Pneumatic Flow Rate Source
Ideal compressor with constant mass flow rate
Library
None (example custom library)
Description
Note
As of Release R2016b, the Gas block library replaces the Pneumatic library as the recommended way of modeling pneumatic systems. The former Pneumatic library is now included in the product installation as an example custom library. The pneumatic domain definition is still provided with the software, and all the pneumatic blocks in your legacy models continue to work as before. However, these blocks no longer receive full production support and can be removed in a future release.
The Pneumatic Flow Rate Source block represents an ideal compressor that maintains a specified mass flow rate regardless of the pressure difference. Use this block when delivery of an actual device is practically independent of the source pressure, for example, in positive displacement compressors. The compressor adds no heat. Block connections A and B correspond to the pneumatic inlet and outlet ports, respectively.
The block positive direction is from port A to port B. This means that the flow rate is positive if it flows from A to B. The pressure differential is determined as p = pA – pB and is negative if pressure at the source outlet is greater than pressure at its inlet. The power generated by the source is negative if the source adds energy to the flow.
Warning
Be careful when driving an orifice directly from a flow rate source. The choked flow condition limits the flow that is possible through an orifice as a function of upstream pressure and temperature. Hence the flow rate value produced by the flow rate source must be compatible with upstream pressure and temperature. Specifying a flow rate that is too high will result in an unsolvable set of equations.
Parameters
- Mass flow rate
Specify the mass flow rate of the source. The default value is
0.001
kg/s.
Ports
The block has the following ports:
A
Pneumatic conserving port associated with the source inlet.
B
Pneumatic conserving port associated with the source outlet.
Version History
Introduced in R2009b