Modelling and Simulation of Tesla Valves

Methodology

Software Used: ANSYS Fluent for designing, meshing, and simulating fluid dynamics.

Boundary Conditions: Each valve had designated inlet and outlet ends, inner walls, and an interior confined space.

Mesh Properties: A fine mesh with 0.0005m face sizing ensured precise calculations.

Simulation Parameters:

Fluid: Water-liquid

Pressure: Static pressure difference of 5 MPa, simulating a domestic water supply.

Flow Models: Viscous k-omega model applied to simulate realistic fluid behavior.

Key Metric: Diodicity was calculated using mass flow rates and pressure differences in forward and reverse flow configurations.

First Tesla Valve for Analysis

Δpr- – reversed flow pressure drop between two ends of the valve

Δpf- – forward flow pressure drop between two end of the valve

Q- – flow rate (the same for both directions)

Key Parameters Analyzed

Velocity Magnitude Contours

Visualizations of the flow fields in both forward and reverse flow configurations.

Highlighted areas of high and low velocities within the valve geometry.

Mass Flow Rates

Forward and reverse flow rates were analyzed to calculate the net flow.

Convergence was verified by achieving a near-zero net mass flow rate in both configurations.

Pressure Drops

Pressure differences between the inlet and outlet were maintained constant for all simulations.

Diodicity was derived from the pressure drops and flow rates in both directions.

Where:

Qf= Forward flow rate

Qr= Reverse flow rate

Δp = pressure difference between the ends of the valve – constant in this case

Analysis of Results

First Tesla Valve Design

Forward Flow:

The flow was relatively unrestricted, achieving a higher mass flow rate.

Velocity contours indicated smoother transitions through the valve geometry.

Reverse Flow:

Greater resistance was observed, as intended for a Tesla valve.

The mass flow rate was reduced significantly compared to forward flow.

Diodicity= ΔP×Q (reverse)/ΔP×Q (forward) = 0.672

Result: The valve provided some degree of directional preference but did not achieve a true one-way flow.

Forward and Backward Flow of the first Tesla Valve Design

Second Tesla Valve for Analysis

Forward Flow:

Improved mass flow rate compared to the first design, indicating better flow efficiency.

Velocity magnitude contours showed a more optimized flow path.

Reverse Flow:

Higher resistance compared to the forward flow, but still allowing significant fluid passage.

Improved flow disruption was observed compared to the first design.

Diodicity= ΔP×Q (reverse) / ΔP×Q (forward)= 0.832

Result: The second design outperformed the first in directional flow control but still fell short of being classified as a one-way valve.

Current State:

Both designs exhibit diodicity values below 1, indicating that reverse flow is not sufficiently restricted.
Further improvements in geometry, such as sharper turns, added flow obstacles, or a more streamlined path for forward flow, could improve diodicity.
Will be updated as I explore parametric studies to systematically test modifications in valve geometry for higher diodicity.

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