Jet liquid-liquid pump
Simscape / Fluids / Hydraulics (Isothermal) / Pumps and Motors
The Jet Pump block represents a jet liquid-liquid pump consisting of a nozzle, throat, and diffuser, as shown in this illustration.
The model is based on these equations, described in :
|q1||Primary flow rate pumped through the nozzle|
|q2||Secondary flow rate|
|qd||Output flow rate|
|p1||Pressure at the nozzle inlet|
|p2||Pressure at the secondary flow rate inlet|
|p0||Pressure at the throat inlet|
|pd||Pressure at the pump outlet|
|a||Diffuser area ratio, Ath / Ad|
|Ad||Diffuser outlet area|
|Kn||Nozzle hydraulic loss coefficient|
|Ken||Throat entry hydraulic loss coefficient|
|Kth||Throat hydraulic loss coefficient|
|Kdi||Diffuser hydraulic loss coefficient|
Equation 1 describes the nozzle, Equation 2 describes the throat entry, and Equation 3 describes the combination of the throat and the diffuser. The equations correspond to a standard configuration of the pump, where all the longitudinal dimensions conform to established, empirically determined values. For more details, see .
The pump parameters are closely related to each other, and the methodology described in  is recommended to determine their initial values.
To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.
Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.
Assumptions and Limitations
The model is based on the one-dimensional theory.
The primary and secondary flows enter the mixing throat with uniform velocity distribution, and the mixed flow leaves the diffuser with uniform velocity distribution.
The fluid in the primary and secondary flows is the same.
The fluid is assumed to be incompressible and containing no gas.
A — Nozzle entry
Hydraulic conserving port associated with the nozzle entry. The nozzle is the primary flow entry.
S — Pump suction
Hydraulic conserving port associated with the pump suction. The pump suction is the secondary flow entry.
P — Pump outlet
Hydraulic conserving port associated with the pump outlet.
N — Internal nonvisible port associated with throat entry section of pump
Internal hydraulic conserving port associated with the throat entry section of the pump. This port is not visible on the block icon. You can view the variables associated with the port by logging the simulation data. For more information, see Data Logging.
Nozzle area — Cross-sectional area of nozzle
1 cm^2 (default) | positive scalar
Cross-sectional area of the nozzle.
Throat area — Cross-sectional area of throat
4 cm^2 (default) | positive scalar
Cross-sectional area of the throat. The throat area is usually two to four times larger than the nozzle area.
Diffuser inlet/outlet area ratio — Ratio between inlet and outlet diffuser areas
0.224 (default) | positive scalar
Ratio between the inlet and outlet diffuser areas. For a standard pump with a 5°–7° included-angle diffuser, the ratio is close to 0.2.
Nozzle loss coefficient — Hydraulic friction loss coefficient in nozzle
0.05 (default) | positive scalar
Hydraulic friction loss coefficient in the nozzle.
Throat entry loss coefficient — Hydraulic friction loss coefficient in throat entry
0.005 (default) | positive scalar
Hydraulic friction loss coefficient in the throat entry.
Throat loss coefficient — Hydraulic friction loss coefficient in throat
0.1 (default) | positive scalar
Hydraulic friction loss coefficient in the throat.
Diffuser loss coefficient — Hydraulic friction loss coefficient in diffuser
0.1 (default) | positive scalar
Hydraulic friction loss coefficient in the diffuser.
 I.J. Karassic, J.P. Messina, P. Cooper, C.C. Heald, Pump Handbook, Fourth edition, McGraw-Hill, NY, 2008
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