Micro-channel heat exchangers
The CTTC is involved in the application of its numerical and experimental knowledge on the field of micro thermal devices. The work is in an early stage but already giving first interesting results for the development of high heat flux cooling systems.
Numerical analysis
The Group has been continuously developing 1D tools for the simulation of internal flows, both for single and two-phase flow situations.
The coupling of this tool with a 3D simulation of the heat conduction through the solid body of a parallel channel micro heat exchanger has allowed carrying out an interesting study of the influence of several operating and geometric parameters on the end performance of the unit.
The first attempts to extend the flow analysis in micro-channel heat exchangers to a multidimensional approach have been the CFD simulation of laminar developing flow in tubes, and the numerical study of diverging flow in manifolds.
These are the fundamental phenomena involved in single phase micro-channel devices, and their successful validation allows the Group to explore next steps in the multi-scale direction (conjugate heat transfer between solid core and fluid flow, distribution of flow among the set of tubes).
The CFD potential of the Group is continuously growing by the implementation of a multi-physics and multi-scale approach, while always developing better solvers to accelerate the simulations. Micro-channel heat exchangers are one of the topics where this approach can be fully applied because of the small dimensions of the device.
Experimental set-up
A water loop has been constructed to test micro-channel heat exchangers. It mainly consists of a gear pump and a Coriolis mass flow meter to generate and measure the corresponding water flow, an electric power source to generate the heat flux to be dissipated, an in-house high heat flux heater, and thermocouples and thermo-resistances to measure temperature in the solids and in the water side respectively. The unit is placed inside an environmental chamber to maintain constant losses through the insulation.
The unit has been used to measure the capacity of available commercial CPU coolers, while the Group is developing alternative micro-coolers which design is still under development and analysis.
