CFD Investigation of a Bladeless Fan

Description:

Overview

Hearing the term “fans” would guide most people to think about fans with blades: be it in an axial or in a radial configuration. A new configuration with a very comparable performance in multiplying airflow has been developed and commercialized in recent years. Theses fans are known as bladeless fans or air-multipliers. Besides it’s conspicuous advantage of saving material cost for blades and their maintenance, these blades are also highly energy efficient.

Despite being patented in 2009, the fans’ aerodynamic performance has not been studied in depth numerically or experimentally. This leaves room for significant performance enhancements and this is where Computational Fluid Dynamics (CFD) can be implemented. This study intends to do just that and verify the results against a previously conducted study [1].

Input Data

  • The geometry can be created, based on the following:


    More detailed parameters for modelling the fan can be found in [1]. Our recommendation would be to create the geometry on Onshape. The geometry can be directly imported from Onshape to the SimScale platform.

  • The details about setting up the validation case can be found in [1]. The CFD analysis of transient flow around the two bridges is the central topic of this validation case.

  • The CFD results are to be validated against measured flow fields. It must be noted here that there is no sufficient and detailed experimental data for the Bladeless fans in existing literature for validation. Now, Since the exit section of the Bladeless fan acts as a jet flow, the physics of both phenomena can be accounted about the same. Hence, experimental data of a circular jet [2] were used to validate the Bladeless fan simulation in this study [1].


More experimental data to be validated against can be found in [1].

Purpose

This project is intended towards validating the flow-fields against experiments. Such a validation project enables the user to enhance their knowledge in parametric design and performance enhancement in a novel air-multiplier and extend it towards applying CFD best practices.

Key Words

Validation, bladeless fan, parametric design, performance enhancement, HVAC, air-multiplier, verification, OpenFOAM.

Literature & Sources

Status

Not yet started.

2 Likes

I’m still trying to understand the operation of these fans. How does the geometry downstream influence the flow. Specifically, there is an 8" ventilation tube in the ceiling of my warehouse. I’m thinking that I can extend it until it is 3/4 of the way to the floor. If I crack open an overhead door at night convection should pull air up the tube.

My questions:

  1. If I place a Bladeless fan ring (no fan) at the bottom of the tube. Will the flow increase?

  2. Do I even need to gap when the fan normally blows air along the inside of the ring?

  3. Will the low pressure zone be disrupted by the long tube after the fan exit? Or is that what causes convection. In the first place?

  4. Do I need to model this or can the model results that you have simply be applied to this use case?

Thanks in advance for any help or advice you can provide.

Hey @galbercook!

Why don’t do a simulation and try it out? We can then discuss the results. Model details can be seen under “Input Data” in the post.

Cheers!

Jousef