- Forschungsthema:Investigation on flow boiling of CO2
- Bearbeitung:Kristen Venditti
Improving the ecological and economical performance of vapor-compression refrigeration systems is essential to reduce the lifecycle greenhouse gas emissions attributed to such a system. Thus, the heat transfer and the pressure drop during flow boiling in the evaporator tubes should be optimized. Such an enhancement could be obtained by integrating metal sponges into the evaporator tubes. Metal sponges are cellular structures with two continuous phases. Owing to their high porosity, metal sponges combine a large internal surface area, a high density of nucleation sites, and a continuous renewal of the thermal boundary layer while providing a moderate pressure drop. Only some experimental and numerical investigations on flow boiling in horizontal tubes filled with metal sponges are published. The results of these investigations are partially contradictory because of the demanding measurement technology and the complex underlying phenomena. Consequently, a test section which allows assessing the enhancement of flow boiling by metal foams is being planned in our institute. Special care is taken to measure the temperature field. Moreover, the results of the test section can be compared to measurements with a smooth and an enhanced tube obtained by the same test rig. The same thermal and geometrical boundary conditions are chosen to ensure comparability. Additionally, the influence of the contact between tube and metal foam can be evaluated. The task of Kristen Venditti is altering an existing LabVIEW routine to obtain and simultaneously assess measurement data by adding further blocks for data acquisition, developing a system for data assessment, and improving the user interface.