A Dimpled Twisted Tape CFD simulation is a computer model used to study how to make heat transfer better inside pipes. These tapes are special inserts that are put inside tubes in heat exchangers, power plants, and chemical factories. This Heat Transfer Enhancement CFD analysis helps engineers design more efficient cooling and heating systems. A Twisted Tape CFD simulation in ANSYS Fluent shows how the tape creates a spinning, or swirl flow. This swirl flow forces the liquid to mix better, which helps transfer heat much faster than in a plain pipe. The small dimples on the tape add to this effect by creating more turbulence. Using a Twisted Tape Fluent model, engineers can accurately measure the increase in heat transfer and the change in pressure drop to find the best design for a Heat Exchanger Inserts Fluent application.

• Reference [1]: Zheng, Lu, Yonghui Xie, and Di Zhang. “Numerical investigation on heat transfer performance and flow characteristics in circular tubes with dimpled twisted tapes using Al2O3-water nanofluid.” International Journal of Heat and Mass Transfer111 (2017): 962-981.

Figure 1: Schematic of a dimpled tape [1]

Simulation Process: Fluent Setup, Wall Heat Flux and Turbulence Modeling for Twisted Tape

To perform this Dimpled Twisted Tape Fluent study, we first designed a detailed 3D model of a pipe with a helical twisted tape insert. This tape features surface dimples, which are small depressions designed to further disturb the flow and enhance heat transfer. We used ANSYS Fluent Meshing to generate a high-quality computational mesh. For boundary conditions, the fluid entered the pipe at a temperature of 300 K (27°C) through a velocity inlet. A constant heat flux of 50,000 W/m² was applied to the tape to simulate a heating process.

Figure 2: The 3D model of the pipe with the Dimpled Twisted Tape insert, showing the helical shape and surface dimples for Heat Transfer Enhancement CFD.

Post-processing: CFD Analysis, Correlating Swirl Flow with Thermal Enhancement and Pressure Drop

The primary goal of this device is heat transfer, and the temperature contours in Figure 4 provide clear evidence of its success. The water enters the pipe at 300 K and exits at approximately 309 K. This temperature rise of 9 K is a significant amount of heating, proving that the constant heat flux from the wall is being effectively transferred to the fluid. From an engineering perspective, achieving this temperature rise in a short pipe length demonstrates excellent thermal performance. The uniform temperature distribution across the pipe’s exit shows that the fluid is well-mixed, which prevents hot spots and improves the overall efficiency of the heat exchange.

Figure 2: Temperature Contours Revealing Heat Transfer Enhancement in Pipe with Twisted Tape

The velocity contours in Figure 3 reveal the physics responsible for this excellent heat transfer. The twisted tape forces the fluid into a strong helical, or swirl flow, pattern. This spinning motion is the key mechanism for heat transfer enhancement. It does two things: first, it increases the distance the fluid travels inside the pipe, giving it more time to absorb heat. Second, and more importantly, it creates strong secondary flows that move fluid from the hot pipe wall towards the cooler center. This constant mixing action breaks up the insulating thermal boundary layer that forms on the pipe wall, allowing heat to transfer into the fluid much more easily. The velocity reaches a maximum of 2.32 m/s in certain regions, and the alternating high and low velocity zones, combined with the turbulence from the dimples, ensure the entire fluid volume is actively mixed.

This enhancement, however, comes at a cost, which is quantified by the pressure contours in Figure 2. The simulation shows a total pressure drop of about 347.8 Pa (from 371.67 Pa at the inlet to 23.84 Pa at the outlet). This pressure drops, or “pressure penalty,” is caused by the friction from the tape and the extra energy needed to make the fluid swirl. While this is higher than in a plain pipe, the analysis confirms the pressure drop is uniform and stable. For a well-designed system, this increase in required pumping power is an acceptable trade-off for the large gain in thermal efficiency. The most important achievement of this simulation is its ability to demonstrate that the dimpled twisted tape produces a robust swirl flow that enhances heat transfer by 9 K, confirming that the significant thermal benefit far outweighs the moderate and stable pressure drop penalty, making it a highly effective engineering solution.

Figure 3: Velocity Contours Displaying Swirl Flow Patterns Generated by Twisted Tape

Figure 4: Pressure Distribution Contours Showing Pressure Drop Along Twisted Tape Pipe