Speaker
Description
Cryogenic mixed refrigerant cycles (CMRCs) offer a cost- and energy-efficient cooling method for the temperature range between 60 and 200 K. The performance of CMRCs is strongly influenced by entropy production in the main heat exchanger. High efficiencies thus require small temperature gradients among the fluid streams, as well as limited pressure drop and axial conduction. As temperature gradients scale with heat flux, large heat transfer areas are necessary. This is best achieved with micro-structured heat exchangers, where high volumetric heat transfer areas can be realized.
The reliable design of CMRC heat exchangers is challenging, since two-phase heat transfer and pressure drop in both fluid streams have to be considered simultaneously. Furthermore, only few data on the convective boiling/condensation kinetics of zeotropic mixtures is available in literature.
This contribution presents the design process of a micro-structured heat exchanger with a newly developed numerical model. The governing equations and the solution strategy are briefly outlined, followed by the final design and first experimental results.
