A Water Jet Pump CFD simulation is a computer model of a special pump that uses a fast fluid to move another fluid. This Jet Pump CFD analysis helps engineers design better pumps for jobs like dredging and irrigation. These pumps work because of the Venturi effect. A high-speed jet of water creates a low-pressure area that sucks in the surrounding fluid. This process is called entrainment. Using ANSYS Fluent, we can perform a Water Jet Pump Fluent analysis to see exactly how this happens. This type of hydraulic pumping CFD is important because these pumps have no moving parts, so they are very reliable. Our study is based on the methods from two valuable research papers [1, 2] to ensure our model is accurate.

• Reference [1]: Aldaş, Kemal, and Rafet Yapıcı. “Investigation of effects of scale and surface roughness on efficiency of water jet pumps using CFD.” Engineering Applications of Computational Fluid Mechanics1 (2014): 14-25.
• Reference [2]: Sheha, A. A. A., et al. “Computational and experimental study on the water-jet pump performance.” Journal of Applied Fluid Mechanics4 (2018): 1013-1020.

Figure 1: Cross-section of the water jet pump used for this Eductor Pump Simulation [1].

Simulation Process: Fluent Setup, Axisymmetric Modeling for Pump Performance Analysis

To perform this CFD Pump Performance analysis, we created the pump geometry based on the reference papers. Because the pump is symmetrical around its center line, we used a 2D axisymmetric model. This smart choice gives the same accurate results as a full 3D model but uses much less computer power. Using ANSYS Meshing, we created a high-quality structured grid with 30,400 cells. A structured grid is very organized and gives the best results for flows that move in one primary direction. In ANSYS Fluent, we used the standard pressure-based solver with the k-epsilon turbulence model to capture the fluid motion. We set a velocity inlet for the high-pressure “motive” fluid and a pressure inlet for the “suction” fluid that is pulled in.

Figure 2: A professional visual of the structured grid used for the Jet Pump Fluent analysis.

Post-processing: CFD Analysis, Flow Dynamics and Pumping Mechanism

The velocity contour provides a professional visual that acts as a diagnostic map of the pump’s “engine”. From an engineering standpoint, this visual shows the core principle of the pump. The primary fluid enters and is forced through the nozzle, where it accelerates to a peak velocity of 23.5 m/s. This high-speed jet is the heart of the pump. The pressure contour confirms why this is so important. The velocity increase creates an area of intense low pressure, dropping to -15,000 Pa. This is a perfect quantitative example of the Venturi effect. This negative pressure zone is not just a number; it is the suction force that powerfully pulls the secondary fluid into the pump’s mixing chamber.

Figure 3: Pressure distribution in water jet pump

Figure 4: Velocity profile showing the high-speed jet reaching 23.5 m/s at the nozzle

This injector pump CFD analysis also shows how the pump recovers energy. After the high-speed jet mixes with the entrained fluid, the combined flow moves into the diffuser, which is a tube that gets wider. The professional visuals show the flow slowing down in this section. This is by design. As the fluid slows down, its kinetic energy (speed) is converted back into potential energy (pressure). This “pressure recovery” is essential for pushing the mixed fluid out of the pump and into the rest of the system. The most important achievement of this simulation is its ability to precisely model the full energy conversion cycle—from high pressure to a 23.5 m/s high-velocity jet that creates a -15,000 Pa suction zone, and then back to a useful output pressure in the diffuser—providing a complete hydraulic performance map of a device with no moving parts.