Tesla pump simulation
A Tesla pump, also known as a disc pump, is a rotating fluid pump that uses viscous forces between closely spaced discs to transfer energy to the fluid. A Tesla pump relies on the interaction between the rotating disc surfaces and the fluid in the narrow gaps between them.
This makes the Tesla pump particularly interesting from a fluid dynamics and CFD simulation perspective. The flow is strongly influenced by disc spacing, rotational speed, fluid viscosity, inlet and outlet geometry, and the development of the boundary layers between the rotating discs. Small changes in these parameters can have a significant effect on pressure generation, flow rate, torque and overall pump efficiency.
COMSOL multiphysics is used to investigate different Tesla pump geometries and operating conditions before building a prototype. Parameters such as disc spacing, rotational speed, number of discs, fluid properties and outlet configuration can be varied systematically to understand their influence on pump performance.
Tesla Pump Design Optimization
Optimizing the design of a tesla pump is very important in order to get an efficient pumping performance. COMSOL CFD simulations are used to trace which parameters are important for a certain design and geometry. The rotational speed, number of discs and disk spacing are among others very important parameters.
Also it is important to test a few solver strategies, for example shown in the figure to the right. We tested solvers on a “standard” geometry, one which was more or less close to the final geometry design of the pump. The k-epsilon solves very quick, but deviates more compared to the other solvers, such as y+plus, k-omega and L_vel solvers.
Effect of Disc Spacing and Rotational Speed
Disk spacing is a crucial parameter in designing a tesla pump. Because the spacing is very small, typically a few mm, the flow within the disk is heavily restricted by the close walls. This means that the flow inside the disk can easily be a laminar type of flow. If the volume flow is significant the flow in other parts of the pump can be turbulent like. Luckily within COMSOL one is able to make an appropriate choice of the solver, meaning the convergence is good.
