This shape refers to the inlet ending in a rounded shape. In this case, the flow of fluid through the inlet is the smoothest, so the rounded edge helps to minimize inlet losses. Since the rounded shape contributes to stabilizing the flow of the fluid and reducing energy losses, this shape is often used in the design of efficient schemes.
- Sharp edge: This form means that the inlet of the pipe ends in a sharp shape. In this case, when the fluid passes through the inlet, the energy loss due to collision and rotation of the turbine is high due to the sharp edge.
- Inward projection: This form means that the piping has a protruding inlet in the form of a penetration, so the energy loss due to collision and rotation of the fluid flow is quite large, and the inlet loss is larger than the sharp edge. These losses are characterized by lower efficiency and should be avoided as much as possible.
| Shape | Energy loss | Reasons to use |
|---|---|---|
| Straight pipe | Least | Used to minimize losses and deliver fluid quickly |
| Round edge | Low | Used to maintain a smooth flow of fluid with minimal losses |
| Sharp edge | High | Used to control the flow of a fluid, disperse it, and direct it in a specific direction |
| Inward projection | Highest | Low-cost systems, when you need to control flow rates |
What is Exit Loss?
Exit loss is the loss of energy at the exit of a piping system. When a fluid exits a pipe, energy is lost as the fluid's velocity or direction changes dramatically. This is caused by velocity changes, pressure changes, and changes in flow direction that occur during the fluid's passage.
Types of exit loss
- Straight Pipe: Suitable for when you want to minimize energy loss as much as possible, without changing the direction or speed of the fluid flow. In this case, the flow of the fluid is constant and steady, resulting in the least amount of energy loss.
- Sudden Expansion: Suitable when the velocity of the fluid needs to be reduced, or when high pressure needs to be converted to low pressure. However, this also requires proper design to minimize energy losses.
| Shape | Feature | Energy loss |
|---|---|---|
| Sudden expansion | Passage size increases dramatically Reducing the velocity of a fluid |
High |
| Straight pipe | No change in fluid flow direction or size | Low |
Conclusion
Both entrance and exit losses are important factors in determining efficiency in vacuum piping systems. Specifically, in vacuum systems, the shape, size, and material of the piping must be considered to minimize these losses.
Each form has its unique characteristics, which, when understood and utilized properly, can increase the efficiency of the system.