Boundary Layer and promoting Turbulent flow

Through our patented complex geometries and by taking advantage of additive manufacturing, we have increased efficiency of  additively manufactured heat exchangers. Our internal geometry encourages swirls and mixing which helps to reduce thickness of boundary layer within our heat exchanger core. 

Anyone within the field of heat exchangers understands the concept of a boundary layer. A simple explanation is that when a fluid flows through a channel or on a surface, a thin layer is formed on the interface between the wall and the fluid. In this thin layer, fluid velocity changes from zero (static) at the wall surface to freestream velocity at a certain distance away from the wall surface.

A thick boundary layer has a negative effect on heat exchanger performance as it impedes heat transfer. Think of it like a blanket, thicker the blanket, the higher the insulation. This is not ideal for heat exchangers core as the main objective is to conduct heat from fluid to wall surface and vice-versa.

Turbulent flow is generally more preferred in heat exchanger design. The swirling and diffusive characteristics of turbulent flow enhances heat transfer. Mixing induced by turbulent flow can also disrupt the growth of boundary layer on heat exchanger core surfaces. However, turbulent flow is often associated with higher pressure drop.

As mentioned, reducing the size of boundary layer and promoting turbulent flow can enhance the performance of a heat exchanger. This can be achieved through the following:
-Increase fluid velocity – Speeding up fluid flow through core is an effective way of increasing heat transfer. However, appropriate balance between heat transfer gain and pressure drop penalty needs to be considered. Having closely packed fins and multipass configuration can increase fluid velocity through core.
-Mixing enhancement features – Addition of features such as turbulators, baffles, and corrugation can further enhance heat transfer.

Conflux Technology has been producing superior heat exchangers with high heat transfer and minimum pressure drop. This is realized through our patented complex geometries, extensive parameters optimization, and by leveraging Additive Manufacturing process and its intrinsic surface roughness.