Jet Pump

The Jet Pump junction is internal to the system and requires two connecting pipes, representing the suction and the discharge. The supply flow is specified explicitly and modeled internally in the junction type.

The Jet Pump Properties window follows the first of the two basic Properties Window formats, displaying the connecting pipes in a fixed format. The flow direction through the junction is determined by the defined directions of the connecting pipes.

The Jet Pump junction is useful for modeling jet pumps, also known as eductors. Jet pumps are devices which use a high pressure injected fluid to entrain a lower pressure fluid and induce motion, thus pumping the lower pressure fluid. The high pressure fluid is referred to as the supply fluid, the low pressure fluid is the suction fluid, and the combined mixture is the discharge fluid. If the supply and suction fluid are different, the variable physical properties model should be used (selected in Analysis Setup on the Heat Transfer/Variable Fluids panel). In such a case, the data for the jet pump will be best entered on a mass flow rate basis, which includes the effect due to density.

To describe the performance characteristics, data must be entered for the pressure ratios at maximum and minimum flow, as well as the flow ratio at maximum flow. Additionally, the supply fluid pressure and flow rates are required.

If the pipe flow model includes heat transfer, a supply temperature is required.

More information on Jet Pump calculations can be found in Karassik, et. al, 1986Karassik I., Krutzsch W., Fraser W. and Messina J., Pump Handbook, 2nd edition, McGraw-Hill, New York, NY, 1986. on pages 4.2-4.9.