Zigzag Channel with Flow Pulsation, Paper Numerical Validation, ANSYS Fluent Training

Description

The present problem simulates the flow of water passing through a canal in a zigzag pattern by ANSYS Fluent software. The simulation is based on a reference paper, “CFD SIMULATIONS OF FLOW AND HEAT TRANSFER IN A ZIGZAG CHANNEL WITH FLOW PULSATION,” and its results are compared and validated with the results in the article.

The channel model is such that the number of stages of channel oscillation in the horizontal direction equals 10. The channel angle in each of these ten stages for modeling is assumed to be 15 degrees.

The inlet velocity of water flow in different models varies based on the Reynolds value. However, the inlet water flow temperature in all models equals 293.15 K. The lower wall of the zigzag channel is insulated. The upper wall has a constant temperature of 276.65 K.

The present model is drawn in three dimensions using Design Modeler software. Also, the width of the channel or the vertical distance between the upper and lower walls is assumed to be equal to 8 mm, and the depth of this channel is equal to 1 mm.

The meshing has been done using ANSYS Meshing software, and the mesh type is unstructured. The element number is 144713, and a boundary layer mesh is used on the upper and lower walls of the canal.

Zigzag Channel Methodology

Several different Reynolds values, including 53, 107, 191, 266, 320, 427, and 534, were used for this simulation; Therefore, due to the low Reynolds numbers, the flow in all models is defined as laminar.

Zigzag Channel Conclusion

The main purpose of the problem is to investigate the amount of Nusselt numbers in the vicinity of the upper wall of the channel. At the end of the solution process, the value of the Nusselt number in different Reynolds simulations was obtained, compared, and validated with the values in the diagram in Figure 6 of the reference paper.

The desired Nusselt number is obtained using the software report on the top wall of the model, which has a constant temperature boundary condition. Of course, in determining the Nusselt number, we must pay attention to the values in the Reference Value section of the software.

For example, in this model, the length is twice the channel cross-section, and the reference Temperature is equal to the average of the inlet and outlet temperature of the flow.

Re	Velocity inlet	Nu
53	0.0033	5.5198
107	0.0067	6.6144
191	0.0119	7.8173
266	0.0167	8.8823
320	0.0201	9.2883
427	0.0268	10.2589
534	0.0335	11.1337

Also, at the end of the solution, three-dimensional velocity, pressure, and temperature contours are obtained and analyzed for three different Reynolds values, including 53, 266, and 534.