Goal: For a high-tech project, a conduction cooling concept based on helium flow is under consideration. The suitability and performance of this method needs to be verified using numerical analysis and experiential verification to qualify the concept.
As a rough starting point for the design of the cooling device the in literature found correlation from Norris and Gnielinski have been used.
Challenging technical aspect for modeling of this cooling concept are the high mass flow rate through a small channel with large heat fluxes and uncertainty in the wall roughness parameters.
Approach: A heat flux is applied to a single channel using joule heating (resistive heating by the use of a high electric current over the channel which is used as the conductor).
A high flowrate helium flow is directed through the channel driven by a high pressure difference (∆P>50 bar).
The flow temperature is measured on both sides of the test channel to determine the heat transfer coefficient. A variety of flowrates and heat fluxes are tested. The results of the experimental are used to refine the parameters used in the CFD model until good agreement was found between the two approaches.
Results: The experimental results and the numerical calculations have demonstrated that helium flow cooling is a suitable method for cooling a workpiece in the high-tech project.
The results are shown together with the existing data from Norris and Gnielinski in the figure to the right.
Further design optimisation can be performed by virtual prototyping using numerical simulations (CFD simulations). The expected large influence of the surface roughness on the pressure drop and heat transfer coefficient is confirmed.