# Using the Compressible Pipe in PIPE-FLO Advantage 17

# Using the Compressible Pipe in PIPE-FLO^{®} Advantage 17

### Introduction

The new **Compressible Pipe** device is used to analyze the flow of *compressible gases* on systems modeled in PIPE-FLO Advantage 17. It is similar to the **Pipe **device used to analyze the flow of *incompressible liquids* (or gases flowing under the assumption of incompressible flow). Assigning a **Fluid Zone**, **Pipe Specification**, length, size, and installing valves and fittings are common to both pipes. Sizing a pipe by using a Mach Number sizing criteria can only be done with a Compressible Pipe. The Prevent Backflow feature is not enabled for a Compressible Pipe. Because the compressible analysis uses a different set of input parameters, the calculated results are more extensive for easier understanding of the complex nature of compressible fluid flow.

The Compressible Pipe can also be used to model liquid applications (i.e. clean-in-place flushing a liquid through a gas pipe), but will not have all the **Pipe** device's incompressible calculation fields.

### Compressible Pipe Calculation Method

- Adiabatic Fanno flow relationships
- Assumptions: flow of compressible gas in constant area ducts with friction, no heat transfer, following Ideal Gas Laws (sometimes referred to as the duct addition method)
- See the program Help File for equations used for the Compressible Pipe

### Compressible Pipe Design Data

- Name (required, auto-generated, no duplicates)
- Design Status (determined automatically): Will change from
*Undesigned*to*Sizing*to*Designed*when the sufficient operational and design data is entered, respectively. - Fluid Zone (required, select from list of user created fluid zones)
- Specification (required, select from list of user created)
- Size (required, can size pipe using a Mach Number, velocity, pressure drop per 100, or head loss per 100 sizing criteria
- Length (required, enter value and select unit)
- K (Valves & Fittings) (optional, opens the Installed Valves & Fittings dialog box)
- Close Pipe (optional, check box to close / open the pipe, can also use the close pipe tool)
- Prevent Backflow (not functional)

### Compressible Pipe Calculated Results

- Mass Flow
- Inlet Volumetric Flow
- Outlet Volumetric Flow
- Standard Flow
- Choked Mass Flow
- Inlet Velocity
- Outlet Velocity
- Inlet Mach Number
- Outlet Mach Number
- Reynolds Number
- Total Pressure Drop
- Static Pressure Drop
- dP per 100
- Inlet Total Pressure
- Inlet Static Pressure
- Outlet Total Pressure
- Outlet Static Pressure
- Pressure Drop Ratio
- Inlet Static Temperature
- Outlet Static Temperature
- Inlet Static Density
- Outlet Static Density
- Head Loss (for liquid applications)
- HL per 100 (for liquid applications)
- Pipe Friction Factor
- % Deviation

### Compressible Pipe Graph